Lewy Body Dementia Precursors

Last week the blog was about how dementia is a symptom of many different cognitive, or mental, dysfunctions, with the main players being Alzheimer's, Lewy body, Vascular and Frontotemporal dementia. Readers also learned that dementias like to hang out together and that even if a person is diagnosed with one kind, an autopsy will likely show that there was at least one more.

This week's blog is about the symptoms leading up to Lewy body dementia.

Like Alzheimer's disease (AD), LBD is caused by normal proteins that become damaged, and then, cause more damage. In the case of LBD, it is the alpha-synuclein proteins that "misfold" into Lewy bodies. These round sticky masses then attack certain neurotransmitters, the chemicals that pass information from neuron to neuron. While AD proteins tend to stay in the cerebral cortex, Lewy bodies migrate, and can spread throughout the nervous system. Thus, they cause a great variety of symptoms. What these symptoms are depends on where in the body the Lewy bodies are located.
One question we often hear is "What causes the proteins to misfold and turn into Lewy bodies?" Well, the answer to that appears to be two-fold. First, a person has to have the genetic tendency. And then they have to be exposed to an environmental toxin. (See the 11/7/14 blog, Genes and Environment, for a more thorough answer to this question. I'll also be talking about it again in a future blog about something called "telomeres.")

Chronic Constipation. Annie, Jim Whitworth's first wife, and his original reason for being on this journey, had chronic constipation as a young woman. Her more conventional LBD symptoms of hallucinations and poor thinking skills didn't appear for almost a half century later. One thinks of LBD being a "brain disease" but it is more a "nerve" disease. Since there are more nerves in the gut than anywhere else in the body, except for the brain, it makes sense that one of the first places Lewy bodies may show up is in the intestinal tract, which isn't nearly so well protected.

REM Sleep Behavior Disorder (RBD). The chemical switch that prevents movement during sleep is situated on the brainstem in the pons. When Lewy bodies find their way here, they damage the switch and people act out their dreams. They can be very active, hence the very accurate description of "Active Dreams." About 50% of those with RBD go on to develop LBD eventually. See our 11/02/12 blog, Active Dreams, for more about RBD.

Parkinson's disease (PD). PD is a movement disorder that occurs when Lewy bodies in the midbrain attack dopamine, a neurotransmitter instrumental in fine motor control. From 60% to 80% of those with PD will eventually go on to experience dementia symptoms. Many people with PD also have Chronic Constipation and or RBD. The more of these "precursor symptoms" a person has, the more likely dementia is. See our books (below) for more about PD.

Hallucinations. When the Lewy bodies travel a little further into the brain, they find the cerebellum, which has a lot to do with making sense out of what a person sees. Here, Lewy bodies interfere with this process and cause a person to hallucinate, or see (or feel or hear) things that aren't really there. These hallucinations can appear very realistic. Even so, a person can usually understand that although they see the little bugs or green men or lady on the sofa, no one else does--at first. Then as the Lewy bodies move into the thought processing parts of the brain, they begin to believe their hallucinations are real. See our books (below) for more about hallucinations.

Mild Cognitive Impairment (MCI). The Lewy bodies have found the cerebral cortex, the area of the brain where the ability to think clearly and do tasks is stored, causing poor decisions or the fumbling of familiar tasks (MCI-LB). If Alzheimer's is involved, MCI may start with memory loss (MCI-AD). In either case, a person can still function and take care of themselves.

Dementia: MCI becomes "dementia" when it interferes with a person's ability to provide adequate and safe self-care. In the case of AD, symptoms usually have to do with memory about things: words, dates, events and such. With LBD, they have more to do with task memory: the ability to perform once easy tasks. Lewy bodies also mess with one's thinking skills and delusions become common. People with hallucinations now believe they are real.

Now, the thing to remember is that with LBD nothing is firm. Every person experiences LBD differently. Any one of these symptoms can occur without the other, or in almost any order, although at least one of them usually occurs prior to the dementia. Lewy bodies tend to travel in the way I've described, but they often don't. They may skip a symptom, such as PD, and move on to the next, or they may travel in a different order. In fact, about 50% of the time, a person with Lewy body dementia will NOT have experienced PD first, although eventually, they will usually have some motor issues. When this happens, it is called Dementia with Lewy bodies.

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
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.

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.