Involvement of the Claustrum in Human Epileptic Seizures

We aimed to assess if the claustrum is involved in seizure networks in humans with epilepsy.

We identified eight patients submitted for presurgical evaluation with stereoelectroencephalography (SEEG) recordings from the claustrum from 2016-2022. Demographic, paraclinical, and outcome data (Engel Classification) was collected from retrospective chart review. We analyzed the ictal and interictal pattern as well as high frequency oscillations (HFOs) in the claustrum.

The ictal onset zone was in the temporal lobe in 87% (n=7) of patients and the cingulate cortex in 12% (n=1). A total of 25 seizures were detected and 96% (n=24) involved the claustrum cortex. Of those seizures involving the claustrum, 88% (n=21) were involved before the rest of the electrodes. Two ictal onset patterns were identified: slow potential shift with HFOs were found in 46% (n=11) of seizures and rhythmic spikes <13 hz were found in 54% of seizures (n=13). The ictal pattern in the claustrum was synchronous with the ictal onset zone in 41% (n=10) seizures, however, in four patients with status epilepticus, the claustrum was noted to stop discharging just before ictal onset. The interictal pattern included high-amplitude slow waves with or without HFOs. HFOs were identified in the claustrum in 83% (n=20) of post-ictal periods. All patients had poor outcomes following surgical resection (Engel Class III-IV).

Our study suggests that the claustrum is often involved during seizures arising from the temporal lobe and cingulate cortexes and could play a role in modulation of the epileptogenic network.