Prognostic value of scalp EEG findings in patients receiving amantadine for comatose state

In this study, continuous electroencephalography (EEG) was performed to patients who were planned to be started on amantadine for disorders of consciousness. It was aimed to determine whether clinical changes and EEG findings were correlated. The study was performed between November 2021 and November 2022, and 5 days of continuous video-EEG monitoring was applied to eligible patients. EEG recordings were started before amantadine treatment and basal EEG parameters were obtained. The patients received an appropriate dose of amantadine, intravenously for 3 days and orally for 4 days. The patients were evaluated with four different scales at the same time every day and the scale scores were noted. EEG data were analyzed daily. The correlation of EEG data and rating scale scores were analyzed by statistical methods. A few patients were excluded for technical reasons, and then 20 patients were included in the study. A frequency increase of ≥1 Hz was observed in 9 patients in EEG background activity. No difference was detected in other EEG parameters. GCS, RSS, RASS, and CRS-R scores were compared with baseline scores after amantadine treatment. After treatment, RSS (p=0.031), RASS (p=0.007), and CRS-R (p=0.033) scores showed statistically significant increases. A statistically significant correlation was found between an increase of ≥3 points in CRS-R and an increase in EEG frequency, p=0.0297). CRS-R category increases (p=0.05) and GCS score increases (1 increase, p=0.094; 2 increases, p=0.070) were the trends supporting this relationship. Additionally, we performed spectral power analysis on 4 patients. It was observed that EEG and clinical findings were correlated in 3 of these 4 patients. As a result, visual analysis of EEG can predict patients who may benefit from treatment.