Temporal resolution in hard-of-hearing patients.

Temporal resolution is, next to frequency resolution, the most important ability of the ear for perceiving speech. A simplified method for measuring temporal resolution clinically is described. It is based on masking period patterns, but measures only their maximum and minimum through the use of continuous and square-wave amplitude-modulated masking noises. Test tones and filtered masking noises are presented at 500, 1 500, and 4 000 Hz. Temporal resolution data of a normally hearing group and of seven pathological groups are given: Patients with conductive hearing loss show normal resolution; those with noise-induced, age-induced, and sudden hearing loss show normal resolution at low and middle frequencies, but reduced resolution at 4 000 Hz; patients with retrocochlear hearing loss and Menière's disorder show a tendency for reduced resolution at all frequencies, but reduction at 4 000 Hz, while ototoxic hearing loss shows the greatest reduction at 1 500 Hz. The method used also gives an indication for reduced frequency selectivity.