The clinical differentiation of seizures arising in the parasagittal and anterolaterodorsal frontal convexities
L. F. Quesney, M. Constain, D. R. Fish and T. Rasmussen
Montreal Neurological Institute and Hospital, Quebec, Canada.
The ictal clinical manifestations of 40 patients with frontal lobe epilepsy
who became and remained seizure free after selective removal of the
parasagittal or anterolaterodorsal convexities were studied. Seizures
arising from the parasagittal region were characterized by a high incidence
of somatosensory auras (60%) and by tonic and/or clonic motor behavior
(100%) and never exhibited automatisms. Conversely, the anterolaterodorsal
convexity group never showed somatosensory auras but often had warnings
more typical of temporal lobe seizures, only displayed partial motor
seizure activity in half the cases, and included a relatively high
incidence of automatisms (30%). These clinical differences may be useful in
the localization of frontal lobe epileptogenic foci. The manifestations of
anterolaterodorsal convexity seizures may reflect frequent spread to the
temporal lobe, whereas parasagittal convexity seizures often show initial
ictal behavior, in keeping with seizure activity in that region. Early
ictal unilateral head turning without other motor manifestations was seen
in 3 of 10 patients in the parasagittal convexity group and in 9 of 30
patients in the anterolaterodorsal convexity group. In 11 of these 12
cases, the head turning was contralateral to the surgical removal.
