Hearing Loss May Skew Alzheimer's Test Results

July 21, 2011 (Paris) -- If you're going to take your elderly parents in for a memory checkup, you may want to have their hearing tested first.

So suggest researchers who found that a substantial number of people may have false-positive results on cognitive tests designed to detect dementia due to undiagnosed hearing problems.

"A hearing test should be imperative prior to cognitive testing," says study researcher Michael Lerch, MD, of Diakonia Mark-Ruhr Hospital in Hagen, Germany.

Hearing problems can be overlooked, especially if they are mild, says William Thies, PhD, chief medical and scientific officer at the Alzheimer's Association.

"Just missing one word can distinctly affect performance on a cognitive test, particularly if it's done in a hurried fashion," he tells WebMD.

Thies' advice: If dementia is suspected, make sure cognitive testing is performed by a doctor with experience treating Alzheimer's disease patients.

Hearing Loss and Dementia

It's not uncommon for hearing loss and dementia to coexist, Lerch says. One in eight people over age 65 have dementia. And more than half of people over age 70 have hearing loss, he says.

The new study involved 1,600 patients in a geriatric practice. About 900 had scores suggestive of dementia on the Mini-Mental State Exam, a brief test of cognitive skills, including attention span and memory. Then, patients underwent hearing testing, with treatment if needed.

One-third of those with possible dementia were found to have a relevant hearing impairment and showed an improvement in cognitive testing results after treatment, Lerner reports.

The findings were presented here at the Alzheimer's Association International Conference 2011.

About 5.4 million Americans and 35 million people worldwide have Alzheimer's disease, the most common form of dementia.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.