• Emilio Delehaye, Saverio Capobianco, Ivano Bruno Bertetto, and Francesco Meloni.
• University Department of Otolaryngology Head and Neck Surgery, viale San Pietro 43, 07100 Sassari, Italy. delemy@tiscali.it
• Auris Nasus Larynx. 2008 Jun 1; 35 (2): 198-202.

ObjectiveDeferoxamine therapy in lifelong transfusion-dependent anaemias, as beta-thalassemia major, is associated with an increased risk of ototoxic changes. With increasing survival rates, prevention and/or early detection of ototoxicity are important for providing management options. The predictive value of pure-tone audiometry in early detection of ototoxicity has been questioned, particularly in the higher frequencies. Otoacoustic emissions appear to be more sensitive to cochlear insult than the conventional pure-tone audiometry. The aim of our study was to compare the efficacy of otoacoustic emissions (distortion-product otoacoustic emissions) with that of pure-tone audiometry as method of audiological monitoring.MethodsBaseline audiometric (0.25-8kHz) and otoacoustic emission testing (distortion-product otoacoustic emissions) was conducted in a group of patients with beta-thalassemia major, 60 of whom met the criteria for inclusion in the study. Comparisons were performed between baseline measurements and those recorded after 20 months. Distortion-product otoacoustic emissions were obtained as DP-grams. The DP-gram amplitude was determined for each child.ResultsThreshold changes from baseline were found to be statistically significant from 4 to 8kHz in 68.4% of the subjects (P<0.01). Distortion-product otoacoustic emissions demonstrated a significant threshold shift and a decreased amplitude in the frequencies >3kHz (P<0.05). Furthermore, DP-gram amplitude also reduced significantly at 3kHz (P<0.05) without any similar change in pure-tone audiometry.ConclusionsAs ototoxicity screening tool DP-gram was extremely sensitive and superior to pure-tone audiometry. Their use is recommended for regular monitoring of cochlear function, aiming in prevention of permanent damage.

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