Continuous Quantitative EEG Monitoring in Hemispheric Stroke Patients Using the Brain Symmetry Index

Abstract

Background and Purpose— There is increased awareness that continuous brain monitoring might benefit neurological patients, because it may allow detection of derangement of brain function in a possible reversible state, allowing early intervention. Here, we explore if quantitative continuous electroencephalography (cEEG) monitoring is technically feasible and possibly clinically relevant in patients with acute ischemic hemispheric stroke. Materials— Twenty-one consecutive patients with an acute hemispheric stroke were monitored in our stroke unit, using cEEG for 12 to 24 hours on the day of admission. EEGs were quantified using a particular measure for symmetry, the brain symmetry index (BSI). This measure was subsequently correlated with the clinical condition of the patient using the National Institute of Health Stroke Scale (NIHSS). Results— cEEG was technically feasible. We found a most satisfying positive correlation between the BSI and the NIHSS, with ρ≈0.86 ( P <0.01). Conclusions— Technically, cEEG monitoring posed no major problems. It was found that the BSI correlates satisfactorily with the clinical neurological condition of our stroke patients. This suggests that the BSI can be used as a measure to monitor possible changes of brain function in this patient category.

Quantitative EEG for the Detection of Brain Ischemia

“…Several parameters correlate with initial stroke severity as measured by the National Institutes of Health Stroke Scale (NIHSS) in both the acute (brain symmetry index [BSI]) [19,31] and subacute periods (relative alpha percen tage, relative alpha-beta percentage, relative delta-theta percentage, delta/alpha ratio, delta-theta/alpha-beta ratio, and global pairwise derived BSI [pdBSI]) [32][33][34]. qEEG parameters correlate with the volume of infarc tion on MRI, such as the acute delta change index [35], global pdBSI [32], relative alpha percentage, relative alpha-beta percentage, relative delta-theta percentage, delta/alpha ratio, and delta-theta/alpha-beta ratio [36].…”

Investigating the ability of post-stroke EEG measures of brain dysfuntion to inform early prediction of cognitive impairment or depression outcomes

“…In a sample of 21 patients with MCA stroke, increased interhemispheric asymmetry (higher BSI) was found to correlate strongly with higher NIHSS scores, indicating greater stroke symptoms (van Putten and Tavy, 2004). Similar results were reported in a group of 31 ischaemic stroke patients.…”

“…Measures of left and right hemisphere symmetry have also been informative in past stroke studies (van Putten and Tavy, 2004). In a sample of 21 patients with MCA stroke, increased interhemispheric asymmetry (higher BSI) was found to correlate strongly with higher NIHSS scores, indicating greater stroke symptoms (van Putten and Tavy, 2004).…”

EEG in ICU: A monitoring tool for critically ill patient

“…Indication for continuous EEG monitoring (cEEG) 63,64,65 with sensitivity 100% and specificity from 50% -84%. cEEG with the specific algorithm (qEEG) is proved to be useful for ischemia detection and prognostification 66,67 .…”