EEG spectral analysis and coherence in children with hemiparetic cerebral palsy.
Hemiparetic cerebral palsy (HCP) is described as having two main forms: arm-dominant, associated with large cortical/subcortical lesions and leg-dominant, associated with central white matter lesions. Twelve children with HCP underwent clinical assessment and imaging studies. For each child, 20 artifact-free EEG epochs, each of 2s duration, were selected for spectral analysis and coherence functions. The objective of this research was to estimate EEG spectral power, interhemispheric coherence (ICoh), and intrahemispheric (Hcoh) coherence in children with HCP as compared to healthy children. Significant differences between the HCP and control children were detected in the distribution of alpha, theta, delta and beta rhythms over the left and right hemispheres. The ICoh values in the alpha band in the temporal, parietal and occipital regions were significantly lower in the HCP patients than in the controls. There was a significant ICoh increase in the HCP in the theta and delta band, involving frontal and temporal derivations. The significantly lower ICoh values in the HCP children in the beta band involved the frontal, central, parietal and occipital derivations. A higher HCoh value in the HCP children in the alpha band was detected at the right hemisphere. The lower ICoh at the temporal, parietal and occipital derivations in the alpha band implies hypoconnectivity between the right and left hemispheres. HCoh asymmetry, which implies relative hypoconnectivity within the left hemisphere as compared with the right, suggests that functional hemispheric differentiation may be diminished.