Electroencephalographic coherence analysis in multiple sclerosis: correlation with clinical, neuropsychological, and MRI findings

Abstract

Band coherence was decreased between homologous areas (p<0.02). Band coherence was decreased both in the local and long distance connections (p<0.0005). These findings were most striking both in patients with high MRI subcortical lesion load and in patients with cognitive involvement. A significant correlation was found between interhemispheric (p=0.02) and (p=0.017) and anteroposterior (p=0.013) coherence and subcortical MRI lesion load, but not with exclusively periventricular lesion load. Conclusions-These findings support the hypothesis that cognitive impairment in multiple sclerosis is mostly dependent on involvement of corticocortical connections related to demyelination and/or axonal loss within the white matter immediately underlying the cortex. (J Neurol Neurosurg Psychiatry 2000;69:192-198)

Individual analysis of EEG frequency and band power in mild Alzheimer's disease

“…Furthermore, these results are in line with previous evidence showing that lesions of the white matter in VaD were directly related to a widespread slowing of EEG rhythmicity (Szelies et al, 1992(Szelies et al, , 1999. The white matter lesions of multiple sclerosis also decreased the frequency of the alpha rhythm (Leocani et al, 2000), while successful immunosuppressive treatment, probably restoring appropriate nerve propagation, resulted in recovery of normal alpha frequency without effects on the relative power (Colon et al, 1981). Finally, tumors of the cerebral white matter, but not of the gray matter, decrease the frequency of the alpha rhythm (Gloor et al, 1968;Goldensohn, 1979).…”

“…Accordingly, these cholinergic inputs would sustain the power of the alpha rhythm (Holschneider et al, 1998;Villa et al, 2000). This explanation agrees with the reduction of functional cortico-cortical coupling, revealed by EEG coherence studies, in AD patients compared to normal controls (Leocani et al, 2000) and VaD patients (Leuchter et al, 1992). The regulation of the alpha frequency would otherwise be relatively independent of the full integrity of the cholinergic systems and corticocortical connections (mainly impaired in mild AD).…”

Vascular damage and EEG markers in subjects with mild cognitive impairment

“…In fact, a theoretical model considering a mean speed propagation in white matter fibers of 7.5 m/s (together with other parameters) is associated with a fundamental mode frequency of 9 Hz (Nunez, 1995;Nunez and Srinivasan, 2006), that is, the typical mode of scalp-recorded EEG. It is to be noted that a correlation between white matter damage and widespread slowing of EEG rhythmicity was found in other studies, following the presence of cognitive decline (d'Onofrio et al, 1996;Szelies et al, 1992Szelies et al, , 1999, multiple sclerosis (Leocani et al, 2000), or cerebral tumors (Gloor et al, 1977;Goldensohn, 1979). In the present study, we found neither impact of vascular damage on the IAF, nor significant correlation between CV damage score and IAF.…”

Stroop event-related potentials as a bioelectrical correlate of frontal lobe dysfunction in multiple sclerosis

“…This pattern of dysfunctions resembles that typical of subcortical dementia and is considered as mostly dependent on the disruption of connections between cortical associative areas, related to demyelination and/or axonal loss within the white matter immediately underlying the cortex [39].…”