Abstract:
It is currently believed that the majority of tinnitus is a consequence of changes in the central auditory pathways following peripheral injury. This change in brain function is known as plasticity. Another form of plasticity occurs as a process of learning or training. The basis of perceptual training is that by exposure to sensory stimuli we learn, usually improving perceptual skills. Perceptual training usually requires the listener to be actively involved in listening and responding to training sounds, unlike sound therapy used in masking or habituation therapies where listeners are passively exposed to sounds. In this paper various forms of perceptual training are introduced before describing Frequency Categorisation Training (FCT) and Frequency Discrimination Training (FDT) and their effects on Tinnitus and late Auditory Evoked Potentials (AEP). Twenty participants underwent assessment and training. Assessment of tinnitus handicap rating and the P1-N1-P2 AEP complex (64 channel BioSemi EEG system) at pitch match, one octave below pitch match and at 750 Hz were undertaken before and after participants completed FCT or FDT for 21 training sessions over 3 weeks. Auditory training was carried out daily in the participants own home using a Palm Tungsten E2 PDA. The THI score reduced by 5.11 points following FDT. Ability to ignore tinnitus improved by 1.36 points following FCT on a ten point rating scale. An increase in average absolute N1 amplitude was seen following FCT, compared to decrease seen following FDT. Similar changes were not observed for the P2 waveform. The results of this study suggest that short-duration perceptual training can contribute to a reduction in tinnitus perception and that these perceptual changes can be observed as changes in auditory evoked potentials.