Philip Yap

Microvascular network alterations in the retina of patients with Alzheimer's disease

Although cerebral small‐vessel disease has been implicated in the development of Alzheimers disease (AD), the cerebral microcirculation is difficult to visualize directly in vivo. Because the retina provides a noninvasive window to assess the microcirculation, we determined whether quantitatively measured retinal microvascular parameters are associated with AD.

Deployment of assistive living technology in a nursing home environment: methods and lessons learned

BackgroundWith an ever-growing ageing population, dementia is fast becoming the chronic disease of the 21st century. Elderly people affected with dementia progressively lose their autonomy as they encounter problems in their Activities of Daily Living (ADLs). Hence, they need supervision and assistance from their family members or professional caregivers, which can often lead to underestimated psychological and financial stress for all parties. The use of Ambient Assistive Living (AAL) technologies aims to empower people with dementia and relieve the burden of their caregivers.The aim of this paper is to present the approach we have adopted to develop and deploy a system for ambient assistive living in an operating nursing home, and evaluate its performance and usability in real conditions. Based on this approach, we emphasise on the importance of deployments in real world settings as opposed to prototype testing in laboratories.MethodsWe chose to conduct this work in close partnership with end-users (dementia patients) and specialists in dementia care (professional caregivers). Our trial was conducted during a period of 14 months within three rooms in a nursing home in Singapore, and with the participation of eight dementia patients and two caregivers. A technical ambient assistive living solution, consisting of a set of sensors and devices controlled by a software platform, was deployed in the collaborating nursing home. The trial was preceded by a pre-deployment period to organise several observation sessions with dementia patients and focus group discussions with professional caregivers. A process of ground truth and system’s log data gathering was also planned prior to the trial and a system performance evaluation was realised during the deployment period with the help of caregivers. An ethical approval was obtained prior to real life deployment of our solution.ResultsPatients’ observations and discussions allowed us to gather a set of requirements that a system for elders with mild-dementia should fulfil. In fact, our deployment has exposed more concrete requirements and problems that need to be addressed, and which cannot be identified in laboratory testing. Issues that were neither forecasted during the design phase nor during the laboratory testing surfaced during deployment, thus affecting the effectiveness of the proposed solution. Results of the system performance evaluation show the evolution of system precision and uptime over the deployment phases, while data analysis demonstrates the ability to provide early detection of the degradation of patients’ conditions. A qualitative feedback was collected from caregivers and doctors and a set of lessons learned emerged from this deployment experience. (Continued on next page) (Continued from previous page)ConclusionLessons learned from this study were very useful for our research work and can serve as inspiration for developers and providers of assistive living services. They confirmed the importance of real deployment to evaluate assistive solutions especially with the involvement of professional caregivers. They also asserted the need for larger deployments. Larger deployments will allow to conduct surveys on assistive solutions social and health impact, even though they are time and manpower consuming during their first phases.

Retinal ganglion cell analysis using high-definition optical coherence tomography in patients with mild cognitive impairment and Alzheimer's disease.

BACKGROUND Alzheimers disease (AD) is a neurodegenerative disorder with emerging evidence that it is associated with retinal ganglion cell loss; however, few data exist to establish this association. OBJECTIVE To determine whether macular ganglion cell-inner plexiform layer (GC-IPL) and retinal nerve fiber layer (RNFL), as quantitatively measured by non-invasive in vivo spectral-domain optical coherence tomography (SD-OCT), are altered in patients with AD and mild cognitive impairment (MCI). METHODS Patients with AD and MCI were recruited from dementia/memory clinics, and cognitively normal controls were selected from the Singapore Epidemiology of Eye Disease program. SD-OCT (Cirrus HD-OCT, software version 6.0.2, Carl Zeiss Meditec Inc, Dublin, CA) was used to measure the GC-IPL and RNFL thicknesses. RESULTS Compared with cognitively normal controls (n = 123), patients with AD (n = 100) had significantly reduced GC-IPL thicknesses in all six (superior, superonasal, inferonasal, inferior, inferotemporal, and superotemporal) sectors (mean differences from -3.42 to -4.99 μm, all p < 0.05) and reduced RNFL thickness in superior quadrant (-6.04 μm, p = 0.039). Patients with MCI (n = 41) also had significantly reduced GC-IPL thicknesses compared with controls (mean differences from -3.62 to -5.83 μm, all p < 0.05). Area under receiver operating characteristic curves of GC-IPL were generally higher than that of RNFL to discriminate AD and MCI from the controls. CONCLUSIONS Our data strengthens the link between retinal ganglion cell neuronal and optic nerve axonal loss with AD, and suggest that assessment of macular GC-IPL can be a test to detect neuronal injury in early AD and MCI.

Orthostatic Hypotension, Hypotension and Cognitive Status : Early Comorbid Markers of Primary Dementia?

