Hi Gordon,

You may want to consider having approximately equal numbers of left
and right handed participants in both the ASD and control groups.
This will ensure that any ASD vs. control differences can't easily be
attributed to handedness issues, and would also let you examine
effects of handedness when you analyze the data.  Otherwise I think
you run the risk (real, or in the minds of reviewers) of confounding
handedness and diagnosis, which could cause problems with
interpretation.  Of course you can argue that handedness is not
thought to be related to what you are interested in, but it would
probably be better to just address it with data.

My 2 cents!  Hope it helps.


On Tue, Mar 24, 2009 at 10:31 AM, Waiter, Dr Gordon D.
<[log in to unmask]> wrote:
> We are about to start recruitment for a study of attention in Autism
> Spectrum Disorder (ASD). A large percentage of our potential ASD
> participants are left handed. I appreciate that trying to minimise variation
> in our sample is desirable but we're not aware that attention is lateralised
> or would be expected to be, so are there still reasons to limit our group to
> right handers only, bearing in mind that our control group will be right
> handed.
> Thanks in advance,
> Gordon