Funding

Title: Audiovisual processing in children with developmental language disorder

Role: Principal Investigator

Agency: NIH-NIDCD

Type: R01

Duration: April 1, 2019 – March 31, 2024

Emerging developmental studies show that visual speech cues facilitate the acquisition of important building blocks of language, such as phonemes and words, and shape the development of both speech production and speech perception. Because visual speech cues influence multiple aspects of typical language acquisition, and speech perception more generally, we ask whether impairment in the processing of visual articulatory movements and/or difficulty in integrating such movements with concurrent auditory speech may underlie some of the deficits observed in children with developmental language disorder (DLD).

DLD is characterized by difficulties in acquiring language in the absence of an easily identifiable cause, such as hearing impairment, frank neurological disorders, or low non-verbal intelligence. It affects approximately 7% of preschool children in the US and is typically a life-long condition. Earlier studies suggest that at least some aspects of audiovisual processing are impaired in DLD, but the causes remain unknown.

In this project, we propose to examine in children with DLD and their typically developing (TD) peers a set of mechanisms that are essential for normal audiovisual processing. These mechanisms include the following: (1) sensitivity to temporal relationships between events in auditory and visual modalities; (2) sensory encoding of speech-relevant visual features, namely shape and motion; (3) allocation of attention to features of complex visual objects; and (4) knowledge of auditory/articulatory correspondences for speech sounds. Examining these mechanisms in the same groups of children with DLD and TD will provide information about both the hetero/homogeneity of audiovisual impairments in DLD and the effects of impairment in just one vs. several mechanisms on audiovisual language use. We combine behavioral measures with ERP and EEG data analyses in order to map the nature of neural processes engaged by each mechanism.

Understanding the causes of audiovisual processing difficulties in DLD has significant clinical implications. Audiovisual integration normally facilitates some of the linguistic skills that are impaired in DLD, such as phonological and lexical processing and speech-in-noise perception. Hence, identifying the mechanisms that prevent children with DLD from using visual speech cues as well as their TD peers do and rehabilitating them could potentially lead to improvements in these linguistic skills. Additionally, comparing the neural processes underlying audiovisual integration in children with typical and atypical language ability provides a unique window into the development of the neural networks connecting auditory and visual modalities and their impact on normal and disordered language function.

Title: Perception of audiovisual speech in school-age children with specific language impairment and their typically developing peers

Agency: Purdue University Clifford B. Kinley Trust Award

Duration: May 1, 2018 – April 30, 2019

Title: Audiovisual processing in specific language impairment

Role: Principal Investigator

Agency: NIH-NIDCD

Type: R03

Duration: February 15, 2013 – January 31, 2016

This grant evaluated behavioral and event-related potential (ERP) indices of audiovisual processing in school-age children with specific language impairment (SLI) and their typically developing (TD) peers at the acoustic, phonemic, and lexical levels of speech perception in order to identify a stage (or stages) of linguistic processing at which audiovisual integration falters in SLI. The results indicate that audiovisual integration mechanisms at the acoustic level are normal in SLI. However, the SLI children differ significantly from their TD peers in matching individual phonemes/syllables with visually observed speech movements. Additionally, the ERP indices of visual processing and attention also significantly differed between the SLI and TD groups.

Title: Electrophysiological indices of attention in language processing

Role: Principal Investigator (Administrator: Laurence B. Leonard)

Agency: NIH-NIDCD

Type: P30DC010745

Duration: 2 years (09/17/2009 – 08/31/2012)

This grant examined the relationship between attention and audiovisual processing in children with SLI and their typically developing peers. It identified audiovisual temporal processing as an area of significant weakness in children with SLI and showed that audiovisual temporal skills in these children are related to their language and attention abilities.