Abstracts

Rationale: Ictal automatisms with preserved responsiveness (APRs) have been reported in several studies, especially in non-dominant temporal lobe epilepsy (TLE). However, pathophysiology of APRs is still poorly understood. Here, we analyzed SISCOM image (Subtraction Ictal SPECT CO-registered to MRI) of subjects with APRs compared to subjects without APRs in right TLE patients. Methods: We retrospectively reviewed medical records of subjects who performed video-EEG monitoring in our hospital from 2003 to 2017, subjects of right TLE with APRs were enrolled. Subjects of control group were enrolled in right TLE patients who showed ictal unresponsiveness during the video-EEG monitoring. Subjects whose injection time index (injection time/duration of seizure) at ictal SPECT were over 0.50, were excluded. Two neurologists reviewed SISCOM images of both groups and defined hyperperfusion of cortical and subcortical structures. Results: 15 subjects with APR and 32 subjects without APR were enrolled, and there was no significant difference in baseline characteristics such as age, sex, seizure onset, proportion of temporal lesion and injection time index. The results of SISCOM image analysis were summarized in Table 1. Hyperperfusion in mesial, lateral, posterior temporal, and temporal stem area were not significantly different between two groups, and involvement of contralateral temporal structure were not significantly different, neither. Among extratemporal cortical areas, hyperperfusion of ipsilateral and contralateral parietal area are significantly more common in control group than APR group (13.3% vs. 59.4%, p=0.004, and 6.7% vs. 40.6%, p=0.037, respectively). Hyperperfusion in frontal area, insula, cingulum and occipital area were not different between two groups. In addition, among subcortical structures, hyperperfusion of contralateral basal ganglia is more common in control group than APR group (0.0% vs. 34.4%, p=0.009). Hyperperfusion in caudate, thalamus and brain stem were not different between two groups. Conclusions: TLE patients with APR showed less ipsilateral, contralateral parietal and contralateral basal ganglia hyperperfusion in SISCOM images. The study suggests ictal spreading to parietal association area and basal ganglia may play an important role in loss of consciousness during seizure in temporal lobe epilepsy. Further investigation with larger population will be needed to determine more detailed pathophysiology of APR in TLE. Funding: None