Olfactory processing in adults with autism spectrum disorders (original) (raw)
Related papers
Olfactory Functions in Adults With Autism Spectrum Disorders
Perception, 2017
Autism spectrum disorders (ASD) are often characterized by atypical sensory behavior (hyper-or hyporeactivity) although evidence is scarce regarding olfactory abilities in ASD; 16 adults with highfunctioning ASD (mean age: 38.2, SD: 9.7) and 14 healthy control subjects (mean age: 42.0 years, SD: 12.5) were assessed in odor threshold, free and cued odor identification, and perceived pleasantness, intensity, and edibility of everyday odors. Although results showed no differences between groups, the Bayes Factors (close to 1) suggested that the evidence for no group differences on the threshold and identification tests was inconclusive. In contrast, there was some evidence for no group differences on perceived edibility (BF 01 ¼ 2.69) and perceived intensity (BF 01 ¼ 2.80). These results do not provide conclusive evidence for or against differences between ASD and healthy controls on olfactory abilities. However, they suggest that there are no apparent group differences in subjective ratings of odors.
Olfaction in the autism spectrum
Perception, 2013
The autism spectrum (AS) is characterised by enhanced perception in vision and audition, described by the enhanced perceptual functioning (EPF) model. This model predicts enhanced low-level (discrimination of psychophysical dimensions), and mid- and high-level (pattern detection and identification) perception. The EPF model is here tested for olfaction by investigating olfactory function in autistic and Asperger participants. Experiment 1 targeted higher-order olfactory processing by assessing olfactory identification in nine Asperger, ten autistic, and eleven typically developed individuals. Experiment 2 focused on low-level olfactory processing; we assessed odour detection thresholds and odour discrimination in five Asperger, five autistic, and five typically developed males. Olfactory identification was impaired in autistic participants relative to control and Asperger participants. Typical performance in low-level olfactory processing suggests that neural mechanisms involved in ...
Olfactory Detection Thresholds and Adaptation in Adults with Autism Spectrum Condition
Sensory issues have been widely reported in Autism Spectrum Conditions (ASC). Since olfaction is one of the least investigated senses in ASC, the current studies explore olfactory detection thresholds and adaptation to olfactory stimuli in adults with ASC. 80 participants took part, 38 (18 females, 20 males) with ASC and 42 control participants (20 males, 22 females). A subgroup of participants (N = 19 in each group) also conducted an adaptation task. Standardized ''Sniffin' Sticks'' were used to measure olfactory detection levels and adaptation. Adults with and without ASC showed similar olfactory detection thresholds, and similar adaptation to an olfactory stimulus. Since diminished adaptation in ASC has been previously suggested, future research needs to examine adaptation in other modalities as well.
Journal of Autism and Developmental Disorders, 2012
Although emotional functioning is impaired in children with autism, it is unclear if this impairment is due to difficulties with facial expression, autonomic responsiveness, or the verbal description of emotional states. To shed light on this issue, we examined responses to pleasant and unpleasant odors in eight children (8-14 years) with high-functioning autism and 8 age-matched typically developing controls. Despite subtle differences in the facial actions of the children with autism, children in both groups had similar facial and autonomic emotional responses to the odors. However, children with autism were less likely than controls to report an emotional reaction to the odors that matched their facial expression, suggesting difficulties in the self report of emotional states.
Enhanced olfactory sensitivity in autism spectrum conditions
Molecular Autism, 2014
Background: People with autism spectrum conditions (ASC) report heightened olfaction. Previous sensory experiments in people with ASC have reported hypersensitivity across visual, tactile, and auditory domains, but not olfaction. The aims of the present study were to investigate olfactory sensitivity in ASC, and to test the association of sensitivity to autistic traits. Methods: We recruited 17 adult males diagnosed with ASC and 17 typical adult male controls and tested their olfactory sensitivity using the Alcohol Sniff Test (AST), a standardised clinical evaluation of olfactory detection. The AST involves varying the distance between subject and stimulus until an odour is barely detected. Participants with ASC also completed the Autism Spectrum Quotient (AQ) as a measure of autism traits.
Research in Autism Spectrum Disorders, 2008
Early olfactory identification deficits have been associated with neurodevelopmental arrest of limbicprefrontal networks. These same networks are implicated in development of autistic-spectrum disorders. We aimed to investigate olfactory identification ability in children with high functioning autism (HFA). Fifteen children with HFA (aged 5-9 years) and 15 age-, gender-and IQ-matched controls (CTL) were compared on their performance on a visual analogue of the University of Pennsylvania Smell Identification Test (UPSIT). The hypothesis that children with HFA would exhibit impaired olfactory identification ability was not supported. However, contrary to the relationship found in the CTLs, smell identification ability was negatively associated with age in HFA. The results suggest some disruption of normal developmental association between olfactory ability and age in HFA. The visual analogue of the UPSIT warrants further investigation to determine its validity and reliability in normal and other clinical populations.
Olfactory Function Assessment in Italian Subjects with Autism Spectrum Disorder
Chemosensory Perception, 2017
Introduction The olfactory system is associated with several brain areas that might be involved in neurodegenerative processes and neurodevelopmental disorders. For this reason, investigation of the olfactory function plays an important role in the assessment of individuals with autism spectrum disorder (ASD), a neurodevelopmental disorder characterized by an impairment in social communication and by a restricted and repetitive pattern of behaviors. The aim of this study was to examine odor detection threshold, discrimination, and identification in participants with ASD compared to typically developing (TD) controls. Methods Thirty Italian subjects (15 with ASD, mean age 19 ± 0.5 years, and 15 TD controls, mean age 21.7 ± 0.4 years) were evaluated by means of the Sniffin' Sticks extended test through three different parameters, odor detection threshold, discrimination, and identification, and their sum the threshold, discrimination, and identification (TDI) score. Results Our results indicated that the participants with ASD showed an impairment in odor detection threshold and TDI score compared to TD controls. No differences were found in odor identification and discrimination. Participants with ASD were significantly poorer in correctly identifying the following odors: leather, apple, rose, cinnamon, garlic, cloves, and anis. However, they were significantly better than TD controls in correctly identifying the odor of the following fruits: orange, banana, and lemon. Conclusion and Implications Our data provide a comprehensive evaluation of the three olfactory components in an Italian population and confirm an impaired odor detection threshold and TDI score in subjects with ASD compared to TD controls. In conclusion, these results suggest that the Sniffin' Sticks extended test might be a valid tool in early detection and differential diagnosis of neurodevelopmental disorders.
Molecular autism, 2016
Atypical responsiveness to olfactory stimuli has been reported as the strongest predictor of social impairment in children with autism spectrum disorders (ASD). However, previous laboratory-based sensory psychophysical studies that have aimed to investigate olfactory sensitivity in children with ASD have produced inconsistent results. The methodology of these studies is limited by several factors, and more sophisticated approaches are required to produce consistent results. We measured olfactory detection thresholds in children with ASD and typical development (TD) using a pulse ejection system-a newly developed methodology designed to resolve problems encountered in previous studies. The two odorants used as stimuli were isoamyl acetate and allyl caproate. Forty-three participants took part in this study: 23 (6 females, 17 males) children with ASD and 20 with TD (6 females, 14 males). Olfactory detection thresholds of children with ASD were significantly higher than those of TD chi...