Transcranial color-coded duplex sonography for subarachnoid hemorrhage

In subarachnoid hemorrhage (SAH), Transcranial color-coded duplex ultrasonography (TCD/TCCS) is used for delayed cerebral ischemia diagnosis (DCI). In previous studies, quantitative electroencephalography (qEEG) also predicted imminent DCI. In a study, Mueller et al. aimed to compare and analyze the ability of qEEG and 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.

There was a moderate correlation between TCD/TCCS frequencies and qEEG alpha power reduction but only qEEG differentiated between patients with and without cerebral infarction.

Significance: qEEG represents a non-invasive, continuous tool to identify patients at risk of cerebral infarction ¹⁾.