Faculty Bibliography

Quantitative descriptors of resting electroencephalogram (EEG) (QEEG) and event-related potentials (QERP) to visual and auditory stimuli were obtained from normal subjects and 94 chronic schizophrenic patients on medication, 25 chronic schizophrenics off medication, and 15 schizophrenics with no history of medication. These schizophrenic groups showed a high incidence of neurometric features that were significantly deviant from normative values. Multivariate discriminant analysis using these features successfully separated the schizophrenic patients from normals with high accuracy in independent replication. The data from the medicated group were subjected to cluster analysis. Newly developed algorithms were used for objective selection of the most effective set of variables for clustering and the optimum number of clusters to be sought. Five clusters were obtained, containing roughly equivalent proportions of the sample with markedly different QEEG profiles. The whole sample was then classified into these clusters. Each cluster contained patients both on and off medication, but patients who had never been medicated were classified into only three of these clusters. No significant clinical or demographic differences were found between members of the five clusters; however, clear differences in QERP profiles were seen. These results are described in detail and possible physiological and pharmacological implications are discussed

We report on the quantitative analysis of the EEG (QEEG), using the Neurometric method, in large samples of normal elderly; normal subjectively impaired elderly; patients with mild cognitive impairment; patients presenting with a continuum of primary cognitive deterioration from mild to moderately severe as measured by the Global Deterioration Scale (GDS), compatible with dementia of the Alzheimer's type (DAT). Neurometric QEEG measures were found to be a sensitive index of degree of cognitive impairment, especially reflected in increased absolute and relative power in the theta band, with delta increasing in later stages of deterioration. While these abnormalities were widespread, neither localized or lateralized, MANOVA's for GDS and relative power in theta reached highest significance in a bilateral temporo-parietal arc. A possible relationship between hippocampal dysfunction, cognitive deterioration, and theta abnormalities is discussed in relation to these findings. The results suggest that Neurometric QEEG features are sensitive to the earliest presence of subjective cognitive dysfunction and might be useful in the initial evaluation of patients with suspected dementia, as well as in estimating the degree of cognitive deterioration in DAT patients

Positron emission tomography (PET) and the deoxyglucose method were used to measure cerebral metabolism in 14 normals and 13 schizophrenics at rest and during performance of simple and complex finger-movement sequences. The normals, but not the schizophrenics, showed significant metabolic activation in mesial frontal and contralateral sensorimotor and premotor regions during the complex movement. The relative metabolism of schizophrenics was significantly lower than normal in frontal regions and higher than normal in thalamus and basal ganglia under all scanning conditions. The results suggest that schizophrenics may have a brain dysfunction which limits their capacity to produce a focal metabolic response to stimulation in several functionally distinct brain regions

Comments on J. B. Welch's (see PA, Vol 82:17554) article on topographic brain mapping, emphasizing the disagreements between neurologists and psychiatrists regarding its usefulness. It is argued that psychiatrists are best able to assess the utility of these techniques for the practice of psychiatry. However, it is clear that to use EEG findings as a method of diagnosis reveals a failure to understand what the data show.

Because of the frequent association of cerebellar structural defects with schizophrenia, the authors reanalyzed the metabolic brain images of patients with chronic schizophrenia to assess if they had abnormalities in cerebellar metabolism. They used carbon-11-2-deoxyglucose and positron emission tomography to study 18 medicated patients with chronic schizophrenia and 12 normal comparison subjects. Patients with schizophrenia showed significantly lower absolute and relative metabolism in the cerebellum than normal subjects

Using the two-dimensional Fourier transform and the brain's centroidal principal axis, a method is developed for the analysis of PET metabolic brain images without the use of predefined anatomic regions of interest. We applied the method to images from a group of 11 normal and 12 medicated schizophrenics tested under resting conditions and under a visual task. A cortical/subcortical spatial pattern was found to be significant in two directions; anterior/posterior and chiasmatic (left-anterior/right-posterior). The best individual clinical classification (Jackknife classification) occurred under visual task at two axial brain levels: at the basal ganglia with correct classification rates of 91% and 84%, while the cerebellum had rates of 82% and 92%. These high classification rates were obtained using only the four coefficients of the lowest spatial frequency. These results point to the generalized brain dysfunction of regional glucose metabolism in chronic medicated schizophrenics both at rest and at a visual image-tracking task

The development of imaging technologies for investigating the living human brain has expanded knowledge about schizophrenia and is providing clues about biological factors associated with the disorder. Drawing on these and other developments in the last two decades, the authors review selected structural, functional, neurochemical, immunological, and infectious factors associated with the schizophrenic syndrome. Many of the biological alterations reported have also been found in other psychiatric, neurological, and medical conditions; therefore, the findings have little specificity for schizophrenia and in fact support the heterogeneity of the disorder