Development of a fast method for measuring sensitivity to temporal fine structure information at low frequencies

Recent work suggests that hearing-impaired subjects are relatively insensitive to temporal fine structure (TFS) information, but that sensitivity among subjects varies considerably. Moore and Sek (2009) developed a fast and easy to administer test of sensitivity to TFS, but it can only be used at medium to high frequencies. Here we describe a binaural method that can be used at lower frequencies. An adaptive two-alternative forced-choice task was used. Each interval contained four tones with frequency f; in one interval all tones were diotic, and in the other tones one and three were diotic while tones two and four had an interaural phase shift, Δϕ. The task was to identify the interval with the phase-shifted tones. For normal-hearing subjects, the effects of sensation level and training on performance were small, and the test could be performed reliably for f = 250, 500, and 750 Hz.