Neural tracking of speech in individuals with age-related hearing loss
Over 70% adults have mild-to-moderate hearing loss in their later life (e.g., >70 yrs old). This condition may not affect listening in quiet but it often causes challenges in speech comprehension in daily noisy listening environments compared to young normally hearing people. Age-related hearing loss is also known as one of the early risk factors of dementia.
We conducted studies that investigated how ageing and hearing loss contribute to atypical sensory neural tracking of speech (brainstem frequency following response (FFR) to fundamental frequency and neural phase locking to speech envelopes in the auditory cortex) in both quiet and noisy backgrounds and how these sensory tracking activities are associated with behavioural performances of speech recognition in noise in ageing adults:
Questions also arise that it is difficult to distinguish contributions between atypical neural speech tracking and various co-occurring factors (e.g., cognitive declines) to breakdown of speech comprehension following ageing and hearing loss. Simple regression analyses may not solve such issue due to collinearity between these factors and neural tracking. We thus employed more proper statistical models to illustrate how individual differences in speech-in-noise performance can be better explained by sensory tracking of speech besides other potential age-related factors in adults with a wide range of age and hearing status:
Neuroplasticity of speech in noise in people with age-related hearing loss
We studied functional changes over time in temporal and frontal cortices using fNIRS in ageing adults with mild-to-moderate hearing loss following a training program of speech comprehension under noisy backgrounds. We illustrated promising success in observing neuroplasticity via fNIRS where we recorded significant improvements in brain functions during speech-in-noise perception:
