Cognitive and physical declines and falls in older people with and without mild cognitive impairment: a 7-year longitudinal study

OBJECTIVES

We examined longitudinal changes in cognitive and physical function and associations between change in function and falls in people with and without mild cognitive impairment (MCI).

DESIGN

Prospective cohort study with assessments every 2 years (for up to 6 years).

SETTING

Community, Sydney, Australia.

PARTICIPANTS

Four hundred and eighty one people were classified into three groups: those with MCI at baseline and MCI or dementia at follow-up assessments (n = 92); those who fluctuated between cognitively normal and MCI throughout follow-up (cognitively fluctuating) (n = 157), and those who were cognitively normal at baseline and all reassessments (n = 232).

MEASUREMENTS

Cognitive and physical function measured over 2-6 years follow-up. Falls in the year following participants' final assessment.

RESULTS

In summary, 27.4%, 38.5%, and 34.1% of participants completed 2, 4, and 6 years follow-up of cognitive and physical performance, respectively. The MCI and cognitive fluctuating groups demonstrated cognitive decline, whereas the cognitively normal group did not. The MCI group had worse physical function than the cognitively normal group at baseline but decline over time in physical performance was similar across all groups. Decline in global cognitive function and sensorimotor performance were associated with multiple falls in the cognitively normal group and decline in mobility (timed-up-and-go test) was associated with multiple falls across the whole sample.

CONCLUSIONS

Cognitive declines were not associated with falls in people with MCI and fluctuating cognition. Declines in physical function were similar between groups and decline in mobility was associated with falls in the whole sample. As exercise has multiple health benefits including maintaining physical function, it should be recommended for all older people. Programs aimed at mitigating cognitive decline should be encouraged in people with MCI.

Incidence of fragility hip fracture across the Asia-pacific region: A systematic review

PURPOSE

This systematic review aimed to update fragility hip fracture incidences in the Asia Pacific, and compare rates between countries/regions.

METHOD

A systematic search was conducted in four electronic databases. Studies reporting data between 2010 and 2023 on the geographical incidences of hip fractures in individuals aged ≥50 were included. Exclusion criteria were studies reporting solely on high-trauma, atypical, or periprosthetic fractures. We calculated the crude incidence, age- and sex-standardised incidence, and the female-to-male ratio. The systematic review was registered with PROSPERO (CRD42020162518).

RESULTS

Thirty-eight studies were included across nine countries/regions (out of 41 countries/regions). The crude hip fracture incidence ranged from 89 to 341 per 100,000 people aged ≥50, with the highest observed in Australia, Taiwan, and Japan. Age- and sex-standardised rates ranged between 90 and 318 per 100,000 population and were highest in Korea and Japan. Temporal decreases in standardised rates were observed in Korea, China, and Japan. The female-to-male ratio was highest in Japan and lowest in China.

CONCLUSION

Fragility hip fracture incidence varied substantially within the Asia-Pacific region. This observation may reflect actual incidence differences or stem from varying research methods and healthcare recording systems. Future research should use consistent measurement approaches to enhance international comparisons and service planning.

Improving hip fracture care: A five-year review of the early contributors to the Australian and New Zealand Hip Fracture Registry

OBJECTIVE

The aim of this study was to examine temporal trends (2016-2020) in hip fracture care in Australian and New Zealand (ANZ) hospitals that started providing patient-level data to the ANZ Hip Fracture Registry (ANZHFR) on/before 1 January 2016 (early contributors).

METHODS

Retrospective cohort study of early contributor hospitals (n = 24) to the ANZHFR. The study cohort included patients aged ≥50 years admitted with a low trauma hip fracture between 1 January 2016 and 31 December 2020 (n = 26,937). Annual performance against 11 quality indicators and 30- and 365-day mortality were examined.

