Early Diagnosis of Degenerative Cervical Myelopathy: A Systematic Review of Current Evidence

Abstract

Study Design

Systematic Review.

Objectives

Degenerative cervical myelopathy (DCM) or cervical spondylotic myelopathy (CSM) is a progressive neurological condition linked to cervical degeneration, often presenting with a wide range of symptoms that complicate diagnosis. This study aims to identify clinical, radiological, and electrophysiological measures that aid in early DCM diagnosis.

Methods

Following PRISMA guidelines a systematic review was performed. Literature from PubMed, Scopus, and the Cochrane Library up to November 2025 was analyzed. Search terms included “degenerative cervical myelopathy”, “cervical spondylotic myelopathy”, “CSM”, “Early clinical signs”, “Diffusion Tensor Imaging”, “Fractional anisotropy”, “Motor-evoked potentials”, “Sensory-evoked potentials”. The included studies primarily focused on clinical examinations, radiological imaging, and electrophysiological tests to detect early signs of DCM.

Results

A total of 36 met the inclusion criteria, involving 4596 patients. Tests for “myelopathy hand” signs showed high negative predictive values in excluding DCM. Lower limb assessments, such as the ten-second step test and Rossolimo reflex, also showed promise for early diagnosis. Among imaging techniques, DTI outperformed traditional T2-weighted Magnetic Resonance Imaging (MRI) in sensitivity, specificity, and predictive value. Kinematic CT myelography (CMCT) also demonstrated potential for early detection. Electrophysiological tests, including SEPs and MEPs, provided valuable insights into disease severity when performed both statically and dynamically.

Conclusions

DCM’s variable profile complicates diagnosis. This review highlights the importance of underused clinical evaluations for earlier detection, with DTI showing promise for early changes and preventive use. Electrophysiological measures, non-invasive and accurate, should be integrated alongside dynamic evaluations for a comprehensive, multi-modal diagnostic approach.

Keywords

degenerative cervical myelopathy early diagnosis clinical signs radiological techniques electrophysiological measures systematic review

Introduction

Degenerative cervical myelopathy (DCM) or cervical spondylotic myelopathy (CSM) is a progressive neurological disorder caused by age-related cervical spine degeneration, leading to spinal cord and/or vascular compression.¹ DCM is the leading cause of non-traumatic spinal cord injury in older adults, accounting for 59% of cases in Japan, 54% in the U.S., 31% in Europe, 22% in Australia, and 4-30% in Africa.² Its prevalence increases with age, affecting 0.6% of individuals under 20 and rising to 9.1% in those over 70.³ More common in men (2.7:1), DCM most frequently involves the C5/6 level, followed by C6/7, C4/5, and C3/4.^4,5 As DCM progresses, the risk of severe neurological impairments increases, leading to greater physical limitations and heightened dependence on caregivers.^1,6-11 Consequently, DCM imposes a major socioeconomic burden, increasing healthcare costs and disability-related losses worldwide.¹²

The diagnosis of DCM is challenging due to its misleading symptoms, unclear clinical signs, and potential mismatch between clinical and radiological features, often leading to delays in diagnosis.¹³

Magnetic resonance imaging (MRI) is widely considered the current standard for diagnosing DCM, with T2-weighted imaging (T2WI) often showing increased signal intensity in advanced cases, indicating swelling, inflammation, ischemia, and gliosis.^14-16 However, not all patients with typical symptoms exhibit this hyperintensity, complicating diagnosis and prognosis.¹⁷ Electrophysiological measures, including Sensory-evoked potentials (SEPs), Motor-evoked potentials (MEPs), and electromyography (EMG), are extensively used in the diagnosis and prognosis of DCM to assess spinal tract and neuron involvement, differentiate from other neuromuscular disorders, and evaluate prognosis for decompressive surgery in a non-invasive and painless manner.^18,19

DCM is commonly classified into three types: preclinical, mild, and clinical. Preclinical DCM involves MRI abnormalities without clear clinical signs, while mild DCM shows neurological changes alongside MRI signs, but less severe than clinical DCM.^19,20 Physical exams may reveal signs like Hoffman’s, Babinski reflex, and Lhermitte’s sign, indicating more advanced stages.^21-23 Indeed, many patients fail to receive an early diagnosis of the disease, often due to misdiagnosis, with the condition typically being identified only in its late stages, where postoperative neurological recovery is limited.²⁴

Due to the considerable heterogeneity in clinical, radiographic, and electrophysiological presentation, the current study seeks to review the scientific literature on clinical examinations, radiological exams, and instrumental neurological tests used in diagnosing DCM, aiming to identify those that could enable an earlier diagnosis.

Materials and Methods

Study Selection and Eligibility Criteria

The formulation of the research question was done using a PIOS approach: Population (P), Intervention (I), Outcome (O), and Study Design (S). This systematic review collected and analysed data on patients with DCM (P). Clinical, radiological and electrophysiological measures (I) were adopted to evaluate its accuracy in detecting pre-clinical phases of DCM in adult patients (O). The following study designs were included (S): Randomized Control Trials (RCT), Retrospective Cohort studies (RC), Prospective Cohort studies (PC), and comparative studies.

The inclusion and exclusion criteria were established before the commencement of the study. Articles that did not focus on the cervical segment, as well as studies involving pediatric patients or patients with alternative diagnoses such as spine tumors, vertebral fractures, other spinal cord injuries, infections, or rheumatological diseases (rheumatoid arthritis and ankylosing spondylitis), were excluded. Studies focused on the general diagnosis or prognosis evaluation of advanced-stage DCM patients, as well as those examining electrophysiological measures for differential diagnosis with other neurological disorders or confirming diagnosis in patients already presenting with mild or clinical DCM, were excluded. Additionally, abstracts, commentaries or opinions, systematic or narrative reviews, case reports, cadaver studies, biomechanical studies, editorials, and studies with fewer than 10 patients were excluded.

Search Strategy

A thorough search of electronic databases, including PubMed, Scopus, and Cochrane Library was conducted from the inception of each database to November 20^th 2025. Only studies concerning humans and published in the English language were selected. Terms specific to degenerative spinal cord compression, degenerative cervical myelopathy, cervical spondylosis, cervical stenosis, cervical spondylotic myelopathy, and early diagnosis were used. The following string was implemented: (“cervical spondylotic myelopathy”[Title/Abstract] OR “CSM”[Title/Abstract] OR “degenerative cervical myelopathy”[Title/Abstract] OR “DCM”[Title/Abstract]) AND (“magnetic resonance imaging”[MeSH Terms] OR (“magnetic”[All Fields] AND “resonance”[All Fields] AND “imaging”[All Fields]) OR “magnetic resonance imaging”[All Fields] OR “mri”[All Fields] OR “DTI”[All Fields] OR “Fractional anisotropy”[All Fields] OR “FA”[All Fields] OR “early clinical signs”[All Fields] OR (“electromyography”[MeSH Terms] OR “electromyography”[All Fields] OR “emg”[All Fields]) OR “SSEP”[All Fields] OR “MEP”[All Fields]).

Data Collection Process

The full text of potentially eligible studies was read and reviewed by two independently working investigators (P.B. and P.F.) to obtain the definite number of studies included in the article. In case of disagreement, the considered article was reviewed, and the conflict was solved after discussion with a third review author (F.R.). The inclusion and exclusion of the reviewed articles are reported below in the PRISMA flowchart, found in Figure 1.

Figure 1.

PRISMA 2020 flow diagram

Data Items

The following data was extracted from the included articles: first author, study groups, sample size, mean age, gender and level of myelopathy. Each clinical, radiological, or electrophysiological measure evaluated in the studies was described in terms of its execution in clinical practice, how it could be considered positive, and its results regarding specificity and sensitivity in aiding the early diagnosis of DCM.

Results

Study Selection and Characteristics

The literature research identified 5913 articles. After duplicate removal, 4238 articles were screened on title and abstract. The full text of 61 articles was reviewed, and 29 were excluded for not focusing primarily on the early diagnosis of DCM. The articles included in this review were 36 (Figure 1). All the articles included in the review had as their main objective to analyse the role of clinical examinations (N = 10 [27,77%]), radiological exams (N = 15 [41,66%]), and instrumental neurological tests (N = 11 [30,55%]) used in the diagnosis of DCM and to identify which have the potential to allow for an earlier diagnosis. A total of 2703 patients were assessed through clinical evaluations, 980 through radiological exams, and 913 through electrophysiological measures.

Clinical Examinations

The majority of the included studies focusing on clinical examinations evaluated changes in strength or sensation in the upper limbs. Specifically, the Dynamic Hoffman’s sign, Wazir hand myelopathy sign, slow grip and release test, and Trömner sign were analyzed, all showing promising results for early DCM detection, with high negative predictive values for excluding cervical myelopathy compared to standard tests.^25-29 Tests focused on the lower limbs, such as the ten-second step test and Rossolimo reflex evaluation, were also analyzed. Both tests demonstrated a correlation with the severity of spinal cord dysfunction in patients, making them useful for predicting postoperative outcomes.^30,31 Additionally, cervicobrachial neuralgia, in addition to gait disturbance, sensory deficits, and motor deficits were evaluated in the study by Özkan at al. They concluded that cervicobrachial neuralgia was the most common initial symptom of DCM and that patients with gait disturbance as their first symptom typically received a diagnosis later (19.5 weeks) compared to those without these clinical signs (16 weeks).³² In addition to the above, the clinical signs analyzed also included inverted supinator sign, Babinski test,³³ ankle plantar flexor maximal voluntary isometric contractions (MVIC) and knee extensor MVIC.³⁴

Detailed study characteristics are provided in Tables 1 and 2.

