A dominant bursting electromyograph pattern in dystonic conditions predicts an early response to pallidal stimulation.
Although chronic pallidal deep brain stimulation (DBS) is effective in the treatment of medically intractable dystonia, there is no way of predicting the variations in clinical outcome, partly due to our limited understanding of the pathophysiological mechanisms underlying this condition. We recorded electromyographic (EMG) activity from the most severely affected muscle groups in seven dystonia patients before and after pallidal DBS. Patient EMG recordings could be classified into two groups: one consisting of patients who at rest demonstrated a dominant low frequency component of activity on power spectral analysis (ranging from 2 to 5 Hz), and one group in which this dominant pattern was absent. Early postoperative improvements (within 2-3 days) were observed in the former group, whereas the latter group benefited more gradually (over several months). Analysis of EMG activity may provide a sensitive means of identifying dystonic patients who are likely to be most responsive to functional neurosurgical intervention.
Yianni
John
J
Oxford Movement Disorder Group, Department of Neurological Surgery, Radcliffe Infirmary, Oxford, OX2 6HE, UK.
Wang
Shou Yan
SY
Liu
Xuguang
X
Bain
Peter G
PG
Nandi
Dipankar
D
Gregory
Ralph
R
Joint
Carole
C
Stein
John F
JF
Aziz
Tipu Z
TZ
D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D004421:Dystonia / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D004599:Electric Stimulation Therapy / Q000379:methods*; D004576:Electromyography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005917:Globus Pallidus / Q000528:radiation effects*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D011237:Predictive Value of Tests; D013997:Time Factors