Auditory fMRI as a reliable diagnostic of schizophrenia?

[Tony Miller <ajmiller@xxxxxxx>]

[I thought some AUDITORY listmembers might be interested... -AJM]

-----------------Press Release--------------------
http://www.yale.edu/opa/newsr/04-04-21-01.all.html

Imaging test could be used to diagnose schizophrenia

New Haven, Conn. -- An abnormal pattern in an area of the brain that
governs hearing may be an accurate method of diagnosing schizophrenia,
according to a study by Yale researchers and collaborators.

"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.

-----------------Pubmed Abstract--------------------

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15050866

Aberrant localization of synchronous hemodynamic activity in auditory
cortex reliably characterizes schizophrenia.

Calhoun VD, Kiehl KA, Liddle PF, Pearlson GD.
Biol Psychiatry. 2004 Apr 15;55(8):842-9.
Institute of Living, Olin Neuropsychiatry Research Center, 200 Retreat
Avenue, Hartford, CT 06106, USA.

BACKGROUND: Among the most prominent features of schizophrenic brains
are abnormalities in auditory cortex structure and function,
particularly in the superior temporal gyrus (STG). In this study, we
attempted to examine auditory cortex function using an intrinsic,
task-uncorrelated measure. METHODS: Using functional magnetic resonance
imaging data, we calculated synchronous hemodynamic independent maps
(SHIMs) of auditory cortex in patients with schizophrenia and matched
healthy control subjects while they performed an auditory oddball task.
RESULTS: Patient SHIMs revealed greater synchrony in ventral and medial
STG regions (including auditory association Brodmann area [BA] 42);
control SHIMs had greater synchrony in dorsal and lateral STG regions
(which did not include BA 42). A within-participant subtractive
comparison of these two sets of regions differentiated schizophrenic
from healthy control subjects with 97% accuracy initially (further
validated by a retest of the healthy control subjects) and performed
with 94% accuracy in a confirmatory study of new subjects scanned at a
different site. CONCLUSIONS: These results shed new light on STG
functional differences in schizophrenia, suggest that aberrant patterns
of coherence in temporal lobe cortical regions are a cardinal
abnormality in schizophrenia, and have the potential to provide a
powerful, quantitative clinical tool for the assessment of schizophrenia.

--
Tony Miller
Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary
243 Charles St, Boston, MA 02114
ajmiller@mit.edu | (617) 510-3629 | http://tonymiller.info