Table 1.

Clinical Signs and Patient Characteristics

Author	Group	Sample	Mean age	Gender	Level of myelopathy	Clinical sign
Denno et al (1990)²⁶	Negative Hoffmann’s group	40	39-71 y	NR	NR	Dinamic Hoffman’s sign
	Positive dynamic Hoffmann’s group	7	32-88 y
	Positive static Hoffman’s group	20	NR
Özkan at al. (2021)³²	Patients with DCM	411	62.6 ± 12.1 y	64% M, 36% F	NR	Cervicobrachial neuralgia, sensory deficits, motor deficits and gait disturbances
Wazir et al (2011)²⁹	Stenosis above the C5-6 level	58	62 ± 6 y	79.4% M, 20.6% F	Above C5-6	Wazir hand myelopathy sign
Wazir et al (2011)²⁹	Stenosis below the C6-7 level	10	62 ± 6 y	79.4% M, 20.6% F	Below C6-7	Wazir hand myelopathy sign
Hosono et al (2010)²⁷	Myelopathy patients admitted for decompressive laminoplasty	30	59.5 ± 10.6 y	66.7% M, 33.3% F	C3/4 in 6 patients, C4/5 in 6, C5/6 in 13, C6/7 in 1, C7/T1 in 1, and 2 or 3 levels in 3	Slow grip and release with the fingers (15-second test)
Hosono et al (2010)²⁷	Healthy controls	42	61 ± 7.52 y	45.2% M, 54.8% F	\	Slow grip and release with the fingers (15-second test)
Yukawa et al (2009)³⁰	Patients with cervical compressive myelopathy who would undergo decompressive surgery	163	63.3 ± 12.3 y	60.7%M, 39.3% F	NR	Ten second step test
Yukawa et al (2009)³⁰	Healthy volunteers	1204	NR	49.8% M, 50.2% F	NR	Ten second step test
Chang et al (2011)³¹	Patients with a clinical diagnosis of CTSM	42	61.3 y	64.3% M, 35.7% F	C5-T9	Rossolimo reflex and its electrophysiological assessment
Chang et al (2011)³¹	Healthy individuals	30	Age-matched	NR	C5-T9	Rossolimo reflex and its electrophysiological assessment
Chaiyamongkol et al (2017)²⁸	Axial pain group: pain and/or stiffness in the posterior neck aggravated with neck rotation and/or extension >3 months	14	47.1 ± 13.5 y	35.7% M, 64.3% F	NR	Trömner sign
	CSR group: Patients diagnosed as cervical radiculopathy pain	19	53.1 ± 10.7 y	31.6% M, 68.4% F
	CSM group	36	59 ± 9.9 y	77.8% M, 22.2% F
	Normal volunteers	14	53.5 ± 10.3 y	21.4% M, 78.6% F
Cook et al (2010)³³	Diagnosed with DCM	88	56.9 y	54.5% M, 45.5% F	NR	Gait deviation, Hoffman’s test, inverted supinator sign, Babinski test
Cook et al (2010)³³	Diagnosed without myelopathy	161	53.3 y	46.9% M, 53.1% F	NR
Raju et al (2025)³⁴	Pre-surgical DCM	32	<60 y: 53.1% >60 y: 46.9%	65.6% M, 34.4% F	NR	Ankle plantar flexor MVIC, knee extensor MVIC
Li et al (2025)²⁵	Diagnosed with DCM	141	57.3 ± 9.4 y	68.1% M, 31.9% F	NR	mJOA score, 10-second grip and release test, 10-second step test, Hoffman sign
Li et al (2025)²⁵	Healthy controls	141	56.9 ± 9.5 y	68.1% M, 31.9% F	NR

y: years; M: male; F: female; NR: not reported; DCM: Degenerative cervical myelopathy; CSM: Cervical spondylotic myelopathy; CSR: Cervical spondylotic radiculopathy; CTSM: Cervical and thoracic spondylotic myelopathy; MVIC: Maximal voluntary isometric contractions.

Table 2.

Clinical Signs Outcomes

Author	Clinical sign	How it is performed	Results	Conclusions
Denno et al (1990)²⁶	Dynamic Hoffman’s sign	Dynamic Hoffman’s sign is elicited by positioning the hand and wrist at rest and then flicking the terminal phalanx of the middle finger by snapping in between the examiner’s thumb and index finger during multiple active full flexion and extension of the neck, as tolerated by the patient. A positive response is present when the patient’s thumb and index terminal phalanx flick simultaneously in response.	A positive dynamic Hoffmann’s sign was present and correlated significantly with a narrow sagittal diameter of the cervical canal (diameters ranged from 10 mm to 12 mm, average 10.2 mm), making early diagnosis of CSM possible.	The dynamic Hoffman’s sign showed great results in terms of identifying early CSM. Nonetheless, a false-positive sign can be observed in normal hyper-reflexic individuals. Because of this, although dynamic Hoffmann’s sign should be part of all neurologic examinations, cervical myelography, or better, high-resolution MRI may be taken into consideration for definite diagnosis.
Özkan at al. (2021)³²	Cervicobrachial neuralgia, sensory deficits, motor deficits and gait disturbances	mJOA Score. 15-second test: with their right palm pronated, each patient was asked to fully grip and release their fingers as fast as possible for 15 seconds. Finger motion was evaluated with respect to the presence of trick motion of the wrist and finger.	The most common first symptom in patients suffering from DCM was cervicobrachial neuralgia, followed by gait disturbance, sensory deficits and motor deficits. Patients presenting with gait disturbance as first symptom typically received a later diagnosis (19.5 weeks) compared to those without these clinical signs (16 weeks).	Cervicobrachial neuralgia, being the most common first symptom of CSM, should be meticulously evaluated. Patients with gait disturbance, being a negative predictor for postoperative neurological outcomes, should be evaluated early with high-resolution MRI to identify DCM and receive prompt treatment.
Wazir et al (2011)²⁹	Wazir hand myelopathy sign	The patient is relaxed. By tapping at the extended wrist around the palmaris longus tendon, patients with cervical myelopathy respond with an exaggerated response by flexing their fingers, thumb, and wrist.	Wazir hand myelopathy sign was positive in 93% of patients in group I. In group 2, Wazir sign was reproducible in three patients, who also presented with myelopathy signs and whose level of stenosis was confirmed by MRI imaging.	The Wazir hand myelopathy sign, along with other hand myelopathy signs, can be usefully used in the early diagnosis of CSM.
Hosono et al (2010)²⁷	Slow grip and release with the fingers (15-second test)	mJOA Score. 15-second test: with their right palm pronated, each patient was asked to fully grip and release their fingers as fast as possible for 15 seconds. Finger motion was evaluated with respect to the presence of trick motion of the wrist and finger coordination. Trick motion was graded as none (grade 0), probable (grade 1), or definite (grade 2).	Preoperatively, the myelopathy group presented with a higher frequency of trick motion and that of uncoordinated finger motion, compared to the control group (trick motion, 11.7% vs 4.8% and uncoordinated finger motion, 15.6% vs 7.1%).	Myelopathy patients presented more frequently with uncoordinated finger motion and trick motion of the wrist. Uncoordinated finger motion was associated with the severity of myelopathy.
Yukawa et al (2009)³⁰	Ten second step test	Number of steps (taken by lifting their thighs parallel to the floor, hip and knee joints in 90° flexion) in 10 seconds without holding onto any object for balance, number of finger grip and release in 10 seconds. JOA score.	The average number of steps was 10.7±5.5 before surgery, compared to 19.6±3.5 in the control group, which was significantly lower in patients with compressive cervical myelopathy and decreased with age in both groups. The number of steps significantly correlated with the number of finger grip and release, the walking grade of JOA scores, and the total JOA score.	The 10-second step test is an easily performed, quantitative task, and useful in assessing the severity of CSM. Moreover, it can correlate with postoperative outcomes.
Chang et al (2011)³¹	Rossolimo reflex and its electrophysiological assessment	A reflex hammer containing a built-in switch was connected to an EMG machine signal trigger. The reflex was triggered by tapping on the plantar surface of the skin on the second metatarsophalangeal joint. The shortest onset conduction latency and the maximum peak-to-peak amplitude of MAPs were recorded using recording electrodes on the flexor digitorum brevis muscle and on the medial aspect of the ankle.	Rossolimo reflexes appeared in all DCM patients, while they were absent in control patients. The MAP amplitude of Rossolimo reflexes tends to correlate to a more severe spinal cord compression in case of DCM.	Electrophysiological assessments of the Rossolimo reflexes showed promising results concerning CSM. It is a reliable neurological sign and its electrophysiological assessment also correlates with the severity of spinal cord dysfunction in patients with DCM
Chaiyamongkol et al (2017)²⁸	Trömner sign	The subject’s hand is held in a relaxed wrist dorsiflexion position. The examiner flicks the volar surface of the distal phalanx of the subject’s middle finger. A positive sign is indicated by involuntary flexion of the subject’s distal phalanxes of both index finger and thumb.	Trömner sign showed a diagnostic sensitivity of 94% and a negative predictive value of 85%. Patients in the CSM group who didn’t show spinal cord signal changes in MRI had negative myelopathic signs, except for Trömner sign.	The Trömner sign is a useful neurological sign to rule out CSM. Moreover, the high incidence of positive signs in presymptomatic cervical cord compression patients indicates its useful role in the early detection of the disease.
Cook et al (2010)³³	Gait deviation, Hoffman’s test, inverted supinator sign, Babinski test	The inverted supinator sign is obtained by stimulating the brachioradial tendon, with flexion of the fingers indicating lesions at C5-C6. The Babinski sign shows possible upper motor neuron dysfunction if the big toe extends.	The inverted supinator sign showed the highest LR+, followed by Achilles hyperreflexia and quadriceps hyperreflexia. The Babinski and Hoffmann tests, the inverted supinator sign, the gait abnormality, and the age of 45 years were retained.	This study showed a combination of clinical findings consisting of gait deviation; + Hoffmann’s test; inverted supinator sign; + Babinski’s test; and age > 45 years, which proved effective in ruling out and confirming cervical myelopathy.
Raju et al (2025)³⁴	Ankle plantar flexor MVIC, knee extensor MVIC	MVIC of the ankle plantar flexors are performed by asking the subject to generate the maximum possible force against a fixed resistance, with the ankle in a neutral or slightly dorsiflexed position. MVIC of the knee extensors are performed with the subject sitting or supine, the knee flexed at a specific angle, and with the instruction to extend the knee against a fixed resistance.	Knee extensor MVICs showed significant positive correlations with gait speed (r = 0.38, P = 0.001), mJOA lower extremity scores (r = 0.41, P = 0.019), and BBS scores (r = 0.44, P = 0.007). Ankle plantar flexor MVICs were not significantly associated with any outcomes (P > 0.05).	MVICs detect subclinical lower extremity weakness in DCM. Knee extensor MVIC was a significant predictor of gait/balance function in pre-surgical DCM patients. Knee extensor MVIC can serve as an objective measure of motor function in DCM and assist with stratification of disease severity.
Li et al (2025)²⁵	mJOA score, 10-second grip and release test, 10-second step test, Hoffman sign	mJOA score. The 10-second grip and release test measures hand motor function, while the Hoffmann test checks the corticospinal tract. The lower limb test assesses leg motor function by asking the patient to alternately lift their feet for 10 seconds.	Brief-BESTest scores and COP parameters showed moderate to strong correlations with mJOA scores (ρ = 0.310-0.768) and varied significantly across mJOA severity levels (P < 0.01). Both the grip and release and step tests also correlated moderately with balance measures (ρ = 0.245-0.640).	Patients with DCM showed substantially impaired balance compared to healthy controls, with COP parameters and Brief-BESTest scores well correlated with mJOA scores.

