What kind of doctor can prescribe testing for a learning disability? Where would you then go for testing?

Many. Your family doctor usually directs the care you receive and the specialists you see. Testing psychologists may perform some of the evaluation, as could a neurologist or developmentalist. Speech and language therapists, occupational therapists, and educational specialists may also be involved.
Neurologist. Testing is done by a neuropsychologist. After results are available, either a neurologist or psychiatrist may prescribe medication.