Abstracts

Sex differences in brain development, structure, and functional organization are well-established. Furthermore, in both the animal and human clinical lietrature, there is evidence to suggest that females are less vulnerable to the effects of brain insults than are males. In seizure disorders, a recent study reported that males with chronic temporal lobe epilepsy (TLE) showed greater volume loss than females in hippocampus and overall hemicranial volumes (Briellmann et al., 2000). The possibility that reliable sex differences exist in vulnerability to brain volume loss in TLE is of considerable clinical and theoretical importance. Thus, the purpose of the current study was to: (1) attempt to replicate the sex difference in hippocampus and overall brain volumes for male and female TLE patients, and (2) provide a more detailed analysis of brain volume integrity by examining both gray and white segmented tissue volumes.
72 TLE patients (25 males, 47 females) and 65 healthy controls (29 males, 36 females) ranging in age from 14-60 years underwent whole brain quantitative MR volumetrics. Male and female TLE patients did not differ in age from their gender matched controls. Male and female TLE patients also did not differ in age, duration of epilepsy, age of recurrent seizure onset, and frequency of current seizures (all p[apos]s [gt] .05). A 2 x2 analysis of covariance, Group (controls, TLE) and Sex (males, females) with ICV as a covariate examined MR indices of total hippocamus volume, total cerebral white matter volume, and total cerebral gray volume.
Overall, the TLE group had significantly smaller volumes of hippocampus and white matter than controls. Of relevance to the issue of sex differences, the group x sex interaction was signficant for hippocampus (p [lt] .005), with a significant trend also for cerebral white matter (p=.08), but not gray matter (p [gt].10). Hippocampal volume in TLE males was 17% smaller than male controls (p [lt] .001) while TLE females showed a 4% reduction compared to female controls (p[gt].10). Similarly, the white matter volume loss for TLE males was 8% compared to control males (p[lt].001), while female TLE patients showed a 4% white matter volume loss compared to female controls (p=.02).
These findings replicate a previous report indicating that male TLE patients exhibit greater hippocampal volume loss than females. In addition, TLE males also showed greater white matter volume loss, but not gray matter compared to controls. TLE males and females did not differ on epilepsy duration, age of recurrent seizure onset or seizure frequency. Additional investigation into the possibility that sex differences exist for the effects of seizures on brain structure and function would appear to be warrented.
[Supported by: NIH 2ROI-37738 and MO1 03186]