Skip to main content Accessibility help
×
Home

Contents:

Information:

  • Access

Actions:

      • Send article to Kindle

        To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

        Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

        Find out more about the Kindle Personal Document Service.

        Author's reply to: Difficulties of diagnosing and managing dementia in people with Down syndrome
        Available formats
        ×

        Send article to Dropbox

        To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

        Author's reply to: Difficulties of diagnosing and managing dementia in people with Down syndrome
        Available formats
        ×

        Send article to Google Drive

        To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

        Author's reply to: Difficulties of diagnosing and managing dementia in people with Down syndrome
        Available formats
        ×
Export citation

We thank Drs Smith and Chicoine for their interest in our work and highlighting some of the practical issues in diagnosing and managing dementia in this group. The association between trisomy 21 and early-onset Alzheimer's disease is well established1 and dementia is now the most common cause of death in adults with Down syndrome. Despite this, there exists relatively little evidence on which to base treatment decisions.

Using a naturalistic study design, we report the effects of antidementia medication on the survival and function of 310 people with Down syndrome and dementia. Notwithstanding the limitations typical of observational studies (discussed in the paper), this work addresses a significant gap in the literature. Kaplan–Meier survival curves demonstrate significantly increased survival in the group prescribed antidementia medication. Baseline differences between those prescribed and not prescribed antidementia medication were accounted for, where possible, in a Cox regression model. This adjusted analysis showed that protection in the treated group remained, although it did not reach statistical significance because of less power and broader confidence intervals.

Functional impairment was measured using the Dementia in Learning Disabilities scale,2 a standardised informant questionnaire that covers several skill domains. These data show an early protective effect of medication in mitigating cognitive decline, as is observed in individuals with Alzheimer's disease without Down syndrome.3 We appreciate the concern of Drs Smith and Chicoine for quality of life. Unfortunately, there are no well-validated measures of quality of life for this group and proxy measures have been subject to limitations in people with intellectual disability. Development of such measures and their use in research studies and routine clinical care would be welcome and could focus efforts on providing optimal holistic support.

The Cochrane reviews that Drs Smith and Chicoine cite highlight the lack of evidence in this field, rather than negative results of drug intervention studies. Two of these Cochrane reviews did not include any studies at all, and the third included only one, small randomised controlled trial. The authors of these reviews, now some years old, highlight the paucity of evidence and conclude that the reviews cannot be used to guide practice.

Our cohort was recruited from specialist memory clinics for people with intellectual disability. Clinician diagnosis of dementia in such clinics is valid and reliable4 and we are confident that clinicians will have adequately assessed potentially reversible causes of decline. It is important not to overlook dementia as an early diagnosis can facilitate prompt pharmacological and psychosocial treatments and effective care planning.5 When dementia is diagnosed, a decision to use medication is, of course, an individual one, and should take account of the views of families and carers. Our paper provides additional evidence that could inform the decision-making process. People with Down syndrome and dementia should not be denied access to antidementia drugs.

1Zis, P, Strydom, A. Clinical aspects and biomarkers of Alzheimer's disease in Down syndrome. Free Radic Biol Med 2018; 114: 39.
2Eurlings, H, Evenhuis, HM, Kengen, M. Dementia Questionnaire for People with Learning Disabilities (DLD). UK Adaptation. Harcourt Assessment, 2006.
3Perera, G, Khondoker, M, Broadbent, M, Breen, G, Stewart, R. Factors associated with response to acetylcholinesterase inhibition in dementia: a cohort study from a secondary mental health care case register in London. PLoS One 2014; 9: e109484.
4Sheehan, R, Sinai, A, Bass, N, Blatchford, P, Bohnen, I, Bonell, S, et al. Dementia diagnostic criteria in Down syndrome. Int J Geriatr Psychiatry 2015; 30: 857–63.
5Dodd, K, Watchman, K, Janicki, MP, Coppus, A, Gaertner, C, Fortea, J, et al. Consensus statement of the international summit on intellectual disability and dementia related to post-diagnostic support. Aging Ment Health 2017; Sept 7 (Epub ahead of print).