Lisa Crosby

Self-efficacy for managing dementia may protect against burden and depression in Alzheimer's caregivers

Background: Self-efficacy is the belief that one can perform a specific task or behaviour and is a modifiable attribute which has been shown to influence health behaviours. Few studies have examined the relationship between self-efficacy for dementia-related tasks and symptoms of burden and depression in caregivers. Methods: Eighty four patient/caregiver dyads with Alzheimers disease were recruited through a memory clinic. Patient function, cognition and neuropsychiatric symptoms were assessed together with caregiver burden, personality, depressive symptoms, coping strategies and self-efficacy for completing tasks related to dementia care. Results: 33% (28) of caregivers reported significant depressive symptoms (CES-D ≥ 10). In multivariate analyses, caregiver burden was predicted by self-efficacy for symptom management, neuroticism, patient function and neuropsychiatric symptoms while caregiver depression was predicted by self-efficacy for symptom management, caregiver educational level, neuroticism, emotion-focused coping, dysfunctional coping and patient function. In patients with moderate to severe impairment (MMSE ≤ 20), self-efficacy for symptom management behaved as a mediator between patient neuropsychiatric symptoms and symptoms of burden and depression in caregivers. Conclusions: Further longitudinal investigation is warranted to determine if self-efficacy might be usefully considered a target in future interventional studies to alleviate symptoms of burden and depression in Alzheimers caregivers.

Evaluation of Falls Risk in Community-Dwelling Older Adults Using Body-Worn Sensors

Background: Falls are the most common cause of injury and hospitalization and one of the principal causes of death and disability in older adults worldwide. This study aimed to determine if a method based on body-worn sensor data can prospectively predict falls in community-dwelling older adults, and to compare its falls prediction performance to two standard methods on the same data set. Methods: Data were acquired using body-worn sensors, mounted on the left and right shanks, from 226 community-dwelling older adults (mean age 71.5 ± 6.7 years, 164 female) to quantify gait and lower limb movement while performing the ‘Timed Up and Go’ (TUG) test in a geriatric research clinic. Participants were contacted by telephone 2 years following their initial assessment to determine if they had fallen. These outcome data were used to create statistical models to predict falls. Results: Results obtained through cross-validation yielded a mean classification accuracy of 79.69% (mean 95% CI: 77.09–82.34) in prospectively identifying participants that fell during the follow-up period. Results were significantly (p < 0.0001) more accurate than those obtained for falls risk estimation using two standard measures of falls risk (manually timed TUG and the Berg balance score, which yielded mean classification accuracies of 59.43% (95% CI: 58.07–60.84) and 64.30% (95% CI: 62.56–66.09), respectively). Conclusion: Results suggest that the quantification of movement during the TUG test using body-worn sensors could lead to a robust method for assessing future falls risk.

Dependence and Caregiver Burden in Alzheimer’s Disease and Mild Cognitive Impairment

The dependence scale has been designed to be sensitive to the overall care needs of the patient and is considered distinct from standard measures of functional ability in this regard. Little is known regarding the relationship between patient dependence and caregiver burden. We recruited 100 patients with Alzheimer’s disease or mild cognitive impairment and their caregivers through a memory clinic. Patient function, dependence, hours of care, cognition, neuropsychiatric symptoms, and caregiver burden were assessed. Dependence was significantly correlated with caregiver burden. Functional decline and dependence were most predictive of caregiver burden in patients with mild impairment while behavioral symptoms were most predictive in patients with moderate to severe disease. The dependence scale demonstrated good utility as a predictor of caregiver burden. Interventions to reduce caregiver burden should address patient dependence, functional decline, and behavioral symptoms while successful management of the latter becomes more critical with disease progression.

