Manipulation of Auditory Inputs as Rehabilitation Therapy for Maladaptive Auditory Cortical Reorganization

[Tinnitus: clinical and pathogenetic aspects]

The article discusses the pathogenetic and clinical features of tinnitus. It is emphasized that various causes contribute to the appearance of tinnitus, including somatic diseases, excess body weight, iatrogenies, otological diseases with an outcome in hearing loss. The anatomical and physiological features of the structure of the central part of the auditory system are considered. It is suggested that the occurrence of tinnitus is associated with the processes of maladaptive neuroplasticity caused by pathological changes in the neuronal activity of cortical structures of the CNS, and not with changes in the peripheral part of the auditory analyzer - the structures of the cochlea. The results of recent studies, including those using functional neuroimaging methods, indicate the significance of cortical connection disorders (human connectome) in patients with tinnitus. In patients with tinnitus, there are changes in regional neuronal activity and connections not only in the auditory cortex, but also in areas not directly related to the analysis of auditory afferentation. Thus, tinnitus can be considered as one of the variants of dysfunction of the human connectome, triggered primarily from the «auditory input».

The Listening Network and Cochlear Implant Benefits in Hearing-Impaired Adults

Older adults with mild or no hearing loss make more errors and expend more effort listening to speech. Cochlear implants (CI) restore hearing to deaf patients but with limited fidelity. We hypothesized that patient-reported hearing and health-related quality of life in CI patients may similarly vary according to age. Speech Spatial Qualities (SSQ) of hearing scale and Health Utilities Index Mark III (HUI) questionnaires were administered to 543 unilaterally implanted adults across Europe, South Africa, and South America. Data were acquired before surgery and at 1, 2, and 3 years post-surgery. Data were analyzed using linear mixed models with visit, age group (18–34, 35–44, 45–54, 55–64, and 65+), and side of implant as main factors and adjusted for other covariates. Tinnitus and dizziness prevalence did not vary with age, but older groups had more preoperative hearing. Preoperatively and postoperatively, SSQ scores were significantly higher (Δ0.75–0.82) for those aged <45 compared with those 55+. However, gains in SSQ scores were equivalent across age groups, although postoperative SSQ scores were higher in right-ear implanted subjects. All age groups benefited equally in terms of HUI gain (0.18), with no decrease in scores with age. Overall, younger adults appeared to cope better with a degraded hearing before and after CI, leading to better subjective hearing performance.