ABR screening for acoustic neuromata: the role of rate-induced latency shift measurements

The audiological assessment of patients considered 'at risk' for an acoustic neuroma is problematic when the patient has a severe hearing loss. The utility of ABR rate-induced latency shift (RLS) measurements was investigated in 189 patients who had passed a conventional assessment and 31 patients with an acoustic neuroma. A test based on the RLS of wave V using rates of 11.1 s-1 and 88.8 s-1 had a sensitivity of 89.5% and a specificity of 90.8% when applied with a dual interpretive criterion which included the loss of wave V at the higher rate. This test was included in an ABR screening protocol which had a sensitivity of 100% and a specificity of 97.9%. The RLS test requires no correction for age, sex, hearing loss or stimulus intensity and may be used in patients with severe hearing loss for whom other ABR tests are inappropriate.