Having tested a number of over-the-counter hearing aids, two researchers warn against buying the products, which may have the opposite effect than the one intended and further damage hearing.

Eleven hearing aids were subjected to the same tests performed on regular hearing aids. The test considered three common forms of hearing impairment.

The tested devices included low cost models priced below $100 and moderate priced aids costing $100 to $500.

The lowest-price group aids were found to emit loud noises into the ear, risking hearing damage. They amplified only lower-frequency sounds and failed to help the users hear the higher-frequencies most commonly affected by hearing loss and particularly important when hearing speech.

The moderately priced hearing aids fared somewhat better than those in the cheapest group. Since they are sold over-the-counter, no professional guidance or assistance in fine tuning the aids is included. The researchers recommend that people who buy these devices consult an audiologist.

The tests were conducted by Jerry Punch, a professor in the Department of Communicative Sciences and Disorders at Michigan State University and Susanna Løve Callaway, a Danish student. The results were published in the American Journal of Audiology.

Source: American Journal of Audiology, Vol 17 June 2008; http://news.msu.edu

[Source: hear-it]