CSM: Cervical spondylotic myelopathy; mJOA: Modified Japanese Orthopedic Association; DCM: Degenerative cervical myelopathy; MRI: Magnetic resonance imaging; MAPs: Muscle action potentials; EMG: Electromyography; MVIC: Maximal voluntary isometric contractions.

Radiological Techniques

A total of 9 out of 15 studies focused on radiological examinations investigated the use of Diffusion Tensor Imaging (DTI) for early detection of DCM. The studies concluded that DTI, performed with either a 1.5 or 3-Tesla unit, offers higher sensitivity, specificity, and negative predictive value in identifying early DCM compared to conventional T2W-MRI.^17,35-41 Additionally, Kerkovsky et al combined DTI of the cervical spine with electrophysiological findings (SEPs and MEPs) and concluded that this approach could enhance the diagnostic capability of the technique, improving the ability to distinguish between symptomatic and asymptomatic DCM cases.⁴² Furthermore, the study by Funaba et al assessed the use of Kinematic CT Myelography (CMCT) for early detection of DCM.⁴³ The study used CMCT to examine the cervical spine in neutral, flexion, and extension positions, revealing that anterior spondylolisthesis during neck extension and neck stiffness during flexion are linked to greater limb dysfunction, highlighting the role of dynamic factors in DCM progression.⁴³ Detailed study characteristics are shown in Tables 3 and 4.

Table 3.

Radiological Techniques and Patient Characteristics

Author	Group	Sample	Mean age	Gender	Level of myelopathy	Radiological technique
Funaba et al (2021)⁴³	Patients with CSM	86	73.3 y	60.5% M, 39.5% F	C2-3 in 1 patient, C3-4 in 38, C4-5 in 35, C5-6 in 12	CMCT
Ahmadli et al (2015)¹⁷	Pure cervical myelopathy, with imaging findings of canal stenosis	18	66.4 y	55.6% M, 44.4% F	NR	DTI
Hori et al (2006)³⁷	Patients with CSM in an early clinical stage	14	17-76 y	64.3% M, 35.7% F	C2-C6	LSDTI
Mostafa et al (2023)³⁸	Patients with neurological symptoms suggestive of CSM	60	44.6 ± 12.2 y	36.7% M, 63.3% F	C2-C7	DTI
Mostafa et al (2023)³⁸	Healthy subjects	30	Correspond in terms of age and sex		C2-C7	DTI
Banaszek et al (2014)³⁶	Symptomatic patients with cervical spondylosis	132	53.6 y	59.1% M, 40.9% F	C2-C6	DTI
Banaszek et al (2014)³⁶	Control subjects	25	45.8 y	NR	/	DTI
Demir et al (2003)³⁹	Patients with signs of myelopathy at physical examination	22	NR	NR	NR	DTI
Demir et al (2003)³⁹	Patients without clinical myelopathy	14	NR	NR	NR	DTI
Kara et al (2011)⁴⁰	Patients with neurological signs and symptoms of CSM	16	59.9 y (27-86)	37.5% M, 62.5% F	NR	DTI
Nischal et al (2021)⁴¹	Patients clinically suspected of CSM	52	53.16 y	46.2% M, 53.8% F	C1-C7	DTI
Kerkovsky et al (2012)⁴²	Clinical signs and symptoms of cervical myelopathy, and decreased mJOA scale	20	59 y (45-78)	65% M, 35% F	NR	DTI, SEPs and MEPs
	Cervical pain and/or cervical radiculopathy, but without symptoms/signs of CSM	32	57 y (39-71)	62.5% M, 37.5% F
	Healthy volunteers	13	57 y (47-67)	69.2% M, 30.8% F
Seif et al (2020)⁵¹	Patients with tSCI	29	47.4 ± 19.8 y	82.8% M, 17.2% F	C2-C8 = neurologic injury level; C3-C4 - C7-D1 = stenosis level	High-resolution T2*-weighted; DWI
	Patients with mild and moderate DCM	20	52 ± 14.5 y	70% M, 30% F
	Healthy controls	22	41.1 ± 11.4 y	63.6% M, 36.4% F	/
ElFiky et al (2023)⁵²	Patients with CSM	103	<50 y: n = 40 >50 y: n = 63	54.4% M, 45.6% F	<50 y: C5-C6 21/40, C3-C4 3/40 >50 y: C3-C4 26/63	Spin echo sequence system for T1-weighted images and a fast spin echo sequence system for T2-weighted images
Berberat et al (2023)⁵³	DCM with visible intramedullary hyperintensity (IHIS+)	10	55.1 ± 11.2 y	60% M, 40% F	C3-4 (50%/18%), C4-5 (30%/27%), C5-6 (30%/73%), and C6-7 (20%/26%)	3T-MRI T2-weighted imaging
Berberat et al (2023)⁵³	DCM without visible intramedullary hyperintensity (IHIS-)	11	58.7 ± 14.3 y	45% M, 55% F		3T-MRI T2-weighted imaging
Park et al (2022)⁵⁴	Patients with CSM	107	58 ± 13 y	43% M, 57% F	/	Sagittal MRI scans
Zhang et al (2024)³⁵	Patients with CSM	47	57 ± 9 y	59.6% M, 40.4% F	/	DTI, DBSI
Zhang et al (2024)³⁵	Healthy controls	21	57 ± 8 y	52.4% M, 47.6% F	/	DTI, DBSI
Freund et al (2023)⁵⁵	Patients with DCM	38	58.5 ± 11.5 y	78.9% M, 21.2% F	Frequently C3-C4 and C5-C6	Quantitative MRI
Freund et al (2023)⁵⁵	Healthy controls	38	41.2 ± 12.8 y	81.6% M, 18.4% F	Frequently C3-C4 and C5-C6	Quantitative MRI

y: years; M: male; F: female; NR: not reported; CSM; cervical spondylotic myelopathy; DCM: Degenerative cervical myelopathy; tSCI: Traumatic spinal cord injury; CMCT: Kinematic CT myelography; DTI: Diffusion tensor imaging; LSDTI: Diffusion tensor MRI; SEPs: Somatosensory evoked potentials; MEPs: Motor-evoked potentials; mJOA: Modified Japanese Orthopedic Association.

Table 4.

