Can the tinnitus spectrum identify tinnitus subgroups?

The tinnitus spectrum is a psycho-acoustic metric of tinnitus. Previous work found a tight relation between the spectrum and the tone audiogram. This suggests that the spectrum and the audiogram provide essentially the same information, and the added value of the spectrum is limited. In order to test whether the spectrum shows tinnitus characteristics that cannot be inferred from the audiogram, we re-examined the relation between the tinnitus spectrum and the tone audiogram, in a group of 80 tinnitus patients. We defined three subgroups of patients, using the shape of their tinnitus spectrum: (1) patients with a spectrum, monotonously increasing with frequency (2) patients with a distinct peak in their spectrum, (3) all other patients. Patients in group 3 typically showed low frequency tinnitus spectra. In all three groups, the largest hearing loss was at high frequencies (>2 kHz). The mean audiograms of group 1 and 2 were remarkably similar; group 3 had an additional hearing loss for the lower frequencies (<2 kHz). The three groups did not differ with respect to age, sex, or tinnitus questionnaire outcomes. In subgroups 2 and 3, the shape of the spectrum clearly differed from that of the tone audiogram. In other words, the spectrum technique provided information that could not have been obtained by tone audiometry alone. Therefore, the spectrum measurement may develop into a technique that can differentiate between classes of tinnitus. This may eventually contribute to the effective management of tinnitus, as various classes of tinnitus may require different therapeutic interventions.

A randomized double-blind crossover study of phase-shift sound therapy for tinnitus.

OBJECTIVE: The purpose of this study was to compare the efficacy of the treatment of tinnitus with a phase-shifting pure tone to that of the same tone treatment without phase shifting. STUDY DESIGN: A double-blind crossover randomized controlled trial. SETTING: This study was conducted at the University Medical Center Groningen. SUBJECTS AND METHODS: Twenty-two patients with predominantly tonal tinnitus underwent both intervention and control treatments. Each treatment consisted of three 30-minute sessions in 1 week. The control treatment was identical to the intervention treatment, except that the stimulus was a pure tone without phase shifting. Questionnaires, tinnitus loudness match, and annoyance and loudness ratings were used to measure treatment effects. RESULTS: Pure-tone treatment and phase-shift treatment had no significant effect on tinnitus according to questionnaires (Tinnitus Handicap Index, Tinnitus Reaction Questionnaire, Hospital Anxiety and Depression Scale, and Maastricht Questionnaire), audiological matching procedures, and loudness and annoyance ratings of tinnitus. Furthermore, phase-shift treatment showed no additional significant improvement in comparison with pure-tone treatment. Changes in questionnaire scores due to pure-tone and the phase-shift treatment were correlated. CONCLUSION: On average across the group, both treatments failed to demonstrate a significant effect. Both treatments were beneficial for some patients. However, a positive effect was not demonstrated that could be attributed to the periodic shifting of the phase of the stimulus tone.