Prognostic Factors in Sudden Sensorineural Hearing Loss

Abstract

Background: Sudden sensorineural hearing loss (SSNHL) is still a complex and challenging process which requires clinical evidence regarding its etiology, treatment and prognostic factors. Therefore, determination of prognostic factors might aid in the selection of proper treatment modality.

Aims: The aim of this study is to analyze whether there is correlation between SSNHL outcomes and (1) systemic steroid therapy, (2) time gap between onset of symptoms and initiation of therapy and (3) audiological pattern of hearing loss.

Study design: Retrospective chart review.

Methods: Patients diagnosed at our clinic with SSNHL between May 2005 and December 2011 were reviewed. A detailed history of demographic features, side of hearing loss, previous SSNHL and/or ear surgery, recent upper respiratory tract infection, season of admission, duration of symptoms before admission and the presence of co-morbid diseases was obtained. Radiological and audiological evaluations were recorded and treatment protocol was assessed to determine whether systemic steroids were administered or not. Treatment started ≤5 days was regarded as "early" and >5 days as "delayed". Initial audiological configurations were grouped as "upward sloping", "downward sloping", "flat" and "profound" hearing loss. Significant recovery was defined as thresholds improved to the same level with the unaffected ear or improved ≥30 dB on average. Slight recovery was hearing improvement between 10-30dB on average. Hearing recovery less than 10 dB was accepted as unchanged.

Results: Among the 181 patients who met the inclusion criteria, systemic steroid was administered to 122 patients (67.4%), whereas 59 (32.6%) patients did not have steroids. It was found that steroid administration did not have any statistically significant effect in either recovered or unchanged hearing groups. Early treatment was achieved in 105 patients (58%) and 76 patients (42%) had delayed treatment. Recovery rates were no different in these two groups; however, when unchanged hearing rates were compared, it was statistically significantly lower in the early treatment group (p<0.05). When hearing outcomes were compared according to initial audiological pattern, significant recovery and unchanged hearing rates did not differ between groups; however, slight recovery rate was highest in the "flat" type audiological configuration (p<0.05).

Conclusion: According to this patient series, oral steroid therapy does not have any influence on the outcomes of SSNHL. However, mid-frequency hearing loss of flat type and initiation of treatment earlier than 5 days from the onset of symptoms, seem to have positive prognostic effects. Further randomized controlled subject groups might contribute to determine prognostic factors of SSNHL.

Keywords: Audiological configuration; delayed treatment; prognostic factors; sudden sensorineural hearing loss; systemic steroids.