Radiological Techniques Outcomes

Author	Radiological technique	How it is performed	Results	Conclusions
Funaba et al (2021)⁴³	CMCT	CMCT was conducted with the patient in the supine position while the cervical spine was in a neutral position or at maximum flexion or extension using a fixation device. Measurements of the cross-sectional area of the spinal cord were obtained during flexion, in neutral position, and during extension.	Significant risk factors specific for severe lower limb dysfunction were greater anterior spondylolisthesis during neck extension and small C2-7 ROM in neutral to flexion.	The study showed that an anterior spondylolisthesis during neck extension and neck stiffness during flexion are associated with greater upper and lower limb dysfunction.
Ahmadli et al (2015)¹⁷	DTI	Axial DTI at 1.5 T together with routine MRI was performed. Quantitative FA and ADC maps were generated. Values at the narrowest cervical levels were compared to pre and poststenotic levels.	FA was significantly reduced at the stenotic level compared to pre stenotic level. No differences between ADC values at stenotic and non-stenotic levels were found.	DTI at 1.5 T is useful to detect any abnormalities in the spinal cord in patients suffering from CSM before the T2W signal anomalies can become apparent. Therefore, DTI should be included in any MRI to show early stage of CSM.
Hori et al (2006)³⁷	LSDTI	A low field strength MR imager was used. SNR in the spinal cord and cerebrospinal fluid, the ADC and FA were evaluated. 3D fiber-tracking was also studied.	LSDTI was better at detecting abnormalities in cervical spinal cord than T2WI in the early clinical stage.	LSDT images at low field can be used to show abnormalities in the spinal cord in early CSM.
Mostafa et al (2023)³⁸	DTI	1.5 Tesla machine was used with patient in the neutral supine position. FA and ADC were calculated. 3D fiber tractography was created.	FA and ADC parameters had higher sensitivity (97.0% and 88.1%, respectively) than conventional T2WI (13.4%) and fibre tractography (10%) in detecting early compressive CSM.	DTI images are great at quantifying early degenerative CSM and should be implemented with routine cervical spine MRI.
Banaszek et al (2014)³⁶	DTI	1.5 T MR unit was used. AP diameter of the spinal canal and the spinal cord was measured. FA and ADC at each cervical level were calculated together with the degree of stenosis.	FA results differed at all cervical levels between the control group and patients with DSD. Moreover, the values of FA correlated positively with the AP diameter of the spinal canal.	DTI images showed great results in revealing microstructural impairments of the cervical spinal cord even before they become apparent in plain MRI. In particular, FA and AP spinal canal diameter are sensitive parameters of alterations of spinal cord integrity in the different stages of CSM.
Demir et al (2003)³⁹	DTI	1.5 T clinical MRI system was used. Sensitivity, specificity, and positive and negative predictive values of both T2WI and DWI were compared.	Patients with myelopathy had higher ADC and ADT with a higher sensitivity and negative predictive value compared to T2WI.	DWIs improve the sensitivity and have a higher negative predictive value in cervical spondylotic myelopathy compared to T2WI, especially regarding early detection of the disease.
Kara et al (2011)⁴⁰	DTI	3-T MRI system was used. FA and ADC were calculated at the level of most severe cervical canal stenosis and at a nonstenotic level.	FA values in the spinal cord were shown to be significantly reduced at the stenotic level, whereas ADC values were increased.	DTI showed potential in identifying abnormalities in the spinal cord before the development of T2 hyperintensity on conventional sequences in patients developing CSM, helping in early diagnosis of the disease.
Nischal et al (2021)⁴¹	DTI	3-T MRI system was used. FA and ADC of stenotic and non-stenotic segments were produced.	The more stenotic the segment, the lower the mean FA and the higher the ADC values compared to the non-stenotic segments. Moreover, FA and ADC showed an overall higher sensitivity in identifying abnormalities compared with T2WI.	DTI metrics (FA value better than ADC) can be a useful addition to MRI in detecting signal abnormalities in the spinal cord of patients suffering from CSM, even with mild clinical signs, before irreversible changes become apparent on T2WI.
Kerkovsky et al (2012)⁴²	DTI, SEPs and MEPs	1.5 T clinical MRI system was used. ADC and FA were evaluated. Short-latency SEPs from median and tibial nerves and MEPs, elicited through transcranial and root magnetic stimulation were obtained.	FA and ADC values were higher at the level of maximum stenosis in symptomatic patients than in asymptomatic patients. Abnormal MEPs and SEPs values were calculated both in the preclinical and symptomatic groups, with higher values in the latter group.	DTI showed promising results in terms of correlating abnormal images with abnormal clinical signs of myelopathy, helping to discriminate between symptomatic and asymptomatic cases. MEPs and SEPs can be used in excluding or diagnosing myelopathy.
Seif et al (2020)⁵¹	High-resolution T2*-weighted; DWI	High-resolution T2* MRI was used. T2* relaxation depends on spin-spin interactions and magnetic field variations. Moreover, DWI was adopted.	While macrostructural MRI measurements revealed a similar degree of cervical spinal cord atrophy, microstructural measurements distinguished more pronounced tract-specific neurodegeneration in patients with tSCI compared to patients with DCM. Tract-specific neurodegeneration was associated with upper limb impairment.	Advanced qMRI measures can detect specific tract changes that are clinically meaningful. Cervical spinal cord DTI could be a suitable biomarker for predicting outcomes and monitoring treatment effects.
ElFiky et al (2023)⁵²	Spin echo sequence system for T1-weighted images and a fast spin echo sequence system for T2-weighted images	T1 spin echo sequences use a 90° pulse followed by a 180° pulse and produce T1 contrast thanks to short TR and TE. Fast spin echo T2 sequences use multiple refocusing pulses after a single excitation to speed up acquisition.	In patients under the age of 50, no MC was found in 61.5% of cases. In patients with MC, Modic II type at the C4-C5 level was observed more frequently. MC was found in 71.4% of patients >/ = 50 years old. In patients with MC, Modic II type at C3-C4 was observed more frequently.	MC in the cervical spine is a common finding in MRI scans of patients with CSM aged ≥50 years. Degenerative changes in the facet joints are found in most patients with CSM, regardless of age. A significant correlation has also been found between MC and changes in the facet joints at the same level.
Berberat et al (2023)⁵³	3T-MRI T2-weighted imaging	The sequences were acquired with the neck in flexion, extension, and neutral position. The protocol included a sagittal T2-weighted TSE sequence and a sagittal DTI sequence.	Significant differences were found between the control level (C2-C3) and pathological segments for IHIS + group in neutral neck position in AD; in flexion in ADC and AD; and in neck extension in ADC, AD, and FA. For IHIS- group, significant differences were found between the control level (C2-C3) and pathological segments only for ADC values in neck extension.	Significant increases in ADC values were found between the control and pathological segments for both groups only in the neck extension.
Park et al (2022)⁵⁴	Sagittal MRI scans	Sagittal cervical MR scans are performed in different neck positions (neutral, flexion, and extension).	Intraobserver reliability and interobserver reliability were 0.64 and 0.52, respectively, for neutral sagittal MRI. The accuracy of neutral sagittal MRI in detecting CSM was 0.735, while that of extension sagittal MRI was 0.932.	Dynamic MRI showed a significant improvement in diagnostic reliability and accuracy of CSM compared to conventional MRI. Furthermore, dynamic MRI showed better results in diagnostic accuracy assessed as postoperative outcome.
Zhang et al (2024)³⁵	DTI, DBSI	DTI tensors include FA, which reflects white matter integrity, and ADC, which measures water movement. DTI also provides axial and radial diffusivity. DBSI combines anisotropic (for axonal diffusion) and isotropic (for extra-axonal diffusion) tensors.	Traditional MRI correctly assigned patients to the healthy control, mild CSM, and moderate/severe CSM cohorts, with an accuracy of 0.647; DTI and DBSI models performed with an accuracy of 0.52 and 0.81, respectively. Traditional MRI correctly predicted patients with CSM who improved at 2-year follow-up, with an accuracy of 0.58; DTI and DBSI models performed with an accuracy of 0.62 and 0.72, respectively.	Advanced imaging techniques, particularly metrics derived from DBSI from dMRI, have been shown to provide granular assessments of spinal cord microstructure that may offer improved diagnostic and prognostic utility.
Freund et al (2023)⁵⁵	Quantitative MRI	A sagittal T2 scan was performed at the level of the lesion, covering the entire cervical spinal cord. Voxelwise analysis with a brain/spinal cord probabilistic model processed multiparametric mapping.	Remote atrophy was observed in the cervical medulla (P = 0.002) and left thalamus (0.026) of the DCM group. Sensory impairments were associated with an increase in iron-sensitive R2* in the thalamus and periaqueductal gray matter in DCM.	It has been found that in mild to moderate DCM, simultaneous qMRI assessments revealed (micro)structural changes above the compression site in the brain and cervical spinal cord of DCM patients with radiological evidence of myelopathy.

CMCT: Kinematic CT myelography; DTI: Diffusion tensor imaging; LSDTI: Diffusion tensor MRI; SEPs: Somatosensory evoked potentials; MEPs: Motor-evoked potentials; MRI: magnetic resonance imaging; ROM: Range of motion; FA: fractional anisotropy; ADC: Apparent diffusion coefficient; CSM: Cervical spondylotic myelopathy; SNR: Signal-to-noise ratio; DSD: Degenerative spine disease; AP: Anteroposterior; T2WI: T2 weighted images; ADT: Apparent diffusion tensor; DWI: Diffusion-weighted imaging.; tSCI = traumatic spinal cord injury; MC = modic changes; AD = axial diffusivity; ADC = apparent diffusion coefficient; RD = radial diffusivity; FA = fractional anisotropy; DTI = diffusion tensor imaging; DBSI = diffusion basis spectrum imaging; R2 = effective transverse relaxation rate; R1 = longitudinal relaxation rate; MT = magnetization transfer.

