Intrahemispheric EEG: A New Perspective for Quantitative EEG Assessment in Poststroke Individuals

Area of Science:

• Neuroscience
• Biomedical Engineering
• Clinical Neurology

Background:

• Brain activity frequency ratios, like delta/alpha ratio (DAR) and Power Ratio Index (PRI), may change post-stroke.
• Few studies quantify interhemispheric differences using these qEEG indices after stroke.

Purpose of the Study:

• To analyze DAR and PRI within each hemisphere and investigate motor impairment-related interhemispheric frequency oscillations.
• To explore a new perspective for analyzing DAR and PRI in post-stroke patients.

Main Methods:

• Quantitative electroencephalography (qEEG) was used to compute intrahemispheric and cerebral indices (DAR and PRI).
• Forty-seven post-stroke subjects (mild/moderate and severe motor impairment) and 12 healthy controls were studied.
• Interhemispheric frequency oscillations related to motor impairment were investigated.

Main Results:

• Cerebral DAR and PRI showed generalized brain activity slowing in post-stroke patients compared to controls.
• Only the intrahemispheric PRI index detected significant interhemispheric differences in frequency oscillations.
• The DAR index was more sensitive to motor impairment-related frequency oscillations, though it didn't detect interhemispheric differences.

Conclusions:

• The intrahemispheric PRI index may offer insights into therapeutic strategies for interhemispheric asymmetry post-stroke.
• qEEG indices like DAR and PRI can reveal stroke-related brain activity changes and motor impairment correlations.