[show abstract][hide abstract] ABSTRACT: Research indicates that patients with chronic temporal lobe epilepsy (TLE) exhibit cerebellar atrophy compared to healthy controls, but the degree to which specific regions of the cerebellum are affected remains unclear. 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 magnetic resonance imaging (MRI) techniques.
Study participants were 46 persons with TLE and 31 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 selected clinical seizure features (age of onset, duration of disorder).
There were no lateralized abnormalities in cerebellar gray matter or white matter in patients with right or left TLE (all p's > 0.2). Compared with controls, unilateral TLE was associated with significant bilateral reductions in the superior (p = 0.032) and inferior (p = 0.023) posterior lobes, whereas volume was significantly increased in the anterior lobes (p = 0.002), especially in patients with early onset TLE, and not significantly different in the corpus medullare (p = 0.71). Total superior cerebellar tissue volumes were reduced in association with increasing duration of epilepsy.
Patients with unilateral TLE exhibit a pattern of bilateral cerebellar pathology characterized by atrophy of the superior and inferior posterior lobes, hypertrophy of the anterior lobe, and no effect on the corpus medullare. Cross-sectional analyses show that specific aspects of cerebellar pathology are associated with neurodevelopmental (anterior lobe) or chronicity-related (superior posterior lobe) features of the disorder.
[show abstract][hide abstract] ABSTRACT: The goal of this work was to determine the presence and degree of cerebellar atrophy in chronic temporal lobe epilepsy, its clinical seizure correlates, and its association with general cortical atrophy.
Study participants were 78 persons with temporal lobe epilepsy and 63 age- and gender-matched healthy controls. All subjects underwent high-resolution MRI with manual tracing of the cerebellum. Clinical seizure features and history were obtained by structured interview and review of medical records.
The epilepsy group exhibited significant abnormality in cerebellar volume, with mean reductions ranging from 4 to 6.6% depending on adjustments. Significantly more individual subjects with epilepsy exhibited cerebellar atrophy compared with controls across all operational definitions or thresholds of abnormality including z < or = -2.0 (13% TLE, 3.4% controls) and z < or = 1.5 (22% TLE, 3.4% controls). Clinical seizure features reflecting both neurodevelopmental (history of initial precipitating injuries) and severity of course (longer duration, increased number of lifetime generalized tonic-clonic seizures) factors were associated with cerebellar atrophy. Atrophy of the cerebellum could be observed independent of more general (cerebral) atrophic processes.
The presence of cerebellar atrophy is a reflection of the extratemporal abnormalities that can be observed in localization-related temporal lobe epilepsy, which may be due, at least in part, to factors associated with epilepsy chronicity.