Con: Are We Ready to Translate Alzheimer\u27s Disease-Modifying Therapies to People with Down Syndrome?

BACKGROUND: Adults with Down syndrome develop Alzheimer\u27s disease neuropathology in an age-dependent manner. This unique feature provides an opportunity to test interventions targeted for prevention of Alzheimer\u27s disease neuropathology and dementia in Down syndrome. DISCUSSION: In considering clinical trial designs, however, there are several challenges that we believe will be critical to examine further. These include: accuracy in dementia, mild cognitive impairment and preclinical Alzheimer\u27s disease diagnoses in Down syndrome; clinical trial outcome measures appropriate for individuals with Down syndrome; in vivo imaging outcome measures (and practical considerations); and contributions of medical co-morbidities to disease progression. Also, when studies are designed, the molecular target may appear to be obvious (for example, targeting beta-amyloid pathology), but chromosome 21 has over 200 additional genes that could influence both positive and negative clinical trial outcomes. SUMMARY: Observational longitudinal studies of aging in Down syndrome will be critically important as there is a need to establish sensitive clinical outcome measures and understand the consequences of gene overexpression in relation to specific interventions

Metabolic and Vascular Imaging Biomarkers in Down Syndrome Provide Unique Insights Into Brain Aging and Alzheimer Disease Pathogenesis

People with Down syndrome (DS) are at high risk for developing Alzheimer disease (AD). Neuropathology consistent with AD is present by 40 years of age and dementia may develop up to a decade later. In this review, we describe metabolic and vascular neuroimaging studies in DS that suggest these functional changes are a key feature of aging, linked to cognitive decline and AD in this vulnerable cohort. FDG-PET imaging in DS suggests systematic reductions in glucose metabolism in posterior cingulate and parietotemporal cortex. Magentic resonance spectroscopy studies show consistent decreases in neuronal health and increased myoinositol, suggesting inflammation. There are few vascular imaging studies in DS suggesting a gap in our knowledge. Future studies would benefit from longitudinal measures and combining various imaging approaches to identify early signs of dementia in DS that may be amenable to intervention

Distinct Patterns of Default Mode and Executive Control Network Circuitry Contribute to Present and Future Executive Function in Older Adults

Executive function (EF) performance in older adults has been linked with functional and structural profiles within the executive control network (ECN) and default mode network (DMN), white matter hyperintensities (WMH) burden and levels of Alzheimer\u27s disease (AD) pathology. Here, we simultaneously explored the unique contributions of these factors to baseline and longitudinal EF performance in older adults. Thirty-two cognitively normal (CN) older adults underwent neuropsychological testing at baseline and annually for three years. Neuroimaging and AD pathology measures were collected at baseline. Separate linear regression models were used to determine which of these variables predicted composite EF scores at baseline and/or average annual change in composite ΔEF scores over the three-year follow-up period. Results demonstrated that low DMN deactivation, high ECN activation and WMH burden were the main predictors of EF scores at baseline. In contrast, poor DMN and ECN WM microstructure and higher AD pathology predicted greater annual decline in EF scores. Subsequent mediation analysis demonstrated that DMN WM microstructure uniquely mediated the relationship between AD pathology and ΔEF. These results suggest that functional activation patterns within the DMN and ECN and WMHs contribute to baseline EF while structural connectivity within these networks impact longitudinal EF performance in older adults

Down Syndrome, Beta-Amyloid and Neuroimaging

This review focuses on the role of Aβ in AD pathogenesis in Down syndrome and current approaches for imaging Aβ in vivo. We will describe how Aβ deposits with age, the posttranslational modifications that can occur, and detection in biofluids. Three unique case studies describing partial trisomy 21 cases without APP triplication, and the occurrences of low level mosaic trisomy 21 in an early onset AD patient are presented. Brain imaging for Aβ includes those by positron emission tomography and ligands (Pittsburgh Compound B, Florbetapir, and FDDNP) that bind Aβ have been published and are summarized here. In combination, we have learned a great deal about Aβ in DS in terms of characterizing age of onset of this pathology and it is exciting to note that there is a clinical trial in DS targeting Aβ that may lead to clinical benefits

A Practical Algorithm for Managing Alzheimer\u27s Disease: What, When, and Why?

