EEG indicators were correlated with clinical items in 174 patients with dementia diagnoses based on the DSM-III-R criteria. The patients' clinical symptomatologies were presented as regional brain syndromes, i.e. parietal lobe, frontal lobe, subcortical and global (nonregional) syndromes. The EEGs were abnormal in 87% of the cases. The typical abnormalities consisted of diffusely distributed slow wave activity. A significant correlation was found between the degree of slow wave abnormality and the degree of dementia. The results of the statistical analysis also suggest that EEG slow wave activity in dementia primarily reflects parietal lobe dysfunction. No association seems to exist between EEG slow wave activity and frontal lobe dysfunction.