How would a child with adhd and asperger syndrome behave?

Adhd and aspergers: Adhd includes inattention, trouble focusing, hyperactivity, and impulse problems. Aspergers tends to be a social problem laden with anxieties. They can be comorbid.

Too complex to say: It's impossible to fully answer your question because each such child would behave in a unique manner depending on the individual profile of symptoms and personality: e.g., 6 or more symptoms of inattention and/or 6 or more symptoms of hyperactivity-impulsivity with impaired social interactions, restricted repetitive & stereotyped behavior, interests and activities, causing significant impairment.

Good question: This can be a difficult differential diagnosis. Both can have mild neuropsychological or soft neurological signs including poor attention. Overdiagnosis of asperger's often occurs in adhd children because evaluators get loose with how severe social skills deficits have to be. Aspergers children show much more stereotypic interest and motor behaviors, though there can be mild manifestion in adhd.

A technical point: adhd symptoms really should be understood to be part and parcel of aspergers. In DSM, it is incorrect to make a second diagnosis of adhd if the child is already on the autism spectrum. Unless the child is so severely adhd that limits function or puts them at risk e.g. climbing so much or running that they injure themselves multiple times per week.

Symptoms of both: A person with Asperger's disorder will have difficulty with anxiety and social interaction. Separately, symptoms of ADHD will be short attention span, easy distractibility, impulsivity and possibly excessive restlessness.

Observable : Behaviors depend on whether he has hyperactivity/impulsivity with his inattention. Inattention, distractibility, being "off-task" often, forgetfulness, impact his academics. Hyperactivity/impulsivity contribute to disruptive behavior.Since the as already causes non-compliance & seemingly oppositional behaviors, proper diagnosis & treatment of adhd ( in 40-70% of kids with asd's) is vital.

Not very differently: Adhd would present similarly in all children however there would some difference in children with asperger's as impulsivity is likely to present with increase stereotypes which are part of asperger's. Other aspects of asperger's might also become more pronounced. Frustration tolerance which is an issue might become more pronounced. Treatment of adhd is more tricky as well as asperger's children.

A technical point: adhd symptoms really should be understood to be part and parcel of aspergers. In DSM, it is incorrect to make a second diagnosis of adhd if the child is already on the autism spectrum. Unless the child is so severely adhd that limits function or puts them at risk e.g. climbing so much or running that they injure themselves multiple times per week.