Reduction of EEG myogenic artifact with botulinum toxin during video-EEG monitoring.
OBJECTIVE
To determine whether EEG myogenic artifact during video-EEG monitoring (VEM) is reduced with targeted scalp botulinum toxin (BTX-A) injections.


METHODS
Twelve consecutive patients scheduled for presurgical VEM were treated 2-3 weeks before admission with subcutaneous BTX-A injections at specific EEG electrode locations. On the basis of clinical data available before VEM, four subjects were treated unilaterally (group 1) and eight bilaterally (group 2). BTX-A efficacy was assessed quantitatively in group 1 subjects by comparing high-frequency (20-100 Hz) power at homologous "treated" and "untreated" electrodes during voluntary forceful jaw closure. The clinical impact of BTX-A treatment was assessed by determining whether > or =5 of the first 10 s of each ictal recording was obscured by muscle artifact, and whether residual myogenic artifact on BTX-A-"treated" electrodes rendered these ictal EEG segments impossible to interpret.


RESULTS
BTX-A treatment reduced high-frequency power by a mean of 53% at electrodes T3/T4 and 52% at electrodes F7/F8. None of 49 ictal EEGs had > or =5 of the first 10 s obscured by myogenic artifact, and all of these ictal epochs were interpretable. Adverse events were limited to two subjects who complained of transient difficulty chewing tough foods.


CONCLUSIONS
Scalp-muscle BTX-A treatment before VEM significantly reduces myogenic artifact in subsequent EEG recordings, including ictal EEG. The clinical utility of this technique for improved or more-rapid seizure localization will be determined only by large, blinded, prospective trials.
Grant
Arthur C
AC
Departments of Neurology, New York University, New York, New York 10016, USA. arthur.grant@med.nyu.edu
Hermanowicz
Neal
N
D000328:Adult; D016477:Artifacts; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000494:pharmacology*; D001931:Brain Mapping; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000187:drug effects* / Q000379:methods / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008410:Masticatory Muscles / Q000187:drug effects* / Q000502:physiology*; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009465:Neuromuscular Agents / Q000008:administration & dosage / Q000494:pharmacology*; D010243:Paralysis / Q000139:chemically induced; D011300:Preoperative Care; D012535:Scalp; D014743:Videotape Recording
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A