Yale Psychiatrist Steps Up Magnetic Stimulation to Curb Auditory Hallucinations in Schizophrenics
A Yale psychiatrist testing the use of magnetic stimulation for schizophrenics who hear voices says increasing the duration of stimulation produces longer periods of relief.
The research by Ralph Hoffman, M.D., associate professor and assistant medical director of the Yale Psychiatric Institute, involves administering repetitive transcraneal magnetic stimulation (TMS) to the area of the brain involved with processing spoken speech.
“The duration of improvement with the increased exposure is now three months and more,” Hoffman said. “When we gave a much lesser amount in our first study, the duration of improvement ranged from one day to three weeks.”
He said the stimulation is intended to reduce the excitability of this area of the brain – the left cerebral cortex, midway between the temporal and parietal region of the brain. “We are not intending, nor is there any evidence to show, that we are doing any damage to the area,” Hoffman said.
Early results show that TMS provides significant relief for some patients - a minimum of 50 percent fewer episodes of auditory hallucinations. Twenty-five patients were administered TMS in the last two years and 70 to 80 percent experienced improvement, he said.
“The significance of this is that 50 to 70 percent of patients with schizophrenia have auditory hallucinations,” Hoffman said. “In most cases they are very distressing and can interrupt and disrupt judgment and behavior. In a small fraction of these people, they can lead to pathological behavior, such as violence and suicide. The real challenge is to find something to help the 25 percent of patients with this symptom for whom medications don’t have much effect.”
In the first phase of the study the patients were given a total of 40 minutes of stimulation over four days, or the equivalent of one magnetic pulse per second. Patients were administered four minutes of TMS the first day, eight minutes the second day, 12 minutes the third day and 16 minutes the fourth day.
Hoffman is now increasing the exposure to 132 minutes over nine days with eight minutes the first day, 12 minutes the second day, and then 16 minutes over seven days, all at a slightly higher power.
TMS is administered with a handheld electromagnetic coil held over the specified portion of the brain. The patients are awake at the time and report feeling a tingling in their scalp and sometimes a contraction of muscles in their scalp and face. “About 10 percent of the patients have reported some pain, but no one has ever decided not to have this because of the pain,” Hoffman said.
All of the studies are done in a double blind, which means the patients are administered TMS at times and a placebo at other times to compare effects.
TMS is based on perceptual testing and neuroimaging data that suggests auditory hallucinations arise from the pathological activation of the neurocircuitry responsible for speech processing and speech perception.