Perceptual Learning of Acoustic Noise by Individuals With Dyslexia

Abstract

Purpose A phonological deficit is thought to affect most individuals with developmental dyslexia. The present study addresses whether the phonological deficit is caused by difficulties with perceptual learning of fine acoustic details. Method A demanding test of nonverbal auditory memory, “noise learning,” was administered to both adults with dyslexia and control adult participants. On each trial, listeners had to decide whether a stimulus was a 1-s noise token or 2 abutting presentations of the same 0.5-s noise token (repeated noise). Without the listener's knowledge, the exact same noise tokens were presented over many trials. An improved ability to perform the task for such “reference” noises reflects learning of their acoustic details. Results Listeners with dyslexia did not differ from controls in any aspect of the task, qualitatively or quantitatively. They required the same amount of training to achieve discrimination of repeated from nonrepeated noises, and they learned the reference noises as often and as rapidly as the control group. However, they did show all the hallmarks of dyslexia, including a well-characterized phonological deficit. Conclusion The data did not support the hypothesis that deficits in basic auditory processing or nonverbal learning and memory are the cause of the phonological deficit in dyslexia.

Informational masking of complex tones in dyslexic children

“…This finding is in line with the "anchoring"-deficit hypothesis, a theory postulating that dyslexic individuals have difficulties extracting regularities from the incoming sensory stream [2,10]. However, other studies showed that, similarly to control individuals, dyslexics were able to benefit from stimuli repetition using both verbal [11] and nonverbal [1] material. In addition, although in the present experiment dyslexics did not improve throughout blocks, they nevertheless might do so with further training.…”

Peripheral and central contribution to the difficulty of speech in noise perception in dyslexic children

“…Yet, other studies also failed to replicate this 'anchoring' deficit with either speech (Di Filippo, Zoccolotti, & Ziegler, 2008) or nonspeech (Agus, Carrion-Castillo, Pressnitzer, & Ramus, 2014) Moreover, similarly to control children, dyslexics' identification of the target consonant was better as the number of simultaneous interfering talkers was smaller. Performance tended to be better amongst four than eight competing talkers, and was significantly better with only one, compared to four, interfering talkers.…”

“…Yet, other studies also failed to replicate this 'anchoring' deficit with either speech (Di Filippo, Zoccolotti, & Ziegler, 2008) or nonspeech (Agus, Carrion-Castillo, Pressnitzer, & Ramus, 2014) material. Further research is needed to explore dyslexics' ability to benefit from repetitions in the auditory stream.…”

Deficits in statistical leaning of auditory sequences among adults with dyslexia

“…The deficit in extracting regularities from A‐AGL might be accounted for by Ahissar's “Anchoring‐deficit Hypothesis” (), which postulated that adults with DD fail to sense the repetitive pattern of the stimuli, which, in turn, renders them incapable to use the anchoring within a sequential stimulus. For example, Daikhin, Raviv, and Ahissar () explored the sensitivity of adults with DD to repetitions using the Repeated‐Noise Detection Task (Agus, Carrión‐Castillo, Pressnitzer, & Ramus, ). Although no overall difference was found between the groups, the researchers did find a highly significant difference between the pattern of performance for participants with and without DD, in which the sensitivity to repeated white noise was smaller among the DD group.…”