Corrigendum to: Murakami et al. (2023)

Abstract – Methods

We clarified the primary outcome in the first sentence of the Methods section as follows: "The primary outcome was the total score of the Fugl-Meyer Assessment of Upper Extremity motor function (FMA total)."

Abstract – Results

To clearly indicate that most results reflect within-group comparisons, we revised this section as follows: "Within-group differences showed that FMA total was significantly improved at both post-intervention (P = .011) and 4 weeks post-intervention (P = .021) in the active group. The control group did not show significant improvement in FMA total at the post-intervention time point. In the active group, MAL-14 AOU scores improved significantly at the post intervention time point (P = .03). Also in the active group, wrist MAS scores improved significantly at both post-intervention (P = .024) and 4 weeks post-intervention (P = .026). No statistically significant between-group differences were found in the changes in FMA total, MAL-14 AOU, or MAS."

Methods

Outcome Measures, Clinical Assessments section (page 300)

“As a primary outcome, upper extremity motor function was assessed using the total score of the Fugl-Meyer Assessment of Upper Extremity motor score (FMA total).”

Data Analysis (page 301)

"Post hoc analyses were conducted to evaluate both within-group and between-group effects. Paired t-tests were used for normally distributed outcomes, and Wilcoxon signed-rank tests were used for non-normally distributed outcomes, based on the Shapiro–Wilk test. Between-group comparisons of change scores were conducted using the Mann–Whitney U test."

Results

Due to the small sample size and to address concerns about statistical power and transparency:

"We found no significant between-group differences in changes in FMA total from baseline to post or baseline to post-4w, as assessed by Mann–Whitney U tests."

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Table 1R.

Clinical details of participants.

		Active group											Control group
Characteristics		1	2	3	4	5	6	7	8	9	10	11	1	2	3	4	5	6	7	8	9	P values
Age (years)		40	46	58	59	61	41	50	44	53	36	66	51	58	25	58	48	60	42	46	60	0.882
Gender (male/female)		female	male	female	male	female	male	female	male	male	male	male	male	male	female	male	male	male	male	female	male	0.642
Type of stroke (ischemic/hemorrhagic)		CI	CH	CI	CH	CH	CH	CH	CH	CH	CH	CI	CH	CH	CH	CH	CH	CH	CH	CI	CI	1.000
Hemiparetic side (right/left)		left	right	left	left	right	left	right	left	left	right	right	right	right	right	left	right	left	left	left	right	1.000
Time from stroke onset (days)		851	2970	720	3835	1548	730	3643	634	271	344	4286	3430	233	3940	3669	213	780	437	204	1096	0.503
FMA	Total	39	41	23	52	50	23	37	27	26	52	40	44	19	31	53	61	30	58	18	56	0.456
A. Shoulder/Elbow/Forearm		26	26	9	28	32	13	24	17	14	29	27	23	11	18	31	34	19	33	11	33	0.603
B. Wrist		0	3	0	8	6	0	3	0	0	6	1	6	0	0	4	9	1	9	0	6	0.412
C. Hand		8	8	10	11	8	6	6	6	8	12	7	10	6	9	13	13	6	10	3	12	0.412
D. Coordination/Speed		5	4	4	5	4	4	4	4	4	5	5	5	2	4	5	5	4	6	4	5	0.552
MAL-14 AOU		0.5833	0.5714	0.0000	0.7500	0.5714	0.1667	0.5714	0.0000	0.2500	0.4286	0.0714	0.0000	0.0000	0.4286	0.5833	0.4286	0.2000	1.2000	0.1667	1.5000	0.882
MAS
Elbow		1	1+	1	1+	1+	1+	2	2	2	2	1	1+	2	2	1+	1	2	1	0	1+	0.766
Wrist		1	1+	0	0	2	2	0	2	2	2	1	1	2	1+	2	1	2	1+	0	1+	0.882
Finger		1	1	1	1+	2	2	1+	2	1+	2	1	1	2	2	2	0	2	1+	1+	1+	0.710
Hmax/Mmax ratio		0.6944	0.5818	0.2090	0.0880	0.5019	0.9414	0.3696	0.9737	0.7977	0.7463	0.3889	0.2675	0.9328	0.8805	1.5708	0.3455	0.6047	0.5326	1.1028	0.7169	0.370
RI
ISI 0 msec		0.9246	1.0270	0.6087	1.8343	0.2371	0.9749	0.9593	0.2606	0.6196	1.1586	1.4651	1.2523	0.8619	0.2839	0.7354	0.5565	1.7339	0.4960	0.9215	0.1605	0.370
ISI 20 msec		0.9105	1.1486	0.6866	0.7913	0.6579	0.9910	0.5439	0.0947	0.7074	1.0336	0.5013	1.0449	0.9272	0.3271	1.0106	0.5868	1.7669	0.6391	0.4775	0.1831	0.882

