Early diagnosis of any disease condition can result in early intervention and improve outcome. Now, researchers at the Weizman Institute of Science in Israel have developed a surprisingly simple sniff test that can diagnose autism spectrum disorder in children, perhaps even in those who are not yet toddlers because it does not involve responding to questions.
The study authors note that autism spectrum disorders associated with impaired sensory-motor coordination. Human olfaction (sense of smell) involves the sniff response where unpleasant and intense odors are sampled with low-magnitude sniffs, but pleasant and mild odors are sampled with high-magnitude sniffs. The sniff response involves fine adjustment of a motor process (the sniff) in precise harmony with sensory input (the odor).
The researchers conducted a study based on the hypothesis that the sniff response will be altered in children with autism spectrum disorder. They stressed that they did not theorize that children with autism spectrum disorder would be unable to sniff, rather that they would generate an inappropriate sniff when presented with a particular odor. Thus, they did not hypothesize a definite motor impairment, but rather an impairment of sensory-motor coordination.
The study group comprised 36 children (average age: 7 years) who were exposed to both pleasant scents such as roses and foul ones such as rotting fish. Half the children did not have autism spectrum disorder, and they reacted the way one would expect: they immediately inhaled more deeply on the pleasant odors and took shorter sniffs on the foul ones. However, the other 18 children who suffered from autism spectrum disorder did not alter their breathing as rapidly. The researchers were unaware of which children had been diagnosed with autism spectrum disorder, but they were able to correctly identify those with the disorder 81% of the time.
The authors noted that the sense of smell is in fact a major component of human social interaction and it is probably altered in children with autism. Thus, olfaction likely represents a component of the social challenge manifested in the disorder. The next phase of the research will be to use the sniff test on younger children and follow them long-term.
According to the American Psychiatric Association, autism spectrum disorders are a range of complex developmental disorders that can cause problems with thinking, feeling, language, and the ability to relate to others. They are neurological disorders, meaning they affect the functioning of the brain. How autism disorders affect an individual and the severity of symptoms are different in each person.
The disorder is usually first diagnosed in childhood. Approximately 1 in 68 children is diagnosed with autism. An autism spectrum disorder is three to four times more common in boys than in girls. In most cases, the disorder is a lifelong condition; however, due to advances in treatment, together with early diagnosis, the number of children with the disorder who can eventually function independently is constantly increasing.
Characteristics of autism spectrum disorder:
Communication problems: difficulty using or understanding language; some children with autism focus their attention and conversation on a few topic areas, some frequently repeat phrases, and some have very limited speech
Difficulty relating to people, things and events: trouble making friends and interacting with people, difficulty reading facial expressions, may not make eye contact
Repetitive body movements or behaviors: hand flapping or repeating sounds or phrases.