Tinnitus may interfere with tough mental tasks

By Karla Gale

Editor: Here's more evidence that tinnitus may interfere with the performance of demanding mental tasks.

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People who suffer from chronic, moderate tinnitus, or ringing in the ears, may have more trouble performing demanding cognitive tasks than individuals without tinnitus, Australian investigators report. "Our results are good news in that there is no difference between groups on everyday, familiar tasks," co-investigator Dr. Catherine Stevens told Reuters Health.

"The differences observed in this controlled experimental setting would not affect people with tinnitus in their daily lives."

In fact, "it may not be the tinnitus per se that is related to distress but negative reactions and negative thoughts associated with tinnitus," she added.

To further understand the effects of tinnitus, Stevens and colleagues at the University of Western Sydney in South Penrith, New South Wales, recruited 19 patients with chronic tinnitus and 19 controls matched according to age, education, occupation, and verbal IQ. They report their findings in the Journal of Speech, Language, and Hearing Research.

Subjects first underwent a Reading Span Test, in which 100 sentences were read in five sets of two sentences up to five sets of six sentences. Respondents were asked to recall the final words of all sentences in the set in the correct order. The reading span was calculated as the number recalled correctly on three out of the five sets.

The mean reading span of the tinnitus group was 3.00, compared with 3.61 for the control group. It thus appears that "some individuals with tinnitus have difficulties concentrating on the task and/or reduced capacity to store and retrieve information from working memory," Stevens' group suggests.

The second experiment involved a dual task divided-attention test involving visual stimuli. Subjects were to click a mouse button when a small rectangle appeared on a computer screen. In addition, a word appeared every 1.5 seconds, and subjects were to name the word. They then were asked to name the subordinate category (cooking, animal, or seascape) to which the word belonged.

The groups were similar in the reaction time and in the word-naming task, but subjects with tinnitus scored more poorly in the category-naming condition.

"The only difference in the performance of the two groups was on the most demanding conditions of two laboratory tasks. These conditions were unfamiliar and challenging," Stevens noted.

She added that there are a number of factors that might be responsible for their findings. "One possibility is that there is a loss of sleep among people with chronic tinnitus and that the difference in performance is not the result of tinnitus directly but rather sleep loss."

Other variables that are sometimes associated with tinnitus are anxiety, depression, and hearing loss, which can impact cognition.

"A final explanation may lie in the nature of the task," she continued. "There was no difference on familiar, over-learned conditions but a slight difference on novel tasks that required controlled, strategic processing. One hypothesis that we will test in the future is whether tinnitus absorbs attention, leaving fewer cognitive resources available for novel tasks that require conscious strategic processing."