The Abbreviations: CI, ischemic; CH, hemorrhagic; Fugl-Meyer Assessment;FMA, Fugl-Meyer Assessment; MAL-14 AOU, motor activity log-14 amount of use; MAS, modified Ashworth scale; RI, reciprocal inhibition; ISI, interstimulus interval.

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Table 2R.

Before, Post, and Post-4w scores of outcome measures in the active and control groups.

		Active group					Control group					Active group - Contrlo group
		Mean difference (95% CI)					Mean difference (95% CI)					Mean difference (95% CI)		P values
		Before	Post	Post-4w	Post - Before	Post-4w - Before	Before	Post	Post-4w	Post - Before	Post-4w - Before	Post - Before	Post-4w - Before	Post - Before	Post-4w - Before
FMA
Total		37.3 ± 11.2	40.6 ± 10.8*	41.8 ± 10.4*	3.36(0.95 to 5.77)	4.55(0.82 to 8.27)	41.1 ± 17.0	43.3 ± 17.8	45.6 ± 16.8*	2.22(-0.57 to 5.01)	3.13(0.43 to 5.82)	1.14(-2.26 to 4.54)	1.42(-3.21 to 6.05)	0.656	0.840
A. Shoulder/Elbow/Forearm		22.3 ± 7.6	24.2 ± 6.6*	25.0 ± 6.3*	1.91(0.33 to 3.48)	2.73(0.73 to 4.72)	23.7 ± 9.4	24.6 ± 8.8	24.8 ± 9.8	0.89(-0.57 to 2.35)	0.50(-0.76 to 1.76)	1.02(-1.02 to 3.06)	2.23(-0.20 to 4.65)	0.230	0.091
B. Wrist		2.5 ± 3.0	2.8 ± 3.1	3.1 ± 2.6	0.36(-0.65 to 1.37)	0.64(-0.42 to 1.69)	3.9 ± 3.8	4.7 ± 4.2	5.5 ± 3.9	0.78(-0.06 to 1.62)	1.25(-0.07 to 2.57)	-0.41(-1.68 to 0.85)	-0.61(-2.16 to 0.93)	0.710	0.442
C. Hand		8.2 ± 2.0	9.2 ± 2.3	9.5 ± 1.9	1.00(-0.20 to 2.20)	1.27(-0.04 to 2.59)	9.1 ± 3.5	10.0 ± 3.8	10.4 ± 2.7	0.89(-0.47 to 2.24)	0.88(-0.34 to 2.09)	0.11(-1.57 to 1.79)	0.40(-1.33 to 2.13)	0.552	0.492
D. Coordination/Speed		4.4 ± 0.5	4.5 ± 0.7	4.3 ± 1.3	0.09(-0.11 to 0.29)	-0.09(-1.01 to 0.83)	4.4 ± 1.1	4.1 ± 1.8	5.0 ± 0.9	-0.33(-0.88 to 0.21)	0.50(-0.13 to 1.13)	0.42(-0.07 to 0.92)	-0.59(-1.73 to 0.55)	0.295	0.492
MAL-14 AOU		0.36 ± 0.27	0.44 ± 0.31*	0.43 ± 0.33	0.08(0.01 to 0.15)	0.07(-0.03 to 0.16)	0.50 ± 0.53	0.63 ± 0.69	0.78 ± 0.54*	0.13(-0.03 to 0.29)	0.24(0.06 to 0.42)	-0.05(-0.20 to 0.10)	-0.17(-0.35 to 0.0007)	0.456	0.062
MAS
Elbow		2.1 ± 0.8	1.6 ± 0.8	1.5 ± 0.9	-0.55(-1.01 to -0.08)	-0.64(-1.09 to -0.18)	1.9 ± 1.1	1.3 ± 1.0	1.1 ± 0.8	-0.56(-0.96 to -0.15)	-0.63(-1.06 to -0.19)	0.10(-0.58 to 0.60)	-0.01(-0.61 to 0.59)	0.882	0.968
Wrist		1.7 ± 1.3	0.9 ± 0.9*	0.8 ± 0.6*	-0.82(-1.41 to -0.23)	-0.91(-1.61 to -0.21)	1.9 ± 1.1	1.4 ± 1.2	1.1 ± 1.0	-0.44(-1.12 to 0.23)	-0.63(-1.51 to 0.26)	-0.37(-1.20 to 0.46)	-0.28(-1.32 to 0.75)	0.456	0.600
Finger		2.0 ± 1.0	0.8 ± 0.9	1.3 ± 0.8	-1.18(-1.84 to -0.52)	-0.73(-1.26 to -0.20)	2.1 ± 1.1	1.8 ± 1.0	1.8 ± 1.0	-0.33(-0.72 to 0.05)	-0.25(-0.84 to 0.34)	-0.85(-1.61 to -0.09)	-0.48(-1.22 to 0.26)	0.056	0.177
H/M ratio		0.57 ± 0.29	0.61 ± 0.30	0.64 ± 0.25	0.04(-0.14 to 0.22)	0.07(-0.06 to 0.20)	0.77 ± 0.40	0.54 ± 0.32*	0.47 ± 0.26*	-0.23(-0.39 to -0.08)	-0.32(-0.67 to 0.03)	0.28(0.05 to 0.50)	0.39(0.09 to 0.69)	0.080	0.004**
RI
ISI 0 msec		0.92 ± 0.48	0.85 ± 0.43	0.80 ± 0.47	-0.07(-0.26 to 0.13)	-0.12(-0.50 to 0.26)	0.78 ± 0.49	0.64 ± 0.23	0.73 ± 0.31	-0.14(-0.57 to 0.29)	0.07(-0.14 to 0.28)	0.07(-0.33 to 0.48)	-0.19(-0.64 to 0.26)	1.000	0.351
ISI 20 msec		0.73 ± 0.29	0.79 ± 0.38	0.81 ± 0.45	0.06(-0.26 to 0.38)	0.08(-0.35 to 0.50)	0.77 ± 0.48	0.89 ± 0.21	0.73 ± 0.42	0.10(-0.35 to 0.56)	0.08(-0.15 to 0.31)	-0.04(-0.54 to 0.45)	-0.003(-0.51 to 0.50)	0.552	0.717

