New research shows that for some autistic kids, voices are difficult to process and may even be irritating.
These findings may help to explain why some autistic children have trouble with social and emotional aspects of human speech.
“Weak brain connectivity may impede children with autism from experiencing speech as pleasurable,” explained senior author Vinod Menon, PhD, a professor of psychiatry and behavioral sciences at Stanford and a member of the Child Health Research Institute at Lucile Packard Children’s Hospital.
“The human voice is a very important sound; it not only conveys meaning but also provides critical emotional information to a child,” said lead author Daniel Abrams, PhD, a postdoctoral scholar in psychiatry and behavioral sciences.
One autism indicator is insensitivity to human voice
Children with autism have a structural difference in brain connections compared to those without the disorder. One indicator for autism is insensitivity to the human voice.
“We are the first to show that this insensitivity may originate from impaired reward circuitry in the brain,” Abrams said.
Weak connections found in certain areas of the brain
The study observed kids with high-functioning autism; they could read and write and had IQs in the normal range. They struggled, however, with conversations and emotional context.
Using fMRI, the researchers observed the part of the brain that responds to the sound of human voices. They discovered that the voice-selective cortex on the left side of the brain was weakly connected to the nucleus accumbens and the ventral tegmental area – the brain structures that release dopamine in response to reward.
The researchers also found that the voice-selective cortex on the right side of the brain, which identifies vocal cues like pitch and intonation, had a weak connection with the amygdala, which responds to emotion. These weakened connections worsen these children’s communication deficits.
Research could improve treatment
Jennifer Phillips, PhD, a clinical associate professor of psychiatry and behavioral sciences at Stanford, said therapies could be improved as a result of this research. Pivotal-response training, a therapy intended to increase social use of language, could be employed for better results.
“Pivotal-response training goes after ways to naturally motivate kids to start using language and other forms of social interaction,” Phillips said.
Source: Proceedings of the National Academy of Sciences, MedicalNewsToday