Electrophysiological Measures

Among the 11 articles included, 6 evaluated SEPs and MEPs, 2 assessed Dynamic Somatosensory Evoked Potentials (DSSEPs), and 2 examined SEPs and MEPs with magnetic brain stimulation. SEPs and MEPs consistently showed promising results for assessing cervical cord dysfunction and predicting the evolution of early DCM.^20,44-48

Magnetic brain stimulation of MEPs revealed that preclinical patients did not show significant differences compared to normal controls, suggesting that while they can be useful for distinguishing between patients with and without cervical myelopathy, they may not be suitable for evaluating preclinical myelopathy.⁴⁹

The evaluation of dynamic motion through electrophysiological measures highlighted that DSSEPs, due to their simplicity, accuracy, and non-invasive nature, are a valuable neurophysiological tool for assessing DCM patients and understanding how dynamic factors impact the condition’s pathogenesis.⁴⁶ Indeed, Qi et al found that at the neutral position, LMC2 amplitude was linked to DCM, but with low diagnostic accuracy, whereas in the dynamic position, changes in the amplitude of LMC2 and LUC2 were determined to be diagnostic of DCM.⁵⁰ Study characteristics are presented in Tables 5 and 6.

Table 5.

Electrophysiological Techniques and Patient Characteristics

Author	Group	Sample	Mean age	Gender	Electrophysiological technique
Bednarik et al (1998)⁴⁵	Clinically “silent” spondylotic cervical cord compression cases	30	50 ± 6.5 y	56.7% M, 43.3% F	SEPs and MEPs
Bednarik et al (1998)⁴⁵	Normal subjects	40	49.3 ± 7.3 y	52.5% M, 47.5% F	SEPs and MEPs
Bednarik et al (2008)²⁰	Clinically asymptomatic spondylotic cervical cord compression	199	51 y (28-82)	52.8% M, 47.2% F	SEPs, MEPs and EMG examination
Bednarik et al (2004)⁴⁶	Clinically asymptomatic spondylotic cervical cord compression	66	50 y (32-75)	51.5% M, 48.5% F	SEPs, MEPs and EMG examination
Qi et al (2019)⁵⁰	Patients with CSM who received decompression and fixation surgery	31	NR	NR	DSSEP
Qi et al (2019)⁵⁰	Control group	15	NR	NR	DSSEP
Morishita et al (2013)⁵⁶	CSM patients	20	64.9 y (47-77)	85% M, 15%F	DSSEP
Morishita et al (2013)⁵⁶	Healthy volunteers	20	46.3 y (13-75)	65% M, 35%F	DSSEP
Yoon et al (2017)⁴⁷	Cervical OPLL patients	153	54 ± 10 y	77.8% M, 22.2% F	SEP
Tavy et al (1999)⁵⁷	Symptoms compatible with cervical radiculopathy but no symptoms or signs of myelopathy	25	57.8 y (41-84)	64% M, 36% F	SEPs and MEPs to magnetic brain stimulation
Tavy et al (1999)⁵⁷	Healthy subject	35	Age-matched	NR	SEPs and MEPs to magnetic brain stimulation
Masur et al (1989)⁴⁸	19 patients with cervical spinal stenosis and cervical radiculopathy, of which 4 showed clinical signs of myelopathy		NR	NR	SEPs and MEPs
Kameyama et al (1995)⁴⁹	Patients with CSM	67	62.6 ± 10.7 y (41-83)	59.7% M, 40.3% F	MEPs to magnetic brain stimulation
	Patients with spinal canal stenosis	24	65.9 ± 10.9 y (45-86)	75% M, 25% F
	Healthy volunteers	35	(23-48)	65.7% M, 34.3% F
Simo et al (2004)⁵⁸	Spinal cord compression on the MRI without symptoms suggestive of CSM	29	54.1 y (35-74)	72.5% M, 27.5% F	SEPs and MEPs
	Spinal cord compression on the MRI and minor symptoms suspicious for CSM	15
	Neurological signs that confirmed clinically the presence of CSM	7
Yu et al (2024)⁴⁴	Patients diagnosed with DCM	102	65.6 y ± 10.7 y	65.7% M, 34.3% F	CMCT and SEP

y: years; M: male; F: female; NR: not reported; SEP: Somatosensory evoked potential; MEP: Motor-evoked potentials; EMG: Electromyography; DSSEP: Dynamic somatosensory evoked potentials; OPLL: Ossification of posterior longitudinal ligament; CSM: Cervical spondylotic myelopathy; MRI: magnetic resonance imaging: CMCT: Central motor conduction time.

Table 6.

Electrophysiological Techniques Outcomes

Author	Electrophysiological technique	How it is performed	Results	Conclusions
Bednarik et al (1998)⁴⁵	SEPs and MEPs	SEPs from the median and tibial nerves were recorded through electrical stimulation of mixed nerves at the wrist and ankle. MEPs were elicited by means of transcranial and root magnetic stimulation and recorded from abductor digiti minim and abductor hallucis muscles.	SEPs and MEPs documented subclinical involvement of the cervical cord in 50% of patients with “silent” spinal cord compression. During the 2-year follow-up period, clinical signs of myelopathy were observed in patients with EP abnormalities.	Both SEPs and MEPs can be used as powerful tools to predict the evolution of early cervical myelopathy in clinically silent patients.
Bednarik et al (2008)²⁰	SEPs, MEPs and EMG examination	SEPs were recorded through electrical stimulation of mixed nerves at the wrist and ankle. MEPs were elicited by means of transcranial and root magnetic stimulation and recorded from abductor digiti minim and abductor hallucis muscles. EMG examination was performed from 6 motor and 4 sensory nerves using conventional techniques.	SEPs, MEPs and EMG abnormalities showed a significant correlation with early development of SCM.	Electrophysiological evaluation is a useful tool in detecting presymptomatic myelopathy. Electrophysiological abnormalities, clinical signs of cervical radiculopathy, and MRI hyperintensity can predict early progression into symptomatic SCM.
Bednarik et al (2004)⁴⁶	SEPs, MEPs and EMG examination		The variables associated with the development of symptomatic SCM were the presence of electromyographic signs of anterior horn lesions and abnormal SEPs.	Electrophysiological abnormalities indicate an early cervical cord dysfunction and can be used as powerful predictors of a progressive clinical course.
Qi et al (2019)⁵⁰	DSSEP	Ulnar and median nerves were stimulated by surface electrodes placed on the upper extremities and SSEPs were recorded using subdermal needle electrodes placed at the C2 and C5 cervical spinous processes and in the scalp over the primary sensory area. SEEPs were recorded firstly at a neutral position, then in a flexed cervical position and extended cervical position.	At the neutral position, the amplitude of LMC2 was associated with CSM but with low diagnostic accuracy. At the dynamic position, the changes of amplitude of LMC2 and LUC2 were determined to be diagnostic of CSM.	DSSEP can provide a simple, accurate, and noninvasive supplementary test for the diagnosis of complicated CSM and may be used as a tool in early diagnosis.
Morishita et al (2013)⁵⁶	DSSEP	The SSEPs were examined with the cervical spine in a neutral position and at a 20° extension for 10 and 20 minutes.	The percent latency and amplitude were almost identical during the extension. When the CSM patients and the healthy controls were compared, a significant difference in the percent amplitude was observed between the 2 groups during the cervical spine extension.	This study suggests the potential of DSSEPs as a useful neurophysiological technique to detect the effect of dynamic factors on the pathogenesis of CSM and help in early diagnosis.
Yoon et al (2017)⁴⁷	SEP	SEP of median and tibial nerves was performed in patients diagnosed with cervical OPLL. SEP was recorded by stimulation of bilateral median nerves at the wrist and bilateral posterior tibial nerves at the ankle by using a bar electrode.	Tibial SEP latency was significantly correlated with the characteristics of OPLL.	The evaluation of tibial SEP latency was correlated with the degree of OPLL and may be a useful tool in the diagnosis of early cervical myelopathy.
Tavy et al (1999)⁵⁷	SEPs and MEPs to magnetic brain stimulation	MEPs: Surface recording electrodes from the abductor digiti minimi, biceps brachii and tibialis anterior muscles and measured with a conventional EMG recording system. SEPs: Stimulation of each median nerve at the wrist and each tibial nerve at the ankle.	Abnormal MEPs (2 of 25 patients) and SEPs (1 of 23 patients) were recorded, though not significantly different from the control group.	MEPs and SEPs were normal in patients with asymptomatic cervical stenosis, making these electrophysiological tests highly sensitive and specific in excluding or diagnosing myelopathy.
Masur et al (1989)⁴⁸	SEPs and MEPs	SEPs were obtained by stimulation of the right and left posterior tibial nerves at the ankle. MEPs were obtained by stimulating the motor cortex with brief single, short-duration high-voltage discharges. EMG responses were recorded from anterior tibial muscles in both legs.	Tibialis SEPs were increased in 12 of the 15 asymptomatic individuals. The 4 symptomatic individuals always showed abnormal SEPs.	SEPs and MEPs can be used as a powerful tool in quantifying subclinical dysfunction of the spinal cord.
Kameyama et al (1995)⁴⁹	MEPs to magnetic brain stimulation	The motor cortex was stimulated percutaneously and EMG records were obtained using surface electrodes placed over the tibialis anterior and abductor pollicis brevis bilaterally. The subjects first relaxed the target muscles, then maximally contracted the target muscles.	The general motor conduction time correlated directly with the state of myelopathy. Preclinical patients showed no significant differences compared with normal controls.	MEPS can be used when excluding patients with or without cervical myelopathy.
Simo et al (2004)⁵⁸	SEPs and MEPs	MEPs were recorded with superficial electrodes on both lower limbs from the tibialis anterior muscle. SEPs were elicited by the electrical stimulation of the tibial nerve at the ankle.	Patients with unspecific symptoms without central nervous system signs had abnormal MEPs, with normal SEPs. Myelopathy patients had abnormalities of MEPs and SEPs.	MEPs showed better sensitivity in identifying early-stage cervical myelopathy, compared to SEPs.
Yu et al (2024)⁴⁴	CMCT and SEP	CMCT measures the time it takes for neural impulses to travel from the motor cortex to the muscle and is prolonged in conditions such as cervical myelopathy. EPNs are electrical responses recorded after stimulation of peripheral nerves.	Abnormal CMCT and SEP findings were observed in 94 (92.2%) and 77 patients (75.5%), respectively. There was a statistically significant correlation between JOA score and APB-CMCT (r = 0.546, P < .001), TA-CMCT (r = 0.517, P < .001), MN-SSEP (r = 0.353, P < .001), and TN-SSEP (r = 0.349, P < .003).	CMCT and SEP may be useful in predicting the severity of myelopathy symptoms in patients with DCM. Patients with severe preoperative myelopathy symptoms showed significantly prolonged CMCT and SEP.

