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Clin Neurophysiol. 2009 Jun;120(6):1039-45. doi: 10.1016/j.clinph.2009.01.021. Epub 2009 Apr 23.

Delta-alpha ratio correlates with level of recovery after neurorehabilitation in patients with acquired brain injury.

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Human Neuropsychology Laboratory, School of Psychology, Department of Experimental Psychology, C/Camilo José Cela s/n, University of Seville, Seville-41018, Andalucia, Spain.



To explore the relationship between three QEEG global indexes and their association with functional outcome after neurorehabilitation in non-acute acquired brain injury (ABI) patients (traumatic brain injury and stroke).


Twenty-one adult ABI patients in post-acute phase were studied. Delta-alpha ratio (DAR), Power Ratio Index (PRI) and Mean Brain Symmetry Index (mBSI) were calculated from resting-state EEG taken at admission. These indexes and other clinical variables were correlated with functional recovery achieved after six months of neurorehabilitation.


DAR showed the highest strength of association with the functional outcome measure (rho=-0.65, P=0.002). The other QEEG indexes and clinical variables showed modest non-significant correlations. A posteriori group analysis showed higher DAR in patients with poor recovery as compared to good recovery patients.


Functional recovery after neurorehabilitation appears to be associated with a number of clinical and neurophysiological variables. Among the latter, the ratio between delta and alpha may play a significant role in predicting and monitoring functional rehabilitation outcome.


Neurophysiological assessment of ABI patients may be an important tool in monitoring and predicting outcomes after neurorehabilitation.

[Indexed for MEDLINE]

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