What would a sensory assessment from an OT involve?

Hi.  I'm mum to a newly diagnosed 16 year old daughter.  She is "high functioning" and I guess that's why only in the last couple of years have there been any problems stemming from what now turns out to be her autism.

On her assessment results, the pyschologist notes that our daughter seems to have some sensory integration/processing difficulties, and recommends a specialist assessment from an OT.  It turns out that this assessment will cost £200.  I wondered whether anyone could help us understand what it will offer so we can decide whether or not to have it?

Our daughter is very articulate, and says that she often feels as if she is "not touching enough" - she does things like stretching out her fingers, and "trying to touch interesting things" to increase her tactile stimulation and has often said she would like a weighted blanket.

She is also sensitive to noise, though mostly this is only when she's already feeling anxious.  She talks about noise cancelling headphones, but I think that what she actually wants is ear defenders, since she doesn't want to listen to music- just to "block out" noise from outside.

When she is stressed she likes pressure against her ears and eyes, and says that she finds hats to be calming because they press on her head.

We could *buy* a weighted blanket, noise cancelling headphones and a hat for little more than the cost of the assessment; but we're unsure about whether the assessment would reveal more than what our daughter is able to tell us about how she can be helped.

Is anyone able to explain what the assessment would involve?

Thanks!

Sarah.