Møller (2007) and Eggermont(2007) describe the possible pathophysiology of tinnitus resulting from neuralsynchrony in the peripheral auditory system, increase in signal firing rates inneurons at various locations, and tonotopic map changes in the peripheralauditory cortex. Møller (2007) stated when the cochlea becomes impaired, bothinhibitory and excitatory signals to the cochlear nucleus may be decreased, butespecially inhibitory signals.
Additionally, other nuclei in the auditorypathway may have increased excitability due to this reduced inhibition. Perceptions from tonotopic map changes werecompared to those sensations experienced and described as a “phantom limb”(Eggermont, 2007). Eggermont stated cochlear injury could be correlated withdecreased inhibition in deafferented frequency regions in the primary auditorycortex, contributing to the perceived sound.
Møller (2007) also indicatedtinnitus may arise from neural plasticity and reorganization of the centralnervous system and non-classical pathways, so parts of the nervous system notusually involved in processing sounds develop a role.Roberts et al.(2010) suggest that the interruption of afferent connections to the central auditorystructures of the brain, such as the sensorineural loss of high-frequencyhearing due to inner ear damage by noise exposure or ototoxic agents, causes anincrease of spontaneous firing rates in more central neurons. These increasedfiring rates may lay the foundation for neural synchrony leading to tinnitus.
The focus of thisstudy will be on Tinnitus Retraining Therapy (TRT), which is based on theneurophysiological model of tinnitus described by Jastreboff (2011) as theappearance of clinically relevant, bothersome tinnitus that involves areas ofthe brain in addition to the auditory system area, namely the limbic andsympathetic autonomic nervous systems, in the negative reaction to theperception of the sounds. The cause of the neural activity producing tinnitusis proposed to be outer and inner hair cell dysfunction, such as describedabove; however, the neurophysiological model for TRT additionally is focused onthe negative reactions from the tinnitus that are perceived by some individualswhen the tinnitus signal spreads to other areas of the brain.Rosing, Schmidt,Wedderkopp, and Baguley (2016) conducted a systematic review of literature andfound a large range in tinnitus rates reported by various studies, withoccurrence from 4.7% to 46% in the pediatric population and 23.5% to 62.2% inchildren with hearing loss, with the samples being children 5-19 years of age.The large ranges were contributed to several causes, including differences instudy design and question proposals to the pediatric patients.
In any patient,tinnitus can have a negative impact on the individual with the perception.According to the American Tinnitus Association (2016), in the generalpopulation, on a scale of 1-10, tinnitus impacts individuals’ daily lives at alevel of 10 in about 5% of the population with the condition. McCormack et al.
(2014) found tinnitus to be bothersome in about 4% of individuals, or 22-26% oftheir sample who reported tinnitus. Some of the effects tinnitus can haveinclude anxiety, sleep problems, and trouble concentrating. How tinnitusaffects children specifically is a topic with limited research. However, Shetyeand Kennedy (2010) report that interference with sleep, difficulty withconcentration at home and school, tiredness, and anxiety are commonly reportedco-occurring symptoms in children with tinnitus.
Currently,there are several possible treatments for individuals suffering from tinnitus,including cognitive behavioral therapy, counseling, sound therapies, and medicalapproaches including pharmacological methods to treat associated conditionssuch as anxiety (Katz, Chasin, English, Hood, & Tillery, 2015). The focusof this study is on Tinnitus Retraining Therapy outcomes for children withtinnitus that impacts their daily lives.