A patient receiving cisplatin chemotherapy is enrolled in an ototoxicity monitoring programme. A baseline DPOAE was recorded before treatment. On the current visit, the highest-frequency DPOAEs have dropped while the speech-frequency emissions and the pure-tone audiogram remain unchanged.
Findings
○ Right — PTA 17 dB (Normal)✕ Left — PTA 22 dB (Normal)
Pure-tone audiogram companion. dB HL increases downward, following clinical convention. Illustrative thresholds — not recorded patient data.
● DP emission▮ Noise floor
A normal DP-gram. The emission sits comfortably above the noise floor at every test frequency — the margin between the two is the signal-to-noise ratio. Simplified teaching model, not calibrated normative data.
Diagnostic question
The audiogram is unchanged but high-frequency DPOAEs have fallen. What is the appropriate interpretation?