Pure-tone auditory thresholds are decreased in depressed people with post-traumatic stress disorder

Background: Depression has been related to sensory modulation and notably to auditory modifications such as alterations in auditory event-related potentials, abnormal patterns of auditory habituation, increased activation of primary and secondary auditory cortex, and higher bilateral auditory thresholds. However, few experiments have considered the exploration of the auditory system in depression. The aim of the experiment is to further explore auditory thresholds across a higher number of frequencies than has previously been undertaken in depressed subjects, to determine whether thresholds are modified as compared to controls, and if so, at which frequencies. Methods: 25 pure-tones covering a large range of frequencies from 125 Hz to 8 kHz were used to measure both air and bone conduction (AC and BC respectively) hearing thresholds. 13 patients with depression and post-traumatic disorder matched for age, sex and education level with 13 healthy subjects, were tested. Results: Hearing thresholds were found to be significantly poorer in depressed participants than in controls for frequencies from 2.75 Hz to 8 kHz in BC, and for 0.5, 0.75, 0.875 and 2.0-8.0 kHz pure-tone frequencies in AC. Limitations: Given that the depressed patients also had comorbid post-traumatic disorder, it should be verified whether their modified pure-tone audiometry is only related to depression. Conclusions: The AC and BC pure-tone auditory threshold measurement may provide new and different insights into the aetiology and evolution of depression. (C) 2010 Elsevier B.V. All rights reserved.