Alzheimer\u27s disease (AD) is the most common form of dementia and its prevalence is increasing. Recent developments in AD management provide improved ways of supporting patients and their caregivers throughout the disease continuum. Managing cardiovascular risk factors, maintaining an active lifestyle (with regular physical, mental and social activity) and following a Mediterranean diet appear to reduce AD risk and may slow cognitive decline. Pharmacologic therapy for AD should be initiated upon diagnosis. All of the currently available cholinesterase inhibitors (ChEIs; donepezil, galantamine, and rivastigmine) are indicated for mild-to-moderate AD. Donepezil (10 and 23 mg/day) and rivastigmine transdermal patch (13.3 mg/24 h) are indicated for moderate-to-severe AD. Memantine, an N-methyl-d-aspartate receptor antagonist, is approved for moderate-to-severe AD. ChEIs have been shown to improve cognitive function, global clinical status and patients\u27 ability to perform activities of daily living. There is also evidence for reduction in emergence of behavioral symptoms with ChEI therapy. Treatment choice (e.g., oral vs. transdermal) should be based on patient or caregiver preference, ease of use, tolerability, and cost. Treatment should be individualized; patients can be switched from one ChEI to another if the initial agent is poorly tolerated or ineffective. Memantine may be introduced in moderate-to-severe disease stages. Clinicians will regularly monitor symptoms and behaviors, manage comorbidities, assess function, educate and help caregivers access information and support, evaluate patients\u27 fitness to drive or own firearms, and provide advice about the need for legal and financial planning. Review of caregiver well-being and prompt referral for support is vital

Longitudinal Assessment of Dementia Measures in Down Syndrome

Introduction: Early detection of dementia symptoms is critical in Down syndrome (DS) but complicated by clinical assessment barriers. The current study aimed to characterize cognitive and behavioral impairment using longitudinal trajectories comparing several measures of cognitive and behavioral functioning. Methods: Measures included global cognitive status (Severe Impairment Battery [SIB]), motor praxis (Brief Praxis Test [BPT]), and clinical dementia informant ratings (Dementia Questionnaire for People with Learning Disabilities [DLD]). One-year reliability was assessed using a two-way mixed effect, consistency, single measurement intraclass correlation among non-demented participants. Longitudinal assessment of SIB, BPT, and DLD was completed using linear mixed effect models. Results: One‐year reliability (n = 52; 21 male) was moderate for DLD (0.69 to 0.75) and good for SIB (0.87) and BPT (0.80). Longitudinal analysis (n = 72) revealed significant age by diagnosis interactions for SIB (F(2, 115.02) = 6.06, P = .003), BPT (F(2, 85.59) = 4.56, P = .013), and DLD (F(2, 103.56) = 4.48, P = .014). SIB progression (PR) had a faster decline in performance versus no‐dementia (ND) (t(159) = −2.87; P = .013). Dementia had a faster decline in BPT performance versus ND (t(112) = −2.46; P = .041). PR showed quickly progressing scores compared to ND (t(128) = −2.86; P = .014). Discussion: Current measures demonstrated moderate to good reliability. Longitudinal analysis revealed that SIB, BPT, and DLD changed with age depending on diagnostic progression; no change rates were dependent on baseline cognition, indicating usefulness across a variety of severity levels in DS

Comparing Clinical Profiles in Alzheimer\u27s Disease and Parkinson\u27s Disease Dementia

BACKGROUND: Greater understanding of differences in baseline impairment and disease progression in patients with Alzheimer\u27s disease (AD) and Parkinson\u27s disease dementia (PDD) may improve the interpretation of drug effects and the design of future studies. METHODS: This was a retrospective analysis of three randomized, double-blind rivastigmine databases (one in PDD, two in AD). Impairment on the Alzheimer\u27s Disease Assessment Scale-cognitive subscale (ADAS-cog), Alzheimer\u27s Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale, 10-item Neuropsychiatric Inventory (NPI-10) and the ADCS-Clinical Global Impression of Change (CGIC) was compared [standardized difference (Cohen\u27s d), similar if \u3c0.1]. RESULTS: Patients with AD or PDD had similar levels of impairment on the ADAS-cog and NPI-10. Scores on the ADCS-ADL scale (standardized difference = 0.47) and the ADAS-cog memory domain (total, 0.33; items, 0.10-0.58) were higher in AD; PDD patients were more impaired in the language (0.23) and praxis (0.34) domains. AD patients receiving placebo showed greater deterioration on the ADAS-cog (0.14) and improvement on the NPI-10 (0.11) compared with patients with PDD. CONCLUSION: Differing patterns of impairment occur in AD and PDD

Metabolic and Vascular Imaging Biomarkers in Down Syndrome Provide Unique Insights Into Brain Aging and Alzheimer Disease Pathogenesis

People with Down syndrome (DS) are at high risk for developing Alzheimer disease (AD). Neuropathology consistent with AD is present by 40 years of age and dementia may develop up to a decade later. In this review, we describe metabolic and vascular neuroimaging studies in DS that suggest these functional changes are a key feature of aging, linked to cognitive decline and AD in this vulnerable cohort. FDG-PET imaging in DS suggests systematic reductions in glucose metabolism in posterior cingulate and parietotemporal cortex. Magentic resonance spectroscopy studies show consistent decreases in neuronal health and increased myoinositol, suggesting inflammation. There are few vascular imaging studies in DS suggesting a gap in our knowledge. Future studies would benefit from longitudinal measures and combining various imaging approaches to identify early signs of dementia in DS that may be amenable to intervention

