Examination of speech processing in noise reveals cognitive deficits in early Huntington's disease

Processing speech amongst noise requires sensory and cognitive abilities that are often affected by Huntington's Disease. However, their impact on daily communication remains unclear. We examined the effects of Huntington's Disease on speech-in-noise processing using everyday sentences and words in noise contexts and conditions that mimic different daily life scenarios. In Premanifest (n = 16) and Manifest Huntington's Disease (n = 12) and Control (n = 26) participants, we examined speech discrimination amongst non-demanding and attentionally demanding noise. We also examined how Huntington's Disease affected the ability to use spatial separation cues to disambiguate speech from noise in single-voice masker or multi-talker backgrounds. Finally, we administered a validated questionnaire where participants rated auditory processing difficulties during daily life activities. Sentence-in-noise discrimination was impaired in individuals with Manifest Huntington's Disease in almost all signal-to-noise ratio conditions with the attentionally-demanding masker and amongst the non-demanding noise masker with the most difficult signal-to-noise ratio. Premanifest Huntington's Disease participants had difficulty perceiving speech in some attentionally demanding noise conditions. Spatial cues provided situational benefits to speech processing under attentionally-demanding conditions for participants at all stages of Huntington's Disease, except for the Manifest Huntington's Disease group when stimuli included a single competing speaker. A logistic regression model using speech processing performance as a predictor successfully distinguished healthy control and Premanifest groups with 87.5% accuracy. Stage-dependent impairments in speech processing were observed under naturalistic noise conditions. These results further our understanding and contextualization of communication difficulties experienced by people with Huntington's Disease.