The Impact of Tinnitus on N-Back Performance in Normal Hearing Individuals

Tinnitus sufferers commonly report concentration difficulties. Despite several previous studies investigating this, the underlying cause and the role of hearing status remains unclear.

To investigate whether there are any differences between normal hearing individuals with and without tinnitus in terms of working memory capacity, and whether working memory capacity correlates with high-frequency hearing thresholds.

Participants had their hearing thresholds measured (0.125-16 kHz) and performed a visual n-back test. All participants completed the Hospital Anxiety and Depression Scale, in addition tinnitus participants filled out the Tinnitus Questionnaire.

Sixty-two individuals participated, 31 had tinnitus (tinnitus group) and 31 did not have tinnitus (control group). Groups were age- and sex matched, and all participants had normal hearing thresholds (20 dB HL or better at 0.125-8 kHz).

Friedman test of differences among repeated measures was conducted on the collected data of n-back performance, and Mann-Whitney U-test was used to compare groups. Age-corrected correlations were calculated for high-frequency hearing and each n-back condition.

We found no significant differences between the groups in terms of n-back task performances, except for the 2-back condition where the tinnitus group performed significantly better than the controls (p = 0.007). Furthermore, we found high-frequency hearing thresholds of the best ear (10-16 kHz) to correlate with performances at more demanding n-back conditions (p = 0.029 for 1-back and p = 0.015 for 2-back).

This suggests that presence of tinnitus might not imply poorer working memory capacity and that deteriorated high-frequency hearing thresholds.