Dementia with Lewy Bodies (DLB)

This section deals only with DLB. Please review the section on Dementia for many other details about dementia in general, especially its care, which are not covered here in detail.

Lewy Bodies is the name for abnormal structures seen in the brain of patients with this type of dementia. They are named after the neurologist who discovered them, Dr. Frederic Lewy.

 

What is the problem in DLB?

DLB is a degenerative disorder caused by abnormal collection of alpha-synuclein type protein waste material in brain cells. Seen under a microscope, affected cells reveal roundish structures called Lewy bodies. This collection somehow leads to malfunction of brain neurons, and their destruction (degeneration). With enough neurons affected, patient may start having symptoms. Symptoms depend upon the location of neurons affected.

 

What are the symptoms of DLB?

Following is the outline of symptoms of DLB:

1. Cognitive: Forgetfulness, confusion (about people, events, situations), spatial disorientation (like difficulty finding the parked car, finding oneself in an unintended location). These symptoms are common in multiple types of dementia. The unique part is that the patient with DLB may have significant fluctuations of these symptoms.
2. Balance and gait: Like a Parkinson disease patient, problem with balance and walking, rigidity, and falls. Patients are commonly misdiagnosed as having Parkinson disease.
3. Psychiatric: Anxiety, paranoia, delusions, anger, hallucinations, and change in personality. Most common are visual hallucinations.
4. Autonomic: Dizziness, fainting, constipation, and bladder control problems.
5. Sleep disorder: REM sleep behavior disorder (please read a separate section on this condition). It may appear before any other symptoms.

 

How is DLB diagnosed?

Following options are available:

1. Clinical features: Most used and usually sufficient.
2. Polysomnogram Formal polysomnogram, or in-house polysomnogram, can also be useful to diagnose REM sleep behavior disorder, which is a key feature of DLB.
3. Cardiac Imaging: If available, cardiac MIBG imaging can also help, which may reveal reduced cardiac sympathetic innervation.
4. CT or MRI brain: Not useful to make a diagnosis but are useful to rule out many other causes.
5. Quantitative EEG: Slowing of EEG in posterior parts of brain is a useful marker and may be present in most patients with DLB.
6. Specialized imaging:
   1. DAT-SPECT shows decreased dopamine transport in basal ganglia and low activity in occipital lobes.
   2. FDG-PET brain can be very useful and may reveal abnormalities unique to DLB, low metabolic signal in occipital lobes and sparing of posterior cingulate gyri, compared to Alzheimer disease or other parkinsonian syndromes.
7. Synuclein Markers: Tests are available to check for alpha-synuclein in the skin, with skin-punch biopsy, or in CSF, with a lumbar puncture.
8. Brain biopsy: Theoretically possible but is almost never done. If needed, diagnosis may be confirmed at autopsy.

 

How DLB is different from Alzheimer?

First, the basic pathology at cell level is different. Second, Alzheimer, at least in early stages, starts in certain localized areas of brain. DLB pathology is more widespread. Patients with early Alzheimer do not have problem with balance and gait, or psychiatric symptoms. Patients with DLB may have these symptoms at presentation. Also, DLB progresses quicker than Alzheimer.

 

How quickly does DLB progress?

It is quicker than Alzheimer, and the life expectancy can be around 5 years.

 

What is the treatment for DLB?

No specific treatment to slow down, stop, or reverse the disease process in DLB is available. In fact, patients with this condition can be particularly sensitive to some medicines used in dementia. With that said, many medicines can be used to treat behavioral and Parkinson type symptoms. For detail, please read the treatment of dementia in the article about Dementia.

 

Is DLB a genetic disorder?

Knowledge is limited about it. On one hand it is considered not a genetic disorder, but on the other having a family member with this condition does carry some risk.

 

Where can I get more information about DLB?

American Academy of Neurology