Abstracts

Rationale: Electrical status epilepticus in sleep (ESES) is an electrographic diagnosis characterized by abundant to near continuous spike wave discharges during non-rapid eye movement (NREM) sleep. ESES has been associated with reversible cognitive or behavioral impairment. Many cases of ESES are resistant to first line treatments aimed at resolving the near continuous spike wave discharges on EEG. A recent study described successful treatment of ESES with amantadine (Wilson RB, Eliyan Y, Sankar R, Hussain SA. Amantadine: a new treatment for refractory electrical status epilepticus in sleep. Epilepsy Behav. 2018 Jul;84:74-78). We sought to evaluate whether similar efficacy is seen in patients treated with amantadine for ESES at our institution.

Methods: We conducted a retrospective chart review study on patients seen at the Texas Children’s Hospital epilepsy clinic who received amantadine to treat EEG-confirmed diagnosis of ESES between June 2019 to May 2022. Clinical characteristics as well as spike wave index (SWI) during NREM sleep before and after treatment with amantadine were obtained from the electronic medical records and tabulated.

Results: We identified 9 patients who received amantadine for the treatment of ESES. All patients had comorbid focal epilepsy in addition to their ESES. Five out of nine patients had a symptomatic etiology to their epilepsy including stroke, mesial temporal sclerosis, focal gliosis and a genetic abnormality. One patient had speech regression and two patients reported subjective cognitive regression at the time of ESES diagnosis, while the remaining six patients did not report clear cognitive regression. Six out of nine patients reported new or worsening behavioral problems at the time of diagnosis. There was a delay between the diagnosis of ESES and initiation of amantadine, with median time to amantadine initiation of 2 years (IQR, 1.2-3.3). All patients have tried at least one unsuccessful treatment for ESES. Median duration of follow up is 9.2 months (IQR, 4.5-12.1) after initiation of amantadine. There is a reduction in the overall SWI before amantadine treatment (80%; IQR, 60%-100%) compared to the most recent follow up (40%; IQR, 30%-80%, p < 0.05). Six of nine patients had improvement in their SWI after treatment with amantadine, 1/9 had worsening of their SWI, and 2/9 had unchanged SWI. Eight out of nine patients reported no clinical improvement in cognition or behavior after treatment with amantadine, regardless of improvement in SWI. One patient had an improvement in attention.