Facial speech processing in children with and without dyslexia

Abstract

What role does the presence of facial speech play for children with dyslexia? Current literature proposes two distinctive claims. One claim states that children with dyslexia make less use of visual information from the mouth during speech processing due to a deficit in recruitment of audiovisual areas. An opposing claim suggests that children with dyslexia are in fact reliant on such information in order to compensate for auditory/phonological impairments. The current paper aims at directly testing these contrasting hypotheses (here referred to as “mouth insensitivity” versus “mouth reliance”) in school-age children with and without dyslexia, matched on age and listening comprehension. Using eye tracking, in Study 1, we examined how children look at the mouth across conditions varying in speech processing demands. The results did not indicate significant group differences in looking at the mouth. However, correlation analyses suggest potentially important distinctions within the dyslexia group: those children with dyslexia who are better readers attended more to the mouth while presented with a person’s face in a phonologically demanding condition. In Study 2, we examined whether the presence of facial speech cues is functionally beneficial when a child is encoding written words. The results indicated lack of overall group differences on the task, although those with less severe reading problems in the dyslexia group were more accurate when reading words that were presented with articulatory facial speech cues. Collectively, our results suggest that children with dyslexia differ in their “mouth reliance” versus “mouth insensitivity,” a profile that seems to be related to the severity of their reading problems.

Perceptual Adaptation to Noise-Vocoded Speech by Lip-Read Information: No Difference between Dyslexic and Typical Readers

“…Given that the dyslexic readers in Baart et al (2012), Keetels et al (2018) and the current study were all university students capable of performing at an academic level, it is conceivable that their dyslexia symptoms were also relatively mild (although we have no access to their diagnosis). If so, the fact that they relied quite heavily on lip-read information in response to the challenging listening conditions aligns with the work by Galazka et al (2021). Van Laarhoven et al (2018) also provided university students (from the same population as in the current study) with a challenging listening environment by presenting speech in background noise.…”

“…This was also observed when the visual signal comprised a mosaic version of the (inverted) talking face in which detailed lip-read information was lost, but the visual gain induced by this low-frequency visual information was smaller for participants with poorer auditory-processing capacity. Thus, under challenging listening conditions, participants with less severe reading problems look more at the mouth (Galazka et al, 2021) and participants with less severe auditory-processing issues show more visual gain from low-level dynamic visual cues (Megnin-Viggars and Goswami, 2013). Given that the dyslexic readers in Baart et al (2012), Keetels et al (2018) and the current study were all university students capable of performing at an academic level, it is conceivable that their dyslexia symptoms were also relatively mild (although we have no access to their diagnosis).…”

“…To reconcile the seemingly contrasting findings across the literature, it is of importance to note that DD's use of lip-read information may be related to task demands. In a recent study with 9-to-13-year-olds (Galazka et al, 2021), participants' eye movements were tracked when listening to auditory sentences or single nonwords while the corresponding talking face was presented. Although the overall proportion of time spent looking at the mouth was comparable for children with and without DD, better readers in the DD group looked longer at the mouth in the nonword condition -which was assumed to be more phonologically demanding than the sentence condition.…”

Dyslexia‐Related Hearing Loss Occurs Mainly through the Abnormal Spontaneous Electrical Activity of Spiral Ganglion Neurons

“…To date, a variety of dyslexia‐related pathological deficits have been identified, such as impaired speech processing, [ 58 ] situs inversus, [ 59 ] short‐term memory impairment, [ 13 ] and difficulties with rapid auditory processing. [ 60 ] In addition, dyslexia patients sometimes suffer from hearing loss, but the mechanism of DRHL is unclear.…”

Using Sound Walls to Promote Independent Spellers

“…Articulatory gestures and speech perception. Researchers have found directly teaching students speech gestures supports students' phonemic awareness and letter-sound knowledge, particularly for students with reading disabilities or at risk for reading difficulty (Boyer & Ehri, 2011;Fälth et al, 2017;Galazka et al, 2021). Therefore, instruction emphasizing articulatory gestures-what the mouth looks like during sound production-can support young children and students with dyslexia in reading and spelling acquisition.…”