Official websites use. Share sensitive information only on official, secure websites. We examined context-dependent encoding of speech in children with and without developmental dyslexia by measuring auditory brainstem responses to a speech syllable presented in a repetitive or variable context.
Typically developing children showed enhanced brainstem representation of features related to voice pitch in the repetitive context, relative to the variable context. In contrast, children with developmental dyslexia exhibited impairment in their ability to modify representation in predictable contexts.
From a functional perspective, we found that the extent of context-dependent encoding in the auditory brainstem positively correlated with behavioral indices of speech perception in noise. The disruption of this mechanism contributes to a critical deficit in noise-exclusion, a hallmark symptom in developmental dyslexia. Verbal communication often occurs in noisy backgrounds. Imagine a conversation with a friend in a noisy restaurant. This task is particularly challenging because the competing noise other talkers has acoustic properties that overlap with the target signal your friend's voice.
Yet, for the most part, communication is unimpeded even under such challenging conditions. This remarkable feat relies on a highly adaptive auditory system that continually modulates its activity based on contextual demands.
Successful completion of this complex task, extracting the speech signal, takes advantage of a predictable, repeating element the pitch of your friend's voice amid the random, fluctuating background of many voices. How the nervous system functionally adapts and fine-tunes the representation of predictable auditory elements in the environment is currently unknown.
