Abstract
This study, the first retrospective review of data on occupational performance and hand function outcomes after participation in the Lee Silverman Voice Treatment (LSVT) BIG program, support the use of the program to increase functional abilities in people with Parkinson’s disease.
Parkinson’s disease (PD) affects approximately 1 million Americans and more than 10 million people worldwide (American Parkinson’s Disease Association, 2019). PD is characterized by a stereotypical cluster of both motor symptoms, such as bradykinesia, tremors, postural instability, and rigidity, and nonmotor symptoms, such as sleep disturbances and cognitive changes, caused by the loss of dopamine-producing neurons in the basal ganglia (Balestrino & Schapira, 2020). These symptoms reduce people’s ability to perform needed daily tasks and affect their overall quality of life (Sabari et al., 2015). Several controlled human studies have suggested that various forms of movement, exercise, and physical training can produce disease-modifying benefits, such as changes in brain structure, vascularity, and cellular processes, that produce improvements in motor and cognitive function (for a review, see Feng et al., 2020).
A popular clinical treatment model for people with PD is the Lee Silverman Voice Treatment (LSVT) BIG® program, which is administered by trained and certified occupational and physical therapists (Fox et al., 2012). The program incorporates large-amplitude multidirectional exercises that help revise participants’ perception of their own movement. These exercises use maximal-effort movements to override hypokinesia and bradykinesia through repetition and sensory feedback and individualized functional task practice to facilitate translation of skills to successful performance of daily living activities.
Although more than 16,000 occupational and physical therapists throughout the world are trained and certified to deliver LSVT BIG (LSVT Global 2021) and, anecdotally, therapists have reported successful outcomes using this approach, limited empirical evidence exists to validate the effectiveness of LSVT BIG in improving daily functional task performance in people with PD. In addition, many studies have focused on purely motor outcomes limited to gross motor strength, lower extremity movement, balance, or gait. A systematic review of four studies found evidence that gait speeds improved after LSVT BIG participation (McDonnell et al., 2018). A case series of 3 individuals indicated improved balance and gait (Fishel et al., 2020), and a larger retrospective chart review (N = 114) suggested improved dual-task performance in walking and mobility after LSVT BIG (Isaacson et al., 2018). Ebersbach et al. (2015) found that LSVT BIG and a short 2-wk protocol using the same exercises were equally effective in improving gross motor function, Box and Block test scores, and Activities of Daily Living subscale scores on the Unified Parkinson’s Disease Rating Scale.
Few studies have measured occupational performance changes after LSVT BIG. Only one case study (N-of-1) used the Canadian Occupational Performance Measure as an outcome measure; the participant’s perception of performance of and satisfaction with occupations improved after LSVT BIG participation (Henderson et al., 2020).
Even fewer studies have examined hand function outcomes, which are often profoundly affected by tremors or rigidity from the PD process, decreasing effectiveness in completing activities of daily living (ADLs). In two studies, fine motor exercises specifically targeting PD hand symptoms resulted in improved dexterity for ADL tasks (Mateos-Toset et al., 2016; Vanbellingen et al., 2017). However, a study using the Nine-Hole Peg Test found no improvement in dexterity after LSVT BIG participation (Janssens et al., 2014).
Because occupational performance deteriorates in the PD process and is central to the practice of occupational therapy, measurement of occupational performance outcomes can inform practice. Hand function skills are necessary for performance of many occupations; therefore, this evidence is critically needed to advance intervention effectiveness knowledge for the population with PD.
In the current study, we explored the effectiveness of LSVT BIG participation in improving occupational performance and hand function in people with PD. To date, no study has retrospectively examined occupational performance and upper extremity motor outcomes in a cohort of people with PD after participation in an LSVT BIG program. The limited existing literature has focused on gross motor changes and impairments, so a large gap exists regarding upper extremity, fine motor, and occupational performance changes after this intervention.
We chose the retrospective review method as a first step to investigate reported outcomes of an LSVT BIG program. This type of review allows a comprehensive overview and examination of implementation strategies, evaluation tools, clinical logistics, and outcomes obtained from one program. By reviewing records at the facility and gathering data on all patients served, we sought to answer the following research questions: (1) What self-perceived occupational performance issues do people with PD identify? (2) Does participation in LSVT BIG result in changes in self-identified occupational performance and satisfaction? (3) Does participation in LSVT BIG result in changes in hand strength? (4) Does participation in LSVT BIG result in changes in hand dexterity?
