Pilot study shows audiovisual entrainment therapy stimulates mood centers in brain.

MONTREAL -- Audiovisual entrainment therapy, which has been shown to improve self-reported depression scores, produces corresponding neurophysiologic changes in the mood-regulating centers of the brain, David Cantor, Ph.D., said at the annual conference of the EEG and Clinical Neuroscience Society.

"To our knowledge, this may be one of the first studies that shows, in a crossover design, that audiovisual entrainment produces changes in brain function in particular regions that are involved in mood regulation," said Dr. Cantor of Duluth, Ga., president of the society.

The pilot study included 16 patients, with a mean age of 45 years, who had a long history of refractory depression that was minimally responsive to medication. Patients were required to stop all medications 1 month prior to the start of the study. Baseline tests included quantitative electroencephalography (QEEG) and the Beck Depression Inventory (BDI).

Patients were divided into two groups of eight, with the first group receiving 20 minutes of audiovisual entrainment (AVE) therapy daily for 4 weeks, at a frequency of 14 Hz. The other group of patients wore the AVE equipment for 4 weeks but did not get the stimulation treatment. The equipment consists of a control device, a goggle-like eyeset, and headphones that produce flashing lights and pulsing sounds.

After 4 weeks, BDI testing revealed "a huge drop" in self-reported depression scores in the treatment group, compared with no change in the untreated group, said Dr. Cantor.

QEEG testing also showed neurophysiologic changes in the treated patients (but not the untreated group) that corresponded to their reports of improved mood. "The QEEG changes we saw were noted in the frontal regions of the brain that have been shown by other studies to be involved in mood regulation," he said.

The groups were then crossed over, so that the untreated group received treatment and vice versa for another 4 weeks. Similar results were noted in the newly treated group, but the group that had received the first phase of treatment showed a sustained effect of treatment, both behaviorally and neurophysiologically, even after 4 weeks of discontinuation. "That is suggestive of an enduring effect of the therapy," Dr. Cantor said.

"We don't know if it can last 2 months or 6 months because we ended the study, but it's a very positive finding. It's one thing to be able to make changes in the course of therapy, but just like medication, once therapy stops, especially if prematurely, patients often start feeling depressed again. In this case, we can say once they've finished a prescribed period of therapy, in this case 4 weeks, at least for the next 4 weeks they are going to feel fine. And the brain measures were also stabilized during that phase," he said.

Research-has shown that there is a disturbance in [beta] wave activity in the anterior brain regions of people with mood dysregulation such as depression. The current study shows that AVE therapy can regulate the EEG pattern and produce corresponding self-reported mood improvements.

Compared with other nonpharmacologic therapies such as neurofeedback, however, AVE is less brain-region specific. "It has a more global effect over wider regions of the brain, but the therapy is also more easily administered," he said, explaining that AVE can passively alter brain activity and does not rely on patient cooperation and participation, as is the case with neurofeedback.

AVE may not work for all forms of depression or for all patients who respond poorly to medication, making it important to identify predictors of response. All patients in this study reported significant improvements with AVE, and baseline testing revealed six brain function variables, principally in the frontal and temporal regions, that might have predictive value. "If these six specific variables show up as abnormal, that would be a potential marker to predict response," he said.

Dr. Cantor said he has no ownership interest in the company that makes the AVE equipment used in his study. He disclosed his partnership with BrainDx, a company that provides QEEG analytic services for health practitioners, although this company is not yet active in terms of selling or distributing its specific software.

BY KATE JOHNSON

Montreal Bureau