Quantitative electroencephalography for delayed cerebral ischemia diagnosis
In a study, Mueller et al. aimed to compare and analyze the ability of qEEG and transcranial color-coded duplex ultrasonography (TCD/TCCS) to early identify patients who will develop later manifest cerebral infarction.
They analyzed cohorts of two previous qEEG studies. Continuous six-channel-EEG with artifact rejection and a detrending procedure was applied. Alpha power decline of ≥ 40% for ≥ 5 hours compared to a 6-hour-baseline was defined as a significant EEG event. Median reduction and duration of alpha power decrease in each channel were determined. Vasospasm was diagnosed by TCD/TCCS, identifying the maximum frequency and days of vasospasm in each territory.
34 patients were included (17 male, mean age 56 ± 11 years, Hunt and Hess grade: I-V, cerebral infarction: 9). Maximum frequencies in TCD/TCCS and alpha power reduction in qEEG were correlated (r = 0.43; p = 0.015). Patients with and without infarction significantly differed in qEEG parameters (maximum alpha power decrease: 78% vs 64%, p = 0.019; summed hours of alpha power decline: 236 hours vs 39 hours, p = 0.006) but showed no significant differences in TCD/TCCS parameters.