Dementia with Lewy bodies

Dementia with Lewy Bodies

LBD: What is it?

Lewy Body Dementia is so called because the brains of affected people develop abnormal spherical masses of protein, called Lewy bodies, inside nerve cells. Lewy bodies are associated with Parkinson’s disease as well as dementia. Thus Lewy body dementia can refer to both Parkinson’s disease dementia and “dementia with Lewy bodies”. Lewy bodies are also often found in the brains of those with Alzheimer’s disease.

Unlike Alzheimer’s, however, dementia with Lewy bodies characteristically (but not invariably) begins with visual hallucinations.

Prevalence of LBD

Estimates of its prevalence are complicated by the lack of clearly defined clinical criteria, and vary widely. A 2005 review1 concluded that the range probably falls between 0 to 5% in the general population, and from 0 to 30.5% of all dementia cases (the very broad range reflects the confusion between Parkinson’s disease dementia (PDD), dementia with Lewy bodies, and Alzheimer’s where Lewy bodies are present).

How does LBD differ from Alzheimer's & PDD?

A comparison of these three disorders found that cognitive impairment in those with Alzheimer's disease and those with Lewy body dementia was similar, and more severe than in those with Parkinson's disease dementia.

The 1997 study2 also found that a simple test, in which patients are asked to draw and copy a clock face, distinguished those with Alzheimer’s and those with Lewy body dementia — of all the groups, only those with Lewy body dementia had equally poor scores in the “copy” part of the test compared to the “draw” part.

For more information:

Mayo Clinic: http://www.mayoclinic.com/health/lewy-body-dementia/DS00795

Lewy Body Dementia Association: http://www.lewybodydementia.org/

References: 

  1. Zaccai, J., McCracken, C. & Brayne, C. 2005. A systematic review of prevalence and incidence studies of dementia with Lewy bodies. Age and Ageing, 34(6), 561-566.
  2. Gnanalingham, K.K. et al. 1997. Motor and cognitive function in Lewy body dementia: comparison with Alzheimer's and Parkinson's diseases. Journal of Neurology, Neurosurgery, and Psychiatry, 62, 243-252.

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Three-minute test detects Lewy Body dementia

  • An easy new rating scale will help those with Lewy Body dementia be diagnosed much more quickly.

After Alzheimer's disease, the next most common type of dementia is Lewy Body disease. Far less widely known, this form of dementia is often diagnosed quite late. A new study has validated a simple rating scale that non-specialist clinicians can use to quickly and effectively diagnose LBD in about three minutes.

The Lewy Body Composite Risk Score (LBCRS) is a simple, one-page survey with structured yes/no questions for six non-motor features that are present in patients with LBD, but are much less commonly found in other forms of dementia.

The study involved 256 patients referred from the community. The LBCRS was able to discriminate between Alzheimer's disease and LBD with 96.8% accuracy, and provided sensitivity of 90% and specificity of 87%.

Earlier diagnosis will not only reduce the strain on sufferers and their families, but also reduce the risk of inappropriate medications that can have potentially serious adverse consequences, and increase the opportunity to receive appropriate symptomatic therapies at the earliest stages when they are likely to be most effective.

http://www.eurekalert.org/pub_releases/2015-10/fau-ttd102315.php

Reference: 

[4041] Galvin, J. E.
(2015).  Improving the clinical detection of Lewy body dementia with the Lewy body composite risk score.
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring. 1(3), 316 - 324.

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Adult ADHD significantly increases risk of Lewy body dementia

February, 2011

Nearly half of those with dementia with Lewy bodies were found to have had adult ADHD — three times the rate of controls and those with Alzheimer’s.

A study involving 360 patients with degenerative dementia (109 people with dementia with Lewy bodies (DLB) and 251 with Alzheimer's) and 149 matched controls, has found that 48% of those with DLB had previously suffered from adult ADHD. This compares with 15% found in both the control group and the group with Alzheimer's. DLB tends to be under-diagnosed, but is thought to account for around 10% of dementia cases in older people.

ADHD and DLB are thought to both involve the same neurotransmitter pathway problems.

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Cognitive decline is not simply a function of getting old

October, 2010

New research suggests that even “normal” cognitive decline with age reflects the type of brain damage that is (in greater amount) characteristic of dementia.

Findings from the long-running Religious Orders Study, from 354 Catholic nuns and priests who were given annual cognitive tests for up to 13 years before having their brains examined post-mortem, has revealed that even the very early cognitive impairments we regard as normal in aging are associated with dementia pathology. Although pathology in the form of neurofibrillary tangles, Lewy bodies, and cerebral infarctions were all associated with rapid decline, they were also associated with “normal” mild impairment. In the absence of any of these lesions, there was almost no cognitive decline.

Previous research has shown that white matter lesions are very common in older adults, and mild cognitive impairment is more likely in those with quickly growing white matter lesions; importantly, the crucial factor appears to be the rate of growth, not the amount of lesions. This new study extends the finding, suggesting that any age-related cognitive impairment reflects the sort of brain pathology that ultimately leads to dementia (if given enough time). It suggests that we should be more proactive in fighting such damage, instead of simply regarding it as normal.

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Mental fluctuations may signal Alzheimer's disease

January, 2010

A study has found that mental fluctuations were very rare in those without Alzheimer's, but occurred in nearly 12% of those with very mild or mild Alzheimer’s.

A study involving 511 older adults (average age 78) has found that 11.6% of those with very mild or mild Alzheimer’s (43% of the participants) had mental lapses, compared to only 2 of the 295 without Alzheimer’s. Those with mental lapses also tended to have more severe Alzheimer’s. Although mental lapses are characteristic of dementia with Lewy bodies, this is the first study to look at them in connection with Alzheimer’s. Having mental lapses was defined as having three or four of the following symptoms:

  • Feeling drowsy or lethargic all the time or several times per day despite getting enough sleep the night before
  • Sleeping two or more hours before 7 p.m.
  • Having times when the person's flow of ideas seems disorganized, unclear, or not logical
  • Staring into space for long periods

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