Method
Design and Participants
We performed a retrospective record review to explore whether patients who had completed LSVT BIG reported changes in occupational performance and hand function. We used the retrospective chart review guidelines suggested by Vassar and Holzmann (2013) to organize the review. The project was approved as an exempt retrospective record review by the university ethics review board.
The LSVT BIG program was conducted at the outpatient services center of a large metropolitan hospital facility. An occupational therapist (Francine Bienvenu) and a physical therapist, both certified in LSVT BIG delivery and with more than 10 yr of combined clinical experience administering the program, worked with the patients whose charts were included in the review. The occupational therapist had more than 30 yr and the physical therapist more than 40 yr of clinical experience working with diverse neurological populations that included people with PD.
Data Collection
We examined the health records of a convenience sample of all patients who had participated in and completed the 16 LSVT BIG sessions from the inception of the program at the facility in 2012 through the most current completed enrollee at the time the decision was made to conduct the review. Before we examined the charts, the information was deidentified by the treating therapists and designated a numerical code by the investigators so that no identifying patient information was available to the research team, which consisted of the investigators (the authors) and six graduate students.
The investigators supervised the extraction of data by the graduate students following suggested guidelines (Vassar & Holzmann, 2013). The investigators instructed the students in specific methods for the review; as a team they completed the extraction of an initial record and reviewed what constituted appropriate data. Scores from each selected outcome measure were then recorded as a team, with all authors validating the accuracy of the data and coming to full agreement on the final recorded data. The extracted data were then reviewed by a different team member to ensure the accuracy and reliability of the data recorded on the data extraction form; if inconsistencies were found, the investigators corrected for accuracy.
Procedure
Intervention
The LSVT BIG program has been comprehensively described elsewhere (Fox et al., 2012). People with even minimal levels of mobility can participate in LSVT BIG because the component movements can be modified to accommodate individual function and can be performed in sitting or supine. The program emphasizes high-intensity, repetitive, large-amplitude exercises with the limbs to counteract the hypokinesia and bradykinesia typically associated with PD. Examples of exercises using large gross motor movements are (1) reaching to the floor and then toward the ceiling from a seated position and (2) twisting from the torso to each side while standing with legs open wide and arms outstretched.
In addition to the exercises, the program incorporates functional component tasks, such as performing the sit-to-stand movement, and hierarchy tasks specific to participant needs, such as “aggressively” extending the elbow to insert the arm into a shirt to assist with dressing or into the pocket of slacks to retrieve a cellphone. Walking is also a central activity of the program and is always performed according to the LSVT BIG protocol (LSVT Global, 2016), which has participants “overexaggerate” the stride and arm swing; very often this strategy produces a more normalized gait pattern, thereby “recalibrating” their internal kinesthetic feedback. The facility therapists followed a strict protocol for using commonly used occupational therapy and physical therapy outcome measures for LSVT BIG participants.
The LSVT BIG program took place in 1-hr sessions 4×/wk, administered by the occupational therapist 2 days of the week and the physical therapist on the other 2 days, for a total of 16 sessions over 4 wk. Clinical outcomes for each participant were measured twice, on the day they began and on the day they completed the LSVT BIG program. The measures were administered by the two treating therapists as part of standard practice (i.e., before this review was planned); therefore, the treating therapists were not involved in any aspect of the data analysis, which was performed by the investigators.
Outcome Measures
The outcomes we reviewed for this study were occupational performance and satisfaction as measured with the Canadian Occupational Performance Measure (COPM; Law et al., 2019), grip strength as measured by dynamometry, and fine motor dexterity as measured with the Minnesota Manual Dexterity Test (MMDT; Lafayette Instrument, Lafayette, IN). These instruments are a complementary mix of patient-rated (COPM) and therapist-rated (dynamometry, MMDT) measures that detect changes from both a patient-centered and a professional clinical perspective.
The COPM is a semistructured interview occupational therapy practitioners use with clients to review function in the areas of self-care, productivity, and leisure. Together practitioners and clients identify five pertinent occupational performance tasks or challenges. Clients rank each task in order of priority and assign a rating on a scale ranging from 1 (low or poor) to 10 (high or good) indicating how well they perform each task and how satisfied they are with this performance. The psychometric properties of the COPM, including reliability and validity, have been shown to be excellent (Carswell et al., 2004).
