Scans Detail Brain's Inner Workings

(Dec. 3, 2003) - Advances in brain imaging technology

HealthyPlace.com Radio Brain Scans May Prove Early Detectors of Schizophrenia: MRI scan may prove effective as an early detector of schizophrenia. listen with real player

are unlocking the secrets of the complex messaging and so-called hard wiring systems of the brain. In doing so, they are permitting a novel understanding of two well-known but poorly understood conditions: dyslexia and schizophrenia.

Dyslexia is estimated to affect about 8 percent of American schoolchildren and can cause lifelong difficulty with understanding the written word. Schizophrenia is a mental illness characterized by a variety of symptoms, including hallucinations, delusions, thought disorder, bizarre behavior and lack of motivation.

The new imaging studies, which are allowing real-time glimpses of brain activity associated with these conditions, are typical of the "tremendous advances in brain imaging that we've seen in the last three years," Dr. David M. Yousem, director of neuroradiology and professor of radiology at Johns Hopkins University in Baltimore, told United Press International.

A display of these new brain images, featured at the annual meeting of the Radiological Society of North America, illustrated Yousem's claim. Stark black-and-white, cross-section views of the brain are replaced by images that light up in neon yellows and oranges to illustrate brain function more clearly.

For example, when neuroradiologist Jonathan Burdette, of Wake Forest University in Winston-Salem, N.C., ran dyslexic and non-dyslexic volunteers through his functional magnetic resonance imaging scanner, the brains of normal readers glowed hot orange in regions that control hearing, sight and touch as the volunteers were put through a series of simple, consonant-and-vowel recognition exercises.

In addition, in the normal readers, a fourth brain area, called the parieto-temporal region -- a "well-known component of the language circuit, also lights up," Burdette said. This region serves as a sorting station for sensory input, separating the needed information from extraneous noise, he said.

By contrast, when Burdette ran 34 dyslexic reader volunteers through the same series of tests with the imaging unit, the crucial sorting region remained dark. This suggests the dark area could serve as a target for new dyslexia treatments.

For example, intense, brain-training approaches that seek to wake up this dark area might improve reading ability in dyslexics. Or, such programs might speed up information processing in these individuals. Burdette's test also indicated dyslexic readers process audio and visual stimuli about "75 milliseconds slower than non-dyslexic readers," he said.

Yousem said Burdette's imaging studies offer intriguing opportunities to develop new approaches for dyslexic patients. But while the studies could pay off soon for dyslexic readers, the imaging technique also offers new information that suggests schizophrenia is associated with changes in the hard wiring of the brain and these changes can be seen even in very young patients.

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This study used a brain scan called diffusion tensor imaging, which is able to detect white matter in the brain. White matter can be likened to electrical wiring that connects a home's electricity source to wall outlets, always delivering the correct voltage. White matter connects brain cells so the correct message is delivered. In patients with schizophrenia, however, changes disrupt this wiring system in much the same way that a poorly wired outlet can cause a short in a home power supply.

When Manzar Ashtari used DTI to study the brains of 12 adolescents -- including nine boys -- diagnosed with schizophrenia and nine normal volunteers, she found clear evidence of this type of faulty wiring in brain regions that affect emotions, hearing, language, and integration of information -- all areas affected by schizophrenia.

Ashtari, an associate professor of radiology and psychiatry at North Shore-Long Island Jewish Health System and Albert Einstein College of Medicine in New York City, said her work with DTI confirms for the first time white matter changes associated with schizophrenia have "their origins early in life."

Asked about a possible clinical role for DTI, she said it is too early in the research process to say whether it can be used as a diagnostic tool, "although we hope that is the case. Early onset schizophrenia is especially disheartening because so many of these teens aren't diagnosed until they are adults. Because these patients develop the disease at an early age when they have not yet built their lives, they tend to have a worse prognosis than those who have adult-onset schizophrenia."

Yousem cautioned it is unlikely the recent advances in brain imaging will yield immediate clinical applications. "I think that is the work of the next 10 years," he said.

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