Analyzing the impact of 23 mg/day donepezil on language dysfunction in moderate to severe Alzheimer's disease

Introduction\ud Progressive language impairment is among the primary components of cognitive decline in Alzheimer's disease (AD). Because expressive and receptive language help to maintain emotional connections to caregivers and support the management of AD patients' functional needs, language plays a critical role in patients' emotional and physical health. Using data from a large prospective clinical trial comparing two doses of donepezil in patients with moderate to severe AD, we performed a post hoc analysis to determine whether a higher dose of donepezil was associated with greater benefits in language function.\ud \ud Methods\ud In the original randomized, double-blind clinical trial, 1,467 patients with moderate to severe AD (baseline Mini-Mental State Examination (MMSE) score 0 to 20) were randomized 2:1 to receive donepezil 23 mg/day or to continue on donepezil 10 mg/day for 24 weeks. In this post hoc analysis, the Severe Impairment Battery-Language scale (SIB-L) and a new 21-item SIB-derived language scale (SIB[lang]) were used to explore differences in language function between the treatment groups. Correlations between SIB-L and SIB[lang] scores and scores on the severe version of the Alzheimer's Disease Cooperative Study-Activities of Daily Living inventory (ADCS-ADL-sev), the Clinician's Interview-Based Impression of Severity-plus caregiver input/Clinician's Interview-Based Impression of Change-plus caregiver input (CIBIS-plus/CIBIC-plus) and the MMSE were also investigated.\ud \ud Results\ud At week 24, treatment with donepezil 23 mg/day was associated with an improvement in language in the full intention-to-treat population, whereas language function declined in the group treated with donepezil 10 mg/day (SIB-L treatment difference 0.8, P = 0.0013; SIB[lang] treatment difference 0.8, P = 0.0009). Similar results were observed in a cohort of patients with more severe baseline disease (MMSE score 0 to 16). At baseline and week 24, correlations between the SIB-derived language scales and the ADCS-ADL-sev and CIBIC-plus were moderate, but the correlations were stronger between the language scales and the MMSE scores.\ud \ud Conclusions\ud Patients with moderate to severe AD receiving donepezil 23 mg/day showed greater language benefits than those receiving donepezil 10 mg/day as measured by SIB-derived language assessments. Increasing the dose of donepezil to 23 mg/day may provide language benefits in patients with moderate to severe AD, for whom preservation of language abilities is especially critical.\ud \ud ClinicalTrials.gov identifier: NCT0047820

Analyzing the impact of 23 mg/day donepezil on language dysfunction in moderate to severe Alzheimer\u27s disease

INTRODUCTION: Progressive language impairment is among the primary components of cognitive decline in Alzheimer\u27s disease (AD). Because expressive and receptive language help to maintain emotional connections to caregivers and support the management of AD patients\u27 functional needs, language plays a critical role in patients\u27 emotional and physical health. Using data from a large prospective clinical trial comparing two doses of donepezil in patients with moderate to severe AD, we performed a post hoc analysis to determine whether a higher dose of donepezil was associated with greater benefits in language function. METHODS: In the original randomized, double-blind clinical trial, 1,467 patients with moderate to severe AD (baseline Mini-Mental State Examination (MMSE) score 0 to 20) were randomized 2:1 to receive donepezil 23 mg/day or to continue on donepezil 10 mg/day for 24 weeks. In this post hoc analysis, the Severe Impairment Battery-Language scale (SIB-L) and a new 21-item SIB-derived language scale (SIB[lang]) were used to explore differences in language function between the treatment groups. Correlations between SIB-L and SIB[lang] scores and scores on the severe version of the Alzheimer\u27s Disease Cooperative Study-Activities of Daily Living inventory (ADCS-ADL-sev), the Clinician\u27s Interview-Based Impression of Severity-plus caregiver input/Clinician\u27s Interview-Based Impression of Change-plus caregiver input (CIBIS-plus/CIBIC-plus) and the MMSE were also investigated. RESULTS: At week 24, treatment with donepezil 23 mg/day was associated with an improvement in language in the full intention-to-treat population, whereas language function declined in the group treated with donepezil 10 mg/day (SIB-L treatment difference 0.8, P = 0.0013; SIB[lang] treatment difference 0.8, P = 0.0009). Similar results were observed in a cohort of patients with more severe baseline disease (MMSE score 0 to 16). At baseline and week 24, correlations between the SIB-derived language scales and the ADCS-ADL-sev and CIBIC-plus were moderate, but the correlations were stronger between the language scales and the MMSE scores. CONCLUSIONS: Patients with moderate to severe AD receiving donepezil 23 mg/day showed greater language benefits than those receiving donepezil 10 mg/day as measured by SIB-derived language assessments. Increasing the dose of donepezil to 23 mg/day may provide language benefits in patients with moderate to severe AD, for whom preservation of language abilities is especially critical. ClinicalTrials.gov identifier: NCT00478205