Neural Regeneration Research ›› 2019, Vol. 14 ›› Issue (7): 1237-1246.doi: 10.4103/1673-5374.251331

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Longitudinal quantitative electroencephalographic study in mono-hemispheric stroke patients

Filippo Zappasodi 1 , Franca Tecchio 2 , Laura Marzetti 1 , Vittorio Pizzella 1 , Vincenzo Di Lazzaro 3 , Giovanni Assenza 3   

  1. 1 Department of Neuroscience, Imaging and Clinical Sciences and Institute for Advanced Biomedical Imaging, “G. D’Annunzio” University, Chieti, Italy
    2 Laboratory of Electrophysiology for Translational NeuroScience (LET’S), ISTC-CNR, and Fondazione Policlinico Gemelli IRCCS, Rome, Italy
    3 Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
  • Online:2019-07-15 Published:2019-07-15
  • Contact: Giovanni Assenza, MD, PhD, g.assenza@unicampus.it.
  • Supported by:

    FZ and FT obtained financial support from the Italian Ministry of Health Cod. GR-2008-1138642 “Promoting recovery from Stroke: individually  enriched therapeutic intervention in Acute phase”, and PNR-CNR Aging Program.

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Abstract:

The identification of individual factors modulating clinical recovery after a stroke is fundamental to personalize the therapeutic intervention to enhance the final clinical outcome. In this framework, electrophysiological factors are promising since are more directly related to neuroplasticity, which supports recovery in stroke patients, than neurovascular factors. In this retrospective observational study, we investigated brain neuronal activity assessed via spectral features and Higuchi’s fractal dimension (HFD) of electroencephalographic signals in acute phase (2–10 days from symptom onset, T0) and sub-acute phase (2.5 months, T1) in 24 patients affected by unilateral middle cerebral artery stroke. Longitudinal assessment of the clinical deficits was performed using the National Institutes of Health Stroke Scale (NIHSS), together with the effective recovery calculated as the ratio between difference of NIHSS at T0 and T1 over the NIHSS value at T0. We observed that delta and alpha band electroencephalographic signal power changed between the two phases in both the hemispheres ipsilateral (ILH) and contralateral (CHL) to the lesion. Moreover, at T0, bilateral higher delta band power correlated with worse clinical conditions (Spearman’s rs = 0.460, P = 0.027 for ILH and rs = 0.508, P = 0.013 for CLH), whereas at T1 this occurred only for delta power in ILH (rs = 0.411, P = 0.046) and not for CHL. Inter-hemispheric difference (ILH vs. CLH) of alpha power in patients was lower at T0 than at T1 (P = 0.020). HFD at T0 was lower than at T1 (P = 0.005), and at both phases, ILH HFD was lower than CLH HFD (P = 0.020). These data suggest that inter-hemispheric low band asymmetry and fractal dimension changes from the acute to the sub-acute phase are sensitive to neuroplasticity processes which subtend clinical recovery. The study protocol was approved by the Bioethical Committee of Ospedale San Giovanni Calibita Fatebenefretelli (No. 40/2011) on July 14, 2011.

Key words: mono-hemispheric stroke, delta band, fractal dimension, inter-hemispheric asymmetries, EEG, plasticity Chinese Library Classification No. R448, R741