One Step Closer towards a Reliable Tinnitus Pitch-Match Frequency Determination Using Repetitive Recursive Matching.
INTRODUCTION: The determination of the tinnitus pitch-match (PM) frequency is not straightforward but an important audiological assessment recommended for clinical and research purposes. We evaluated repetitive recursive matching using an iPod-based matching procedure as a method to estimate a patient's PM frequency without audiometric equipment. METHODS: One hundred and seventeen patients with chronic tonal tinnitus (uni- and bilateral tinnitus) measured their tinnitus in 10 sessions using a self-administered automated iPod-based procedure comprising a recursive 2 interval forced-choice test. RESULTS: Mean SD of the PM frequency of all participants across sessions was 0.41 octaves. The internal consistency measured by Cronbach's alpha was very high (0.8->0.95). As an example, 7 PMs obtained excellent internal consistency (alpha = 0.93). The exclusion of the first and/or second session led to more definite PMs with a decreased SD. Outliers were identified by PMs departing 2 SDs (i.e., 0.94 octaves) from the mean variability (n = 5). CONCLUSION: Repetitive recursive matching together with recommendations for the exclusion of initial and redundant sessions as well as outlier identification and treatment can enable a reliable estimation of the PM frequency.