Developmental Trajectory of McGurk Effect Susceptibility in Children and Adults With Amblyopia.
OBJECTIVE
The McGurk effect is an audiovisual illusion that involves the concurrent presentation of a phoneme (auditory syllable) and an incongruent viseme (visual syllable). Adults with amblyopia show less susceptibility to this illusion than visually normal controls, even when viewing binocularly. The present study investigated the developmental trajectory of McGurk effect susceptibility in adults, older children (10-17 years), and younger children (4-9 years) with amblyopia.


METHODS
A total of 62 participants with amblyopia (22 adults, 12 older children, 28 younger children) and 66 visually normal controls (25 adults, 17 older children, 24 younger children) viewed videos that combined phonemes and visemes, and were asked to report what they heard. Videos with congruent (auditory and visual matching) and incongruent (auditory and visual not matching) stimuli were presented. Incorrect responses on incongruent trials correspond to high McGurk effect susceptibility, indicating that the viseme influenced the phoneme.


RESULTS
Participants with amblyopia (28.0% ± 3.3%) demonstrated a less consistent McGurk effect than visually normal controls (15.2% ± 2.3%) across all age groups (P = 0.0024). Effect susceptibility increased with age (P = 0.0003) for amblyopic participants and controls. Both groups showed a similar response pattern to different speakers and syllables, but amblyopic participants invariably demonstrated a less consistent effect.


CONCLUSIONS
Amblyopia is associated with reduced McGurk effect susceptibility in children and adults. Our findings indicate that the differences do not simply indicate delayed development in children with amblyopia; rather, they represent permanent alterations that persist into adulthood.
Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada.
Cindy
C
Narinesingh
Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada.
Herbert C
HC
Goltz
Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada.
Rana Arham
RA
Raashid
Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada.
Agnes M F
AM
Wong
D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000150:complications / Q000503:physiopathology*; D001307:Auditory Perception / Q000502:physiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006311:Hearing Disorders / Q000209:etiology; D006801:Humans; D007088:Illusions / Q000502:physiology*; D008297:Male; D014786:Vision Disorders / Q000209:etiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
McGurk effect; amblyopia; multisensory integration; visual capture