Two Types of Lewy Body Dementia

Last week the blog was about the symptoms leading up to LBD. This week is about the two different types of LBD. Last week's blog mentioned that LBD can show up either before or after movement issues. This is important because how it originally shows up determines its name.

If the Lewy bodies follow that path described in last week's blog, and travels from the midbrain into the cerebral cortex, then the dementia that follows will be called Parkinson's with dementia, or PDD. However, about 50% of the time, the Lewy bodies start in the cerebral cortex and spread out from there. When that happens, the disorder is called dementia with Lewy bodies. In each case, symptoms depend on the area of the brain affected. That is, when the Lewy bodies are in a certain area of the brain, the symptoms will be similar, no matter where they started. Therefore, Lewy body dementia has become an umbrella term that refers to both kinds.

Dementia with Lewy Bodies (DLB): This describes the type of Lewy body dementia that starts without motor symptoms. Diagnosed onset is from age 40 through 80, with the average in 70's. It is not uncommon for a care partner to say later that they remember certain symptoms starting much earlier, especially RBD and anger management issues.

First symptoms are often not recognized because they seldom include memory loss:

• Active dreams (RBD) can start many years before any mental problems are noticed. Jim's first wife, Annie, had these. They just laughed about them, and considered them an idiosyncrasy that didn't really cause any problems.
• Executive skills gradually fade. These include skills such as decision making, doing sequences, planning, and thinking in general. One woman, a supervisor in a busy office had to take an early retirement. She had became unable to file reports; her ability to alphabetize in a sequential manner was damaged. People with LBD tend to loose these skills well before losing the ability to remember names and events.
• Anger management issues are common, due to diminished impulse control and damaged thinking skills. That is, a person may perceive a slight or other problem where there is none and then become angry when others don't see the same issue. In the workplace, this can be serious. One man, a well-loved school counselor began angrily accusing his work-mates of lies and such. When his irrational behavior spread to his students, he was warned that unless he changed his behavior, he would be fired. Luckily, he had a driving accident that required him to see a doctor. The doctor diagnosed him with LBD and he was allowed a medical retirement.
• Hallucinations are another early symptoms. They are common with most dementias, but tend to show up much earlier with LBD than others such as AD. In fact, they are often the first symptom recognized as a true problem, and the one that drives a couple to the doctor.

Parkinson's with Dementia. When person with Parkinson's (PD) begins to have mental issues, this is called Parkinson's with Dementia (PDD).We believe that everyone with PD will eventually develop some dementia symptoms...if they live long enough. That usually starts about 15 years after a PD diagnosis, but it can be much longer. Onset for PD can be as early as 30 but is more likely in the 60's. (However, people with early-onset PD are less likely to experience early dementia.) The person who arrives at dementia via Parkinson's, has some advantages and some disadvantages.

The advantage is that most people are aware that dementia can be a symptom of PD. Therefore, when the odd behavior starts, people around them are more likely to recognize it for what it is and not, as in the example above, a behavior issue that needs to be changed. With PDD, the first symptoms are usually attributed to PD alone because they occur so often with it. Active dreams and slower thinking both fit this category. But when hallucinations appear, a doctor will usually start considering the possibility of dementia. By then, executive skills will likely have been affected as well.

The disadvantage is that that PD doctors are movement, not dementia, specialists. Preserving mobility is their primary goal. However, PD meds are anticholinergics. That isn't a problem until the Lewy bodies get into areas of the brain where they begin causing cognitive symptoms. Then the PD meds may increase cognitive symptoms. With PDD, a person needs a doctor that understands that treatment is a balancing act, with some mobility forfeited for better cognition, and vice versa.

Mixed Dementia. When types of LBD are discussed, mixed dementia also needs to be addressed. The truth is that people usually don't have just one kind of dementia. Even if a person is only diagnosed with LBD, they are likely to have Alzheimer's as well. Or maybe they have vascular dementia. Each of these will have different early symptoms and this cause a doctor to have difficulty with the diagnosis. The bottom line is that if there is a possibility that a person has LBD, that is the one to be concerned about because of the drug sensitivities involved. If you treat a person as though their dementia is LBD, they will do fine, no matter what kind they have. If you don't, they could be given a drug that LBD doesn't tolerate well, with possibly dire results.

For a much more involved description of all of the above read our books (below).

Next week's blog will be more about the two types of Lewy body dementia...the kind that starts with PD and the kind that doesn't.

Acronyms:
LBD: Lewy body dementia
AD: Alzheimer's disease
RBD: REM sleep behavior disorder (also called Active Dreams)
PlwD: person living with dementia
PlwLBD: person living with LBD
DLB: dementia with Lewy bodies
PDD: Parkinson's disease with dementia
MCI: mild cognitive impairment
MCI-LB: the form of MCI that precedes LBD
MCI-AD: the form of MCI that precedes AD
BPSD: behavioral and psychological symptoms of dementia

For information about Lewy body disorders, read our books:
A Caregivers’ Guide to Lewy Body Dementia
Managing Cognitive Issues in Parkinson's and Lewy Body Dementia

Helen and James Whitworth are not doctors, lawyers or social workers. As informed caregivers, they share the information here for educational purposes only. It should never be used instead of a professional's advice.