"These results seem to point to a cardinal abnormality in schizophrenia," said Godfrey Pearlson, M.D., professor of psychiatry at Yale School of Medicine, director of the Olin Neurospychiatry Research Center at the Institute of Living in Hartford, and senior author of the study published in Biological Psychiatry. "Using this imaging test, we were able to identify patients with schizophrenia with 97 percent accuracy."
Pearlson, Vince Calhoun and Kent Kiehl later replicated their initial finding with an independent sample and achieved a 94 percent rate of accuracy. Calhoun and Kiehl have appointments at the Olin Center and Yale.
Currently, the clinical diagnosis of schizophrenia is based on a constellation of psychiatric symptoms. The mental illness also has been associated with both structural and functional abnormalities in neocortical networks including frontal, parietal, and temporal regions of the brain, but there has been no diagnostic test for the disorder.
Abnormalities in auditory cortex structure and function are prominent features of the brains in persons with schizophrenia, particularly in the superior temporal gyrus (SRG). Reduction in size of the SRG may correlate with the severity of auditory hallucinations and of formal thought disorder. However, all of these previously documented anatomic differences overlap significantly with those of healthy controls and are thus not useful for diagnosis.
"Therefore, this newly reported functional brain change results in almost total separation of patients and healthy controls in two independent samples, and thus has possible diagnostic utility," Pearlson said.
Data were collected from two locations. One group consisted of 17 outpatients with chronic schizophrenia matched with 17 healthy persons in Vancouver, B.C. Another group consisted of eight patients and eight healthy persons in Hartford, Conn.
"These results have the potential to provide a powerful, quantitative clinical tool for the assessment of schizophrenia," Pearlson said.
Citation: Biological Psychiatry, Vol. 55 (8): 842-849, April 15, 2004