Tinnitus and Hearing Loss

Abstract

Tinnitus is a symptom present in approximately 15% of the world, and this proportion increases to 33% in individuals over 60 years Jastreboff and Hanzel, 1993). It carries a negative impact on quality of life for 20% of them. May be associated with more than 300 diseases (Gananca et al, 1994), with a hearing loss of the most common (Hiller and Goebel, 2006). Only 80-10% of patients with tinnitus have normal hearing (Barnea et al, 1990), while 85 to 96% have some degree of hearing loss (Fowler, 1994; Sanchez e Ferrari, 2002). The influence of hearing loss in the degree of suffering of tinnitus remains no consensus (Baskell and Coles, 1999). Findings relate tinnitus severity to hearing loss at high frequencies (Weisz et al, 2004). Mazurek et al (2010) found a significant correlation between the degree of hearing loss and tinnitus loudness. They found that patients with decompensated chronic tinnitus had more hearing loss than those with compensated tinnitus. The study concluded had evidence that indirectly support the hypothesis that the degree of hearing loss affects the severity of tinnitus (Mazurek et al, 2010). Clinically significant hearing loss in patients with tinnitus was associated with anxiety and depression as a reaction to hearing loss that could interfere with the impact of tinnitus (McKinney et al, 1999). However it is not possible to say whether the hearing loss is only one cause of tinnitus or whether it also influences the severity and handicap (Davis, 1996). Searches related to gender discomfort is inconclusive. While Davis (1983) observed higher scores for discomfort due to tinnitus in women compared with men (Davis and Cole, 1983 and Coelho et al, 2004), and Hiller and Goebel (2006) a higher intensity and severity of tinnitus annoyance in older men. Meric et al (1998) and Pinto et al (2010) assessed the impact of tinnitus on quality of life and found no correlation between age, sex or duration of tinnitus and the annoyance it causes. The subjectivity of tinnitus, its symptoms, the different characteristics of each patient and the many causes of tinnitus are issues that require investigation. It is known that hearing loss is one of the largest generators of tinnitus and its pathology and diagnostics must be studied and known to offer the patient the 'most successful treatment option in symptom remission. It is well established that after lesions of the peripheral auditory receptor, the cochlea, increased spontaneous activity (hyperactivity) develops in central auditory nuclei. This plasticity has been demonstrated in a wide range of animal models, using either mechanically, acoustically, or drug-induced cochlear lesions (Brozoski et al., 2007; Bauer et