BACKGROUND: Tinnitus suppression following acoustic stimulation is a well-known phenomenon also termed residual inhibition (RI). Some individuals may experience prolonged RI (PRI), which can last for several hours or even days, after a single short-term acoustic stimulation. Exact mechanisms of this phenomenon are unknown and current evidence anecdotal.
OBJECTIVES: The aim of our report is to collect, present, and discuss cases of PRI from our studies on acoustic stimulation in tinnitus with the aim to better understand this phenomenon as well as its implications for individualized treatments.
METHODS: We pooled cases of PRI from four of our studies with a total sample size of n = 130. The criterion was set on a PRI duration which is at least sustained twice as long as the acoustic stimulation duration.
RESULTS: We report a total number of about 5% of all participants experiencing some form of PRI, with rates of 3%-7% across the individual studies. PRI lasted from 20 min up to several days and was induced by the first stimulus in four out of six cases. Four out of six individuals experiencing PRI were female and PRI mostly occurred when acoustic stimuli were matched to the frequency or type of the tinnitus.
CONCLUSION: PTS seems to be elicitable in a small subset of tinnitus patients which could inform future individualized treatment options. Future studies should investigate if and how identified factors like stimulus type, position, sex, and chronification grade uphold experimental scrutiny. We propose that the set of methods is furthermore extended with neurophysiology in particular.