DLB - Dementia with Lewy Bodies in 2009
Under-diagnosed and Strangely Related to Parkinson’s Disease
Sep 9, 2009
The most common dementia, at least in the northern hemisphere and Europe, is Alzheimer's. The second most common is either DLB or Vascular Dementia (link). DLB is diagnosed in ten to 20% of dementia cases, but probably actually accounts for around 40%, according to experts at a recent web-based seminar (AlzForum, June 10, 2009).
How DLB is Different from Alzheimer's
The differences show up in the early stages. In the person with DLB, the memory may remain more-or-less intact, while it is always affected in Alzheimer's. What characterizes DLB are its core characteristics.
DLB Core Signs
The person must have some change in brain function that is noticeable and interferes with some function in life. In addition, the diagnosis is suggested if there are:
- Hallucinations. These are usually visual (seeing something or someone that no on else does) and often the person interacts with the other person (talks to or shares a conversation).
- Fluctuations in Brain Function. These are more than “good days and bad days,” which we all have. They are fairly abrupt episodes of confusion or loss of attention.
- Parkinsonism. Signs of a Parkinson’s Disease-like condition include muscle stiffness, changes in gait such as not picking the feet up normally, and decreased “vitality” in the appearance of the face. Muscle stiffness slows reaction time, and people with DLB are more likely to trip and fall.
DLB Supportive Signs
The diagnosis is supported by the presence of certain other characteristics.
- Neuroleptic sensitivity. Even low doses of drugs like Haldol, Thorazine, Risperdal, Seroquel, or Zyprexa may cause important adverse reactions.
- Myoclonus. Muscles tend to go into spasm when activated.
- Sleep Disturbance. Thrashing about in sleep, perhaps sleep walking, talking while asleep.
- Depression
Relation to Parkinson’s Disease (PD): The Lewy Body
Both DLB and PD are characterized by Lewy Bodies, specific microscopic changes in the brain. When stained, they look like reddish circles surrounded by a clear halo, and they lie within neurons, the brain cells. They were first described by Dr. Lewy, a German pathologist. (His name is sometimes pronounced Lay-vee, but in the US, it's usually Loo-ee.)
The difference is that in PD, the Lewy Bodies attack brain cells that control muscle action, so the condition usually starts by causing a tremor. Stiffness occurs, but the brain functions normally otherwise. After about ten years, though, people with PD often develop dementia, a condition called Parkinson’s Dementia. On the other hand, in DLB, the Lewy Bodies attack parts of the brain that control thinking and attention. After a few years, people with DLB often develop all the signs of PD. So the differences are where the Lewy Bodies start, and changes seen by the family early in the condition.
It is important to note that Lewy Bodies do not cause the conditions; they represent the product of the process, which many believe is different in PD and DLB.
How DLB is Different from Alzheimer's
Alzheimer's starts with short term memory loss. Hallucinations and Parkinsonism may show up later. In Alzheimer's, the hippocampus is affected early; in DLB, it is spared early.
The rate of decline is more rapid in DLB. In one measure, the MMSE , the decline is about 3 points each year in Alzheimer's, and about 5 points a year in DLB.
The quality of life is poorer in DLB. Patients are more likely to have problems with life activities that require solving problems, are more likely to have delusions, and more likely to have apathy (withdrawal that resembles depression). (Bostrom, F et al., Alzheimer’s Disease and Associated Disorders, 2007; 21: 150)
Why Making the Correct Diagnosis Makes a Difference
If the family knows the problem is DLB, then the periods of confusion or lack of attention are understandable, and not due to pique or childishness. Clinicians will know that if a neuroleptic can‘t be avoided, to use a very low dose. Understanding how large the problem is may lead to more research, ultimately leading to successful treatments.
Source: Webinar, Alzforum, 06-10-2009 (A Webinar is an online seminar)
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