Basal ganglia involvement in rotational seizures.

Body rotation during partial epileptic seizures remains a poorly understood clinical feature, possibly related to the ictal involvement of specific cortical areas (e.g. vestibular cortex). However, there are both experimental and clinical arguments which support the hypothesis of basal ganglia asymmetric activation during such complex motor behavior. We report a patient exhibiting rotational seizures which proved to arise from right anterior temporal lobe structures and the orbito-cingular cortex, as demonstrated during stereotactic EEG recordings. An ictal 99mTc-ECD-SPECT study was performed during an electrically induced seizure, similar to the seizures usually experienced by the patient but without a rotatory component, showing a marked increase of cerebral blood flow in the lenticular nucleus, ipsilaterally to the epileptogenic area. This finding suggests that lenticulate involvement might be necessary to produce an ictal circling behavior. As circling behavior can be observed during epileptic seizures originating from areas widely distributed in the cortex, one may postulate that the basal ganglia involvement is the "final common pathway" underlying the rotational part of the clinical symptomatology.