Determinants of the Desire to Institutionalize in Alzheimer’s Caregivers

Background: The desire to institutionalize is an important predictor of future institutionalization. Few studies have examined potentially modifiable caregiver characteristics which might be the focus of future interventional strategies. Methods: A total of 102 patient/caregiver dyads with Alzheimer’s disease (n = 84) or mild cognitive impairment were recruited through a memory clinic. Cross-sectional analyses of a range of patients, caregivers, and context of care-related characteristics were conducted. Results: Caregiver desire to institutionalize was significantly associated with a number of potentially modifiable variables including caregiver coping style, self-efficacy, depression, burden, and the presence of an unmet service need. In a multivariate analysis, caregiver burden, depression, and nonspousal status were the only significant independent predictors of caregiver desire to institutionalize in a model which correctly classified 80.4% of caregivers. Conclusions: Interventions which seek to reduce caregiver desire to institutionalize should adopt a multifactorial approach to reduce symptoms of burden and depression in caregivers.

Displacement of centre of mass during quiet standing assessed using accelerometry in older fallers and non-fallers

Postural sway during quiet standing is associated with falls risk in older adults. The aim of this study was to investigate the utility of a range of accelerometer-derived parameters of centre of mass (COM) displacement in identifying older adults at risk of falling. A series of instrumented standing balance trials were performed to investigate postural control in a group of older adults, categorised as fallers or non-fallers. During each trial, participants were asked to stand as still as possible under two conditions: comfortable stance (six repetitions) and semi-tandem stance (three repetitions). A tri-axial accelerometer was secured to the lower back during the trials. Accelerometer data were twice integrated to estimate COM displacement during the trials, with numerical techniques used to reduce integration error. Anterior-posterior (AP) and medial-lateral (ML) sway range, sway length and sway velocity were examined, along with root mean squared (RMS) acceleration. All derived parameters significantly discriminated fallers from non-fallers during both comfortable and semi-tandem stance. Results indicate that these accelerometer-based estimates of COM displacement may improve the discriminative power of quiet standing falls risk assessments, with potential for use in unsupervised balance assessment.

Frailty and quality of life for people with Alzheimer's dementia and mild cognitive impairment.

Background: Our aim was to investigate the relationship between frailty and health-related quality of life (HR-QOL) in cognitively impaired elderly individuals. Methods: A cross-sectional observational study of a convenience sample of 115 patients with a diagnosis of Alzheimer’s dementia or mild cognitive impairment. Frailty was measured using the biological syndrome model and HR-QOL was measured using the DEMQOL-Proxy. Regression models were constructed to establish the factors associated with HR-QOL. Results: Frailty and neuropsychiatric symptoms were associated with HR-QOL, with Mini-Mental State Examination (MMSE) scores ≥21 (P = .037, P ≤ .001, and R 2 = .362). Functional limitation was associated with HR-QOL, with MMSE scores ≤20 (P = .017 and R 2 = .377). Conclusion: Frailty and neuropsychiatric symptoms were the determinants of HR-QOL in the earlier stages of cognitive impairment. Functional limitation predicted HR-QOL in the later stages of cognitive impairment. Frailty may represent a novel modifiable target in early dementia to improve HR-QOL for patients.

Quantitative falls risk estimation through multi-sensor assessment of standing balance

Falls are the most common cause of injury and hospitalization and one of the principal causes of death and disability in older adults worldwide. Measures of postural stability have been associated with the incidence of falls in older adults. The aim of this study was to develop a model that accurately classifies fallers and non-fallers using novel multi-sensor quantitative balance metrics that can be easily deployed into a home or clinic setting. We compared the classification accuracy of our model with an established method for falls risk assessment, the Berg balance scale. Data were acquired using two sensor modalities--a pressure sensitive platform sensor and a body-worn inertial sensor, mounted on the lower back--from 120 community dwelling older adults (65 with a history of falls, 55 without, mean age 73.7 ± 5.8 years, 63 female) while performing a number of standing balance tasks in a geriatric research clinic. Results obtained using a support vector machine yielded a mean classification accuracy of 71.52% (95% CI: 68.82-74.28) in classifying falls history, obtained using one model classifying all data points. Considering male and female participant data separately yielded classification accuracies of 72.80% (95% CI: 68.85-77.17) and 73.33% (95% CI: 69.88-76.81) respectively, leading to a mean classification accuracy of 73.07% in identifying participants with a history of falls. Results compare favourably to those obtained using the Berg balance scale (mean classification accuracy: 59.42% (95% CI: 56.96-61.88)). Results from the present study could lead to a robust method for assessing falls risk in both supervised and unsupervised environments.

