Use of the acoustic reflex threshold at 3 kc/s for setting optimal click-presentation level in ABR testing.

Ten otoscopically and tympanometrically normal young men with noise-exposed hearing loss (mn HTL at 1 kc/s = 25 db, and at 3 and 4 kc/s = 50 db) were examined for threshold of acoustic reflex (AR) at 3 kc/s. Wave V latency was then determined to a click of which the peak SPL was equivalent to the AR threshold at 3 kc/s, and at 4 additional levels +/- 5 and +/- 10 db. At the equivalent AR threshold level, 6 Ss yielded Wave V latency within normal limits, while at +5, and also at +10 db, all 10 Ss did so. It was concluded that an optimal setting of click level for ABR diagnostic use was +5 db re AR threshold at 3 kc/s, at least for the shielded circumaural earphone/cushion unit used here.