Abstracts

Cerebellar lesions are associated with epilepsy but it is not known what type of epilepsy is associated with them. There are reports of seizures originating in the cerebellum itself in patients with cerebellar lesions, but it is not known how often this is the case in patients with congenital or acquired cerebellar lesions. Here we characterized epilepsy associated with cerebellar malformations by reviewing the records of all patients in our database with cerebellar malformations. We identified patients with documented epilepsy from our database. Medical records were reviewed for age, gender, age at seizure onset, family history for epilepsy, risk factors for epilepsy including febrile seizures, seizure type, localization and frequency, response to treatment, epilepsy surgery if performed, and eventual outcome at follow-up. Symptoms and neurological examination signs cerebellar dysfunction were reviewed. Brain CT and MRI images were reviewed for cerebellar as well as extracerebellar abnormalities. We excluded patients with only cerebellar atrophy. We identified 10 patients (8 women) with cerebellar lesions and epilepsy in our database of 2288 epilepsy patients. Their ages ranged from 26 to 52 years (mean 37.5); age at seizure onset ranged from 2 weeks to 30 years (mean 10.2). The cerebellar malformations included Dandy-walker cyst (3 patients), cerebellar tumors (3 patients), posterior fossa arachnoid cyst (2 patients- one with abnormal cerebellar segmentation and one with cerebellar hemisphere and vermis hypotrophy), agenesis of the left cerebellar hemisphere (1 patient), Chiari malformation and cerebellar hypotrophy (1 patient). Cerebellar exam abnormalities were present in four patients. The epilepsy was classified as partial in 9 patients (2 left mesial temporal, 3 right mesial temporal, 1 left frontal, 1 left occipital, 2 unclassified), and one symptomatic generalized. A presurgical evaluation was performed in 6 patients. The epileptogenic focus was temporal in 5 and in the supplementary motor area in one. The brain abnormality considered responsible for epilepsy was hippocampal sclerosis in 4 patients, hippocampal malformation in 1 patient, temporal tip cortical malformation in 1 patient. Five patients had epilepsy surgery (4 temporal, 1 mesialfrontal). All had a favorable initial response to surgery becoming seizure-free (Engel class I) or almost seizure-free (Engel class II), but seizures eventually recurred in 2 patients after one year with no seizures. Epilepsy with cerebellar structural abnormalities is most often of temporal lobe origin. There is usually associated temporal lobe pathology accounting for the seizure tendency, including hippocampal sclerosis and temporal developmental malformations. Cerebellar pathology should not preclude epilepsy surgery