In response to Cost analysis of asymmetric sensorineural hearing loss investigations.

In their article titled ‘‘Cost Analysis of Asymmetric Sensorineural Hearing Loss Investigations,’’ Wilson et al. conclude that serological testing of patients is superior to magnetic resonance imaging (MRI) in detecting potentially treatable causes of asymmetric sensorineural hearing loss (ASNHL). Their article supports routine use of a serologic testing battery on all patients and only selective use of MRI. Unfortunately, their conclusions are invalidated by defects in the study design, their assumptions regarding the etiology of ASNHL, and a selective/defective citation of the literature. I submit that the literature argues that the most cost effective way to evaluate patients with significant ASNHL is to use serological testing selectively, and routinely use focused MRI as advocated by Carrier and Arriaga. In their introduction, the authors indicate that ‘‘many authors’’ advocate a costly battery of serological testing as a typical part of the evaluation of asymmetric sensorineural hearing loss. To support their claim, they cite an article published in Australian Family Physician in 2008. This citation can hardly be considered authoritative. The authors later cite Sabini and Sclafini as a source for which serologic tests to order, but somehow ignore their conclusion that serologic testing should be performed selectively based on history and physical examination rather than as a screening battery. In their study design, Wilson et al. focus exclusively on a comparison of serologic testing and MRI. With exception of the discussion section, they completely ignore the question of whether auditory brainstem response (ABR) testing should be part of an algorithm to evaluate ASNHL. It is widely acknowledged that the evaluation of ASNHL is the search for retrocochlear pathology. The likelihood that a systemic disease would cause purely unilateral sensorineural hearing loss (SNHL) is highly unlikely. History and physical examination would likely uncover potential systemic disease that may warrant selective serologic testing, hence the recommendation by Sabini and Sclafini. Any discussion of costs in a screening algorithm for ASNHL should incorporate how ABR would be used and its impact on cost. In the discussion section, the authors cite Leong et al. as a source supporting the use of MRI only on SNHL patients with neurological symptoms. Clearly, this article is focused on the topic of sudden SNHL, not ASNHL in general. Furthermore, the authors cite Ruckenstein et al. as a reference for the specificity and negative predictive value of stacked ABR, when in fact this study did not use stacked ABR (as it had not yet been reported) but rather used standard ABR. Furthermore, this article advocated for use of MRI as the preferred screening test for patients with ASNHL. Stacked ABR was first reported in the literature in 1997 by Don et al. Finally, it is puzzling how the authors were able to find and cite (although erroneously) the preliminary study of Ruckenstein et al. reporting on 47 patients, and miss the completed larger study looking at 312 patients that was published later as this writer’s Triological Society thesis. This study clearly indicates that ABR is inadequate as a screening tool of ASNHL, as nearly 30% of causative lesions found on MRI were missed by ABR. Furthermore, this prospective multi-institutional study found that MRI was positive in nearly 10% of the screened ASNHL population. Focused MRI should be an integral part of the evaluation of patients with significant ASNHL. Missing the early diagnosis of a small acoustic neuroma has potentially devastating consequences for the patient. If a focused type of MRI is used, the cost of this gold standard test is dramatically reduced. We can all agree that cost containment in healthcare is important, but not at the expense of quality care. Selective use of serologic tests avoids wasteful expenditures, whereas routine use of focused MRI to screen patients with significant ASNHL yields the most cost-effective evaluation of ASNHL.