Determine the prevalence of clinical insomnia and its associations with anxiety, depression, and tinnitus in adult cochlear implant (CI) users.
Self-reported information on tinnitus, sleep, and demographic variables was collected from adult CI users (n = 127). Tinnitus presence, its persistence, related emotional distress, and difficulties with sleep were assessed using questions from the UK Biobank study (www.ukbiobank.ac.uk). Tinnitus-related handicap was assessed using the Tinnitus Handicap Inventory. Clinical insomnia symptoms were characterized using the Insomnia Severity Index (ISI), and clinical anxiety and depression symptoms using the Hospital Anxiety and Depression Scale (HADS). Regression models were used to compare the data from CI users with and without tinnitus, and to test the associations between clinical insomnia, anxiety, depression and tinnitus handicap.
About a half (53%) of CI users reported tinnitus, of whom 54% described it as persistent, 41% as emotionally distressing and 73% reported having difficulties with sleep based on the UK Biobank questions. The ISI suggested that clinically abnormal insomnia symptoms were more likely to occur with tinnitus (odds ratio [OR] = 2.60, 95% confidence interval 1.04 to 6.45; p = 0.040) and were found in 41% of CI users with tinnitus. Post-hoc exploratory analyses on the ISI suggested that CI users with tinnitus experienced greater levels of difficulty falling asleep, lower satisfaction with sleep patterns, greater interference of sleep problems with daily activities, and a greater impact on their quality of life. The HADS scores suggested that those with tinnitus were also more likely to have clinically abnormal anxiety (42%; OR = 3.50, 95% confidence interval 1.49 to 8.22; p = 0.004) and depression symptoms (14%; OR = 6.18, 95% confidence interval 1.17 to 32.82; p = 0.032). The clinical insomnia observed in CI users with tinnitus was associated with tinnitus handicap (p = 0.028), and the levels of clinical anxiety (p = 0.012) and depression (p < 0.001).
Clinically abnormal insomnia symptoms are prevalent, potentially affecting over 40% of CI users with tinnitus. The associations between clinical insomnia, anxiety, and depression symptoms, and tinnitus-related handicap suggest that all of these symptoms should be considered when assessing the tinnitus-related burden and its impact on the quality of life after cochlear implantation. The present findings also have potential implications for the clinical management of CI recipients with tinnitus, in whom it may be advisable to monitor sleep problems so that they can be addressed where appropriate. Further research is needed to investigate the mechanisms and causal links behind insomnia and tinnitus-related symptoms in this population. Future studies should also investigate the feasibility and effectiveness of night time use of CIs to alleviate tinnitus-related insomnia. The potential impact of insomnia on the quality of life of CI users with tinnitus highlights the importance of including sleep measures in future evaluations of the effectiveness of cochlear implantation for the alleviation of tinnitus.