As social beings, communicating with others is critical. A diagnostic feature of children and adults with Autism Spectrum Disorder is communication impairment, both verbal and nonverbal. The extent of impairment can vary considerably. Some children with ASD are able to communicate within the normal range of function while others are unable to speak1. The use of language can also vary. Unlike neurotypical children who use language for social purposes, some children with ASD tend to use language one-sidedly and non-reciprocally.

Verbal communication includes spoken language, the tone of the words, and other sounds, like laughter, crying, or expressions of alarm. What is nonverbal communication? When we talk to someone, we gauge their meaning not just from their words but from their facial expression, body language, and gestures. These nonverbal aspects also help convey the “tone” of the conversation. When either the tone or the nonverbal aspects are not present or are incorrectly interpreted, the emotional meaning of the words can be lost, leading to an inappropriate response by the listener. Probably everyone has misinterpreted an email or text message because of the lack of information about the tone. If communication is consistently misinterpreted, the ability to initiate or maintain a social relationship is harmed.

How do we study the neural basis of communication? Neural and behavioral studies have helped us understand the tasks of the sender (the one communicating) and the receiver (the one listening or watching). Studies of vocal animals like birds, frogs, or bats helped identify the brain’s building blocks, from the auditory cortex which processes all sounds, to higher-order cortical areas specialized for communication. Studies of other animals, however, could not help us understand the neural basis of language, because other animals don’t have language.

Studies of people have shown that there are areas in the brain unique to humans and to language, including Broca’s area and Wernicke’s area2. These regions were identified post-mortem from patients with severe language disorders. Further insight into language processing was gained with electrodes applied to the skull during a language task. However, the resolution of this technique was too coarse to determine precise brain locations. New research tools have helped identify brain regions active in language. Functional magnetic resonance imaging (FMRI) helped identify the regions, while diffusion tensor imaging (DTI)3 helped identify the connections between regions.

Understanding language is complex. After describing the components of language, this section describes the communication circuits in the brain, how language and other types of communication develop in neurotypical children, how patients with ASD are impaired in communication, and the research challenges and advances in understanding communication disorders in ASD patients.

Key Points

• Communication impairment is one of the three diagnostic traits for ASD.
• The extent of impairment can vary, from inability to speak to normal language ability.
• Both verbal and nonverbal communication are impacted.
• Extensive behavioral intervention can improve language difficulties.

Misconception

Fact