SEP: Somatosensory evoked potential; MEP: Motor-evoked potentials; EMG: Electromyography; DSSEP: Dynamic somatosensory evoked potentials; OPLL: Ossification of posterior longitudinal ligament; SCM: Spondylotic cervical myelopathy; MRI: magnetic resonance imaging; CMCT: Central motor conduction time; (APB): Abductor pollicis brevis; (TA): Tibialis anterior (TA); (MN): Median nerve; (TN): Tibial nerve.

Discussion

This study aimed to review the literature on the diagnosis of DCM, emphasizing the importance of early clinical signs and innovative radiological and electrophysiological methods. An earlier and more accurate diagnosis of the disease enables timely treatment, helping clinicians identify patients at risk of myelopathy or those exhibiting mild signs of DCM, ultimately enhancing clinical outcomes.

DCM is often called one of the great mimickers in medicine because of its varied symptoms and difficult diagnosis.⁵⁹ Even though it is a well-acknowledged disease, being first described in 1956 by Clarke and Robinson as the evolution of cervical spondylosis, there have been no significant advancements in the ability to achieve an early diagnosis of the condition over the past few decades.⁶⁰ Incorrectly diagnosing DCM can have devastating outcomes for both individuals and society, with rising social costs annually.^5,61,62 As DCM is age-related, its incidence and prevalence are expected to increase with the aging population, making it an increasingly significant issue.⁶³

Decompressive surgery is the standard treatment for clinical DCM, but most patients are diagnosed in advanced stages, leading to limited postoperative improvement and mostly halting disease progression.⁶⁴

On the other hand, as shown by a study that analyzed data from the Swedish national spine registry, it is clear that decompressive treatment in patients with DCM, both young and elderly, shows reasonable recovery rates that justify the choice of a surgical approach to the condition.⁶⁵

For this reason, in recent years, various efforts have been made to identify effective methods for early diagnosis of DCM.⁶⁶ Functional outcome measures, such as the Japanese Orthopaedic Association (JOA) and modified mJOA, are commonly used to assess neurological status, though they rely on subjective patient reports and can be influenced by other disabilities, potentially leading to bias and inaccurate conclusions.^67,68 Clinical signs like Hoffmann’s, Lhermitte’s, and Babinski’s are commonly used in the diagnosis of DCM,^21-23 but they often appear only in advanced stages and have variable sensitivity in diagnosing the condition.⁶⁹ DCM often manifests with characteristic hand dysfunctions, known as “myelopathy hand,” resulting from reflex and motor neuron pathway involvement.⁷⁰ In the present study, several tests assessing finger coordination and hand strength, including variants of Hoffmann’s test, have been shown to effectively identify early DCM and exclude cervical myelopathy, with high negative predictive values compared to standard tests.^26-28

In particular, Cook et al showed how the presence of a positive Hoffman’s test, positive Babinski test, inverted supinator sign, and gait deviation represent valid clinical criteria for confirming the presence of cervical myelopathy.³³ With regard to clinical signs, it can be noted that, in the study by Raju et al, the maximal voluntary isometric contractions (MVIC) of the ankle plantar flexors and the MVIC of the knee extensors were significant predictors of gait and balance function in pre-surgical patients with DCM.³⁴ Finally, it was observed that the 10-second grip and release test was moderately correlated with balance measures.²⁵

These non-invasive clinical signs, including those for the lower limbs, should be incorporated into routine clinical practice, especially for patients over 50, to detect DCM in both its preclinical and mild phases.

Routine MRIs, especially T2WI, are the standard for diagnosing DCM, but they often show alterations in later stages of the disease, where recovery is usually not possible.¹⁶ To address this issue, DTI has been developed, using water molecule diffusion to assess white matter integrity, and it proved to be valuable not only for spinal conditions but also for diagnosing various neurological and psychiatric disorders.^71,72 Changes in fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values indicate degenerative spinal changes, particularly at the stenotic level, reflecting conditions like disc degeneration and spinal canal narrowing that could lead to clinical DCM⁷³ and DCM.⁵³ Moreover, DTI can assess various biomolecular factors in the spinal cord during chronic damage, such as ischemic injury, excitotoxicity, and cellular apoptosis, often detecting abnormalities before they appear on conventional T2WI-MRI images.⁷⁴ Given its effectiveness in detecting early cervical spinal changes, DTI could be used during the preclinical phase of DCM in patients with positive T2WI-MRI signs but no symptoms, to confirm the diagnosis. Furthermore, the widespread adoption of DTI could lower costs and make it a potential preventive tool for certain age groups in the future.^75,76

In particular, Seif et al showed how microstructural measurements, performed using DTI, distinguished more pronounced tract-specif neurodegeneration in patients with traumatic spinal cord injury (tSCI) compared to patients with DCM.⁵¹

In any case, even when equipped with excellent diagnostic tools, the diagnostic process for the condition in question is often flawed by the time lost by patient in the long journey between the general practitioner, the performance of the required diagnostic tests, and finally the definitive diagnosis made by the spine surgeon.⁷⁷ Analysis of this process lays the foundations for possible future healthcare initiatives aimed at reducing the time lost, with the ultimate goal of making a diagnosis that is both early and rapid.

Regarding radiological techniques, dynamic MRI showed a significant improvement in the diagnostic reliability and accuracy of DCM.⁵⁴ Furthermore, MRI scans revealed a significant correlation between Modc changes (MC) and degeneration in facet joints at the same level.⁵²

Dynamic factors in DCM cause spinal cord compression: flexion leads to impingement by osteophytes or disc protrusions, while hyperextension compresses it between the vertebral body and posterior structures.^78,79 Repetitive neck movements may accelerate degenerative changes in the cervical spine, ultimately leading to DCM.⁸⁰ To aid in early diagnosis, CMCT is being investigated as a radiological tool to assess the impact of dynamic motion and detect intersegmental instabilities contributing to DCM.⁸¹ The included article by Funaba et al found that excessive anterior displacement of the vertebral bodies during extension, along with stiffness and contracture during flexion, may be linked to limb dysfunction.⁴³ However, further research is needed to confirm the clinical value of CMCT in the early detection of DCM.

Electrophysiological and neurophysiological examinations provide a non-invasive assessment of central and peripheral neural pathway integrity, aid in differentiating neuromuscular disorders, and can detect early spinal cord dysfunctions with high negative predictive value, helping predict outcomes and rule out DCM in patients.^82-85 Bednarik et al found that abnormalities in MEPs and SEPs are positively correlated with the onset of symptoms and clinical signs, concluding that both tests are powerful tools for predicting the progression of early DCM in asymptomatic patients.⁴⁵ Several studies in this review highlight the value of non-invasive electrophysiological measures in the early diagnosis of DCM, particularly in the preclinical phase, serving as complementary tests to confirm myelopathy in patients with T2WI alterations but no clear clinical signs, thereby guiding appropriate treatment decisions.^19,57

In particular, Yu et al highlighted how CMCT and SSEPs (or SEPs) can be useful in predicting the severity of myelopathy symptoms in patients with DCM, and that pre-operative patients with myelopathy symptoms showed significantly prolonged CMCT and SSEPs.⁴⁴

Recent electrophysiological techniques, such as contact heat-evoked potentials (CHEPs) and laser-evoked potentials (LEPs), have been explored to detect early spinothalamic tract alterations and are primarily used to assess sensory nerve conduction damage after traumatic spinal cord injury, showing superiority over SEPs.^19,86 Despite their promise, research on the use of these techniques in chronic central neurological conditions like DCM remains limited, underscoring the need for further investigation.^87,88

In this systematic review, we analyzed the potential of DTI in the early diagnosis of degenerative processes affecting the cervical spine. The mJOA scale, clinical signs in the lower limbs, and electropysiological measurements are useful tools for monitoring the evolution and symptomatic improvement of patients treated with decompression surgery. On the other hand, it is clear that these tools must be used together in order to improve not only diagnostic process but also the post-operative evaluation of patients with CSM.

Strengths and Limitations

A strength of this review is the similarity in the mean age of participants across all studies, leading to a more homogeneous population. However, the study has several limitations, including the potential bias from observer-reported or self-reported tools used to assess results and outcomes across the included articles. Additionally, the limited number of studies, particularly those examining dynamic factors in DCM patients, is a constraint. Furthermore, the data on early clinical signs are highly heterogeneous, as they cover a variety of distinct signs with the common objective of evaluating their effectiveness in diagnosing DCM early.

Nevertheless, to the best of available knowledge, this study is the only comprehensive systematic review in the literature that evaluates clinical signs, radiological, and electrophysiological alterations for the early diagnosis of DCM.

