Turns-amplitude analysis of the electromyographic recruitment pattern following upper motor neuron lesions.
OBJECTIVE
To assess the pattern of motor unit recruitment of weak muscles in upper motor neuron (UMN) lesions.


METHODS
Ten patients underwent turns-amplitude analysis (TAA) on the paretic and healthy brachial biceps muscles, in the acute and subacute stages of hemiparesis. The control group comprised 10 age- and sex-matched subjects.


RESULTS
Although absent in the acute stage, five patients developed a myogenic cloud pattern in their paretic extremities in the subacute stage; which was statistically significant when compared with controls (P = 0.033). Mean amplitude was reduced in both acute and subacute stages of the hemiparesis compared with controls (P = 0.000). The turns/mean amplitude ratio in the subacute stage was increased compared with both the paretic limbs examined in the acute stage (P = 0.000) and to controls (P = 0.000).


CONCLUSIONS
Abnormalities in the recruitment of motor units in UMN lesions give rise to a myogenic cloud pattern in the TAA, which is prominent in the third month after the initial insult. This may result from the increase in motor unit activity, while the recruitment of bigger motor units is still defective.
Cengiz
B
B
Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey.
Kuruoglu
H R
HR
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000503:physiopathology*; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation; D010291:Paresis / Q000503:physiopathology