Event-related potentials to repeated speech in 9-month-old infants at risk for autism spectrum disorder.
BACKGROUND
Atypical neural responses to repeated auditory and linguistic stimuli have been reported both in individuals with autism spectrum disorder (ASD) and their first-degree relatives. Recent work suggests that the younger siblings of children with ASD have atypical event-related potentials (ERPs) to repeated tones at 9 months of age; however, the functional significance is unclear, and it is unknown whether this atypicality is also present in response to linguistic stimuli.


METHODS
We analyzed ERPs to repetitive and deviant consonant-vowel stimuli at 9 months in 35 unaffected high-risk-for-autism (HRA) infant siblings of children with ASD and 45 low-risk control (LRC) infants. We examined a positive component, the P150, over frontal and central electrode sites and investigated the relationships between this component and later behavior.


RESULTS
Over frontal electrodes, HRA infants had larger-amplitude ERPs to repetitions of the standard than LRC infants, whereas ERPs to the deviant did not differ between HRA and LRC infants. Furthermore, for HRA infants, the amplitude of ERPs to the standards was positively correlated with later language ability.


CONCLUSIONS
Our work suggests that atypical ERPs to repeated speech during infancy are a possible endophenotype of ASD but that this atypicality is associated with beneficial, rather than disordered, language development. Potential mechanisms driving these relationships and implications for development are discussed.
Department of Pediatrics, New York University School of Medicine, New York, NY 10016 USA.
Anne
A
Seery
Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215 USA.
Helen
H
Tager-Flusberg
Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children's Hospital, Boston, MA 02215 USA ; Harvard Medical School, Boston, MA 02115 USA.
Charles A
CA
Nelson
Auditory evoked potentials; Autism spectrum disorders; Endophenotype; Event-related potentials; Infancy; Language; Speech processing