Conclusion

DCM exhibits a highly variable clinical, radiographic, and electrophysiological profile, which complicates its diagnosis. This systematic review has brought attention back to clinical evaluations that were previously underused, despite their potential for earlier DCM detection compared to standard clinical signs. DTI shows promise in detecting early degenerative changes in the cervical spine, and its broader use could improve outcomes, reduce long-term costs, and potentially be applied preventively in certain age groups. Additionally, electrophysiological measures, due to their simplicity, accuracy, and non-invasive nature, should be integrated as supplementary diagnostic tools from the preclinical phase of DCM and enhanced by dynamic evaluations. A comprehensive, multi-modal approach to diagnosing DCM should incorporate the tests highlighted in this review to enhance the standard of care for this prevalent and challenging condition.

Footnotes

ORCID iDs

Fabrizio Russo

Giuseppe Francesco Papalia

Gianluca Vadalà

Author Contribution

Conceptualization, F.R., P.B.; methodology, G.F.P., P.B., F.R., P.F.; validation, F.R., G.F.P. R.P., G.V., V.D.; formal analysis, G.F.P., P.B. and P.F.; investigation, P.B., P.F., G.F.P.; data curation, G.F.P, P.B., N.F., P.F.; writing—original draft preparation, P.B., G.F.P., F.R., N.F.; writing—review and editing, F.R., G.F.P.; visualization, R.P., V.D.; supervision, G.V., R.P. and V.D.; project administration, R.P. and V.D.; funding acquisition, R.P., and V.D. All authors have read and agreed to the published version of the manuscript.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

References

Iyer

Azad

Tharin

. Cervical spondylotic myelopathy. Clin Spine Surg. 2016;29:408-414.

Imajo

Kanchiku

Suzuki

, et al. Assessment of spinal cord relative vulnerability in C4–C5 compressive cervical myelopathy using multi-modal spinal cord evoked potentials and neurological findings. J Spinal Cord Med. 2021;44:541-548.

Lohnert

Látal

. [Cervical spondylotic myelopathy]. Bratisl Lek Listy. 1995;96:395-400.

Northover

Wild

Braybrooke

Blanco

. The epidemiology of cervical spondylotic myelopathy. Skelet Radiol. 2012;41:1543-1546.

Al-Ryalat

Saleh

Mahafza

Samara

Ryalat

Al-Hadidy

. Myelopathy associated with age-related cervical disc herniation: a retrospective review of magnetic resonance images. Ann Saudi Med. 2017;37:130-137.

Stoffman

Roberts

King

. Cervical spondylotic myelopathy, depression, and anxiety: a cohort analysis of 89 patients. Neurosurgery. 2005;57:307-313.

Lubelski

Alvin

Nesterenko

, et al. Correlation of quality of life and functional outcome measures for cervical spondylotic myelopathy. J Neurosurg Spine. 2016;24:483-489.

Bisson

Mummaneni

Michalopoulos

, et al. Sleep disturbances in cervical spondylotic myelopathy: prevalence and postoperative Outcomes-an analysis from the quality outcomes database. Clin Spine Surg. 2023;36:112-119.

Hejrati

Pedro

Alvi

Quddusi

Fehlings

. Degenerative cervical myelopathy: where have we been? Where are we now? Where are we going? Acta Neurochir. 2023;165:1105-1119.

10.

Tamai

Suzuki

Terai

, et al. Improvement in patient mental well-being after surgery for cervical spondylotic myelopathy. Spine. 2020;45:E568-E575.

11.

Moghaddamjou

Wilson

JRF

Martin

Gebhard

Fehlings

. Multidisciplinary approach to degenerative cervical myelopathy. Expert Rev Neurother. 2020;20:1037-1046.

12.

Davies

Phillips

Clarke

, et al. Establishing the socio-economic impact of degenerative cervical myelopathy is fundamental to improving outcomes [AO spine RECODE-DCM research priority number 8]. Glob Spine J. 2022;12:122S-129S.

13.

Toledano

Bartleson

. Cervical spondylotic myelopathy. Neurol Clin. 2013;31:287-305.

14.

Al-Mefty

Harkey

Middleton

Smith

Fox

. Myelopathic cervical spondylotic lesions demonstrated by magnetic resonance imaging. J Neurosurg. 1988;68:217-222.

15.

Nouri

Martin

Mikulis

Fehlings

. Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques. Neurosurg Focus. 2016;40:E5.

16.

Tachibana

Oichi

Kato

, et al. Spinal cord swelling in patients with cervical compression myelopathy. BMC Musculoskelet Disord. 2019;20:284.

17.

Ahmadli

Ulrich

Yuqiang

Nanz

Sarnthein

Kollias

. Early detection of cervical spondylotic myelopathy using diffusion tensor imaging: experiences in 1.5-tesla magnetic resonance imaging. NeuroRadiol J. 2015;28:508-514.

18.

Mayfield

. Cervical spondylotic radiculopathy and myelopathy. Adv Neurol. 1979;22:307-321.

19.

Pan

Chen

Peng

Ling

Zou

. Application of electrophysiological measures in degenerative cervical myelopathy. Front Cell Dev Biol. 2022;10:834668.

20.

Bednarik

Kadanka

Dusek

, et al. Presymptomatic spondylotic cervical myelopathy: an updated predictive model. Eur Spine J. 2008;17:421-431.

21.

Madonick

. Statistical control studies in neurology. III. The Hoffman sign. AMA Arch Neurol Psychiatry. 1952;68:109-115.

22.

van Gijn

. The Babinski reflex. Postgrad Med J. 1995;71:645-648.

23.

Khare

Seth

. Lhermitte’s sign: the current status. Ann Indian Acad Neurol. 2015;18:154-156.

24.

Tetreault

Kalsi-Ryan

Davies null

, et al. Degenerative cervical myelopathy: a practical approach to diagnosis. Glob Spine J. 2022;12:1881-1893.

25.

, et al. Quantitative assessment of postural stability in individuals with degenerative cervical myelopathy compared with healthy controls. J Neurosurg Spine. 2025;42:551-560.

26.

Denno

Meadows

. Early diagnosis of cervical spondylotic myelopathy. A useful clinical sign. Spine. 1991;16:1353-1355.

27.

Hosono

Makino

Sakaura

Mukai

Fuji

Yoshikawa

. Myelopathy hand: new evidence of the classical sign. Spine. 2010;35:E273-E277.

28.

Chaiyamongkol

Laohawiriyakamol

Tangtrakulwanich

Tanutit

Bintachitt

Siribumrungwong

. The significance of the trömner sign in cervical spondylotic myelopathy patient. Clin Spine Surg. 2017;30:E1315-E1320.

29.

Wazir

Kareem

. New clinical sign of cervical myelopathy: Wazir hand myelopathy sign. Singapore Med J. 2011;52:47-49.

30.

Yukawa

Kato

Ito

, et al. ‘Ten second step test’ as a new quantifiable parameter of cervical myelopathy. Spine. 2009;34:82-86.

31.

Chang

C-W

Chang

K-Y

Lin

S-M

. Quantification of Rossolimo reflexes: a sensitive marker for spondylotic myelopathy. Spinal Cord. 2011;49:211-214.

32.

Özkan

Chihi

Schoemberg

, et al.

First neurological symptoms in degenerative cervical myelopathy: does it predict the outcome?

Eur Spine J. 2022;31:327-333.

33.

Cook

Brown

Isaacs

Roman

Davis

Richardson

. Clustered clinical findings for diagnosis of cervical spine myelopathy. J Man Manip Ther. 2010;18:175-180.

34.

Raju

Hauer

Jalloh

, et al. Subclinical knee extensor weakness predicts gait and balance impairment in degenerative cervical myelopathy. GeroScience. 2025;47:6765-6776.

35.

Zhang

Yakdan

Kaleem

, et al. Spinal cord metrics derived from diffusion MRI: improvement in prognostication in cervical spondylotic myelopathy compared with conventional MRI: presented at the 2024 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves. J Neurosurg Spine. 2024;41:639-647.

36.

Banaszek

Bladowska

Szewczyk

Podgórski

Sąsiadek

. Usefulness of diffusion tensor MR imaging in the assessment of intramedullary changes of the cervical spinal cord in different stages of degenerative spine disease. Eur Spine J. 2014;23:1523-1530.

37.

Hori

Okubo

Aoki

Kumagai

Araki

. Line scan diffusion tensor MRI at low magnetic field strength: feasibility study of cervical spondylotic myelopathy in an early clinical stage. J Magn Reson Imaging. 2006;23:183-188.

38.

Mostafa

NSA-A

Hasanin

OAM

Al Yamani Moqbel

EAH

Nagy

. Diagnostic value of magnetic resonance diffusion tensor imaging in evaluation of cervical spondylotic myelopathy. Egyptian Journal of Radiology and Nuclear Medicine. 2023;54:175.

39.

Demir

Ries

Moonen

CTW

, et al. Diffusion-weighted MR imaging with apparent diffusion coefficient and apparent diffusion tensor maps in cervical spondylotic myelopathy. Radiology. 2003;229:37-43.

40.

Kara

Celik

Karadereler

, et al. The role of DTI in early detection of cervical spondylotic myelopathy: a preliminary study with 3-T MRI. Neuroradiology. 2011;53:609-616.

41.

Nischal

Tripathi

Singh

. Quantitative evaluation of the diffusion tensor imaging matrix parameters and the subsequent correlation with the clinical assessment of disease severity in cervical spondylotic myelopathy. Asian Spine J. 2021;15:808-816.

42.

