Abstracts

Rationale:
Ictal central apnea (ICA) can have significant health risks, including sudden unexpected death in epilepsy (SUDEP) in patients with epilepsy. Based on studies utilizing plethysmography, ICA occurs in 40-48% in patients with focal seizures. However, ICA is easily missed even during closed circuit television electroencephalography (CCTV-EEG) studies. Timely diagnosis and treatment of ICA may be important in prevention of SUDEP.
Method:
We present a 35 year old female with Lennox-Gastaut Syndrome, medically intractable on multiple antiseizure medications, status post vagal nerve stimulator (not active for 6 years) and deep brain stimulator (implanted 6 years ago), who was admitted to our epilepsy monitoring unit in dyscognitive (complex partial) status epilepticus. CCTV-EEG over 7 days was recorded and reviewed. When she was considered clinically stable, she was transferred for polysomnography (PSG). She was treated with continuous positive airway pressure (CPAP) and adaptive servo ventilation (ASV) titration.
Results:
CCTV-EEG showed more than 30 clinical and more than 100 electrographic seizures. Clinical seizures were characterized by head and eye deviation to the left with unresponsiveness. The EEG showed a desynchronization followed by larger amplitude paroxysmal fast activity (PFA) seen maximally in the left parietal chain followed by rhythmic delta in the right temporal region. During careful review of the electrographic seizures, it was noted that the patient stopped breathing during the PFA, as there was a time locked correlation between the time of onset of the PFA and the absence of chest or abdominal rise, followed by taking a deep breath at the end of the PFA. The patient was amnestic to these events. Of note, she had multiple CCTV-EEGs done previously at multiple epilepsy centers, with similar EEG findings and no mention of apneic events. During PSG, she was noted to have obstructive sleep apnea (OSA) with an apnea hypopnea index (AHI) of 40.5/hr on the baseline portion of the study, effectively treated with CPAP therapy. However, emergence of central sleep apnea (CSA), time-linked to periods of generalized PFA, resulted in a residual central AHI greater than 5/hr on CPAP. Ultimately, CSA was effectively treated during PSG with ASV titration (AHI < 5/hr). Objective data monitoring demonstrated continued effective treatment of apneas with nightly use.