Staragate, ADN, ASN, RN 380 Posts Specializes in Dialysis. Has 5 years experience. Aug 22, 2011 As a nursing student who works as a CNA in a Alz ward, I want to put out a theory. If I am totally off base, please tell me.You said these pts were in a LTC, but you did not mention if they had a shared diagnosis. If they are there for dementia/Alz reasons, then I would relate the lack of PERRLA to the neuro dx. The damage done to Alz cells come from a warping of the shape of the neurons. I would think that could translate to the brainstem or transmission of the cranial nerve impulse to the brain. The tone of the pupils could be compromised from a interruption in neuro transmissions, resulting in a change in pupil shape, rxn to light, etc.I've noticed from working with developmental disabled kids, that when there is a neuro deficit in one place, there is often one in another. (Nystagmus = balance issues)Am I close or am I off base?