Autism spectrum disorder. a clinical neurophysiology approach II

Abstract

One of the most controversial issues in the study of autism spectrum disorder (ASD) is the involvement and dysfunction of sensory systems that underlie atypical behaviors, which could be evaluated through neuroimaging and electrophysiological techniques. Auditory disturbances are the most frequently reported sensory deficits that could explain language and communication deficits shown in ASD patients. Event–related potentials such as auditory brainstem response, mismatch negativity, P50, and P300 have shown differences between patients and normal subjects, supporting the existence of an abnormal auditory processing. Somesthetic perception is also distorted in this heterogeneous group of patients, probably associated with deficits in communication, motor ability, and social skills. It has been confirmed by abnormalities in short–and long–latency somatosensory evoked potentials. Visual processing impairment has also been described in children and young adults with autism. Dipole source analysis revealed that the visual cortex, fusiform gyrus, and medial prefrontal lobe are less active in autism compared with control subjects during the execution of emotion processing tasks. ASD patients also have problems to integrate information from multiple sensory sources necessary to a successful social behavior, and consequently, they show deficits with social and cognitive processes. Electrophysiological and imaging techniques may constitute useful tools in the diagnosis, classification, and therapeutic strategies of ASD patients, considering the diversity of this spectrum.