Are early measured resting-state EEG parameters predictive for upper limb motor impairment six months poststroke?

OBJECTIVES

Investigate whether resting-state EEG parameters recorded early poststroke can predict upper extremity motor impairment reflected by the Fugl-Meyer motor score (FM-UE) after six months, and whether they have prognostic value in addition to FM-UE at baseline.

METHODS

Quantitative EEG parameters delta/alpha ratio (DAR), brain symmetry index (BSI) and directional BSI (BSIdir) were derived from 62-channel resting-state EEG recordings in 39 adults within three weeks after a first-ever ischemic hemispheric stroke. FM-UE scores were acquired within three weeks (FM-UE) and at 26 weeks poststroke (FM-UE). Linear regression analyses were performed using a forward selection procedure to predict FM-UE.

RESULTS

BSI calculated over the theta band (BSI) (β = -0.40; p = 0.013) was the strongest EEG-based predictor regarding FM-UE. BSI (β = -0.27; p = 0.006) remained a significant predictor when added to a regression model including FM-UE, increasing explained variance from 61.5% to 68.1%.

CONCLUSION

Higher BSI values, reflecting more power asymmetry over the hemispheres, predict more upper limb motor impairment six months after stroke. Moreover, BSI shows additive prognostic value regarding FM-UE next to FM-UE scores, and thereby contains unique information regarding upper extremity motor recovery.

SIGNIFICANCE

To our knowledge, we are the first to show that resting-state EEG parameters can serve as prognostic biomarkers of stroke recovery, in addition to FM-UE scores.