If a child's sleep apnea caused developmental delays, the problem was solved with a t&a, how long would it take for them to catch up?

Hard to say. To the extent that a child is unrested, lack of attention may cause them to fall behind their peer group in many areas of development. Improvement in their sleep quality may allow for catch-up progress over time, but this is hard to predict.If the child had other ongoing issues, or the sleep apnea was bad enough to produce some impairment, a return to normal may be difficult.
Developmental delay. Sleep apnea cannot be the sole reason for developmental delay. See a neurologist to investigate further.

Related Questions

Can sleep apnea in children cause developmental delays?

Learning disabilitie. Sleep apnea has been shown to increase the risk of learning disabilities. There is also a risk of behavioral problems similar to adhd. There area my things that can lead to troubles learning, behaving, and socializing. Be sure all things are investigated and don't rely on one solution to answer all the questions. Read more...
Yes. Sleep apnea causes less rest and sleep which can have multiple effects. It will not stop development but not sleeping and resting could cause development ot slow down a bit. Read more...
Yes. Most of the times this kids by mistake diagnose with adhd and treat them for that instead of their sleep apnea. Read more...
no data on this. Sleep apnea in children has been linked to adhd-like behavior and other behavioral problems, problems with school performance, and poor concentration, but not developmental delays. Children with global delays, especially motor delays, are more likely to have sleep apnea because of problems with their neurologic system. Read more...