The EEG response to photic stimulation is not increased in alcohol-related seizures

To investigate the occipital EEG response to 18 and 24Hz photic stimulation (the H-response) in alcohol-related seizures (ARS).

Twenty-two ARS patients, 15 of whom had a withdrawal seizure (WS) were compared with patients with recent seizures of other causes: 21 patients with epilepsy, and 30 Alcohol Use Disorders Identification Test (AUDIT) negative patients with other seizures. EEG from 37 out-patients with epilepsy and 79 sciatica patents served as patient-controls. The spectral amplitude around 18 and 24Hz and a new photic H-ratio (24/18Hz relative amplitude) was calculated.

The H-ratio was significantly reduced in the ARS group compared to the sciatica group. H-ratio reduction correlated with the AUDIT score in ARS patients (p=0.02). No differences between WS and non-WS patients were found for H-response variables.

A dose-response relationship between AUDIT and the photic response H-ratio was observed in ARS patients. The EEG-driving response to 24Hz flashes was not increased in ARS.

The relative decrease in 24Hz photic response in ARS reflected drinking severity. The H-ratio is a candidate biomarker for ARS on the group level, although the moderate effect size precludes its use in individual patients.