RESULTS

Compared to 2016/2017, year-on-year improvements were demonstrated for preoperative cognitive assessment (2020: OR 3.57, 95% confidence interval [95% CI] 3.29-3.87) and nerve block use prior to surgery (2020: OR 4.62, 95% CI 4.17-5.11). Less consistent improvements over time from 2016/2017 were demonstrated for emergency department (ED) stay of <4 h (2017; 2020), pain assessment ≤30 min of ED presentation (2020), surgery ≤48 h (2020) and bone protection medication prescribed on discharge (2017-2020; 2020 OR 2.22, 95% CI 2.03-2.42). The odds of sustaining a hospital-acquired pressure injury increased in 2019-2020 compared to 2016. The odds of receiving an orthogeriatric model of care and being offered the opportunity to mobilise on Day 1 following surgery fluctuated. There was a reduction in 365-day mortality in 2020 compared to 2016 (OR 0.86, 95% CI 0.74-0.98), whereas 30-day mortality did not change.

CONCLUSIONS

Several quality indicators improved over time in early contributor hospitals. Indicators that did not improve may be targets for future care improvement activities, including considering incentivised hip fracture care, which has previously been shown to improve care/outcomes. COVID-19 and reporting practices may have impacted the study findings.

Variation in care and outcomes for people after hip fracture with and without cognitive impairment; results from the Australian and New Zealand Hip Fracture Registry

BACKGROUND

People with dementia have poorer outcomes after hip fracture and this may be due in part to variation in care. We aimed to compare care and outcomes for people with and without cognitive impairment after hip fracture.

METHODS

Retrospective cohort study using Australian and New Zealand Hip Fracture Registry data for people ≥50 years of age who underwent hip fracture surgery (n = 49,063). Cognitive impairment or known dementia and cognitively healthy groups were defined using preadmission cognitive status. Descriptive statistics and multivariable mixed effects models were used to compare groups.

RESULTS

In general, cognitively impaired people had worse care and outcomes compared to cognitively healthy older people. A lower proportion of the cognitively impaired group had timely pain assessment (≤30 min of presentation: 61% vs 68%; p < 0.0001), were given the opportunity to mobilise (89% vs 93%; p < 0.0001) and achieved day-1 mobility (34% vs 58%; p < 0.0001) than the cognitively healthy group. A higher proportion of the cognitively impaired group had delayed pain management (>30 mins of presentation: 26% vs 20%; p < 0.0001), were malnourished (27% vs 15%; p < 0.0001), had delirium (44% vs 13%; p < 0.0001) and developed a new pressure injury (4% vs 3%; p < 0.0001) than the cognitively healthy group. Fewer of the cognitively impaired group received rehabilitation (35% vs 64%; p < 0.0001), particularly patients from RACFs (16% vs 39%; p < 0.0001) and were prescribed bone protection medication on discharge (24% vs 27%; p < 0.0001). Significantly more of the cognitively impaired group had a new transfer to residential care (46% vs 11% from private residence; p < 0.0001) and died at 30-days (7% vs 3% from private residence; 15% vs 10% from RACF; both p < 0.0001). In multivariable models adjusting for covariates with facility as the random effect, the cognitively impaired group had a greater odds of being malnourished, not achieving day-1 walking, having delirium in the week after surgery, dying within 30 days, and in those from private residences, having a new transfer to a residential care facility than the cognitively healthy group.

CONCLUSIONS

We have identified several aspects of care that could be improved for patients with cognitive impairment - management of pain, mobility, nutrition and bone health, as well as delirium assessment, prevention and management strategies and access to rehabilitation. Further research is needed to determine whether improvements in care will reduce hospital complications and improve outcomes for people with dementia after hip fracture.

Associations between psychotropic and anti-dementia medication use and falls in community-dwelling older adults with cognitive impairment

OBJECTIVES

Evidence for effective fall prevention strategies is limited for people with cognitive impairment. Understanding what factors contribute to fall risk identifies potential intervention strategies. We aimed to determine if psychotropic and anti-dementia medication use are associated with falls in community-dwelling older people with mild-moderate cognitive impairment and dementia.

DESIGN

Secondary analysis of an RCT (i-FOCIS).

PARTICIPANTS AND SETTING

309 community-dwelling people with mild to moderate cognitive impairment or dementia from Sydney, Australia.

