Impaired temporal reproduction performance in adults with high-functioning autism (HFA)

Background: In recent years there has been surprisingly little research examining temporal processing in the autism literature (although see Szelag et al., 2004). However there are a number of reasons to suspect that people with autism may have particular difficulties judging the passage of time. Time processing deficits have been observed in a number of psychiatric and neurological conditions related to autism, and the performance of people with autism spectrum disorders (ASDs) on a range of tasks that relate to the judgement of time is consistent with underlying difficulties in time perception (Boucher et al., 2006).

Objectives: The aim of the present study was to examine the performance of adults with higher functioning autism on a temporal reproduction task. Methods: The present study tested a group of 20 high-functioning adults with autism and 20 matched comparison participants on a temporal reproduction task. Participants were presented with 42 auditory tones ranging from 500 to 4100ms. After each study tone was presented, a second identical tone was presented which participants were asked to stop (by clicking on a mouse) when it reached the same duration as the study tone.

Results: The tone duration estimates of the ASD group were significantly longer or shorter than the durations of the study tones than were the estimates of the comparison group (F(1,38)=16.38, p=0.00)). The ASD estimates were also more variable (F(1,38)=8.05, p=0.01)). Furthermore the AS group showed particular difficulties as the duration of the target tones increased; they tended to underestimate to a much greater degree than the comparison group.

Conclusions: These findings support earlier evidence that temporal processing is impaired in people with ASDs, and suggest that further research using a variety of different experimental methods is necessary in order to further clarify the nature and source of these differences.