Negative motor seizure arising from the negative motor area: is it ictal apraxia?
OBJECTIVE
Seizure manifesting motor arrest, that is, negative motor seizure (NMS), is a rare epileptic condition in which only inability to conduct voluntary movements or praxis is produced, although consciousness is preserved. The negative motor area (NMA) seems to be responsible, but its generator mechanism has not yet been clarified.


METHODS
Three patients manifesting NMS were investigated. Two patients (ages 33 and 17) with intractable frontal lobe epilepsy had subdural grid implantation for epilepsy surgery, and one (age 77) had scalp electroencephalography (EEG) monitoring.


RESULTS
Ictal semiologies commonly observed, at least in the two patients, were found as follows; (1) indescribable or ill-localized aura, (2) repetitive involuntary vocalization, (3) inability to speak, (4) inability to move the extremities, and (5) subsequent evolution to positive motor seizures. Awareness and comprehension were preserved throughout the episode before generalized seizures. In two patients with epicortical EEG recording, ictal activity arose from the lateral NMA in one, and from the rostral supplementary motor area in the other. Cortical stimulation at NMA in one patient elicited symptoms identical to NMS. Another patient had scalp EEG and magnetic resonance imaging (MRI) abnormality, both suggesting the epileptogenic focus in the mesial frontal area.


CONCLUSIONS
We showed that (1) NMS was a rare condition in patients with seizure focus in the frontal lobe, and (2) that the NMA was responsible for the symptoms. The documented state in the present study may reflect ictal apraxia, but it requires further investigation.
Ikeda
Akio
A
Department of Neurology, Kyoto University School of Medicine, Shogoin, Sakyo-ku, Kyoto, Japan. akio@kuhp.kyoto-u.ac.jp
Hirasawa
Ken-ichi
K
Kinoshita
Masako
M
Hitomi
Takefumi
T
Matsumoto
Riki
R
Mitsueda
Takahiro
T
Taki
Jun-ya
JY
Inouch
Morito
M
Mikuni
Nobuhiro
N
Hori
Tomokatsu
T
Fukuyama
Hidenao
H
Hashimoto
Nobuo
N
Shibasaki
Hiroshi
H
Takahashi
Ryosuke
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D001072:Apraxias / Q000175:diagnosis / Q000601:surgery; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis* / Q000601:surgery; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D009044:Motor Cortex / Q000601:surgery*; D009069:Movement Disorders / Q000175:diagnosis / Q000601:surgery; D009155:Mutism / Q000175:diagnosis / Q000601:surgery; D012640:Seizures / Q000175:diagnosis* / Q000601:surgery; D013064:Speech Disorders / Q000175:diagnosis / Q000601:surgery