Predictors of brain atrophy in focal epilepsy.

BACKGROUND

Epilepsy as a progressive disease is a topic of dispute, with only limited evidence supportive of a neurodegenerative hypothesis across structural etiologies other than hippocampal sclerosis.

METHODS

We performed cross-sectional brain volumetry on T1-weighted MRI scans in 59 people with drug-resistant focal epilepsy (PWFE), who had undergone extensive evaluation at a tertiary epilepsy center and were compared to three independent age-and sex-matched healthy control cohorts. 36 (61%) PWFE showed structural pathologies such as malformations of cortical development, low-grade epilepsy-associated neuroepithelial tumours and hippocampal sclerosis or encephaloceles, 23 (19%) PWFE were MRI-negative.

RESULTS

59 PWFE (female/male: 25/34, mean age 32.4 years, SD: 10.5) presenting with a median seizure frequency score (SFS) of 7 (range 1-10) and mean epilepsy duration of 14.3 years (SD: 9.9) were compared to 59 healthy control subjects (f/m: 33/26, mean age 33.7 years, SD 9.9). Adjusted for effects of age and gender, cortical gray matter volume in PWFE with a high SFS (≥ 7) was decreased by 30.1 ml (CI: -46.92 ml - -13.34 ml, p < 0.001). Similar results were observed for total deep gray matter volume, decreasing -4.35 ml (CI: -6.13 ml - -2.58 ml, p < 0.001) and white matter volume -40.65 ml (CI: -57.70 ml - -23.59 ml, p = 0.001) in patients suffering from a high seizure frequency. This effect was not significantly influenced by the structural etiology, seizure severity, nor lesion location.

CONCLUSIONS

Widespread brain volume loss, exceeding that of normal aging, shows correlation with a high seizure frequency irrespective of structural etiology in focal epilepsy.