Cortical responses to lipread and text-based audiovisual stimuli in adults with and without dyslexia
Year: 2026
Type: article
Abstract: Phonetic recalibration enables listeners to adjust their perception of ambiguous speech sounds based on visual contextual information. In line with a specific difficulty in forming letter-speech sound associations, adults with dyslexia have been found to show no text-based, but intact lipread-based, recalibration. The underlying neural mechanisms remain unclear however. This fMRI study examined cortical responses during text-based and lipread-based phonetic recalibration in 34 adults (18 with dyslexia, 16 typical readers). Participants were exposed to ambiguous speech sounds /a?a/ paired with disambiguating visual information (“aba”/“ada” text or lipread videos), followed by auditory-only categorization trials. Contrary to previous findings, both groups showed robust text-based and lipread-based behavioral recalibration effects, with no significant group differences between typical and dyslexic readers. Neuroimaging data did yield group differences in the underlying cortical activation. Most notably, dyslexic readers demonstrated increased bilateral fusiform activation compared to typical readers during exposure to lipread videos and ambiguous speech sounds, with left fusiform activation specifically correlating with increased phonological processing difficulties. Additionally, typical readers exhibited higher right frontal activation during text-based audiovisual stimuli. These findings suggest that while adults with dyslexia did not differ significantly from typical readers in behavioral recalibration effects, they employed different neural processing strategies. Unexpectedly, this was particularly the case for lipread audiovisual stimuli. The relatively increased fusiform and superior temporal activation to lipread audiovisual stimuli in dyslexic readers possibly relates to subtle difficulties in phonological processing of ambiguous speech signals.
Source: Frontiers in Human Neuroscience
Institutions: Maastricht University, John Cabot University
Language: English
Subfield: Developmental and Educational Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7223288233