The effect of top-down control of attention on speech perception and effort in adverse listening conditions
02 / 2013 - 02 / 2016
Listening to speech in a noisy environment is an effortful task in particular for hearing impaired people. Attending to a persons face, voice, and his relative location can improve speech reception in adverse listening conditions. How these top-down attentional processes affect listening effort, a major cause of fatigue in the hearing impaired, is unknown. The proposed studies will investigate the effect of auditory attention on speech comprehension, its relation to listening effort, and the effect of hearing loss on these processes. Recent research shows that pupil dilation, an independent measure for listening effort, is sensitive to speech intelligibility level and deployment of speech related (cognitive) processes. The speech reception threshold (SRT) test used in these studies presents speech in background noise while maintaining a fixed intelligibility level. This allows for studying the effects of attention on speech reception and listening effort independently. In separate studies the effect of time, location, and talker-voice uncertainty on listening effort by will be investigated. In case of time uncertainty, the predictability of the onset of speech will be manipulated. Similarly the predictability of location and talker will be investigated. Both normal hearing and hearing-impaired individuals will participate in the experiments. Additionally, possible interactions between these attentional processes will be investigated. I hypothesize that attending to speech will lead to better comprehension and will result in a lower (i.e. better) speech reception threshold. Additionally, attending to speech will increase cognitive load, which results in a larger pupil response, an indication of enhanced listening effort. The proposed studies will investigate the idea that speech comprehension in noise is based on both sensory auditory functioning (SRT) and cognitive functions (pupillometry). Measuring both aspects of speech comprehension gives better understanding into the importance of auditory attention in communication difficulties experienced by individuals.