RESIDUAL INHIBITION OF TINNITUS.
Residual Inhibition (RI) of tinnitus is the reduction or abolition of tinnitus following exposure to a sound stimulus. This is usually temporary but can increase in duration and become permanent with repeated exposure to the sound signal.
Residual Inhibition was first recorded in 1906 by Spaulding, a New York physician who observed that his tinnitus patients did not hear their tinnitus after he stopped playing his violin. He noted that it took 30 to 60 seconds before the tinnitus returned. This phenomenon was subsequently named Residual Inhibition which is defined as the reduction or complete absence of tinnitus after exposure to a sound stimulus.
Despite extensive research efforts during the 1970's, RI could not be made to last longer than 30 to 60 seconds and this was considered insufficient to be useful in treating tinnitus. The underlying physiology producing RI is still not known and it remains a clinical curiosity.
The TIPA research project was commenced in 2001 to find out whether modifying the characteristics of the sound stimulus would increase the duration of RI. Audio engineering software and digital synthesisers were used to create new sounds. However as there were no established objective correlates of tinnitus in humans RI could only be detected by the subjective response of the patient and therefore clinical progress was very slow. These initial studies confirmed that RI could be prolonged by manipulation of the characteristics of the sound stimulus. The resulting sound was TIPA which has subsequently been used in the clinical treatment of tinnitus with successful results
In August 2011 Magnetoencephalograpy (MEG) was used at Macquarie University in Sydney to demonstrated objective correlates of tinnitus before and after tinnitus was inhibited following exposure to TIPA. These findings were first published at the Tinnitus Research Initiative Conference in Buffalo, New York in August 2011 and also on this website.
Clinical and laboratory research with TIPA has continued and results are published on the "Clinical Trial 2014" page.