A Qualitative Study on Factors Modulating Tinnitus Experience.

OBJECTIVES: It is well recognized that tinnitus can severely interfere with important aspects of life such as sleep, concentration abilities, social activities, and mood. However, the impact of tinnitus may vary greatly from one individual to another, with some being severely affected and others only experiencing a slight handicap. Information from participants' experiences with tinnitus could help explain such variability. The full experience of living with tinnitus from a patient's perspective has been under-investigated, especially in comparison with the large and extensive body of qualitative research on hearing loss. This study aims to contribute to fill this gap and assess participants' experience of living with tinnitus. DESIGN: As part of a larger mixed design study, this inquiry used qualitative analyses to investigate participant's experiences with tinnitus. Twenty-seven tinnitus participants of different ages, sexes, audiometric profiles, and tinnitus severities were invited to discuss their tinnitus through semistructured interviews and journal entries. The interviews took place 1 month after participants completed a 3-week trial period with tinnitus maskers. RESULTS: The findings were grouped into three main themes: participants' appraisal of their tinnitus, factors modulating tinnitus experience, and consequences of tinnitus. Regarding participants' appraisal of their tinnitus, a dissociation between the tinnitus sensation (pitch, loudness) and tinnitus experience (annoyance/distress) was reported. Factors modulating tinnitus experience were classified as environmental factors and individual-specific factors, which were further divided into soundscape and other environmental factors for the former and attentional focus, stress level, physical state, fatigue, and auditory effort for the latter. Consequences of tinnitus included distraction, disrupted mental health and mood, headaches, fatigue, sleep disturbances, hearing difficulties, disrupted social life, and frustration. CONCLUSIONS: Two of the main themes (participants' appraisal of their tinnitus and consequences of tinnitus) were consistent with findings from a few previous qualitative studies. Factors modulating tinnitus experience also emerged as a prominent theme. Indeed, participants described a plethora of factors that affected their experiences of tinnitus. On the basis of these findings, an attentional model is proposed to account for how these factors might modulate the effects of tinnitus.

Individual Differences in the Frequency-Following Response: Relation to Pitch Perception.

The scalp-recorded frequency-following response (FFR) is a measure of the auditory nervous system's representation of periodic sound, and may serve as a marker of training-related enhancements, behavioural deficits, and clinical conditions. However, FFRs of healthy normal subjects show considerable variability that remains unexplained. We investigated whether the FFR representation of the frequency content of a complex tone is related to the perception of the pitch of the fundamental frequency. The strength of the fundamental frequency in the FFR of 39 people with normal hearing was assessed when they listened to complex tones that either included or lacked energy at the fundamental frequency. We found that the strength of the fundamental representation of the missing fundamental tone complex correlated significantly with people's general tendency to perceive the pitch of the tone as either matching the frequency of the spectral components that were present, or that of the missing fundamental. Although at a group level the fundamental representation in the FFR did not appear to be affected by the presence or absence of energy at the same frequency in the stimulus, the two conditions were statistically distinguishable for some subjects individually, indicating that the neural representation is not linearly dependent on the stimulus content. In a second experiment using a within-subjects paradigm, we showed that subjects can learn to reversibly select between either fundamental or spectral perception, and that this is accompanied both by changes to the fundamental representation in the FFR and to cortical-based gamma activity. These results suggest that both fundamental and spectral representations coexist, and are available for later auditory processing stages, the requirements of which may also influence their relative strength and thus modulate FFR variability. The data also highlight voluntary mode perception as a new paradigm with which to study top-down vs bottom-up mechanisms that support the emerging view of the FFR as the outcome of integrated processing in the entire auditory system.