Correlates of frailty in Alzheimer's disease and mild cognitive impairment

SIR—The global prevalence of dementia is rising with Alzheimer’s disease (AD) accounting for 50–60% of all cases and mild cognitive impairment (MCI) its precursor [1, 2]. Although the clinical hallmark of AD is progressive loss of memory and cognition, several studies have also shown changes in mobility and body composition suggesting frailty [3, 4]. Frailty represents age-related reduction in physiological reserve and resistance to stressors that can be delineated from comorbidity [5, 6]. It infers increased risk of health decline, disability and mortality regardless of concurrent illnesses. Intervention in the early stages may lead to reversal of frailty and prevent some of its adverse outcomes [6]. Individual components of frailty; impaired grip strength, slowed gait and low body mass index (BMI), have been shown to predict development of dementia and are associated with incident MCI [7–10]. The frailty syndrome within cognitively impaired patients may represent an important area for intervention that has yet been adequately investigated. A diagnosis of AD or MCI can mean considerable heterogeneity in terms of age, comorbidity, course of illness, cognitive impairment, functional limitations and abnormalities of behaviour. This study enables a consideration of the relation, if any, between frailty and these domains of clinical heterogeneity in a group of patients with AD and MCI.

Early identification of declining balance in higher functioning older adults, an inertial sensor based method

Higher functioning older adults rarely have their balance assessed clinically and as such early decline in balance is not captured. Early identification of declining balance would facilitate earlier intervention and improved management of the ageing process. This study sought to determine if (a) a once off inertial sensor measurement and (b) changes in inertial sensor measurements one year apart can identify declining balance for higher functioning older adults. One hundred and nineteen community dwelling older adults (58 males; 72.5±5.8 years) completed a timed up and go (TUG) instrumented with inertial sensors and the Berg balance scale (BBS) at two time points, one year apart. Temporal and spatio-temporal gait parameters as well as angular velocity and turn parameters were derived from the inertial sensor data. A change in balance from baseline to follow-up was determined by sub-components of the BBS. Changes in inertial sensor parameters from baseline to follow-up demonstrated strong association with balance decline in higher functioning older adults (e.g. mean medial-lateral angular velocity odds ratio=0.2; 95% CI: 0.1-0.5). The area under the Receiver operating characteristic curve (AUC) ranged from 0.8 to 0.9, a marked improvement over change in TUG time alone (AUC 0.6-0.7). Baseline inertial sensor parameters had a similar association with declining balance as age and TUG time. For higher functioning older adults, the change in inertial sensor parameters over time may reflect declining balance. These measures may be useful clinically, to monitor the balance status of older adults and facilitate earlier identification of balance deficits.

Taking balance measurement out of the laboratory and into the home: Discriminatory capability of novel centre of pressure measurement in fallers and non-fallers

We investigated three methods for estimating centre of pressure excursions, as measured using a portable pressure sensor matrix, in order to deploy similar technology into the homes of older adults for longitudinal monitoring of postural control and falls risk. We explored the utility of these three methods as markers of falls risk in a cohort of 120 community dwelling older adults with and without a history of falls (65 fallers, 55 non-fallers). A number of standard quantitative balance parameters were derived using each centre of pressure estimation method. Rank sum tests were used to test for significant differences between fallers and non-fallers while intra-class correlation coefficients were also calculated to determine the reliability of each method. A method based on estimating the changes in the magnitude of pressure exerted on the pressure sensor matrix was found to be the most reliable and discriminative. Our future work will implement this method for home-based balance measurement.