Dementia with Lewy Bodies. Identification, frequency and sleep-disturbances. A cross-sectional clinical dementia cohort study
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Background: Dementia with Lewy Bodies (DLB) has existed as a formal consensus diagnosis since 1996 and is defined by dementia and the core features parkinsonism, visual hallucinations and cognitive fluctuations. The original consensus criteria had low sensitivity (20-60%) although the specificity was satisfying. (80-100%) From 2005 the additional suggestive features rapid eye movement (REM) sleep behaviour disorder (RBD), low uptake on Dopamine Transporter Scan (DaTSCAN ) and neuroleptic sensitivity have been included to improve sensitivity of the clinical diagnosis. The nosological status of DLB is still discussed, and the frequencies of DLB, and of RBD and other sleep disturbances in DLB, are not known. Objectives: In our first paper we sought to find the frequency of DLB in the Dementia Study of Western Norway, (The DemVest-Study) applying the revised clinical diagnostic DLBcriteria. We compared the frequency of DLB in our cohort applying both the new revised and the original consensus criteria for diagnosing DLB to find if the new criteria are more sensitive. In the second paper we compared the frequency of sleep disturbances in Lewy Body Dementia (LBD) as compared to Alzheimer’s Dementia (AD) and healthy controls. In the third paper we examined how the core and suggestive features of DLB were distributed among all individuals with mild dementia to find empirical support for diagnosing DLB as an own diagnostic entity and to find cut- off values for core and suggestive features designating DLB. Methods: All referrals to 5 specialists out patient clinics doing dementia work up in Western Norway were screened during a 2 year inclusion period. Particular care was taken to screen all included patients for the core and suggestive features of DLB. We offered inclusion to everybody presenting with a first time diagnosis of mild dementia with a MMSE score 20. Exclusion criteria were normal cognition or mild cognitive impairment, severe dementia, organic or functional psychosis and a diagnosis of severe or terminal physical illness. For the first paper dementia was diagnosed according to DSM-IV criteria and DLB according to both the 1996 and 2005 criteria. For the second paper we applied the Mayo Sleep Questionnaire (MSQ) and the Neuropsychiatric Inventory (NPI) to screen for sleep disturbances. Healthy elderly subjects from the Mayo Clinic Study of Aging were available for comparison. In the third paper we used a two step cluster analysis to classify persons with mild dementia according to continuous scores on scales for the DLB symptoms; hallucinations, fluctuations, parkinsonism and RBD. Results: 196 subjects were included in the first paper and of these 20 % had DLB according to the revised consensus criteria. We compared the 1996 criteria to the 2005 criteria and found a 25% increase in patients fulfilling the probable DLB category with the new criteria. The proportion with DLB did not differ according to age bands and dementia severity. (CDR) In the second paper 155 patients with mild dementia who had a caregiver who was also their bed-partner and 420 age matched controls without dementia were included. Participants with Lewy Body Dementia, i.e. DLB and PDD combined, had significantly more sleep disturbances than those with AD (89% vs. 64%, p=0.008) particularly regarding RBD. (39% vs. 9%, p<0.0005) Having any sleep disturbance correlated with both anxiety (p=0.02) and depression. (p=0.03) In the third paper we included 139 persons with mild dementia who had a complete data set for hallucinations, parkinsonism, fluctuations and RBD. Four clusters were identified, one containing persons with high scores on scales for hallucinations, fluctuations and motor parkinsonism (the “LBD-cluster”). A distinct cognitive profile was found for this cluster, with more marked visuospatial deficits. The three other clusters included subjects with very mild or no DLB symptoms (“non LBD-cluster”) and two cluster with pronounced RBD or Visual hallucinations. (VH) Cut-off scores on scales for the DLB symptoms were suggested based on the scores in the four clusters. Conclusions: DLB is the second most frequent primary dementia in specialist out patients’ clinics in Western Norway and accounts for 20% of the mild dementia population in this setting. The revised clinical diagnostic criteria have increased sensitivity as compared to the original criteria. LBD patients have significantly more sleep disturbances as compared to AD supporting the incorporation of RBD in the clinical diagnostic criteria for DLB. Sleep disturbances in mild dementia is related to anxiety and depression underlining their clinical importance. The core and suggestive features of DLB cluster in our sample of persons with mild dementia, thereby supporting the validity of DLB as a distinct diagnostic entity. The differentiation of DLB from other types of mild dementias can be made according to suggested cut-off values on scales for the core and suggestive DLB features.
Paper I: Dementia and Geriatric Cognitive Disorders 26(5), Aarsland, D.; Rongve, A.; Nore, S. P.; Skogseth, R.; Skulstad, S.; Ehrt, U.; Hoprekstad, D.; Ballard, C., Frequency and case identification of dementia with lewy bodies using the revised consensus criteria, pp. 445- 452. Copyright 2008 S. Karger. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1159/000165917Paper II: Journal of the American Geriatrics Society 58(3), Rongve, A.; Boeve, B. F.; Aarsland, D., Frequency and correlates of caregiver-reported sleep disturbances in a sample of persons with early dementia, pp. 480-486. Copyright 2010 the Authors, Journal compilation The American Geriatrics Society. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1111/j.1532-5415.2010.02733.xPaper III: Dementia and Geriatric Cognitive Disorders 29(4), Rongve, A.; Brønnick, K.; Ballard, C.; Aarsland, D., Core and suggestive symptoms of dementia with lewy bodies cluster in persons with mild dementia, pp. 317-324. Copyright 2008 S. Karger. Full text not available in BORA due to publisher restrictions. The published version is available at: http://dx.doi.org/10.1159/000295111