global developmental delay

My 21 month old daughter was recently diagonsed with global developmental delay.  I was wondering if I should have her tested to find out the cause or just proceed with therapy.  If anyone has a child with gdd maybe you could help me.  Do children usually do well in therapy?  I have a lot of questions so any response is greatle appreciated.

[Kevin Kennedy, Ph.D.]

How was the diagnosis reached? The only 'testing' that might be useful at this age would involve a determination if there is any chromosomal abnormality. You might ask about this. Other than that, proceeding with the various interventions (physical therapy, occupational therapy, speech/language therapy, e.g.) would be prudent.

[Kalidasu]

A related discussion, delyayed development was started.