High-frequency oscillations of ictal muscle activity and epileptogenic discharges on intracranial EEG in a temporal lobe epilepsy patient.
OBJECTIVE
During seizures, intracranial EEG electrodes can record ictal muscle movements. Our purpose was to differentiate the high-frequency oscillations (HFOs) of extracranial muscle contractions from those of intracranial epileptogenic discharges.


METHODS
Using intracranial video-EEG (IVEEG), we recorded seizures in a 17-year-old boy with left mesial-temporal lobe epilepsy. We used multiple band frequency analysis (MBFA) to differentiate extracranial HFOs of craniofacial muscle activities from intracranial HFOs recorded ictally and interictally.


RESULTS
During 11 seizures, IVEEG showed low-amplitude fast waves ( approximately 60Hz) starting at the left mesial-temporal electrodes. Ictal facial grimacing projected low-amplitude ( approximately 20muV) fast waves ( approximately 160Hz) on inferior lateral-temporal electrodes. Interictal chewing projected medium-amplitude ( approximately 100muV) fast waves ( approximately 140Hz) correlating to mouth movements. MBFA topographic power spectrograms revealed a sustained, consistent ictal fast-frequency band from electrodes in the seizure-onset zone and randomly scattered HFOs without a specific frequency band from ictal and interictal extracranial muscle contractions.


CONCLUSIONS
MBFA power spectrograms differentiated randomly scattered muscle HFOs without a specific frequency band at electrodes close to temporal muscles from ictal epileptic HFOs with a sustained, fast-frequency band in the seizure-onset zone.


CONCLUSIONS
The pattern and distribution of frequency power spectrograms of extracranial HFOs differ from those of intracranial HFOs.
Otsubo
Hiroshi
H
Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, 555 University Avenue, Toronto, Ont., Canada M5G 1X8. hiroshi.otsubo@sickkids.ca
Ochi
Ayako
A
Imai
Katsumi
K
Akiyama
Tomoyuki
T
Fujimoto
Ayataka
A
Go
Cristina
C
Dirks
Peter
P
Donner
Elizabeth J
EJ
D000293:Adolescent; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005152:Facial Muscles / Q000502:physiology; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D014741:Video Recording