Predictive value of motor-evoked potentials for motor recovery in patients with hemiparesis secondary to acute ischemic stroke

Figures & data

Figure 1. Study flow chart. MEP: motor-evoked potential; ICU: intensive care unit.

Table 1. Clinical characteristics of all patients with stroke.

	Total (n = 61)	Range
Age (years)	66.2 (9.4)	(43–84)
Sex (male)	32 (52.5%)
First visit day^a	6.7 (1.8)	(2–10)
Smoking	21 (34.4%)
Drinking	7 (11.5%)
BMI (kg/m^2)	25.6 (3.7)	(17.2–33.4)
Comorbidity
Hypertension	50 (82.0%)
Diabetic mellitus	26 (42.6%)
Transient ischemic attack	1 (1.6%)
Dyslipidemia	46 (75.4%)
Atrial fibrillation	7 (11.5%)
Myocardial infarction	1 (1.6%)
Chronic renal disease	3 (4.9%)
Chronic liver disease	2 (3.3%)
COPD	4 (6.6%)
Stroke Location
Cortex	10 (16.4%)
Subcortex	34 (55.7%)
Brain stem	17 (27.9%)
TOAST classification
Large artery	11 (18.0%)
Small vessel	16 (26.2%)
Cardioembolism	6 (9.8%)
Cryptogenic	28 (45.9%)
NIH Stroke Scale (NIHSS)	6.9 (3.7)	(2–18)
Fugl-Meyer assessment score	25.9 (18.7)	(4–65)
MEP+	35.9 (18.2)	(8–65)
MEP−	13.2 (9.2)	(4–38)

Category variable: n (percentage), Continuous variable: mean (standard deviation) and range.

^a Time interval (days) between stroke onset and first visit.

COPD: chronic obstructive pulmonary disease; NIH: National Institutes of Health; BMI: body mass index; MEP: motor-evoked potential.

Figure 2. Fugl-Meyer Assessment (FMA) score and proportional recovery over time in the two groups. T1: ≤10 day after stroke, T2: 30-day after stroke, T3: 90-day after stroke. *p < 0.05, **p < 0.001

Table 2. Clinical characteristics of patients with stroke with an initial FMA score of ≤38 (group A) or >38 (group B).

	Group A (n = 42)			Group B (n = 19)
	MEP+ (n = 15)	MEP– (n = 27)	p
Age (years)	71.1 (8.2)	65.0 (9.3)	.040	64.0 (9.7)
Sex (male)	8 (53.3%)	15 (55.6%)	.890	9 (47.4%)
Smoking	5 (33.3%)	10 (37.0%)	.810	6 (31.6%)
Drinking	0 (0.0%)	4 (14.8%)	.279^a	3 (15.8%)
BMI (kg/m^2)	25.2 (2.3)	25.3 (3.8)	.934	26.2 (4.6)
Comorbidity
Hypertension	11 (73.3%)	21 (77.8%)	1.00^a	18 (94.7%)
Diabetic mellitus	5 (33.3%)	13 (48.1%)	.353	8 (42.1%)
Dyslipidemia	10 (66.7%)	21 (77.8%)	.481^a	15 (78.9%)
Atrial fibrillation	2 (13.3%)	2 (7.4%)	.608^a	3 (15.8%)
Myocardial infarction	1 (6.7%)	0 (0.0%)	.357^a	0 (0.0%)
Chronic renal disease	0 (0.0%)	0 (0.0%)		3 (15.8%)
Chronic liver disease	0 (0.0%)	1 (3.7%)	1.00^a	1 (5.3%)
COPD	3 (20.0%)	1 (3.7%)	.122^a	0 (0.0%)
Stroke location			.558
Cortex	1 (6.7%)	5 (18.5%)		4 (21.1%)
Subcortex	9 (60.0%)	15 (55.6%)		10 (52.6%)
Brain stem	5 (33.3%)	7 (25.9%)		5 (26.3%)
TOAST classification			.260
Large artery	4 (26.7%)	2 (7.4%)		5 (26.3%)
Small vessel	4 (26.7%)	5 (18.5%)		7 (36.8%)
Cardioembolism	1 (6.7%)	2 (7.4%)		3 (15.8%)
Cryptogenic	6 (40.0%)	18 (66.7%)		4 (21.1%)
NIH Stroke Scale (NIHSS)	7.0 (2.6)	8.8 (4.1)	.140	4.3 (1.6)
Initial FMA score	17.9 (9.2)	13.2 (9.2)	.122	50.1 (7.5)

Category variable: n (percentage), Continuous variable: mean (standard deviation).

Student’s t-tests for comparison of continuous variables and chi-square tests (or Fisher’s exact tests) for comparison of categorical variables between MEP + and MEP- patients in group A.

COPD: chronic obstructive pulmonary disease; FMA: Fugl-Meyer assessment; BMI: body mass index, NIH: National Institutes of Health.

^a Fisher’s exact test.

Table 3. Motor recovery after a stroke at different time points.

	Group A		Group B
Post-stroke	MEP (+)	MEP (–)	MEP (+)
FMA score
≤10 day	17.9 (9.2)	13.2 (9.2)	50.1 (7.5)
30 days	41.1 (15.1)	24.9 (18.4)	60.4 (4.8)
90 days	52.3 (12.3)	36.8 (21.9)	63.9 (2.9)
Proportional recovery (%)
≤10 days	0	0	0
30 days	51.3 (24.1)	25.6 (26.5)	65.2 (27.0)
90 days	73.4 (22.9)	49.0 (35.8)	83.7 (24.6)

Mean (standard deviation).

MEP: motor-evoked potential; FMA: Fugl-Meyer assessment.

Table 4. Comparison of FMA score and proportional recovery at different time points between MEP + and MEP- patients in group A.

	T1	T2	T3	Wald X^2,a	Post-hoc test
FMA score
MEP (+)	17.9 (9.2)	41.1 (15.1)	52.3 (12.3)	175.72**	T1 < T2,T1 < T3,T2 < T3
MEP (−)	13.2 (9.2)	24.9 (18.4)	36.8 (21.9)	61.26**	T1 < T2,T1 < T3,T2 < T3
Wald X^2,b		9.13*	4.09*
Proportional recovery (%)
MEP (+)	0	51.3 (24.1)	73.4 (22.9)	209.11**	T1 < T2,T1 < T3,T2 < T3
MEP (−)	0	25.6 (26.5)	49.0 (35.8)	58.57**	T1 < T2,T1 < T3,T2 < T3
Wald X^2,b		13.90**	7.84*

T1: ≤10 days after stroke, T2: 30 days after stroke, T3: 90 days after stroke.

^a GEE of simple time (T1, T2, T3) effect.

^b GEE of simple group (MEP+, MEP-) effect.

* p < 0.05, **p < 0.001.

MEP: motor-evoked potential; GEE: generalized estimating equation; FMA: Fugl-Meyer assessment.

Table 5. Analysis of good functional outcome (mRS ≤1) at 90-day after stroke.

	mRS ≤ 1	mRS > 1	Adjusted OR^a	95% CI (lower-upper)	p
Group A	8 (19.0%)	34 (81.0%)			-
MEP+	4 (26.7%)	11 (73.3%)	9.08	0.92-89.95	0.059
MEP−	4 (14.8%)	23 (85.2%)	Reference	-	-
Group B	10 (52.6%)	9 (47.4%)

^a Adjusted variables: age.

OR: odds ratio; mRS: modified Rankin scale; MEP: motor-evoked potential; CI: confidence interval.

Data availability statement

The data that support the findings of this study are available from the corresponding author, Dr. Ching-Huang Lin, upon reasonable request.