The Roles of Contextual Stimuli and Personality Traits in Determining an Adaptation Level for Tinnitus

Abstract

This study assessed the validity of a recent psychoacoustic model of tinnitus put forth by Searchfield et al. (2012), based on Helson's (1964) adaptation level theory (ALT). An internal adaptation level is proposed to act as a reference point for all tinnitus-related judgments. This level is susceptible to change from attention, background (context) and residual (personality, memory, arousal and emotion) influences. The effects of each component can theoretically be quantified and modelled mathematically, making the model distinctive and significant for future tinnitus research. Two components of the ALT model - contextual noise levels and personality traits - were systematically measured to see the extent to which these variables corresponded with tinnitus audibility and distress outcomes, and whether these effects were in line with the ALT framework. 20 participants, 13 females and 7 males, were recruited. NBN was administered for twenty minutes each in quiet, at threshold level, 10 dB sensation level and 20 dB sensation level in a sound-proof booth. Personality variables were measured using the Multidimensional Personality Questionnaire Form NZ (MPQ-Form NZ). Tinnitus measures included loudness level matches, and visual analogue scale (VAS) ratings of loudness and distress. The results indicate tinnitus loudness and distress might represent different underlying constructs with different adaptation levels. Tinnitus distress-contextual noise interactions were consistent with the ALT model, but tinnitus loudness did not change under noise. The emergence of 'adaptation-sensitive' and 'adaptation-insensitive' persons was observable. An interaction between the personality traits of social closeness, positive emotionality, stress reaction and negative emotionality and contextual noise effects on tinnitus was observable. 20 dB SL lead to the greatest reduction in outcome measures, which roughly approximates what the ALT model predicts. The precise ideal noise level is proposed to be at/near the mixing point - as this was not measured individually, it was not possible to discern whether this prediction held or not. The model's conceptualization of the tinnitus loudness paradox was supported. As such, the first empirical findings of the ALT tinnitus model are promising. Suggestions for future investigations are provided.