[Abstract Title]. - Society for Neuroscience

Poster
276. Voluntary Movement: Stroke, Damage, or Disease
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 276.2/KK12
Topic: D.17.a. Kinematics and muscle activity
Support: NIH Grant HD050123
VA Grant VA-B37091
VA Grant VA-B2801R
VA Grant VA-3790R
Title: EMG coupling between synergist muscles is functionally relevant in patients post stroke
Authors: K. KISIEL-SAJEWICZ 1,3 , Y. FANG 1 , V. SIEMIONOW 1 , J. J. DALY 4 , V.
SAHGAL 2 , *G. H. YUE 1 ;
1 Dept Biomed Engineer/ND20, 2 Physical Med. and Rehabil., Cleveland Clin. Fndtn, Cleveland,
OH; 3 Dept. of Kinesiology, Univ. Sch. of Physical Educ. in Wroclaw, Wroclaw, Poland;
4 Depatment of Res., Cleveland VA Med. Ctr., Cleveland, OH
Abstract: AIM: A reaching movement toward a front target consists primarily of shoulder
flexion and elbow extension. It has been shown that in patients post-stroke, coordination of the
shoulder flexor and elbow extensor muscles during a reaching movement is impaired and that
contributes to poorly performed reaching. Coherence is a measure of strength of functional
coupling between two signals on frequency domain. We hypothesized that a potential
mechanism behind poor coordination in reaching in stroke patients was weakened coupling
(measured by coherence) between EMG signals of the shoulder flexor and elbow extensor.
METHODS: Twenty one stroke patients (59.6±8.6 years) and eight healthy controls (60.6±6.3
years) participated in the study. The subjects performed a reaching task of the affected (patients)
and dominant (controls) arm. Surface EMG from the anterior deltoid (ATD) and triceps brachii
(TB) muscles and force were measured during the task. Coherence between EMG signals of the
two muscles as a function of movement time was calculated to determine if functional coupling
between the two synergists in stroke patients was weakened. Correlation between the coherence
and force variation (standard deviation [SD] of the mean force) was evaluated.
RESULTS: Coherence between EMGs of the ATD and TB during the reaching movement was
significantly lower in stroke compared to healthy subjects at a frequency range 0-13Hz (Table 1).
In this frequency range a significant negative correlation (P