Identifying dead regions in the cochlea through the TEN test.

UNLABELLED An audiogram is not sufficient to indicate cochlear dead regions. AIM To investigate cochlear dead regions in sensorineural hearing loss subjects using the TEN test. SITE: CEDALVI/ HRAC-USP-Bauru/Sao Paulo/Brazil, August 2003 to February 2004. STUDY DESIGN A contemporary cross-sectional cohort study. MATERIAL AND METHODS The TEN test was applied in three groups: G1(5 women with pure-tone thresholds within normal limits); G2(4 women and 5 men with moderate sensorineural flat hearing loss); G3(19 women and 24 men with mild to severe sloping sensorineural hearing loss). RESULTS In the G1 group the TEN value required to eliminate the test tone was, on average, close to the absolute threshold for all frequencies. No dead regions were found in the ears tested in group G2. 76 ears were tested in group G3, and six showed no evidence of dead regions in the cochlea. CONCLUSIONS The TEN test was an effective test to indicate a dead region in the cochlea of subjects with sloping sensorineural hearing loss. There is evidence that pure-tone detection is different for subjects with high frequency sensorineural hearing loss and flat hearing loss; we observed a significant difference between the masked threshold and the absolute threshold only in sloping hearing loss and not for flat hearing loss.