Quantitative EEG in subcortical neglect.

Right-sided capsulo-lenticular strokes may cause left visuo-spatial neglect. The neural mechanism most frequently evoked to account for the occurrence of related cognitive disorders is remote cortical dysfunction in the posterior part of the right hemisphere. We studied 33 patients with capsulo-lenticular stroke, with (n = 16) or without (n = 17) associated subcortical neglect. A 20-channel EEG cartography system was used. Four regions of interest were delineated on the topographic map. Absolute delta and thêta amplitude peaks were obtained, as well as left-to-right ratios between activities in homologous regions of interest. The population was subdivided into two groups according to the presence or absence of neglect. Delta activity was higher in neglect patients than in patients without neglect, but the magnitude of delta activity differences between the two groups of patients did not depend on the site. The left-to-right ratio of delta activity between posterior homologous regions was lower in neglect patients, suggesting that right posterior dysfunction producing an imbalance between these regions might contribute to the emergence of the attention disorder.