Associated reaction and spasticity among patients with stroke.
OBJECTIVE
The objectives were to investigate the relationship between associated reaction (AR) and clinical spasticity in the paretic arm.


METHODS
The participants were ten patients with hemiparetic stroke, mean age of 65.2 yrs, and duration of stroke of 13.3 mos. The AR of the hemiparetic arm was analyzed with surface EMG, and AR ratio was calculated on the basis of comparison of the surface amplitude of the affected side to that of the nonaffected side. Simultaneously, we measured M-, H-, and T-wave amplitudes and calculated H/M and T/M in the paretic arm. The AR ratio, H/M, and T/M were compared with spasticity as assessed with the modified Ashworth scale (MAS). We repeated the same measurements after median nerve block to examine its effects on the parameters.


RESULTS
The AR ratio correlated significantly with MAS (P < 0.01), whereas H/M and T/M did not. Median nerve block did not alter these relationships.


CONCLUSIONS
AR, which could be elicited easily in patients with spastic hemiparesis, correlated strongly with spasticity, both before and after the median nerve block. However, the so-called monosynaptic reflex (H- and T reflexes) did not correlate significantly with spasticity. These results indicate that AR and spasticity partially share common pathways.
Keio University Tsukigase Rehabilitation Center, Shizuoka, Japan.
Kaoru
K
Honaga
Yoshihisa
Y
Masakado
Tomomi
T
Oki
Yukiko
Y
Hirabara
Toshiyuki
T
Fujiwara
Tetsuo
T
Ota
Akio
A
Kimura
Meigen
M
Liu
D000328:Adult; D000368:Aged; D020820:Dyskinesias / Q000209:etiology / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve; D008875:Middle Aged; D009128:Muscle Spasticity / Q000209:etiology / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000294:innervation*; D009407:Nerve Block; D009434:Neural Pathways; D010291:Paresis / Q000150:complications* / Q000534:rehabilitation; D012023:Reflex, Monosynaptic; D018709:Statistics, Nonparametric; D020521:Stroke / Q000150:complications*; D000071939:Stroke Rehabilitation