Investigating the relationship between cognitive control and speech-in-noise recognition in tinnitus from perceptual, neuroanatomical, and electrophysiological aspects

Purpose: Individuals with tinnitus commonly report difficulties understanding speech in adverse listening environments. Although such speech-in-noise (SiN) difficulties are believed to relate to deficits in cognitive control, there is as yet no evidence to underpin this assumption. The aim of this dissertation was to investigate the relationship between cognitive control and SiN recognition in individuals with tinnitus and normal hearing sensitivity. Method: Three studies linking behavioral to brain imaging measures were conducted. In the first study, the effect of tinnitus pitch on the recognition of consonants in noise at various frequency ranges was examined to better understand if the tinnitus percept impacts SiN recognition. Using voxel-based morphometry, the second study investigated the relationship between SiN performance and gray matter volume in auditory and cognitive processing regions in individuals with tinnitus. Lastly, using electroencephalogram to record brain activity during Go/Nogo tasks, the third study examined whether event-related potentials related to cognitive control are associated with SiN performance in individuals with tinnitus. Results and Discussion: Overall, the findings of the three studies suggest that 1) perceiving tinnitus at a given frequency does not interfere with speech recognition at the same frequency, suggesting that the effect of tinnitus on SiN recognition may involve higher-level cognitive processes rather than being solely mediated by perceptual abilities; 2) individuals with tinnitus and normal hearing showed comparable SiN recognition and neuropsychological performance relative to hearing-matched controls, however, they still demonstrated neuroanatomical changes and neural alterations pertaining to cognitive control; and 3) individuals with tinnitus may use different cognitive control strategies relative to hearing-matched controls to maintain their performance of daily tasks. Conclusions: The findings confirmed that incorporating multimodal approaches to examine the relationship between cognitive control and SiN recognition can be beneficial to detect neuroanatomical or neural alterations before any overt changes in behavioral performance. Further, the results will serve as the baseline for future endeavors to explicitly investigate the effect of tinnitus and hearing loss on cognitive control abilities and SiN recognition, which can be invaluable in advancing tinnitus consultation and intervention

Phonetic Mistakes Made During Speech-In-Noise Test by Tinnitus Patients

In an aging society with a great deal of noise exposure, hearing disorders have become prevalent. One such disorder is tinnitus, which is defined as phantom ringing or noises in the ears. Some patients are bothered by their tinnitus, but some are not. Previous studies have found severe tinnitus to affect attention, cognition, and speech in noise performance. This study aims to expand on those discoveries, finding how tinnitus affects speech recognition in noise at the phonetic level. Through the use of the speech-in-noise test, we have broken down each sentence to determine which words these patients missed. Furthermore, we have taken the results and looked phoneme by phoneme and will compare the results of the tinnitus patients with those without tinnitus. By phonetically pinpointing the errors made by these tinnitus patients, we can attempt to conclude the phonemes that they miss in everyday speech. Doing so will allow researchers to further expand the findings, possibly investigating how the frequencies of these phonemes correlate with the pitch of tinnitus perceived by patients, to overall help these patients have a better quality of life.Ope