Clinical and surface EMG characteristics of valproate induced tremors.
OBJECTIVE
To describe the Clinical and Surface EMG characteristics of Valproate induced Tremors. Sodium Valproate is known to produce tremors as a side effect. We analyzed clinical and surface electromyographic characteristics of tremors in epileptic subjects who presented with tremors while on sodium valproate.


METHODS
Neurological examination and surface electromyographic recordings were performed on 20 subjects with sodium valproate induced tremors. Surface electromyographic tremerogram was correlated with clinical presentation of tremors.


RESULTS
This study revealed sodium valproate induced tremors involving primarily upper limbs symmetrically. In the present study, all patients presented with action postural tremors except two, who had tremors in the resting position as well. None of these patients had tremors in goal-directed position. The tremors typically were of high frequency (mean 10 Hz), low amplitude, short burst duration and synchronous burst pattern (Synchronous EMG activity in the agonist and antagonistic muscles).


CONCLUSIONS
Frequency, amplitude, burst duration and burst pattern of sodium valproate induced tremors resembles benign essential tremors on surface electromyographic recordings.
Professor of Neurology, Department of Neurology, G.B.Pant Hospital, New Delhi-110002, India. mmehndi@hotmail.com
M M
MM
Mehndiratta
M
M
Satyawani
S
S
Gupta
G A
GA
Khwaja
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000008:administration & dosage / Q000009:adverse effects*; D004576:Electromyography; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D006225:Hand / Q000503:physiopathology; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012146:Rest / Q000502:physiology; D014202:Tremor / Q000139:chemically induced* / Q000503:physiopathology*; D014635:Valproic Acid / Q000008:administration & dosage / Q000009:adverse effects*
D000927:Anticonvulsants; D014635:Valproic Acid