Olfaction and taste processing in autism.
BACKGROUND
Autism is often associated with sensory symptoms, but few studies have examined chemosensory functions in this population. We examined olfactory and taste functioning in individuals with autism to characterize chemosensory processing and test competing hypotheses about underlying brainstem versus cortical abnormalities.


METHODS
Twenty-one participants (10-18 years) with autism were compared with 27 well-matched control participants with typical development. Taste identification was tested via sucrose, NaCl, citric acid, and quinine solutions applied to standard locations on the anterior tongue. Taste detection thresholds were established in the same regions with electrogustometry, and olfactory identification was evaluated with "Sniffin' Sticks."


RESULTS
Participants with autism were significantly less accurate than control participants in identifying sour tastes and marginally less accurate for bitter tastes, but they were not different in identifying sweet and salty stimuli. Taste detection thresholds via electrogustometry were equivalent. Olfactory identification was significantly worse among participants with autism.


CONCLUSIONS
True differences exist in taste and olfactory identification in autism. Impairment in taste identification with normal detection thresholds suggests cortical, rather than brainstem dysfunction. Further research is needed to determine the neurologic bases of olfactory and taste impairments, as well as the relationship of chemosensory dysfunction to other characteristics of autism.
Bennetto
Loisa
L
Department of Clinical and Social Sciences in Psychology, University of Rochester, Rochester, New York 14627, USA. bennetto@psych.rochester.edu
Kuschner
Emily S
ES
Hyman
Susan L
SL
D000293:Adolescent; D001321:Autistic Disorder / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009812:Odorants; D011601:Psychophysics; D011803:Quinine; D012684:Sensory Thresholds / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D012965:Sodium Chloride; D013395:Sucrose; D013649:Taste / Q000502:physiology*; D014059:Tongue / Q000502:physiology
D012965:Sodium Chloride; D013395:Sucrose; D011803:Quinine