A sensorineural hearing loss (SNHL) of 30dB or more affecting at least three frequencies and occurring over less than three days is classified as ‘sudden’ SNHL (SSNHL). Treatment is urgently undertaken with systemic and/or intra-tympanic steroids, and ijn some cases anti-virals and hyperbaric oxygen. In this challenging condition, changes in ABR at the time of onset do seem to occur and whether or not they can predict prognosis remains interesting. In this study of 43 patients treated similarly, wave 1 and 5 latencies and amplitude were studied and correlated to prognosis. It was noted that the latency of wave 1 increased significantly in patients with SSNHL. It was also observed that patients with more favourable outcomes had smaller wave 1 latency initially and greater amplitude as compared with those who did not respond to treatment. Wave 1 latency was a single factor correlating to prognosis. The same parameters studied in wave 5 did not matter. Another observation was that, in the favourable response group, hearing in the unaffected ear was better. Other studies in literature showing generally similar results have been mentioned. The limitations of this research are small numbers and that the exact site of damage, whether cochlear or retro-cochlear, is impossible to determine. However, wave 1 does represent only the cochlea and, according to the authors, treatment can be focused and optimised.