Researchers Identify Brain Area Responsible for Hearing Voices in Schizophrenia

By Dorothy L. Tengler via Multibriefs

Schizophrenia affects more than 21 million people worldwide. Between 0.2 percent and 2 percent of the population suffer with this disorder. Characterized by deficits in thought processes — delusions, muddled thoughts and hallucinations — the complexity of schizophrenia continues to challenge healthcare professionals.

In schizophrenia and schizoaffective disorder, auditory verbal hallucinations — a disturbing symptom — are not uncommon, affecting nearly 70 percent at some point in their illness. To those with schizophrenia, the voices coming from inside them are very real and are indistinguishable from real people's voices.

Sometimes, the person may hear voices of relatives or friends, while for others, the voices have no distinct personality. Sometimes they may hear the voice of someone close to them who has died, which can be confusing.

For some people, the voices will be clear to hear, whereas for others they may appear as a constant mumbling in the background. Sometimes only one voice will be heard, but other people may hear a number of different voices at the same time.

According to studies, the same parts of the brain activated by real speech are also activated by the voices people with schizophrenia hear in their heads. Until recently, the mechanism and pathophysiology of auditory verbal hallucinations, although widely speculated on, has remained largely unknown.

Now, researchers have targeted and identified an area of the brain involved in hearing voices and have targeted this area with magnetic pulses to improve the condition in some patients.

According to lead researcher, Professor Sonia Dollfus, University of Caen, CHU, France, this is the first controlled trial to determine an anatomically defined brain area where high-frequency magnetic pulses can improve hearing voices. The research team worked with 26 patients treated with transcranial magnetic stimulation (TMS) and 33 control patients who were interviewed using a standard protocol, the Auditory Hallucinations Rating Scale.

The treated patients received a series of 20 Hz high-frequency magnetic pulses over two sessions per day for two days. Using magnetic resonance imaging (MRI), the pulses were targeted at a specific brain area in the temporal lobe — specifically, the crossing of the projection of the ascending branch of the left lateral sulcus and the left superior temporal sulcus, which is associated with language.

After two weeks, the researchers found that 34.6 percent of the patients treated by TMS showed significant response (more than a 30 percent decrease in the Total Auditory Hallucinations Rating scale score); only 9.1 percent of patients in the control group responded.

Identifying the anatomical area of the brain associated with auditory verbal hallucinations in schizophrenia will hopefully make a difference to some sufferers, although more research is needed to determine if TMS is the best way to treat these patients long term.

Dorothy L. Tengler, MA, is a freelance medical writer/communication specialist with nearly 20 years of experience in the pharmaceutical and medical communication industries. She has developed educational and medical marketing materials, including monographs, slide kits, health articles, primary and review manuscripts, and pharmaceutical sales training materials.