In some ways, I was fortunate to have been born as early as I was. In the late 1960s and 1970s there was a fair body of professional literature that promoted a curious perspective. Apparently trying to resolve the dilemma presented by the fact that children with significant brain damage were in many cases developing pretty well in spite of that fact. The explanation put forth in the literature was that children with hydrocephalus had verbal and reading skills that fooled people into thinking they were more intelligent than they really were. Anyway, I was spared from that interpretation.
Testing is kind of problematical for people with lifelong neurological involvement.
Neuropsychological batteries were developed for people who acquired brain injury as adults, which means sudden losses of function and generally site-specific damage. Those of us who have lifelong neurological involvement more often have disruption of function. As an example - It took me forever to learn to drive. I cannot talk and make a sandwich at the same time. But a neuropsych battery fails to reveal any motor problems.