Neuro is very much based on the medical model. Like all of medicine, the jobs are described by what they treat, not who they treat. Lifespan neuropsych is one of the most difficult things to do. It requires one to keep up on the literature children and adult to include: development, school laws and techniques, cultural considerations including what’s hip with the kids and new relevant parenting ideas, neuropathology, adult resources such as nursing homes, pharmacology, etc. How one would spend that much time in that specific endeavor and then say, “but I only want to see patients from X group” is beyond my understanding.
Legally, there are likely problems with racial restrictions on who someone sees.
Pragmatically, you’re talking about finding X number of people with relatively rare neurological illnesses, who have insurance, who are seeking care, etc. Exclusively seeing ethnic minorities of lower SES is probably going to represent a challenge to the financial viability of a practice. Most practitioners lose money on Medicaid.
This things being said: the one loophole I can imagine would be if you spoke a foreign language and lived in an area where that population was huge (e.g., there’s a strangely large population of Somalis in Maine. If you speak Somali and lived there and took whatever insurance they have, then I would guess you’d be full.). Even with that, I would highly doubt one could be competent in every type of exam.