[Use of jerk-locked back averaging for detecting the epileptiform discharge in a patient with supplementary motor seizure].
A 23-year-old, right handed women has suffered from supplementary motor seizures manifesting tonic followed by clonic contractions of the left foot, occasionally spreading to the left hand and trunk, since the age of 7 years. The mean frequency of seizures on admission was about 10 times per day. A brain MRI showed an abnormal intensity area about 3 cm in diameter in the right mesial frontal lobe involving the superior frontal and cingulate gyri. Six habitual seizures were recorded during long-term monitoring with digital EEG segments time-locked to the clonic contractions of the left foot, a negative spike was detected about 50 ms before the EMG onset at the midline fronto-central area slightly lateralized to the left. In the focal motor seizure arising from the mesial frontal lobe like in the present case, jerk-locked back averaging helps detecting the epileptiform activity which is otherwise undetectable.
Kuzuya
A
A
Department of Neurology, Kyoto University School of Medicine.
Yazawa
S
S
Ikeda
A
A
Nagamine
T
T
Kunieda
T
T
Taki
W
W
Kimura
J
J
Shibasaki
H
H
D000328:Adult; D003265:Contingent Negative Variation; D004569:Electroencephalography / Q000379:methods*; D004576:Electromyography / Q000379:methods; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008991:Monitoring, Physiologic