Objective: Few studies have explored the relationship between orthostatic hypotension (OH) and cognition. The aim of this study was to examine the association of OH with cognitive impairment and decline in a cohort of Chinese elderly, and its effect modification by blood pressure (BP) status at baseline. Method: Among 2,321 community-living older adults, free of cardiovascular disease and stroke, baseline BP measurements were used to determine the presence of OH and categorize participants as hypotensives, normotensives or hypertensives. The Mini-Mental State Examination (MMSE) was used to assess cognitive impairment (MMSE score <24). Cognitive decline (decrease in MMSE score by ≧1) was assessed from 1 to 2 years of follow-up for 1,347 participants without baseline cognitive impairment. Results: Mean age of the subjects was 65.5 years and 381 (16.6%) showed OH. OH was not associated with cognitive impairment overall. However, among hypotensives, OH increased the odds of cognitive impairment (OR = 4.1, 95% CI = 1.11–15.1), while hypertensives with OH showed reduced odds of cognitive impairment (OR = 0.48, 95% CI = 0.26–0.90). Among cognitively intact participants, OH was not associated with cognitive decline overall or in BP subgroups. Conclusion: The increased risk of cognitive impairment in hypotensives with OH suggests that hypotension with OH may be an early comorbid marker of a primary incipient dementia.

A controlled naturalistic study on a weekly music therapy and activity program on disruptive and depressive behaviors in dementia.

Aim: This study explores the effects of a weekly structured music therapy and activity program (MAP) on behavioral and depressive symptoms in persons with dementia (PWD) in a naturalistic setting. Methods: PWD attended a weekly group MAP conducted by a qualified music therapist and occupational therapist for 8 weeks. Two validated scales, the Apparent Emotion Scale (AES) and the Revised Memory and Behavioral Problems Checklist (RMBPC), were used to measure change in outcomes of mood and behavior. Results: Twenty-eight subjects completed the intervention, while 15 wait-list subjects served as controls. Baseline AES and RMBPC scores were not significantly different between the intervention and control groups. After intervention, RMBPC scores improved significantly (p = 0.006) with 95% CI of the difference between the mean intervention and control group scores compared to baseline at –62.1 to –11.20. Total RMBPC scores in the intervention group improved from 75.3 to 54.5, but worsened in the control group, increasing from 62.3 to 78.6. AES scores showed a nonsignificant trend towards improvement in the intervention group. Conclusion: The results suggest that a weekly MAP can ameliorate behavioral and depressive symptoms in PWD.

Predicting Gains in Dementia Caregiving

Background: Caregiver gain is an important yet less-explored phenomenon. Being conceptually distinct from burden, factors associated with burden and gain can differ. This study aims to explore factors associated with the experience of gains in dementia caregiving. Method: Cross-sectional study involving caregivers recruited from a tertiary hospital dementia clinic and the local Alzheimer’s Association. Caregivers completed a questionnaire containing the following scales: gain in Alzheimer’s care Instrument (GAIN), General Health Questionnaire (GHQ-28), Dementia Management Strategies Scale (DMSS), Revised Memory and Behavioral Problems Checklist (RMBPC) and Zarit Burden Interview (ZBI). Demographic information for the person with dementia (PWD) and the caregiver was also recorded. Initial screening with univariate analyses (t tests, ANOVAs, Pearson’s correlations) was performed to identify significant (p < 0.05) variables, which were then entered into a multiple regression model to identify variables associated with gain. Result: The final sample comprised 334 caregivers with a mean age of 51.5 years (SD = 10.9, range = 22–85), the majority of whom where Chinese (94.6%) females (71%). Mean GAIN score was 30 (SD = 6.6, range = 7–40). Regression analysis identified 3 factors significantly associated with gains (adjusted R2 32.3%): mental well-being of the caregiver, use of active management as a caregiving strategy, and participation in caregiver educational and support group programmes. Conclusion: The results have important implications for caregiver interventions. Interventions should target maintaining mental well-being, encouraging participation in educational and support programmes, and teaching appropriate coping and dementia specific management strategies to derive good outcomes.

Why Family Caregivers Choose to Institutionalize a Loved One with Dementia: A Singapore Perspective

Aim: To examine factors associated with family caregivers’ choice of care setting (own home vs. nursing home) for their relatives with dementia. Methods: Cross-sectional study involving caregivers recruited from a tertiary hospital dementia clinic and the local Alzheimer’s association. Caregivers completed a questionnaire containing demographics of the person with dementia (PWD) and caregiver, their choice of care setting and the following scales: Gain in Alzheimer Care Instrument, General Health Questionnaire, Short Sense of Competence Questionnaire, Revised Memory and Behavioral Problems Checklist and Zarit Burden Interview. Multiple logistic regression was performed to identify significant variables associated with the outcome of interest. Results: The final sample comprised 266 caregivers, the majority of whom were Chinese, female and children of PWD. Most (85.7%) preferred care at home, only 38 (14.3%) chose institutionalization. Four factors were associated with choice of nursing home: caregiver working (OR = 6.363, 2.120–19.086), no domestic maid (OR = 3.27, 1.458–7.331), lower caregiver gain (OR = 0.935, 0.882–0.992) and behavioral problems in PWD (OR = 1.011, 1.005–1.018). Conclusion: Strategies to minimize institutionalization must first address the provision of a dedicated caregiver at home. Consequently, interventions to help caregivers cope with behavioral problems in PWD and enhance caregiver gain are relevant.

