Multimodal evaluation of receptive communication reveals specific strengths and weaknesses in nonspeaking children with Angelman syndrome

• In Event: Poster Session 03
  In Poster Session: PS 03 Topic - Language, Communication

Abstract

Background: Angelman Syndrome (AS) is a neurodevelopmental disorder characterized by significant intellectual, communicative, and motor disabilities caused by a loss of function of the UBE3A gene on the maternal chromosome 15 (Kishino et al., 1997; Buiting, 2010). The vast majority of children with AS do not develop spoken language. Evaluation of receptive communication in AS is challenging because most of the conventional standardized psychological assessments have not been designed for use in participants unable to provide reliable verbal or motor responses, and therefore may not be sufficiently sensitive to capture the full range of functioning in AS. The lack of sensitive measures makes it difficult to track progress related to development and/or interventions over time. Alternative measures of speech and language processing, such as measures of brain activity and eye gaze may offer additional insights into communicative functioning in AS.

Methods: This study evaluated receptive communication abilities in nonspeaking children and adolescents with AS (n=21, age 4-18 years) and typical controls matched on chronological age (n=33) using auditory event-related potentials (ERPs) and eye tracking during passive listening paradigms to capture individual differences in auditory attention (incidental memory for novel nonwords, Key et al., 2018), word-nonword differentiation (Mills et al., 2004), and word-level comprehension (Looking While Listening, Fernald et al., 2008). The stimulus words were selected based on the typical age of acquisition of 16 months or less. Caregivers of children with AS provided reports of word knowledge (MCDI Words and Gestures) and adaptive functioning (Vineland Adaptive Behavior Scales-3). All data were collected during a single visit lasting 30-60 minutes. The ERP and eye tracking tasks lasted 3-6 minutes each and thus placed minimal attentional demands. Typical development in the comparison group was verified using Kaufman Brief Intelligence Test-2 and caregiver-reported history free of genetic, neurological, or learning disabilities.

Results: Auditory ERPs revealed that children with AS were comparable to typical controls in the self-directed attention to spoken inputs and the ability to detect stimulus repetition as reflected by the parietal old/new ERP response (300-500ms). They also differentiated spoken real words from novel nonwords (left temporal response, 200-500ms). Eye tracking demonstrated greater than typical interindividual variability in comprehension (speed and probability of orienting gaze to the named object), with higher probability of gaze on the correct objects when paired with a semantically unrelated vs. related stimulus (e.g., cookie-sock vs. cookie-banana). The correlational analyses examining associations between caregiver reports and physiological measures are currently ongoing.

Conclusion: The auditory ERP results indicate that the basic neural mechanism underlying receptive communication (spontaneous attention to and short-term memory for discrete spoken inputs, detection of known words among novel stimuli) are functional in nonspeaking children with AS. Conversely, eye tracking findings suggest that the speed of real-time language processing may be delayed in AS and depends on the broader context (semantically related vs. unrelated distractors). These physiological results supplement and extend caregiver reports of receptive abilities in AS and provide new insights into the potential targets for interventions.

Authors

• Alexandra Key, Vanderbilt University Medical Center
  Presenting Author

• Sydney Roth, Vanderbilt University
  Non-Presenting Author

• Dorita Jones, Vanderbilt University Medical Center
  Non-Presenting Author