Can an evaluator deny a client looking or having a copy of a neuropsychological exam?

You usually have an absolute right to your medical tests.  The limitations arise only usually when provided without approval to third parties.  See the following:

12-2292. Confidentiality of medical records and payment records

A. Unless otherwise provided by law, all medical records and payment records, and the information contained in medical records and payment records, are privileged and confidential. A health care provider may only disclose that part or all of a patient's medical records and payment records as authorized by state or federal law or written authorization signed by the patient or the patient's health care decision maker.

B. This article does not limit the effect of any other federal or state law governing the confidentiality of medical records and payment records.

In terms of misinterpreting the facts, it would be most likely up to you to get either a second opinion or review of the test.

You may wish to consult with an attorney in your state about this particular matter if you feel your medical rights have been unduly violated.  Try www.attorneypages.com.