Atypical signatures of motor variability found in an individual with ASD.

We provide objective metrics of sequential movements and study a young adolescent with Autism Spectrum Disorders (ASD) in relation to novice typical controls (TC) as they learned to perform beginners' martial-arts routines. We studied segments staged to hit an opponent simultaneously performed with supplemental segments. In TC instructed changes in speed had profound differential effects on the intended vs. supplemental segments that were absent in the ASD case. Moreover, the frequency-distribution of velocity and acceleration maxima in TC was well fitted by a Gamma distribution but in the ASD case the fit was exponential yielding uncannily precise motions with atypically low-range of spatio-temporal variability.