In a descriptive analysis of 158 patients
with temporal lobe epilepsy, Taylor (1969) reported that
the age of first seizure varied systematically as a function
of laterality and sex. We conducted inferential
analyses of Taylor's original data which (1) provided
support for his proposal of disproportionate left hemisphere
vulnerability to seizure onset in early life, but (2) failed
to provide evidence of sex differences in age of onset
of unilateral seizures. Examination of these effects in
a larger sample of 844 patients drawn from the Bozeman
Epilepsy Consortium provided some additional support for
findings from the inferential analysis. Specifically, the
left hemisphere appeared more vulnerable to seizure onset
in childhood, this increased vulnerability extending to
about age 5 years. Age of onset of seizures was not different
when males and females were compared. Thus, reanalysis
of Taylor's original data as well as examination of
data from a larger, more contemporary sample suggest that
seizure onset varies as a function of laterality, but not
sex. (JINS, 1997, 3, 428–434.)