Kerkovský

Bednarík

Dušek

, et al. Magnetic resonance diffusion tensor imaging in patients with cervical spondylotic spinal cord compression: correlations between clinical and electrophysiological findings. Spine. 2012;37:48-56.

43.

Funaba

Imajo

Suzuki

, et al. Radiological factors associated with the severity of corticospinal tract dysfunctions for cervical spondylotic myelopathy: an analysis of the central motor conduction time and kinematic CT myelography. J Clin Neurosci. 2021;94:24-31.

44.

Chang

Jeon

Kim

. Diagnostic and prognostic significance of preoperative evoked potential tests in degenerative cervical myelopathy. Spine J. 2024;24:87-93.

45.

Bednarík

Kadanka

Vohánka

, et al. The value of somatosensory and motor evoked evoked potentials in pre-clinical spondylotic cervical cord compression. Eur Spine J. 1998;7:493-500.

46.

Bednarik

Kadanka

Dusek

, et al. Presymptomatic spondylotic cervical cord compression. Spine. 2004;29:2260-2269.

47.

Yoon

Park

Eun

, et al. The cutoff value of ossification of posterior longitudinal ligament (OPLL) for early diagnosis of myelopathy using somatosensory evoked potential in cervical OPLL patients. Spinal Cord. 2017;55:606-611.

48.

Masur

Elger

Render

Fahrendorf

Ludolph

. Functional deficits of central sensory and motor pathways in patients with cervical spinal stenosis: a study of SEPs and EMG responses to non-invasive brain stimulation. Electroencephalogr Clin Neurophysiol. 1989;74:450-457.

49.

Kameyama

Shibano

Kawakita

Ogawa

. Transcranial magnetic stimulation of the motor cortex in cervical spondylosis and spinal canal stenosis. Spine. 1995;20:1004-1010.

50.

Huang

Ling

, et al. A new diagnostic medium for cervical spondylotic myelopathy: dynamic somatosensory evoked potentials. World Neurosurg. 2020;133:e225-e232.

51.

Seif

David

Huber

Vallotton

Curt

Freund

. Cervical cord neurodegeneration in traumatic and non-traumatic spinal cord injury. J Neurotrauma. 2020;37:860-867.

52.

ElFiky

Bessada

Stienen

Siam

Hasan

. Endplate and facet joint changes in cervical spondylotic myelopathy. World Neurosurg. 2023;175:e361-e366.

53.

Berberat

Andereggen

Gruber

Hausmann

Reza Fathi

Remonda

. A diagnostic biomarker for cervical myelopathy based on dynamic magnetic resonance imaging. Spine. 2023;48:1041-1046.

54.

Park

W-T

Min

W-K

Shin

J-H

, et al. High reliability and accuracy of dynamic magnetic resonance imaging in the diagnosis of cervical Spondylotic myelopathy: a multicenter study. BMC Musculoskelet Disord. 2022;23:1107.

55.

Freund

Boller

Emmenegger

, et al. Quantifying neurodegeneration of the cervical cord and brain in degenerative cervical myelopathy: a multicentre study using quantitative magnetic resonance imaging. Euro J of Neurology. 2024;31:e16297.

56.

Morishita

Maeda

Ueta

Naito

Shiba

. Dynamic somatosensory evoked potentials to determine electrophysiological effects on the spinal cord during cervical spine extension: clinical article. J Neurosurg Spine. 2013;19:288-292.

57.

Tavy

Franssen

Keunen

Wattendorff

Hekster

Van Huffelen

. Motor and somatosensory evoked potentials in asymptomatic spondylotic cord compression. Muscle Nerve. 1999;22:628-634.

58.

Simó

Szirmai

Arányi

. Superior sensitivity of motor over somatosensory evoked potentials in the diagnosis of cervical spondylotic myelopathy. Eur J Neurol. 2004;11:621-626.

59.

Thelen

Ross

Tall

. Cervical myelopathy: diagnosing another great impostor. US Army Med Dep J 2014;31-38.

60.

Clarke

Robinson

. Cervical myelopathy: a complication of cervical spondylosis. Brain. 1956;79:483-510.

61.

Houten

Shahsavarani

Verma

. The natural history of degenerative cervical myelopathy. Clin Spine Surg. 2022;35:396-402.

62.

Witiw

Smieliauskas

Fehlings

. Health economics and the management of degenerative cervical myelopathy. Neurosurg Clin N Am. 2018;29:169-176.

63.

Smith

Stewart

Davies

Kotter

MRN

. The prevalence of asymptomatic and symptomatic spinal cord compression on magnetic resonance imaging: a systematic review and meta-analysis. Glob Spine J. 2021;11:597-607.

64.

Lawrence

Jacobs

Norvell

Hermsmeyer

Chapman

Brodke

. Anterior versus posterior approach for treatment of cervical spondylotic myelopathy: a systematic review. Spine. 2013;38:S173-S182.

65.

El-Hajj

Staartjes

Charalampidis

, et al. Patient-reported outcome measures and satisfaction after laminectomy for degenerative cervical myelopathy in octogenarians: an observational study from the national Swedish spine registry. Eur Spine J. 2025;34:3003-3011.

66.

Gallagher

Taghlabi

Bondar

Saifi

. Degenerative cervical myelopathy: a concept review and clinical approach. Clin Spine Surg. 2024;37:1-8.

67.

Dalitz

Vitzthum

H-E

. Evaluation of five scoring systems for cervical spondylogenic myelopathy. Spine J. 2019;19:e41-e46.

68.

Benzel

Lancon

Kesterson

Hadden

. Cervical laminectomy and dentate ligament section for cervical spondylotic myelopathy. J Spinal Disord. 1991;4:286-295.

69.

Jiang

Davies

Zipser

, et al. The value of clinical signs in the diagnosis of Degenerative Cervical Myelopathy - a Systematic review and meta-analysis. Glob Spine J. 2024;14:1369-1394.

70.

Lancet . Myelopathy hand. 1987;2:721-722.

71.

Meoded

Huisman

TAGM

. Diffusion tensor imaging of brain malformations: exploring the internal architecture. Neuroimaging Clin N Am. 2019;29:423-434.

72.

Podwalski

Szczygieł

Tyburski

Sagan

Misiak

Samochowiec

. Magnetic resonance diffusion tensor imaging in psychiatry: a narrative review of its potential role in diagnosis. Pharmacol Rep. 2021;73:43-56.

73.

Mamata

Jolesz

Maier

. Apparent diffusion coefficient and fractional anisotropy in spinal cord: age and cervical spondylosis-related changes. J Magn Reson Imaging. 2005;22:38-43.

74.

Zhao

Chen

Fang

Zhang

. Diffusion tensor magnetic resonance imaging of white matter integrity in patients with HIV-associated neurocognitive disorders. Ann Transl Med. 2020;8:1314.

75.

Ouyang

Zhang

Hong

Ouyang

Meng

. A meta-analysis of the role of diffusion tensor imaging in cervical spinal cord compression. J Neuroimaging. 2023;33:493-500.

76.

Al-Shaari

Fulford

Heales

. A systematic review of repeatability and reproducibility studies of diffusion tensor imaging of cervical spinal cord. Br J Radiol. 2023;96:20221019.

77.

Hilton

Tempest-Mitchell

Davies

Kotter

. Route to diagnosis of degenerative cervical myelopathy in a UK healthcare system: a retrospective cohort study. BMJ Open. 2019;9:e027000.

78.

Penning

van der Zwaag

. Biomechanical aspects of spondylotic myelopathy. Acta Radiol Diagn. 1966;5:1090-1103.

79.

Bohlman

Emery

. The pathophysiology of cervical spondylosis and myelopathy. Spine. 1988;13:843-846.

80.

Joaquim

Baum

Tan

Riew

. Dynamic cord compression causing cervical myelopathy. Neurospine. 2019;16:448-453.

81.

Sakamoto

Funaba

Imajo

, et al. The impact of anterior spondylolisthesis and kyphotic alignment on dynamic changes in spinal cord compression and neurological status in cervical spondylotic myelopathy: a radiological analysis involving kinematic CT myelography and multimodal spinal cord evoked potentials. Spine. 2021;46:72-79.

82.

Dvorak

Sutter

Herdmann

. Cervical myelopathy: clinical and neurophysiological evaluation. Eur Spine J. 2003;12(Suppl 2):S181-S187.

83.

Nardone

Höller

Brigo

, et al. The contribution of neurophysiology in the diagnosis and management of cervical spondylotic myelopathy: a review. Spinal Cord. 2016;54:756-766.

84.

Badhiwala

Ahuja

Akbar

, et al. Degenerative cervical myelopathy - update and future directions. Nat Rev Neurol. 2020;16:108-124.

85.

Travlos

Pant

Eisen

. Transcranial magnetic stimulation for detection of preclinical cervical spondylotic myelopathy. Arch Phys Med Rehabil. 1992;73:442-446.

86.

Jutzeler

Rosner

Rinert

Kramer

JLK

Curt

. Normative data for the segmental acquisition of contact heat evoked potentials in cervical dermatomes. Sci Rep. 2016;6:34660.

87.

Jutzeler

Ulrich

Huber

Rosner

Kramer

JLK

Curt

. Improved diagnosis of cervical spondylotic myelopathy with contact heat evoked potentials. J Neurotrauma. 2017;34:2045-2053.

88.

Scheuren

Hupp

Pfender

, et al. Contact heat evoked potentials reveal distinct patterns of spinal cord impairment in degenerative cervical myelopathy beyond MRI lesions. Eur J Neurol. 2025;32:e70001.