This post focuses on DLB (Dementia with Lewy Bodies). It says nothing about PDD (Parkinson's Disease Dementia).
I'm not sure how many of you will be interested in this article. It may be that only those who have donated the brains of their family members will be interested in this article. As I read a lot of neuropathology reports from the Mayo Clinic in Jacksonville, FL, this article is of interest to me. (Many of this article's authors are from Mayo Jax and others are from Mayo Rochester.) Many of the neuropathology reports I've read with the autopsy-confirmed diagnosis is "Lewy body disease" refer to this important article.
You might also be interested in this article if you follow the diagnostic accuracy of neurologists making the diagnosis of DLB. The Mayo clinicians in this small study of 43 patients diagnosed with DLB got the diagnosis right between 70% and 93% of the time, depending on how you define "accurately diagnosed."
The full article is available at no charge online at:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2745052/ --> HTML version
http://www.ncbi.nlm.nih.gov/pmc/article ... 131610.pdf --> PDF version
Highlights are:
* The Third Consortium on DLB (CDLB) pathological criteria "recommend that the neuropathologic diagnosis should be in the form of a probability statement related to the likelihood that the pathology would be associated with the DLB clinical syndrome and that the probability is positively correlated with the distribution of Lewy bodies and negatively correlated with the severity of Alzheimer-type pathological features. This recommendation was based upon prevailing evidence that the greater extent of Alzheimer-type pathology, the less likely the patient would have presented with the DLB clinical syndrome, even if widespread cortical Lewy bodies were present at autopsy."
* The clinical diagnoses of the study participants included 43 patients with probable DLB, 9 with possible DLB, and 24 with probable AD.
* Table 1A is worth looking at:
http://www.ncbi.nlm.nih.gov/pmc/article ... /table/T1/It shows that all of the people with RBD and all of the people with fluctuating cognition had "probable DLB" diagnoses clinically. All of the people with visual hallucinations had either probable DLB or possible DLB diagnoses.
* The pathological diagnoses of the 76 study participants included "29 patients had high-likelihood, 17 had intermediate-likelihood, and 6 had low-likelihood DLB pathology. ... For the sake of discussion, cases that fell into the high- and intermediate-likelihood of DLB categories were considered to have the pathological diagnosis of DLB." So, 24 of the study participants did not have DLB pathology (76 minus 29 minus 17 minus 6).
* Table 2 is worth looking at:
http://www.ncbi.nlm.nih.gov/pmc/article ... /table/T2/It shows that of "the 43 clinically probable DLB patients, 40 had intermediate- or high-likelihood DLB pathology. More than 80% of the cases with clinically probable DLB had diffuse cortical Lewy bodies."
So, in this small sample size of 43 clinically probable DLB, the diagnostic accuracy was 93% (40 out of 43) or 80%, depending on how you defined "accuracy."
* "One clinically probable DLB patient had PSP with concurrent Alzheimer-type pathology (Braak NFT Stage VI), but no Lewy bodies. This patient had 2 core clinical features as well as RBD. There were only 2 cases with low-likelihood DLB pathology; both had advanced Alzheimer-type pathology with limbic Lewy bodies."
* "Only 2 out of 9 clinically possible DLB cases had intermediate- or high-likelihood DLB pathology."
So, in this small sample size of 52 patients with clinically probable or possible DLB, 42 had intermediate- or high-likelihood DLB pathology, or 80%. I'm not sure we are told how many of the 52 patients had diffuse cortical Lewy bodies. Assuming none of the patients with clinically possible DLB had diffuse cortical Lewy bodies, then the diagnostic accuracy was just under 70% (36 out of 52).
There are at least two reasons why the diagnostic accuracy is higher in this study than we've seen in other studies. First, the Mayo clinicians are some of the best in the US at diagnosing DLB. Second, the sample size is very small.
* Table 3 is worth looking at:
http://www.ncbi.nlm.nih.gov/pmc/article ... /table/T3/It shows that if a DLB patient had visual hallucinations within 3 years of symptom onset, there was a great likelihood that this patient had DLB.
"In this series, 2 clinically possible DLB cases had advanced Alzheimer pathology with Lewy bodies confined to amygdala. Visual hallucinations occurred in these patients at 5 and 7 years after the onset of dementia."
I've copied the abstract below.
Robin
Journal of Neuropathology and Experimental Neurology. 2008 Jul;67(7):649-56.
Validation of the neuropathologic criteria of the third consortium for dementia with Lewy bodies for prospectively diagnosed cases.
Fujishiro H, Ferman TJ, Boeve BF, Smith GE, Graff-Radford NR, Uitti RJ, Wszolek ZK, Knopman DS, Petersen RC, Parisi JE, Dickson DW.
Department of Pathology and Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
Abstract
There is limited information on the validity of the pathologic criteria of the Third Consortium on Dementia with Lewy bodies (CDLB), and none are based on prospectively diagnosed cases.
In this study, the core clinical features of dementia with Lewy bodies (DLB) and the suggestive clinical feature of rapid eye movement sleep behavior disorder were assessed using a battery of standardized clinical instruments in 76 patients with the clinical diagnosis of either DLB or Alzheimer disease.
At autopsy, 29 patients had high-likelihood, 17 had intermediate-likelihood, and 6 had low-likelihood DLB pathology.
The frequency of core clinical features and the accuracy of the clinical diagnosis of probable DLB were significantly greater in high-likelihood than in low-likelihood cases. This is consistent with the concept that the DLB clinical syndrome is directly related to Lewy body pathology and inversely related to Alzheimer pathology.
Thus, the Third Consortium on DLB neuropathologic criteria scheme performed reasonably well and are useful for estimating the likelihood of the premortem DLB syndrome based on postmortem findings.
In view of differences in the frequency of clinically probable DLB in cases with Braak neurofibrillary tangle stages V (90%) and VI (20%) and diffuse cortical Lewy bodies, a possible modification of the scheme is to consider cases with neurofibrillary tangle stage VI to be low-likelihood DLB.
PubMed ID#: 18596548 (see pubmed.gov for this abstract and a link to the full article, available at no charge online)
