Behavior Intervention for the Impulsive and Aggressive Asperger's kid

What intervention should be made when a young (pre-school age) asperger's child goes off beating another child on the head very aggressively due to another child having the toy wanted or taking his pencil??  His reaction is so quick and impulsive, it is impossible to prevent.  Afterwards, he seems remorseful but is still unable to control this reaction.

[Kevin Kennedy, Ph.D.]

Severe impulsivity, particularly of an aggressive sort, is generally treated with a combination of behavior modification and medication. The youngster should be evaluated by a pediatric mental health clinician