Audiovisual Speech Perception in Children
With Developmental Language Disorder
in Degraded Listening Conditions
Auli Meronen,a,b Kaisa Tiippana,c Jari Westerholm,a and Timo Ahonend
Purpose: The effect of the signal-to-noise ratio (SNR) on the
perception of audiovisual speech in children with and without
developmental language disorder (DLD) was investigated by varying
the noise level and the sound intensity of acoustic speech. The main
hypotheses were that the McGurk effect (in which incongruent
visual speech alters the auditory speech percept) would be weaker
for children with DLD than for controls and that it would get
stronger with decreasing SNR in both groups.
Method: The participants were 8-year-old children with DLD and
a sample of children with normal language development. In the
McGurk stimuli, the consonant uttered by the voice differed from
that articulated by the face. Three sound intensities (24, 36, and
48 dB) and noise levels (–12, 0, and +6 dB) were used. Perception
of unisensory visual speech was also measured.
Results: The children with DLD experienced a weak McGurk effect,
that is, a weak influence of visual speech on audiovisual speech
perception, which remained rather constant across SNR levels. The
children with DLD were inaccurate at lipreading.
Conclusions: Children with DLD have problems in perceiving spoken
consonants presented audiovisually and visually. The weaker
McGurk effect could be accounted for by the poorer lipreading
ability of children with DLD.
Key Words: developmental language disorders, audiovisual
speech perception, McGurk effect, specific language impairment,