METHODS

Demographic information, medical history, and medication use were collected at baseline and participants were followed up for 1-year for falls using monthly calendars and ancillary telephone falls.

RESULTS

Psychotropic medication use was associated with an increased rate of falls (IRR 1.41, 95%CI 1.03, 1.93) and slower gait speed, poor balance and reduced lower limb function when adjusting for age, sex, education and cognition, as well as RCT group allocation when examining prospective falls. Antidepressants use increased the rate of falls in a similarly adjusted model (IRR 1.54, 95%CI 1.10, 2.15), but when additionally adjusting for depressive symptoms, antidepressant use was no longer significantly associated with falls while depressive symptoms was. Anti-dementia medication use was not associated with rate of falls.

CONCLUSIONS

Psychotropic medication use increases fall risk, and anti-dementia medication does not reduce fall risk in older adults with cognitive impairment. Effective management of depressive symptoms, potentially with non-pharmacological approaches, is needed to prevent falls in this population. Research is also required to ascertain the risks/benefits of withdrawing psychotropic medications, particularly in relation to depressive symptoms.

The association between white matter hyperintensity volume and cognitive/physical decline in older people with dementia: A one-year longitudinal study

OBJECTIVES

Understanding the relationship between white matter hyperintensities (WMHs) and cognitive and physical decline in people with dementia will assist in determining potential treatment strategies. Currently there is conflicting evidence describing the association between WMHs and cognitive decline and, WMHs association with declines in objective measures of physical function have not been examined. We examined the relationship between baseline WMH volume and physical/cognitive decline over one-year in older people with dementia.

METHODS

Twenty-six community-dwelling older people with dementia (mean age = 81 ± 8 years; 35% female) were assessed at baseline and follow-up (one-year) using the Addenbrooke's Cognitive Examination-Revised (including verbal fluency), Trail Making Test A, the Physiological Profile Assessment (PPA), timed-up-and-go (TUG) and gait speed. WMH volumes were quantified using a fully automated segmentation toolbox, UBO Detector.

RESULTS

In analyses adjusted for baseline performance, higher baseline WMH volume was associated with decline in executive function (verbal fluency), sensorimotor function (PPA) and mobility (TUG). Executive function (semantic/category fluency) was the only domain association that withstood adjustment for age, and additionally hippocampal volume.

CONCLUSIONS

In unadjusted analyses, WMH volume was associated with one-year declines in cognitive and physical function in older people with dementia. The association with executive function decline withstood adjustment for age. More research is needed to confirm these findings and explore whether vascular risk reduction strategies can reduce WMH volume and associated cognitive and physical impairments in this group.

Risk factors for falls in community-dwelling older people with mild cognitive impairment: a prospective one-year study

Objective

Mild cognitive impairment (MCI) is considered an intermediate stage between normal cognitive function and dementia. Fall risk is increased in this group, but there is limited literature exploring specific fall risk factors that may be addressed in fall prevention strategies. The aim of this study was to examine risk factors for falls in older people with MCI, focusing on cognitive, psychological and physical factors.

Methods

Participants (n = 266, 45% women) were community-dwelling older people aged 70-90 years who met the criteria for MCI. Cognitive, psychological, sensorimotor and physical assessments, physical activity levels, medication use, general health and disability were ascertained at baseline. Falls were monitored prospectively for 12 months.

Results

During follow-up, 106 (40%) participants reported one or more falls. Poorer visual contrast sensitivity, increased postural sway, lower levels of weekly walking activity, higher levels of depressive symptoms and psychotropic medication use were significantly associated with faller status (≥1 falls) in univariable analyses. Of these factors, poor visual contrast sensitivity, increased postural sway and psychotropic medication use were found to be significant independent predictors of falls in multivariable analysis while controlling for age and sex. No measures of cognitive function were associated with falls.

Conclusions

Poor visual contrast sensitivity, impaired balance and psychotropic medication use predicted falls in community-dwelling people with MCI. These risk factors may be amenable to intervention, so these factors could be carefully considered in fall prevention programs for this population.

