Understanding deep brain stimulation

Dr. Reina Isayama
Dr. Reina Isayama

Deep brain stimulation is a surgical intervention used to treat the tremors, rigidity, stiffness and slow movements that people with Parkinson’s disease experience. Although researchers know the technique works by changing abnormal electrical signals deep in the brain’s basal ganglia, they don’t understand the mechanisms involved.

Dr. Reina Isayama is exploring the basal ganglia’s relationship with the cerebral cortex, on the surface of the brain. She is trying to determine how the two areas of the brain interact and why deep brain stimulation (DBS) also affects the circuitry in that cerebral cortex, which, in people with Parkinson’s, has a particularly abnormal signalling pattern.

“We know that DBS works for Parkinson’s motor symptoms, but we still don’t know how it works,” says Isayama.

Isayama, a neurologist and Clinical Fellow at Toronto Western Hospital’s Movement Disorders Clinic, will use electroencephalograms (EEGs) to record the surface of the brain, where cells are activated and are communicating following DBS. She’ll study their relationship with the clinical benefits of DBS. Her two-year, $100,000 Clinical Research Fellowship is funded by the Parkinson Canada Research Program.

Isayama hopes by understanding how DBS works on the brain’s cortex, she will be able to suggest better adjustments to the technique, such as delivering the electrical stimulus to the brain at higher or lower frequencies, to shorten the time necessary to improve the symptoms. She may also identify areas on the surface of the brain that can be treated with other brain stimulation techniques in future.

“If we understand the influence of DBS to the cortex, we may be able to develop some less invasive techniques,” she says.

During her residency training in her native Japan, Isayama’s first research project involved Parkinson’s disease. She was struck by the “willingness and kindness” of the patients she worked with.

“I always hoped that I would be involved in research studies related to movement disorders and Parkinson’s disease,” she says.

Isayama believes it’s important to conduct research as well as to treat people with Parkinson’s in a clinical setting, so that she can apply her knowledge to make a difference in her patients’ lives.

“I’d like to be a person who can apply research results in a real clinical setting,” she says.

Watch our interview with Dr. Isayama and read about other researchers recently funded by the Parkinson Canada Research Program.