Generalised Time Processing Impairment in Autism Spectrum Disorders

Background: Individuals with ASD have been known to show a poor sense of time “to a degree that is markedly discrepant with their level of intelligence” (Wing, 1996: 89). Deviations in the processing of time do not currently form diagnostic criteria, but may affect every day behaviour and could feed into many diagnostic domains. In particular, efficient interaction and communication are reliant on accurate timing of durations and events. Hence, timing has received increasing attention in recent research (for a review see Allman & Falter, 2015). Yet, a lack of systematic studies testing different aspects of timing in the same sample of participants, prevents a conclusive assessment of whether there is a generalised time processing deficit in ASD and whether there is any relationship to diagnostic symptoms.

Objectives: The aim of this study was to test performance across time processing functions, scales and modalities in the same group of individuals.

Methods: 17 children diagnosed with ASD and 18 typically developing age- and IQ-matched controls carried out a set of motor and perceptual timing tasks: free tapping, simultaneity judgment, auditory duration discrimination, and verbal time estimation. In addition, parents of participants filled out a questionnaire assessing the sense and management of time.

Results: Children with ASD showed faster and more variable free tapping than controls. Auditory duration discrimination thresholds were higher in the ASD compared to the control group in a sub-second version of the task, while there were no group differences in a supra-second discrimination of intervals. Children with ASD showed more variable thresholds of simultaneity judgment, and they received lower parental scores for their sense and management of time. No group differences were observed in the verbal time estimation task in the minute-range. Importantly, we found an inter-correlation between timing functions in the ASD group only, pointing towards less differentiation and specification of timing functions in ASD. Finally, autistic symptom severity was associated with several timing measures.

Conclusions: The time processing deficit in ASD can be generalised to motor timing, perceptual timing, and temporal perspective, and it is associated with autistic symptom severity. An interrelation between timing functions suggests that, in contrast to control participants, individuals with ASD might apply a similar strategy irrespective of task demands and context.

References:

Allman, M. J., & Falter, C. M. (2015). Abnormal timing and time perception in Autism Spectrum Disorder? A review of the evidence. In: Vatakis, A., & Allman, M. J. (eds.) Time Distortions in Mind: Temporal Processing in Clinical Populations. Brill: Leiden, pp. 37–56.

Wing, L. (1996). The Autistic Spectrum. Constable, London.