Salivary cortisol levels, subjective stress, and tinnitus intensity in tinnitus sufferers during noise exposure in the laboratory

Abstract

Tinnitus, a chronic internal noise, is thought to increase in intensity during or following external noise exposure. Yet there is no empirical evidence for this complaint in the extant literature. Recently, cortisol has been advanced as a useful tool for studying the physiological effects of noise on stress, but few, if any, studies have examined the short-term effects of noise on cortisol levels in tinnitus sufferers. This study assesses the effects of noise exposure on cortisol levels and subjective stress in tinnitus participants and controls without tinnitus. Twenty tinnitus participants and 20 controls without tinnitus were exposed to a 20-min broadband noise with amplified low frequencies. Saliva samplings for cortisol analysis and subjective stress and tinnitus intensity ratings (for tinnitus participants) were performed at regular intervals throughout testing. Results show higher cortisol levels for both groups immediately before, immediately after, and 10min after the end of noise than at other time points. The tinnitus group had lower overall cortisol levels than controls. In contrast, subjective stress ratings were higher for the tinnitus group, and higher at midpoint and immediately after the noise ended. Tinnitus subjective intensity increased throughout testing, especially for the group with high tinnitus-related distress. Overall results show that noise exposure influences cortisol response, subjective stress, and tinnitus intensity.