By Sherman, Carl
Clinical Psychiatry News , Vol. 31, No. 5
NEW YORK -- Transcranial magnetic stimulation shows promise for one of the most persistent of schizophrenia symptoms--hallucinated voices, Dr. Ralph E. Hoffman said at a conference on schizophrenia sponsored by Columbia University.
The modality, which has been used experimentally with some success for depression and movement disorders, effected significantly more improvement in auditory hallucinations than sham stimulation, and for many patients the gains persisted for months after conclusion of the study, said Dr. Hoffman of Yale University; New Haven.
Hallucinated voices--usually whole phrases, sentences, even conversations--are experienced by 60%-70% of individuals with schizophrenia and 10%-20% of bipolar patients, as well as some individuals without psychotic illness. They are highly recognizable--the same voices occur day after day--and their content is typically emotionally charged, often vulgarly sexual or violent.
"It is extremely disruptive, sometimes disabling experience," Dr. Hoffman said at the conference, cosponsored by the New York State Psychiatric Institute.
The course is variable: The symptom may war and wane, or persist. But once voices appear, the patient will remain vulnerable. In 25% of affected patients, voices fail to respond to medication.
"They seem one of the most resistant symptoms of schizophrenia often the last holdout symptom," he said.
There is evidence that such hallucinations originate in the part of the brain that processes perceived speech. The voices have distinct perceptual character--they sound like a particular person, while the normal "inner monologue" sounds like ourselves--and hearers report they "feel like" they are coming from outside, like words spoken aloud.
In one-third to one-half of cases, the hallucinations can be triggered by innocuous sounds, like running water, which are transformed into words and phrases. Patients often misperceive spoken speech as well, Dr. Hoffman said.
Imaging studies have shown that the temporal brain region involved in speech perception (Wericke's area) is activated when patients hear voices, he said.
Dr. Hoffman described several small studies to investigate the use of repeated transcranial magnetic stimulation (rTMS), a modality that manipulates electromagnetic fields to induce small electrical currents in the brain, to alleviate hallucinated voices. …