Mom has all the classic symptoms of dementia. At the same time, she also has all the classic symptoms of NPH. We were told to look for WWW - wacky, wobbly, wet. I don't think you can sort one wacky out from another and urinary incontinence comes with both also. But what about falling? With NPH the falls are backwards - is it the same with dementia? Mom definitely has a preference for falling backwards. Testing for NPH requires a surgical procedure. Is it worth it?
The testing is not difficult - it's an outpatient procedure and takes a few hours. They insert a needle and drain some spinal fluid out. It's supposed to relieve the pressure temporarily and mimic the effect of the surgery.
The surgery did help my Mom somewhat, in the incontinence issue mostly. It was not a miracle cure. It can be, though, especially with the falling. My mother doesn't fall as much but she still can't walk more than a dozen steps. I think she was already too debilitated to gain as much benefit from the surgery as someone treated when younger and healthier. It really depends on your parent's overall health and capability. Good luck!
I think if the tests aren't too invasive and there's any question, it's worth testing. Does your mom have the shuffling gait that people with NPH often have? Have you seen the 60 Minutes segment on it? If not, go to youtube and search for "60 Minutes + NPH" to watch it.