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Difficulties of diagnosing and managing dementia in people with Down syndrome

Published online by Cambridge University Press:  19 October 2018

David Smith
Affiliation:
Physician, Down Syndrome Clinic of Wisconsin, USA Email: dssmith@mac.com
Brian Chicoine
Affiliation:
Advocate Medical Group Adult Down Syndrome Center, USA.
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Abstract

Type
Correspondence
Copyright
Copyright © The Royal College of Psychiatrists 2018 

As practising clinicians who provide care to adults with Down syndrome, we appreciate Eady and colleagues’ attempt to address a real concern in this patient population.Reference Eady, Sheehan, Rantell, Sinai, Bernal and Bohnen1 However, we have significant concerns about clinicians potentially using in their practice the conclusions drawn by the authors. The study conclusions offer false hope and may result in wasted resources.

The authors themselves state that the treated and untreated groups have significant differences that would favour the treated group: ‘There were significant baseline differences between the groups prescribed and not prescribed antidementia medication. Those who were not prescribed medication were older, more likely to have severe–profound intellectual disability, and had more severe dementia symptoms at baseline’. Given those differences, it is difficult to understand how the authors can come to the conclusion that treatment with antidementia medications is of benefit.

Also of concern is the question of what the clinical significance would be from a functional perspective. Dementia takes a tremendous toll on the caregivers and families. Even if the medications do extend life, where is the benefit? What kind of life will they have? We believe quality of life would have been a more useful measured outcome.

Furthermore, there are four published studies and Cochrane reviews that show no benefit with donepezil,Reference Mohan, Carpenter and Bennett2 rivastigmine,Reference Mohan, Bennett and Carpenter3 memantine,Reference McShane, Areosa Sastre and Minakaran4, Reference Hanney, Prasher, Williams, Jones, Aarsland and Corbett5 or galantamine.Reference Mohan, Bennett and Carpenter6 Another Cochrane Review in 2015 showed no benefit of pharmacological interventions for cognitive decline in people with Down syndrome.Reference Livingstone, Hanratty, McShane and Macdonald7

In our experience as the directors of Down syndrome clinics for adults, the big issue is really how the diagnosis of dementia is made. Clinicians tend to easily apply the diagnosis of Alzheimer's dementia without looking at all the potential causes of pseudodementia in this population.Reference Chicoine, McGuire, Hebein and Gilly8 They often assume that loss of ability is as a result of dementia because of a study published in 1985 that showed plaques and tangles in the brain tissue of all people with Down syndrome over the age of 35.Reference Wisniewski, Wisniewski and Wen9 Wisniewski & Rabe subsequently wrote that there was a discrepancy between neuropathology and the occurrence of dementia in people with Down syndrome.Reference Wisniewski and Rabe10 Just as in the population of typically developed older adults, the diagnosis of Alzheimer's dementia in people with Down syndrome should be made only after evaluation for causes of pseudodementia.

References

1Eady, N, Sheehan, R, Rantell, K, Sinai, A, Bernal, J, Bohnen, I, et al. Impact of cholinesterase inhibitors or memantine on survival in adults with Down syndrome and dementia: clinical cohort study. Br J Psychiatry 2018; 212: 155–60.Google Scholar
2Mohan, M, Carpenter, PK, Bennett, C. Donepezil for dementia in people with Down syndrome. Cochrane Database Syst Rev 2009; 1: CD007178.Google Scholar
3Mohan, M, Bennett, C, Carpenter, PK. Rivastigmine for dementia in people with Down syndrome. Cochrane Database Syst Rev 2009; 1: CD007658.Google Scholar
4McShane, R, Areosa Sastre, A, Minakaran, N. Memantine for dementia. Cochrane Database Syst Rev 2006; 2: CD003154.Google Scholar
5Hanney, M, Prasher, V, Williams, N, Jones, EL, Aarsland, D, Corbett, A, et al. Memantine for dementia in adults older than 40 years with Down's syndrome (MEADOWS): a randomised, double-blind, placebo-controlled trial. Lancet 2012; 379: 528–36.Google Scholar
6Mohan, M, Bennett, C, Carpenter, PK. Galantamine for dementia in people with Down syndrome. Cochrane Database Syst Rev 2009; 1: CD007656.Google Scholar
7Livingstone, N, Hanratty, J, McShane, R, Macdonald, G. Pharmacological interventions for cognitive decline in people with Down syndrome. Cochrane Database Syst Rev 2015; 10: CD011546.Google Scholar
8Chicoine, B, McGuire, D, Hebein, S, Gilly, D. Development of a clinic for adults with Down syndrome. Ment Retard 1994; 32: 100–6.Google Scholar
9Wisniewski, KE, Wisniewski, HM, Wen, GY. Occurrence of neuropathological changes and dementia of Alzheimer's disease in Down's syndrome. Ann Neurol 1985; 17: 278–82.Google Scholar
10Wisniewski, HM, Rabe, A. Discrepancy between Alzheimer-type neuropathology and dementia in persons with Down's syndrome. Ann N Y Acad Sci 1986; 477: 247–60.Google Scholar
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