Abstracts

Rationale: Unilateral rhythmic ictal non-clonic hand motions (RINCH) or non-manipulative proximal upper extremity automatisms (NMUEA) have been reported as useful contralateral lateralization signs of temporal lobe seizures although such movements can be seen ipsilaterally. We hypothesized that their lateralizing value could be related to the timing of their occurrence during the seizure. Methods: We retrospectively identified consecutive temporal lobe epilepsy patients who underwent bitemporal depth electrode recording using three 1x8 electrodes placed stereotactically in each temporal region aiming for anterior, middle and posterior temporal regions. We defined RINCE movements as a variety of unilateral, sustained, rhythmic or semi-rhythmic, non-clonic, non-tremor, non-manipulative movements of extremities lasting ≥5 s during focal seizures. Results: We reviewed 85 seizures in 16 patients. RINCE movements were identified in 8 complex partial seizures (9%) from 2 patients (13%). Both patients had bitemporal independent seizure onsets, involving either mesial or lateral temporal contacts. RINCE movements involved the upper extremities, and consisted of hitting, picking, waving or clenching. They were ipsilateral to seizure onset in 5/8 (63%) and contralateral in 3/8 (37%) of seizures. RINCE movements occurred at seizure onset or up to 88 s after onset in conjunction with other typical features of temporal lobe seizures. Contralateral seizure foci were associated with early-onset RINCE movements (mean 27 s after EEG onset, 95% CI 17-36 s) whereas ipsilateral seizure foci were associated with late-onset RINCE movements (mean 64 s after EEG onset, 95% CI 33-95 s) (p=0.04). All of the late-onset RINCE movements in the extremities ipsilateral to the seizure foci occurred at or within 21 s of contralateral spread of the ictal discharge. Conclusions: RINCE movements are rare semiologic features of temporal lobe seizures. Early- and late-onset RINCE movements lateralize to contralateral and ipsilateral temporal seizure onsets respectively. Close timing of RINCE movements to ictal EEG onset or contralateral ictal EEG spread supports the existence and preferential ictal activation of a highly-specific, unilateral neuronal network in patients with independent bitemporal epilepsy.