More MS news articles for March 2001

Eye Movements Linked to Tinnitus; Ringing in Ears

Researchers have identified connections between tinnitus -- a ringing in the ears -- and eye movements. Their study suggests that tinnitus is a complex phenomenon involving more than one site in the brain. (Neurology, 2-27-01)

http://www.newswise.com/articles/2001/2/NEURLOGY.VAR.html

Veterans Affairs
27-Feb-01

Study Identifies Neural Sites Attributed to Gaze-evoked Tinnitus

BUFFALO, N.Y. - Reporting in the February 27 issue of Neurology, researchers from the Veterans Affairs (VA) Western New York Health Care System and the State University of New York at Buffalo (UB) have identified connections between tinnitus -- a ringing in the ears -- and eye movements. Their study suggests that tinnitus is a complex phenomenon involving more than one site in the brain.

The idea that tinnitus may be due to an imbalance in brain systems is a unique concept and could point the way to new approaches to tinnitus and related disorders. These findings came from a study of patients with gaze-evoked tinnitus (GET), a rare disorder in which patients note an increase in the loudness and pitch of their tinnitus associated with eye movements. GET may develop after surgical removal of tumors of the auditory nerve.

The VA/UB team used positron emission tomography (PET) to identify the parts of the brain that are associated with the phantom sounds of tinnitus and eye movements in eight GET patients.

"This is the first research to show that a failure of the complicated way our brain systems talk to each other contributes to the cause of tinnitus," said Alan H. Lockwood, MD, the study's lead author.

"Tinnitus is not the simple problem we hoped for," added Dr. Lockwood, a neurologist at the Buffalo Division of the VA Western New York Health Care System and Professor of Neurology, Nuclear Medicine and Communicative Disorders and Sciences at the State University of New York at Buffalo. He also directs the Center for Positron Emission Tomography, a joint VA/UB venture.

Lateral gaze activated an extensive neural network in both controls and patients, according to Lockwood. These sites included portions of the brain linked to the perception of sounds, confirming earlier VA/UB findings that the auditory system is a culprit for tinnitus.

"We believe that tinnitus is the result of changes in the auditory circuits of the brain. Tinnitus might be viewed as the auditory-system equivalent to phantom limb pain," said Lockwood.

In normal people lateral gaze suppresses brain activity in the auditory system. This balance between visual and auditory parts of the brain was not present in the GET patients. The researchers believe that this may explain why gaze-evoked tinnitus becomes louder when patients look to the side.

Tinnitus affects 50 million Americans and may be associated with anxiety, sleep disturbances, depression and other disabling symptoms. Currently, there is no effective drug treatment of this common condition.

Primary funding for the study came from a $1.2 million grant from the National Institute on Deafness and Other Communication Disorders. Additional support came from The James H. Cummings Foundation of Buffalo, NY.

VA research provides improved medical care for veterans, as well as the general population. Through its unique affiliation with medical schools, VA plays a crucial role in educating future physicians in research and clinically oriented areas.

Contact:
Dr. Lockwood can be reached for interviews at (716) 862-8788 or by e-mail at: alan@petnet.buffalo.edu. He will be out of the country and unavailable from February 24 thru March 7, 2001.
Co-authors Richard Salvi, Ph.D. and Robert Burkard, Ph.D. may be reached at (716) 829-2001, x 13 and x19.