Can patients determine their tinnitus frequency using recursive matching?
23 April 2019 (online)
Determining the individual tinnitus frequency of tinnitus patients is a standard requirement in clinical settings and is important for research and treatment alike. However, the method used to reliably measure this frequency is controversial.
(Dominant) tinnitus frequency was measured in patients (N = 117) suffering from chronic tinnitus using an iPod-based recursive matching procedure. To get an estimate for individual variability measurements were performed twice a day on five consecutive days. For this procedure, the frequency range (1 to 16 kHz) is bisected into two equally large subintervals of which the patient has to decide being more similar to their tinnitus. Depending on the outcome, new subintervals are calculated. The smallest step size was 1/12 octave.
Mean and median across measures were almost identical. The mean standard deviation turned out to be less than 1/2 octave. In a data driven approach we determined patients with particularly high variability. These were patients (N = 5) whose standard deviation (SD) across the ten measures differed more than two SD (about 1/2 octave) from the mean SD of the whole sample. Inspecting these cases on an individual basis suggested high variability on the first two days as well as the occurrence of octave confusion, however with sometimes more than three octaves. Reducing systematically the number of measurements resulted in slightly more patients with high deviation of the mean and higher variability across the whole sample.
Taken together, repetitive recursive matching appears to be a promising method to reliably estimate the individual tinnitus frequency for both research and clinical purposes alike.