Thursday, December 15, 2011

Autism: Associated Deficits in Temporal Processing

Currently idiopathic autism is typically diagnosed according to an observational assessment of certain behavioral, social, and cognitive tendencies across dimensions of language, social interaction, imaginative play, and restricted or repetitive cognitions and behavior.

Parent interview is required to confirm presence of specific tendencies within the first 3 years of life. There is, as yet, no bio-medical test or marker for autism, although certain neurological, genetic, and physiological differences are known.

There are often common co-morbid disorders, such as problems with sleep, motor function and attention-hyperactivity. An individual is diagnosed along spectrum of impairment (autistic disorder or autism spectrum disorder).

Thus any psychological theory of autism is required to describe differences, and similarities, across a range of behavioral, social and cognitive abilities, within and between affected individuals. Arguably the three most dominant theories of autistic disorder relate to weak central coherence (or information processing), executive functioning, and theory of mind.

There may be another hitherto, rather unacknowledged possibility: a deficit in temporal processing.

An adaptive sensitivity to the duration of events, and time between them, is critical to adaptive cognitive, behavioral, and social function. There are anecdotal and clinical reports of problems with time in autistic disorder, and successful applied behavioral educational and therapeutic supports with this population often include external signals to indicate the passage of time, temporal structure, and upcoming events.

Currently, the empirical literature on temporal processing in autistic disorder is relatively scant, and encompasses findings spanning a range of psychology; neurological, genetic, behavioral, and cognitive, observational, and computational assessments.

These include reports that children with autism experience difficulties imaging past and future changes of a current situation and understanding that successive events are part of a unitary process; differences in temporal reproduction and duration perception (in the interval range); and electrophysiological reports of disordered temporal binding of stimulus input, apparently over extended periods (than is typical).

These findings are usually complementary, although vary greatly in the nature of the methods and analysis used (for a review, see Allman and Meck, 2011). There is preliminary evidence from data modeling to suggest that aspects of the perception of duration might be “developmentally delayed” in this population (see Allman et al., 2011).

Consistent among these aforementioned findings is the interpretation of results within the context of a deficit in (some aspect of) temporal processing in autistic disorder (e.g., Boucher et al., 2007).

These range from suppositions that affected individuals experience problems thinking about time and higher temporal cognition, to notions that there are fundamental differences in the quality of the “subjective present” as it relates to the temporal processing of sensory information.

Clock gene anomalies have been related to sleep, memory, and timing problems in autistic disorder. There have been several attempts to assert a hypothesis of temporal processing disturbance in autistic disorder, both within the discussion of published reports, or in more speculative accounts which go so far as to describe diagnostic features of autistic disorder as manifestations of atypical aspects of temporal processing (for details, see Allman and DeLeon, 2009).

However, there is as yet, no well-defined profile of temporal processing abilities in these individuals, and no sufficiently specified theory.

Read more of this article and published paper: Deficits in Temporal Processing Associated with Autistic Disorder

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