LXXXVII Sudden Deafness

Investigation of Stress Levels before the Onset of Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVES

We hypothesized that patients with idiopathic sudden sensorineural hearing loss (ISSHL) would have experienced more stress prior to the onset than they typically did. This study investigated stress levels in patients before the onset of ISSHL.

MATERIALS AND METHODS

Forty-two patients with ISSHL were investigated. We used an original questionnaire to evaluate subjective stress levels in 1 week before onset. Serum hemoglobin A1c (HbA1c) and total cholesterol were examined to evaluate biochemical stress markers reflecting the preceding 1 to 2 months. The results on admission were compared with those at the follow-up visit.

RESULTS

Significantly more patients reported greater physical exhaustion, greater mental exhaustion, or a worse physical condition on admission than at follow-up (p<0.01, for each variable). On admission, 81% of patients reported greater than normal stress with regard to at least 1 of 3 items. The mean serum HbA1c was slightly but nonsignificantly lower at the follow-up visit (p=0.10), while the mean serum total cholesterol was significantly lower at follow-up than on admission (p<0.01).

CONCLUSION

The results indicate that patients were under a greater degree of stress before the onset of ISSHL, suggesting that stress plays a role in inducing ISSHL.

Surdez súbita idiopática: aspectos etiológicos e fisiopatogênicos

Vários fatores têm sido postulados como causa da surdez súbita idiopática. Por meio de uma revisão bibliográfica foi feita uma análise crítica quanto aos aspectos etiológicos e fisiopatogênicos desta manifestação clínica. Estudos atuais sugerem que os distúrbios vasculares, a ruptura de membranas da orelha interna e as doenças auto-imunes são possíveis causas, mas a afecção viral tem recebido maior atenção nos últimos anos, embora ainda pouco se conheça sobre os mecanismos da surdez súbita idiopática. Os vírus podem causar a perda súbita da audição na infecção aguda, mas a forma latente, com uma possível reativação viral, também tem sido considerada no mecanismo de agressão à cóclea. Apesar de uma alteração da viscosidade sangüínea poder explicar a perda auditiva, estudos experimentais e clínicos não mostram sinais de ossificação e de fibrose na cóclea ou de ruptura de membranas do labirinto. Estes fatos contrapõem, respectivamente, a teoria vascular e a da fístula labiríntica. A eventual presença de anticorpos contra a orelha interna sugere que a surdez súbita idiopática possa ser de natureza auto-imune, fato este também não confirmado pela falta de relação entre os aspectos clínicos e morfológicos da doença auto-imune e da perda auditiva. A surdez súbita idiopática é, ainda, um tema controverso e obscuro em diversos aspectos.

Idiopathic sudden sensorineural hearing loss: etiopathogenic aspects

Several factors have been postulated to elicit the etiology of idiopathic sudden sensorineural hearing loss. Through a bibliographic review, we made a critical analysis of the different etiopathogenic aspects of its clinical manifestation. The most recent studies concerning the possible causes of sudden hearing loss suggest vascular disorders, rupture of the inner ear membrane and autoimmune diseases; however, viral infections have received a great deal of attention in recent years. Little is known about the mechanism of sudden hearing loss. Viruses can cause sudden hearing loss in an acute infection, however the latent form, and its possible reactivation have also been considered as explanations of the cochlear injury mechanism. Even though hearing loss can be explained by a blood viscosity change, experimental and clinical studies do not show any evidence of labyrinthine fibrosis and new bone formation, or labyrinthine membrane breaks. These findings are not in agreement with vascular and rupture membrane factors, respectively. The eventual presence of antibodies against the inner ear suggests that sudden hearing loss pathogenesis may be of autoimmune nature, but the difficulty in establishing the correlation of its morphological and clinical aspects to the hearing loss also do not help to support this statement. Sudden hearing loss is still a controversial and obscure subject in several aspects.

Idiopathic bilateral sensorineural hearing loss: its clinical study in cases with rapidly progressed deafness

In a series of 127 patients with idiopathic bilateral sensorineural hearing loss (IBSH) at the Hearing Clinic in the Department of Otolaryngology, Kitasato University Hospital, 20 cases showed rapid progression of hearing impairment. These patients had been treated with the same therapeutic regimen used in sudden deafness (SD). Improvement of hearing loss after treatment was generally less effective in the cases with rapidly progressed IBSH than in the cases with SD. However, hearing improvement was achieved in some cases with rapidly progressed IBSH when the treatment had started in the early stages after the onset of rapidly progressive hearing loss.

Total bilateral hearing loss as a complication of myeloma

A 58-year-old lady relapsed from longterm remission of multiple myeloma and developed a sudden and complete hearing loss in the left ear followed two weeks later by the right ear. This permanent loss was almost certainly due to inner ear haemorrhages.

Hemodilution in sudden deafness: first results

The technique of hemodilution was assessed in 12 cases of sudden hearing loss as it is known to improve peripheral circulation. Good results were obtained in nine patients. The immediacy of the effects suggests the real efficacy of hemodilution as opposed to spontaneous recovery. Hemodilution is supposed to improve oxygenation in the cochlea. This technique is very simple and quick to perform.

The effects of vascular occlusion on the human inner ear

Occlusion of the anterior vestibular artery has resulted in severe degeneration and new bone formation limited to the utricle, saccule, and superior and lateral semicircular canals. Depriving the inner ear of its main blood supply, i.e. the internal auditory artery, has resulted in severe degeneration and ossification of the entire membranous labyrinth, except the endolymphatic duct and sac. A more severe cochlear sclerosis was seen when both arterial and venous blood supplies to the cochlea were occluded. The implications of these findings on the etiology and management of inner ear disorders are emphasized.

Fibrinolytic activity in patients with sudden sensorineural hearing loss

Fibrinolytic activity and capacity were studied in a group of 18 patients with sudden sensorineural hearing loss of unknown etiology. The fibrinolytic activity and capacity were found reduced in 12 patients. No distinct changes in platelet aggregation in vitro could be demonstrated. Further, repeated studies in this category of patients should be performed.

Natural history of sudden sensorineural hearing loss

This is a prospective in-depth study of patients with sudden idiopathic sensorineural hearing loss. We found that 65% recover completely to functional hearing levels spontaneously and independent of any type of medical treatment. The majority do so within 14 days and many within the first few days. Prognosis can be predicted according to the slope of the initial audiogram (low-frequency losses do better than high-frequency losses), hearing at 8 kHz, erythrocyte sedimentation rates, in some select instances spatial disorientation symptoms, and speech discrimination scores. There was a very poor correlation between hearing and vestibular test abnormalities, except hypoactive calories. There were no correlations with age (excepting the very elderly), with antecedent respiratory infections, hypertension, diabetes, or other chronic diseases. We conclude that there is a fundamental difference in the behavior of apical and basal cochlea losses, that hearing recovery is always better at low than at high frequencies, that because of the high spontaneous recovery rates, tympanotomies seeking peri-lymph fistulas should be delayed ten days unless there is a progressive hearing loss, and that none of the current recommended treatments, especially histamine, have any effect on the outcome.