Cyberonics Inc announced that a recent study found that VNS may have positive effects on neurocognitive function in treatment-resistant depressed patients. Neurocognitive tests were performed during the D-01 study of VNS as a depression treatment and showed that patients, especially those whose depression was improved with VNS, exhibited enhanced neurocognitive functioning following treatment.

The study was led by Harold A. Sackeim, of the New York State Psychiatric Institute.

Neurocognitive tests assess abilities in broad and diverse areas of thinking and mental operations such as attention, concentration, planning and abstract thinking, learning, memory and motor function. Researchers performed a battery of neuropsychological tests on 27 patients with treatment-resistant depression before and after ten weeks of VNS therapy. The 13 tests evaluated skills such as motor speed, psychomotor function, language, attention, memory and executive function. The results showed no evidence of deterioration in any of these skills after the patients were treated with VNS, and there were marked improvements in many cases.

Results from the initial 30 patients who were implanted as part of the D-01 study showed that 40 per cent of patients with treatment-resistant depression achieved at least a 50 per cent reduction in symptoms after ten weeks of vagus nerve stimulation therapy. Researchers believe that some instances of neurocognitive improvement correlated with a reduction in depressive symptoms, as many patients with severe depression manifest deficits in neurocognitive function.

"The primary aim of our study was to determine whether vagus nerve stimulation results in neurocognitive deterioration," said Harold A. Sackeim, Chief of the Department of Biological Psychiatry, New York State Psychiatric Institute. "The study results suggest that VNS does not disrupt the cognitive function of treatment-resistant patients or result in deterioration. In fact, there were several indications of neurocognitive improvement among this patient population. Improvements in executive function, such as problem solving, abstract reasoning, and attention and concentration, can have a very positive impact on quality of life for depressed patients."

"The positive results from the continued research on VNS are very encouraging," said Robert P. ("Skip") Cummins, Cyberonics' President and Chief Executive Officer. "This latest finding on enhanced neurocognitive function in depression patients demonstrates once again that we continue to accomplish our mission of improving the lives of people touched by epilepsy and other disorders that may prove treatable with our patented therapy, VNS."