WINSTON-SALEM, N.C. - In a finding that could have implications for future treatment of both psychiatric and neurological disorders, a researcher is using one of the latest forms of ultrasound to actually "see" when people are thinking, and when they are not.
Dr. Albert E. Roberts, a psychologist at Catawba College in Salisbury, N.C., is using transcranial Doppler ultrasound to monitor the flow of blood through the brain. "Typically blood flow increases" during thinking, Roberts said.
"As long as they're engaged in the task the speed is increased. If they resolve a task the blood flow typically slows down--or if they decide they can't do it and they quit, the blood flow also will slow back down."
Roberts is displaying his research August 12-17 at International Neurosonology '97, an international gathering of doctors in Winston-Salem, N.C., to review the latest research on the use of ultrasound on the brain. The meeting is being sponsored by the World Federation of Neurology and the Bowman Gray School of Medicine of Wake Forest University.
Current technologies for looking inside the brain, such as positron emission tomography (PET) and functional magnetic resonance imaging (MRI) produce a "snapshot" of cerebral activity. But transcranial Doppler offers a way to monitor brain activity as it is happening.
"I use the analogy between a noun and a verb," Roberts said. "With other technologies you see the end result, you get the noun. What I see is a verb, the on-going activity."
Transcranial Doppler ultrasound sends high-frequency sound waves through the skull and into the brain, where they are reflected back by red blood cells in the brain's arteries. This enables researchers to "see" the blood flow changes in the brain as a person thinks.
Dr. William McKinney, a professor of neurology at Bowman Gray and one of the pioneers in the use of ultrasound, says that Roberts' research has many implications for medicine, especially in monitoring the reaction to drugs in treating mental illness ranging from severe schizophrenia to depression and anxiety attacks.
"This gives us a new window to the brain to visualize thought," McKinney said. "We currently have no way to measure the effect of drugs in the brain, other than vocal and motor behavior."
This technique, he said, may allow doctors to monitor blood flow changes in the brain in response to specific drugs and adjust the dosage accordingly.
The research also could change the way doctors assess and treat the loss of brain function arising from strokes, severe concussions, Alzheimer's disease or genetic problems, McKinney said.
"Suppose somebody is dyslexic. Would their blood flow during reading be different than a normal person? The answer is likely yes. . . . It could even lead to physiologic monitoring of responses similar to lie-detector tests for use in interrogation," he said. "I would think it requires more blood to lie than to tell the truth. It takes more effort to lie."
Roberts used college students for his study. He measured each student's blood flow in repose and then while performing separate visual and verbal tasks. For example, students were asked to mentally rotate a drawing of a three-dimensional object, or to find words among sets of letters.
Roberts' research also strikes a blow for gender equality. Men are commonly thought to be better at visual thinking, Roberts said, "but what we're finding in terms of the rate of cerebral blood flow is that women may engage more effectively than the men."
The next step, Roberts said, is to measure the blood flow velocities of healthy older adults when they're thinking. Then, researchers will have a baseline of data to start measuring blood flow in adults with impaired brain function as a first step toward moving the research out of the testing lab and into the examining room.
For further information, call Mark Wright (email: mwright@bgsm.edu) or Bob Conn (email: rconn@bgsm.edu) at 910-716-4587.
Once the International Neurosonology '97 has begun on August 13, call the conference press room at 910-724-6923.