Poster #: 18
Topic: Clinical applications (incl. consciousness)
Friday, Sep 11, 2015
Regularity encoding in autism spectrum disorders: brainstem responses to repeated amplitude-modulated sounds
1Department of Psychiatry and Clinical Psychobiology, University of Barcelona, Barcelona, Spain
Children with Autism Spectrum Disorders (ASDs) often show atypical sensitivity to auditory stimulation and exhibit difficulties in the processing of auditory information. However, little is known about the underlying mechanisms yielding to atypical auditory processing in these children. In this study, we aimed at characterizing how repetitive stimulus presentations modulate the frequency following response (FFR) of the auditory brainstem in children diagnosed with ASD, a response that reflects the neural phase-locking to the periodic features of a sound. To test this, we used a roving standard paradigm consisting of 10 pure tones, each with different carrier frequencies and a common amplitude modulation of 380 Hz. Each tone was repeated 8, 10 or 12 times with a constant stimulus onset asynchrony (333ms). Electroencephalographic recordings were obtained from 17 children with ASD and 18 matched typically developing (TD) children (age range: 6.5-12 years). We found that in children with ASD, the FFR power amplitude to the AM frequency increased with stimulus repetitions, while a suppression of the power amplitude was observed in TD children (p=0.024, RMANOVA). Additionally, the increase of FFR power amplitude with repetition correlated with the severity of auditory hypersensitivities. These findings suggest that the ability to reduce the brainstem representation of repetitive stimuli is altered in children with ASD and is associated with the existence of auditory sensitivities in these children.