Transcript Title of article

JAMA Ophthalmology Journal Club Slides:
Amblyopia and Visual-Auditory Speech Perception
Burgmeier R, Desai RU, Farner KC, et al. The effect of amblyopia on visualauditory speech perception: why mothers may say “look at me when I’m
talking to you.” JAMA Ophthalmol. Published online September 11, 2014.
doi:10.1001/jamaophthalmol.2014.3307.
Copyright restrictions may apply
Introduction
•
Speech perception is a multimodal phenomenon, integrating auditory input
with the visual input of the speaker’s oral and extraoral facial movement.
•
One of the most striking demonstrations of how vision influences the
perception of sound is the McGurk effect, demonstrated on the next slide.
•
When viewing the video, keep your eyes open looking at the screen and
have the speaker volume raised. Which sounds do you hear?
Copyright restrictions may apply
Introduction
McGurk Effect Video
Copyright restrictions may apply
Introduction
The McGurk Effect
Copyright restrictions may apply
Objective
•
To determine whether a history of amblyopia is associated with abnormal
visual-auditory speech integration.
•
Amblyopic children were hypothesized to less frequently perceive /ta/.
Copyright restrictions may apply
Methods
•
Study Design: Retrospective observational study at an academic pediatric
ophthalmologic clinic with an average of 4 years of follow-up.
•
Participants: Participants were at least 3 years of age. Amblyopic participants
(n = 24) had best-corrected visual acuity of 20/20 in their nonamblyopic eye.
Controls (n = 9) had visual acuity of 20/20 OU. Exclusion criteria were any
history of developmental delay, neurologic disorders (eg, seizure, brain injury,
cerebrovascular accident, congenital malformation, neoplasm, or autism
spectrum disorder), or hearing disorders.
•
Exposures: Participants were presented with the McGurk effect video and
asked to report which sound was perceived: /ka/, /pa/, or /ta/. All participants
viewed the stimuli binocularly; those who wore corrective spectacles were
tested while wearing them. A subset of the participants with amblyopia were
additionally tested monocularly.
Copyright restrictions may apply
Methods
•
Participants were also presented with audio-only /pa/ and /ka/ stimuli (ie, with a
blank screen). Those who did not correctly perceive these stimuli in ≥66% of
trials were excluded from analysis.
•
Participants were also excluded if they incorrectly perceived a visual-only /pa/
stimulus (ie, with no audio) or the normal bimodal audio-visual /pa/ and audiovisual /ka/ stimuli.
•
Participants who perceived the McGurk effect (ie, visual /ka/ with audio /pa/) in
≥80% of trials were considered to have normal visual-auditory fusion, whereas
those who perceived the effect in <20% of trials were considered to have
abnormal visual-auditory fusion.
•
Resolution of amblyopia was considered to have occurred when the patient’s
visual acuity was equal in both eyes and patching was no longer required.
Copyright restrictions may apply
Results
•
The McGurk effect was perceived by 11 of 24 participants with amblyopia
(45.8%) and all 9 controls (100%) (adjusted odds ratio, 22.3 [95% CI 1.2426.0]; P = .005).
•
The McGurk effect was perceived by all the participants with amblyopia that
had resolved by 5 years of age and by all the participants whose onset of
amblyopia developed at or after 5 years of age.
•
Only 3 of the 16 participants with amblyopia that was unresolved by 5 years of
age (18.8%) perceived the McGurk effect (adjusted odds ratio, 27.0 [95% CI,
1.1-654.0]; P = .02).
Copyright restrictions may apply
Results
Timeline of Amblyopic
Children and Their
Perceptions of the
McGurk Effect
Copyright restrictions may apply
Comment
•
Children with a history of amblyopia exhibit impaired visual-auditory
integration and perceive speech differently, even when binocularly viewing
a stimulus with a nonamblyopic eye with visual acuity of 20/20.
•
Early childhood appears to serve as an approximate point for the
development of successful visual-auditory fusion, by which time amblyopia
must have either resolved or begun.
•
Studies have demonstrated that children with language learning
impairment and autism spectrum disorders also fail to perceive the McGurk
effect. These studies did not assess visual acuity in each eye; hence,
monocular amblyopic patients may have been included in the studies,
possibly confounding their results. The current study contributes to the
literature by demonstrating how amblyopia itself can influence the
perception of sound.
Copyright restrictions may apply
Comment
•
Limitations:
– Small sample size.
– Retrospective determination of onset of amblyopia through chart
review.
– Recall bias owing to follow-up visits scheduled based on clinical need.
– Arbitrary cutoff of 5 years to determine onset or resolution of
amblyopia. Five years of age was chosen because most patients were
recruited between 4 and 6 years of age during preschool vision
screenings.
– Lack of required formal audiological testing. However, patients were
excluded if they failed to correctly perceive audio-only stimuli /pa/ and
/ka/ (ie, with the visual track as a blank screen).
– No standardized tests for grammatical understanding or intelligence.
Copyright restrictions may apply
Contact Information
•
If you have questions, please contact the corresponding author:
– Rajen U. Desai, MD, Department of Ophthalmology, Feinberg School of
Medicine, Northwestern University, 645 N Michigan Ave, Ste 440,
Chicago, IL 60611 ([email protected]).
Funding/Support
•
Dr Desai is supported by the Heed Ophthalmic Foundation and the Society
of Heed Fellows. The design and conduct of the study were supported by
grants from the Knights Templar Eye Foundation Inc and Research to
Prevent Blindness.
Conflict of Interest Disclosures
•
None reported.
Copyright restrictions may apply