Effects of three contralateral maskers on pure-tone thresholds using manual audiometry.

This study investigated how central masking associated with low-level maskers would affect thresholds obtained using a standard clinical technique. Signals included 500, 1,000, 2,000, and 4,000 Hz; maskers, presented at 40 dB SL, consisted of (a) a wideband masker (WBM), (b) a narrow-band masker (NBM) centered about each signal frequency, and (c) a pure-tone masker (PTM) identical to each signal. Only the PTMs caused significant threshold shifts, that is, poorer masked thresholds. The WBM and NBMs caused no shift 60% of the time and a 5-dB threshold improvement 16% of the time. The findings weigh against the clinical use of a central-masking correction when a low-level WMB or NBM is used.