Grip strength was measured in both hands using hydraulic analog dynamometers (Jamar, Inc., Chicago, IL) and adhering to the protocol established by the American Society of Hand Therapists (Shechtman & Sindhu, 2011), which includes recording force in pounds over three trials and calculating an average. Dexterity was measured using the MMDT, which consists of a placing test, performed unilaterally with the left and right hands, and a turning test that incorporates bilateral hand use. Participant scores on the turning test were extracted for the record review because of the bilateral nature of the test. This test requires that the patient use both hands to lift, turn, and replace 60 small disks (3.5 cm diameter) into designated holes on the test board as quickly as possible. Performance is scored in number of seconds required to turn and place all of the disks on the board. Two turning tests were conducted for each participant, one starting from the right and moving left and the other starting from the left and moving right. Reported reliability for the turning test is 91% to 95% (Lafayette Instrument, 1998).
Data Analysis
All data were entered into an Excel document and analyzed with SigmaStat (Version 3.5; SYSTAT Software, Chicago, IL). Descriptive statistics and measures of central tendency were calculated for participant demographics and all variables measured. For the first research question (self-perceived occupational performance issues), which yielded qualitative data, terms and phrases from the COPM-identified priority activities were input into Excel spreadsheets and frequencies were calculated. Results were organized into the three COPM categories of self-care, productivity, and leisure. We calculated participants’ average COPM Performance and Satisfaction scores for their top three occupational performance priorities and compared the results from before entering and after completion of the program.
To address the other three research questions, which yielded quantitative data, average bilateral grip strength and MMDT turning test scores were similarly compared before and after program completion. Wilcoxon signed-rank tests were used for all outcomes that included ordinal data and for data that were not normally distributed. Medians and interquartile ranges are reported. An α level of p < .05 was set for statistical significance.
Results
We examined only the charts of patients who completed the LSVT BIG protocol in its entirety (16 sessions). A total of 75 patients were referred for LSVT BIG training during the selected time period. Six patients (8%) began but did not complete the program; these patients self-discharged (n = 2), did not complete the initial evaluation (n = 3), or experienced a fall and did not reenroll (n = 1), leaving 69 charts eligible for review. One chart was excluded because of illegible outcome data and 2 were excluded because of a nondefinitive PD diagnosis; therefore, 66 charts were included in the final review. Of the participants represented in the charts, 74.2% (n = 49) were male and 25.7% female (n = 17), and their average age was 71.6 yr (SD = 7.7, range = 53–84). Average time from diagnosis or onset to enrollment in the LSVT BIG program was 2.7 yr (SD = 3.7). The participants completed an average of 9.0 (SD = 2.3) of the 16 sessions with the occupational therapist and 7.9 (SD = 2.3) sessions with the physical therapist.
Results on the outcome measures before and after the LSVT BIG intervention are reported in Table 1. COPM- identified priority areas showed changes in reported performance levels and satisfaction with performance between the initial day of LSVT BIG intervention and the final day. For participants’ three top-priority occupational challenges, changes on the 10-point Likert scale for Performance and Satisfaction ranged from 3 points to 6 points, indicating statistically significant change; a change of ≥2 points is considered clinically meaningful (Law et al., 2008). Participants also showed significant increases in bilateral grip strength and reductions in time to complete the MMDT disk turning test. Effect sizes for paired data are also reported in Table 1; small (d ≥ 0.20) and moderate (d ≥ 0.50) effects (Ferguson, 2009) were found for all pre–post comparisons.
Outcome Measure Results for Occupational Performance and Satisfaction, Grip Strength, and Fine Motor Dexterity (N = 66)
Note. COPM = Canadian Occupational Performance Measure; MMDT = Minnesota Manual Dexterity Test; Q = quartile.
Cohen’s ds ≥ 0.20 indicate a small effect and ≥ 0.50 indicate a medium effect.
Participants’ occupational performance priority areas were categorized as self-care, productivity, or leisure. Sample goals included “washing feet with independently with left hand,” “putting on my belt independently,” “unloading dishwasher,” “increase activity tolerance,” “increase strength for holding baby,” and “improving brain memory.” Figure 1 shows that of the three priority categories (self-care, productivity, leisure), self-care issues were paramount. Frequently reported self-care issues included handwriting, lower extremity dressing, and manipulating buttons and fasteners. Other problematic areas reported, though less frequently, were difficulty with memory and slowed speed of thinking and processing (see Table 2).
Categories of participants’ top three priorities identified using the Canadian Occupational Performance Measure.
