Do neuropsychological assessments or tests usually take place in one sitting? if so, it may not capture *trouble thinking* that comes and goes.

Testing: may lead to further testing scheduled at another time. NP testing is incredibly extensive and will not miss baseline deficits. Sleep deprivation, anxiety, distraction, intercurrent illness, or intoxication, could alter your performance. You are very unlikely to fool the testing. Fluctuating deficits may not be captured AND NP testers are well aware of "trouble thinking" that comes and goes.