Working Memory, Sleep, and Hearing Problems in Patients with Tinnitus and Hearing Loss Fitted with Hearing Aids

Tinnitus is a common condition and there is a need to evaluate effects of tinnitus management in relation to moderating factors such as degree of hearing loss. As it is possible that tinnitus influences concentration, and thus is likely to disturb cognitive processing, the role of cognitive functioning also needs to be investigated.

To compare a group of patients with sensorineural hearing loss and tinnitus to a control group with only sensorineural hearing loss (and no tinnitus). To investigate working memory, sleep, and hearing problems measured before and after hearing rehabilitation.

A prospective study.

The sample consisted of 100 patients, 50 with hearing loss and tinnitus, and 50 controls with hearing loss but no tinnitus. All patients were between 40 and 82 yr old and had a pure-tone average (PTA; average of 0.5, 1, 2, and 4 kHz) <70 dB HL.

Patients were tested before and after rehabilitation with hearing aids with regard to their working memory capacity, sleep quality, hearing problems, speech recognition, and tinnitus annoyance.

Eight patients dropped out of the study. Thus, a total of 92 patients were included for analysis, with 46 in each group. As a consequence of unplanned age and PTA differences between the groups, an age-matched subsample (n = 30 + 30) was selected for further analysis. Tests including the Reading Span, Hearing-in-Noise Test (HINT), Tinnitus Handicap Inventory (THI), Hearing Handicap Inventory for the Elderly (HHIE), and Pittsburgh Sleep Quality Index (PSQI) were administered before and after hearing aid rehabilitation.

There were no between-group differences at baseline in the full sample (n = 92), with the exception of the THI (p < 0.001) and the PSQI (p < 0.002), on which the hearing loss and tinnitus group had significantly higher scores. Pre/post changes were significant for both groups on the Reading Span, and HHIE. However, these improvements were significantly larger for the patients in the hearing loss and tinnitus group on the Reading Span test (p < 0.001) and the PSQI (p < 0.001). Patients with tinnitus and hearing loss also exhibited significantly improved THI scores at follow-up, compared to baseline (p < 0.001). We conducted the same analyses for the age-matched subsample (n = 30 + 30). For the baseline data, only the THI (p < 0.001) and the PSQI (p < 0.015) difference remained significant. With regard to the pre/post changes, we found the same differences in improvement in Reading Span (p < 0.001) and the PSQI (p < 0.015) as in the full sample.

Patients with tinnitus benefited from hearing aid rehabilitation. The observed differences in cognitive function were unexpected, and there were larger score improvements on the Reading Span test in the hearing loss and tinnitus group than in the hearing loss group. Patients with tinnitus and hearing loss may receive extra benefit in terms of cognitive function following hearing aid rehabilitation.