Abstracts

Rationale: Research indicates that patients with chronic temporal lobe epilepsy (TLE) exhibit cerebellar atrophy compared to controls. The degree to which specific regions of the cerebellum are affected remains to be clarified. The purpose of this study was to characterize the extent and lateralization of atrophy in individual cerebellar lobes and subregions in unilateral TLE using advanced quantitative MRI techniques. Methods: Study participants were 31 persons with TLE and 46 age- and gender- matched healthy controls. All participants underwent high-resolution MRI with manual tracing of the cerebellum yielding gray and white matter volumes of the right and left anterior lobes, superior posterior lobes, inferior posterior lobes, and corpus medullare. The degree to which asymmetric versus generalized abnormalities was evident in unilateral chronic TLE was determined and related to clinical seizure features and history which were obtained by structured interview and medical record review. Results: There were no lateralized gray matter (p = 0.48) or white matter (p = 0.48) cerebellar lobar abnormalities in patients with right or left TLE. Compared with controls, unilateral TLE was associated with significant bilateral reductions in the superior (p = 0.032) and inferior (p = 0.023) posterior lobes while volume was significantly increased in the anterior lobes (p = 0.002), and not significantly different from controls in the corpus medullare (p = 0.71). The volume of the inferior (-0.417, p = 0.004) and superior (-0.364, p = 0.026) posterior lobes was negatively correlated with the duration of epilepsy. Conclusions: Patients with unilateral TLE exhibit a pattern of cerebellar pathology characterized by bilateral atrophy of the superior and inferior posterior lobes, hypertrophy of the anterior lobe, and no effect on the corpus medullare. This cerebellar pathology is associated with the duration of epilepsy. The precise mechanism of hypertrophy of the anterior lobe remains unclear.