Metabolic Syndrome and the Risk of Mild Cognitive Impairment and Progression to Dementia: Follow-up of the Singapore Longitudinal Ageing Study Cohort

IMPORTANCE The association of the metabolic syndrome (MetS) and component cardiovascular risk factors with the risk of developing mild cognitive impairment (MCI) and MCI progression to dementia is not well established. OBJECTIVE To investigate the association of the MetS and its component cardiovascular risk factors with the incidence of MCI and its progression to dementia. DESIGN, SETTING, AND PARTICIPANTS Prospective longitudinal study from September 1, 2003, through December 31, 2009, in communities in 5 districts in the South East region of Singapore. Study participants were a population-based sample of 1519 cognitively normal adults 55 years and older. MAIN OUTCOMES AND MEASURES Prespecified outcomes were incident MCI and MCI progression to dementia. RESULTS The study cohort comprised 1519 participants. Their mean (SD) age was 64.9 (6.8) years, and 64.8% (n = 984) were female. Baseline characteristics associated with an increased risk of incident MCI were MetS (hazard ratio [HR], 1.46; 95% CI, 1.02-2.09), central obesity (HR, 1.41; 95% CI, 1.01-1.98), diabetes mellitus (HR, 2.84; 95% CI, 1.92-4.19), dyslipidemia (HR, 1.48; 95% CI, 1.01-2.15), and 3 or more component cardiovascular risk factors (HR, 1.58; 95% CI, 1.13-2.33). Baseline characteristics associated with an increased risk of MCI progression to dementia were MetS (HR, 4.25; 95% CI, 1.29-14.00), diabetes mellitus (HR, 2.47; 95% CI, 1.92-4.19), and 3 or more component cardiovascular risk factors (HR, 4.92; 95% CI, 1.39-17.4). CONCLUSIONS AND RELEVANCE The MetS was associated with an increased incidence of MCI and progression to dementia. Identifying individuals with diabetes mellitus or the MetS with or without MCI is a promising approach in early interventions to prevent or slow progression to dementia.

Metabolic Syndrome and Amnestic Mild Cognitive Impairment: Singapore Longitudinal Ageing Study-2 Findings

Metabolic syndrome (MetS) is reported to be associated with cognitive decline and dementia, in particular vascular dementia. However, the evidence linking MetS to Alzheimers disease (AD) and amnestic mild cognitive impairment (aMCI), a precursor of AD, is inconsistent and limited. This study examined the association of MetS and its components with aMCI and how APOE-εe4 and younger age influenced this association. Participants with aMCI (n = 98) and cognitively normal controls (n = 802) were identified from baseline data in a second wave cohort of older subjects aged 55 and over in the Singapore Longitudinal Ageing Study-2 (SLAS-2) in 2009/2010. The associations of MetS and its individual components with aMCI were analyzed using logistic regression controlling for age, gender, education, current smoking, alcohol drink, leisure time activities score, Geriatric Depression Scale score, APOE-ε4, and heart disease or stroke. The analysis was repeated for associations stratified by age and APOE-ε4 status. In multivariate analysis, MetS was associated with an elevated risk of aMCI (OR = 1.79; 95% CI 1.15-2.77). Among MetS components, central obesity showed a significant association with aMCI (OR = 1.77; 95% CI 1.11-2.82). The association between MetS and aMCI remained significant on repeated analysis among subjects free of heart disease and stroke. This association was particularly stronger among participants with APOE-ε4 allele (OR = 3.35; 95% CI, 1.03-10.85) and younger (<65 years) participants with APOE-ε4 (OR = 6.57; 95% CI, 1.03-41.74). MetS was found to be associated with aMCI, especially in individuals with APOE-ε4 at younger age in this middle-aged and older cohort.

Eating activity primitives detection - a step towards ADL recognition

Activity of daily living (ADL) monitoring is important in order to determine the well being of elderly persons in their home settings. One important question is, ldquoIs the elderly person able to eat properly on his own?rdquo In this paper we present some results of our preliminary work on an algorithm for detection of the eating activity. The algorithm uses a dynamic Bayesian network based approach to reduce the complexity of determining states. Initial results are quite promising and point to a general algorithmic approach that a) uses multiple modalities of sensors for gathering data, b) detects activity primitives and c) stores detected activity primitives as micro-context for future use.