The values are presented as the mean ± standard deviation . Asterisks* indicate significant differences between the baseline (before) and Post or Post-4w by a paired t-test or Wilcoxon signed rank test (*P < .05). ** indicates significant difference btween active group and control group (p<0.01) by Mann-Whitney U test. Abbreviations: FMA, Fugl-Meyer Assessment; MAL-14 AOU, motor activity log-14 amount of use; MAS, modified Ashworth scale; RI, reciprocal inhibition; ISI, interstimulus interval.

Discussion

To better clarify findings regarding interaction effects and the limitations of the study design, the following revisions were made

"Although improvements were observed in the active group, the difference between the active and control groups was not statistically significant. Further research with larger sample sizes is warranted to determine the comparative effectiveness of AI-integrated EMG-driven robotic hand therapy relative to passive robotic interventions."

Additional clarification of ANCOVA interaction terms

“Although a formal interaction between time and group was detected only for the MAL-14 AOU in the ANCOVA analysis, the pattern of within-group improvements in FMA seen in the active group, but not in the control group, suggests a potential time × group interaction that may not have reached statistical significance due to limited sample size and power. These patterns should be interpreted cautiously and explored in future trials.”

Supplementary Material

Tables 1R and 2R, including individual outcome data and between-group differences, are available in the supplementary material to support transparency and reproducibility.

Final Note

We apologize for the lack of clarity in the original reporting of our statistical methods and results. These revisions aim to clarify our approach and improve the interpretability of the findings. The original article has been updated accordingly, and the Journal Editor, alongside consultation with a statistician have confirmed that the overall conclusions still remain.