Figure 1.

Line graphs showing ABR recordings (A–D) in control (n = 12) and noise-exposed (n = 36) rats at 80 dB SPL for frequencies between 0.5 and 32 kHz. When compared to the ABR pattern of unexposed rats (A), noise exposure (118 dB SPL) for 4 h/day during 4 consecutive days resulted in an almost complete absence of the typical ABR waves at all frequencies and time points assessed following the exposure (B–D). Progression of the auditory thresholds (E,F) indicated that noise-exposed rats at all survival times had higher values than those observed in unexposed animals (E). The threshold shift values fluctuated between 32 and 42 dB (F). Recordings in (A–D) are represented at 80 dB SPL.