Controversial Technique May Combat Auditory Hallucinations

In 1998, Ralph Hoffman, M.D., a Yale University psychiatric scientist, started tinkering with a technique called “repetitive transcranial magnetic stimulation,” which many people have viewed as hocus-pocus.

The technique involves placing a magnetic coil over a person’s skull, then using the coil to transmit repetitive magnetic pulses. The pulses then become electric current in the individual’s brain, and the current in turn presumably stimulates neurons and effects changes in the larger neurocircuitry of the brain.

In fact, “rTMS is such a different approach in psychiatry that I sometimes questioned my choice in traveling down this road,” Hoffman admitted recently to Psychiatric News.

Nonetheless, he has been pitting rTMS against medication-resistant auditory hallucinations and is getting encouraging results.

The left temporoparietal cortex of the brain is known to be involved in speech perception; it is also suspected of being implicated in the production of auditory hallucinations. Also, low-frequency rTMS, in which stimulation is once each second, has been shown to produce sustained reductions in reactivity of the brain area stimulated. Thus, Hoffman and his colleagues applied rTMS to the left temporoparietal cortex of 12 right-handed schizophrenia subjects experiencing medication-resistant auditory hallucinations.

This technique was used for up to 16 minutes a day over a four-day period. Eight of the subjects experienced a substantial reduction in their hallucinations after receiving the treatment, and the effect lasted up to about two weeks (Psychiatric News, June 2, 2000).

These results then prompted Hoffman and his coworkers to pit rTMS against auditory hallucinations in a more sophisticated trial. This time they gave subjects more rTMS exposure than before—a total of 132 minutes versus 40 minutes in the previous study, and given over a nine-day instead of a four-day period. And this time they also tested rTMS in a double-blind manner. Specifically, 24 right-handed subjects with schizophrenia or schizoaffective disorder whose auditory hallucinations had not been controlled with medications were randomly allocated to get either rTMS or a sham stimulation during the nine-day treatment period. The subjects were assessed neuropsychologically at the start of the study and during and after it.

‘Robust Reductions’ Evident

Compared with the sham stimulation, rTMS produced “robust reductions in auditory hallucination severity,” Hoffman and his team reported in the January 2003 Archives of General Psychiatry. Duration of treatment benefits ranged widely, with half the subjects getting rTMS maintaining improvement for at least 12 weeks. Repetitive TMS was also well-tolerated by those subjects who received it; that is, without any signs of neuropsychological impairment.

The authors’ report of a case from France—a young man named “Pierre”—also raises the possibility that rTMS can dampen auditory hallucinations.

Just a few days after the terrorist attack on the World Trade Center in New York City, Pierre suddenly developed schizophrenia symptoms. He heard two voices—those of “God and the devil”—speaking to him and giving him orders that he felt compelled to execute. He became convinced that his mother was a demon, and killed her.

Antipsychotics Didn’t Help

After he was hospitalized, Pierre was given high doses of antipsychotic medications to quell his voices. None helped. So Nicolas Franck, M.D., Ph.D., associate professor at Le Vinatier Hospital in Bron, France, and colleagues offered to perform rTMS on Pierre. He agreed to it. He received rTMS of the left temporoparietal cortex 10 times during a two-week period.

After the treatments were finished, Pierre said that he felt relieved, and his clinical status improved remarkably as well, Franck and his coworkers reported in the August 2003 Psychiatric Research. For instance, although he continued to hallucinate, he kept his distance from the content of his “voices” and no longer behaved as if he were under their control. He was calmer and nonaggressive and eventually able to leave isolation. And since then, Franck told Psychiatric News, Pierre has gotten even better—he no longer experiences auditory hallucinations and is able to attend school in the hospital setting.

Franck and his coworkers are likewise studying how rTMS compares with a sham treatment in countering auditory hallucinations. Preliminary results, he said, “are very promising.”

Dutch Study Encouraging

A small Dutch study, too, is bolstering the hypothesis that rTMS can subdue auditory hallucinations. Eight Dutch subjects with medication-resistant auditory hallucinations received 20-minute rTMS sessions daily during a two-week period. The sessions were given by Alfredo A.L. d’Alfonso, M.D., of Utrecht University in the Netherlands, and colleagues. However, the magnetic pulses were delivered to the left superior temporal cortex (the auditory cortex) rather than to the left temporoparietal cortex, because some brain-imaging studies of hallucinating subjects have suggested that auditory hallucinations originate in the left middle-superior temporal cortex.

After rTMS treatment was finished, none of the subjects stopped hallucinating. However, the seven subjects receiving the antipsychotic drug clozapine showed less-severe hallucinations than they had before, whereas the subject taking olanzapine did not. “This finding,” the researchers wrote in the winter 2002 Journal of Neuropsychiatry and Clinical Neuroscience, “suggests that interactions may occur between type of medication and effectiveness of TMS, a possibility that should be studied in more detail.”

“Another important finding of this study,” they added, “was that daily TMS stimulation during two weeks did not have adverse effects on cognitive functioning.”

“Obviously, rTMS is not a panacea for auditory hallucinations,” Hoffman told Psychiatric News. “Nor does it help all patients. But all in all, results to date are encouraging.”

“Dr. Hoffman's work with TMS in schizophrenia is interesting and intriguing,” Mark George, M.D., a professor of psychiatry, radiology, and neurology at the Medical University of South Carolina, told “Psychiatric News.” “[However] we do not understand yet whether the stimulation is location- or frequency-specific. Thus, more work is needed.” ▪