2025 American Academy of Neurology Abstract Website

Objective:

We investigated the relationship between serotonin reuptake inhibitors (SRIs) use and respiratory changes surrounding seizures in adults with refractory epilepsy (AWE) undergoing stereo-electroencephalography (SEEG).

Background:

Sudden Unexpected Death in Epilepsy (SUDEP) is the leading cause of mortality in people with epilepsy. Animal model studies suggest that SRIs reduce seizure-induced respiratory dysfunction. Data in AWE are scarce and conflicting, with one study suggesting that SRIs are associated with reduced likelihood of ictal oxygen desaturation during focal-onset seizures, while another found no protective effect of SSRIs against SUDEP.

Design/Methods:

AWE with peri-sylvian SEEG implantations were invited to undergo continuous polysomnography (PSG) to study relationships between seizures and ventilation. PSG signals included airflow, effort, SpO2, and end-tidal (EtCO2)/transcutaneous CO2 (TcpCO2). Participants were classified by SRI use. Wilcoxon rank-sum, Pearson’s chi-square, or Fisher’s exact tests were used. Analyses were conducted using SAS software (version 9.4), with significance set at 0.05.

Results:

28 participants contributed 61 seizures including 6 taking SRIs (13 seizures) and 22 not taking SRIs (48 seizures). In total, 31 seizures were generalized tonic clonic, including 4 (30.8%) in SRI group and 27 (56.2%) in No SRI group. Median seizure duration was comparable between SRI and No SRI groups (125 [66, 198] vs. 82 [32, 187]sec, p=0.49). Baseline and ictal respiratory rates (RR) were higher in SRI vs. No SRI groups (24.0 ± 3.3/28.4 ± 3.5 vs. 21.2 ± 3.3/23.9 ± 4.2, p=0.02/0.003 respectively), and baseline and peak EtCO2 levels were lower (23.8 [17.1, 26.4]/ 38.1 [27.3, 44.8] vs. 39.8 [32.8, 43.9]/ 48.5 [43.6, 53.2] mmHg, p=0.015/0.047, respectively). TcpCO2 and respiratory event parameters were comparable between groups.

Conclusions:

Observed differences in RR and EtCO2 between groups may suggest enhanced respiratory sensitivity to CO2 by serotonin in the SRI group. Further work is needed to elucidate the protective effect of SRIs in AWE.