Relationship between Depressive Symptoms and Cognitive, Psychological, and Physical Performance in Community-Dwelling Older People with Cognitive Impairment

INTRODUCTION

Dementia and depression often coexist. Understanding how concomitant comorbidities affect function can improve assessment and management strategies. We examined the relationship between cognitive, psychological, and physical function and depressive symptoms in people with cognitive impairment.

METHODS

Cross-sectional study using baseline data from the iFOCIS randomized controlled trial involving 309 participants with mild-moderate cognitive impairment. The association between cognitive (Addenbrooke's Cognitive Examination-III [ACE-III], Frontal Assessment Battery), psychological (Goldberg Anxiety Scale; Iconographical Falls Efficacy Scale), and physical (Physiological Profile Assessment; Short Physical Performance Battery [SPPB]) function, and quality of life (QoL), physical activity levels and activities of daily living, and depressive symptoms (15-item Geriatric Depression Scale [GDS]) were assessed (adjusted for age, sex, education, and ACE-III as appropriate).

RESULTS

Participants with depressive symptoms (GDS ≥4) had significantly more falls in the previous year and a higher number of comorbidities than people without depressive symptoms (GDS <4). Each point increase in the GDS was associated with better memory, higher levels of anxiety and concern about falling, poorer balance, slower gait speed, and reduced QoL. The relationship between the GDS and poor balance and QoL withstood additional adjustment for comorbidity tertiles. The relationship between GDS and concern about falls withstood additional adjustment for previous falls (12 months) and SPPB scores.

CONCLUSIONS

Depressive symptomatology is associated with poorer physical and psychological function and reduced QoL in people with cognitive impairment. These factors should be considered when assessing and intervening in this group. Future research could examine these relationships longitudinally to establish causality and examine intervention efficacy in this group.

Implementation of the StandingTall programme to prevent falls in older people: a process evaluation protocol

INTRODUCTION

One in three people aged 65 years and over fall each year. The health, economic and personal impact of falls will grow substantially in the coming years due to population ageing. Developing and implementing cost-effective strategies to prevent falls and mobility problems among older people is therefore an urgent public health challenge. StandingTall is a low-cost, unsupervised, home-based balance exercise programme delivered through a computer or tablet. StandingTall has a simple user-interface that incorporates physical and behavioural elements designed to promote compliance. A large randomised controlled trial in 503 community-dwelling older people has shown that StandingTall is safe, has high adherence rates and is effective in improving balance and reducing falls. The current project targets a major need for older people and will address the final steps needed to scale this innovative technology for widespread use by older people across Australia and internationally.

METHODS AND ANALYSIS

This project will endeavour to recruit 300 participants across three sites in Australia and 100 participants in the UK. The aim of the study is to evaluate the implementation of StandingTall into the community and health service settings in Australia and the UK. The nested process evaluation will use both quantitative and qualitative methods to explore uptake and acceptability of the StandingTall programme and associated resources. The primary outcome is participant adherence to the StandingTall programme over 6 months.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the South East Sydney Local Health District Human Research Ethics Committee (HREC reference 18/288) in Australia and the North West- Greater Manchester South Research Ethics Committee (IRAS ID: 268954) in the UK. Dissemination will be via publications, conferences, newsletter articles, social media, talks to clinicians and consumers and meetings with health departments/managers.

TRIAL REGISTRATION NUMBER

ACTRN12619001329156.

The association between white matter hyperintensity volume and gait performance under single and dual task conditions in older people with dementia: A cross-sectional study

BACKGROUND

Understanding the relationship between white matter hyperintensities (WMHs) and gait may assist in understanding the central control of gait and determining treatment modalities. These relationships are yet to be realized in older people with dementia.

OBJECTIVE

To examine the association between WMH volume and gait under single-task and dual task (DT) conditions in people with dementia.