Problem Areas Most Frequently Identified as COPM Priorities 1, 2, and 3
Discussion
To date, only limited research has examined the effectiveness of the LSVT BIG program in improving participant outcomes related to occupational performance (Henderson et al., 2020) and hand function (Mateos-Toset et al., 2016; Vanbellingen et al., 2017). Perhaps the paucity of literature on the program is because research on outcomes after the intervention began only in 2001 (LSVT Global, 2019). Our retrospective chart review is one of the few studies to find that notable occupational performance and hand function changes occurred after participation in LSVT BIG. More specifically, participant-reported performance of and satisfaction with desired tasks increased, and significant improvements in grip strength and dexterity were observed.
The results of this chart review provide valuable evidence that people who participate in LSVT BIG can perceive improvements in their ability to perform desired tasks and in their satisfaction with that performance. Because participation is central to outcomes for people with PD, LSVT BIG may enable and facilitate reengagement in daily living, which can improve overall quality of life (Sabari et al., 2015). Occupational performance is an integral domain of the profession, but little evidence exists that changes in occupational performance are associated with engagement in diagnosis-specific interventions. The findings from this initial study suggest that participation in LSVT BIG can result in improved occupational performance for people with PD; these findings can facilitate more comprehensive intervention effectiveness research moving forward.
Interestingly, the top three priority areas participants identified on the COPM included handwriting, lower extremity dressing, and dressing components (e.g., buttoning, fastening, zipping). Because these tasks are necessary to perform ADLs and thus are within the domain of occupational therapy as defined by the Occupational Therapy Practice Framework: Domain and Process (4th ed.; American Occupational Therapy Association, 2020), this finding confirms that occupational therapy should play a key role in rehabilitation for people with PD.
Our postintervention data show important and novel results, namely that both grip strength and dexterity improved after participation in LSVT BIG. For grip strength, participants moved closer to normative values for their age group and gender (in lb; men, right hand 65.7 [SD = 21.0], to 89.7 [SD = 20.4], left hand 55.0 [SD = 17.0] to 76.8 [SD = 20.3]; women, right hand 42.6 [SD = 11.0] to 55.1 [SD = 10.1], left hand 37.6 [SD = 8.9] to 45.7 [SD = 10.1]; Mathiowetz et al., 1985). With increased grip strength and bilateral dexterity, participants can improve their performance of functional tasks requiring fine motor components, potentially leading to greater performance and satisfaction in the priorities set using the COPM.
Study Limitations
Our study and findings have limitations. The chart review was limited to people who had completed the LSVT BIG program at one local facility. We were provided with a limited data set, and additional demographic information on participants might have shown effects on outcomes. Because this was a retrospective data review, no random assignment or control group existed that would have enabled causality to be more definitively determined. The program was delivered and outcomes collected by two therapists employed at the facility; therefore, outcomes of LSVT BIG at other facilities administered by other therapists may have differing results. Outcomes were reported by the treating therapists, so a degree of rater bias may be present. Because we examined outcomes only of participants who completed the program, the outcomes for people who did not complete the program are unknown and could produce different findings. Although the intervention program and methods are designed to be consistently administered, individual personal characteristics and therapy delivery are variable among therapists and may account for differing outcomes. Additionally, whether results were maintained once participants began an independent home LSVT BIG program is not known and warrants further study.
Implications for Occupational Therapy Practice
The results of this study have the following implications for occupational therapy practice and research: Occupational therapy practitioners should consider the LSVT BIG intervention as a viable option to improve occupational performance in people with PD. The LSVT BIG intervention can result in improvements in hand function, specifically strength and dexterity. More research is needed that explores the effectiveness of LSVT BIG in improving occupational performance using objective, performance-based, therapist-reported measures that corroborate self-reported improvement in daily functional tasks.
Conclusion
Intervention effectiveness research is critically needed in occupational therapy. Studies that validate the effectiveness of a specific therapeutic intervention targeted to a particular patient population are valuable not only in terms of daily practice and patients served, but for reimbursement purposes as well. Our findings from this retrospective chart review are foundational and therefore should be interpreted cautiously, but we believe that the results can be meaningful for future prospective studies.
Footnotes
Acknowledgments
No conflicts of interests or financial or other support exists between LSVT Global, Inc., and the authors of this study. We gratefully acknowledge the significant contributions of several Louisiana State University Health Sciences Center master of occupational therapy students involved in the initial data collection for this study: Brittany Hidalgo, Stephanie Incaprera, Suzanna Keenan, Katie Pecot, Melissa St. Philip, and Emily Wilton.