People often confuse, and come up to me and ask what’s the difference between having Parkinson’s Disease or Lewy Body Dementia. So Lewy Body Dementia effectively is a cross between Parkinson’s and Alzheimer’s Disease, both pathologically and clinically. Clinically what we see with Lewy Body Dementia is patients who present looking a bit like Parkinson’s, where their walking isn’t so good or they might have a tremor, but on top of that the predominant feature is memory loss, so they will struggle just like an Alzheimer’s patient laying down new facts.
Unlike Alzheimer’s, they often have early problems with what we call visual spatial perception and this may manifest as things like bad driving, so patients veering off in their lane, struggling to park their car or perhaps being too close to another car – not being able to judge things properly.
It is challenging to tell people what’s the difference between Parkinson’s and Lewy Body Dementia because the pathology is very similar. Under the microscope both of these diseases have got tangled alpha-synuclein, inside dying brain cells, known as Lewy Bodies. In addition, both diseases can have a bit of Alzheimer’s pathology. Indeed, in Parkinson’s Disease patients who go on to get dementia, you’ll often see some of the pathological features of Alzheimer’s Disease in those brains, but in Lewy Body Dementia we see more of it. So, in addition to these sign nucleons changes that you see in Parkinson’s we see very florid amyloid and tau protein deposits in the brain as well, which is what we see in Alzheimer’s Disease.
People are confused between Parkinson’s and Lewy Body Dementia – and it’s not just patients. It’s actually my community too, so the Parkinson’s world have defined Parkinson’s to include Lewy Body Dementia. Whereas, the Lewy Body Dementia societies say “no, no, no” – they’re different.
We can distinguish those cases who present with early memory problems. They dement within the first 12 months. They might look like having Parkinsonism and slowness, but they are a very different diagnosis. So Lewy Body Dementia generally, is more aggressive. Patients will have a shorter life span as opposed to Parkinson’s, where the lifespan is generally near normal. And when Parkinson’s patients often will live a relatively normal life but have higher rates of memory problems. However, with Lewy Body Dementia we really know that that’s going to be a much more florid challenge. Patients requiring more assistance may be losing their independence within the first two to five years, as opposed to Parkinson’s who really seem to have a normal duration and might just need a little bit of help the last twelve months or two years of their lives.