METHODS

Twenty-eight community-dwelling older people with dementia (median age=83 years; [IQR=77-86]; 36% female) had timed gait speed assessed at usual pace. Gait (speed, stride length, cadence) was assessed using the GAITRite® mat under three conditions (n = 18/28): a) single-task, b) functional DT: carrying a glass of water and c) cognitive DT: counting backwards from 30. WMH volumes were quantified using a fully automated segmentation toolbox.

RESULTS

Total, temporal and parietal WMH volumes were negatively correlated with timed and functional DT gait speed, and with stride length under single-task, functional DT and cognitive DT conditions. Frontal WMH volumes were negatively correlated with timed gait speed and stride length under single-task and functional DT conditions. Participants with higher total WMH burden had significantly slower timed and functional DT gait speed and reduced stride length under single-task, functional DT and cognitive DT conditions compared to participants with lower WMH burden.

CONCLUSIONS

WMH volume was associated with slower gait speed and reduced stride length, but not cadence, under single-task and DT conditions in people with dementia. Further research is needed to confirm these findings and determine whether vascular risk management can improve gait in older people with dementia.

Cognitive Domain Associations with Balance Performance in Community-Dwelling Older People with Cognitive Impairment

BACKGROUND

In older people with cognitive impairment (CI), executive function (EF) has been associated with motor performance including balance and gait. The literature examining and supporting a relationship between balance performance and other cognitive domains is limited.

OBJECTIVE

To investigate the relationship between global cognition and cognitive domain function and balance performance in older people with CI.

METHODS

The iFOCIS randomized controlled trial recruited 309 community-dwelling older people with CI. Baseline assessments completed before randomization were used for analyses including the Addenbrooke's Cognitive Examination-III (ACE-III; global cognition) and its individual cognitive domains (attention; memory; verbal fluency; language; visuospatial ability) and the Frontal Assessment Battery (FAB), a measure of EF. A composite balance score was derived from postural sway and leaning balance tests.

RESULTS

In linear regression analyses adjusted for covariates, global cognition and each cognitive domain were significantly associated with balance performance. EF (verbal fluency; β= -0.254, p < 0.001, adjusted R2 = 0.387) and visuospatial ability (β= -0.258, p < 0.001, adjusted R2 = 0.391) had the strongest associations with balance performance. In a comprehensively adjusted multivariable model including all of the ACE-III cognitive domains, visuospatial ability and EF (verbal fluency) were independently and significantly associated with balance performance.

CONCLUSION

Poorer global cognition and cognitive domain function were associated with poorer balance performance in this sample of people with CI. Visuospatial ability and EF were independently associated with balance, highlighting potential shared neural networks and the role higher-level cognitive processes and spatial perception/processing play in postural control.

Sensorimotor, Cognitive, and Affective Functions Contribute to the Prediction of Falls in Old Age and Neurologic Disorders: An Observational Study

OBJECTIVE

To determine whether impairments across cognitive and affective domains provide additional information to sensorimotor deficits for fall prediction among various populations.

DESIGN

We pooled data from 5 studies for this observational analysis of prospective falls.

SETTING

Community or low-level care facility.

PARTICIPANTS

Older people (N=1090; 74.0±9.4y; 579 female); 500 neurologically intact (NI) older people and 3 groups with neurologic disorders (cognitive impairment, n=174; multiple sclerosis (MS), n=111; Parkinson disease, n=305).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Sensorimotor function was assessed with the Physiological Profile Assessment, cognitive function with tests of executive function, affect with questionnaires of depression, and concern about falling with falls efficacy questionnaires. These variables were associated with fall incidence rates, obtained prospectively over 6-12 months.

RESULTS

Poorer sensorimotor function was associated with falls (incidence rate ratio [95% CI], 1.46 [1.28-1.66]). Impaired executive function was the strongest predictor of falls overall (2.91 [2.27-3.73]), followed by depressive symptoms (2.07 [1.56-2.75]) and concern about falling (2.02 [1.61-2.55]). Associations were similar among groups, except for a weaker relationship with executive impairment in NI persons and a stronger relationship with concern about falling in persons with MS. Multivariable analyses showed that executive impairment, poorer sensorimotor performance, depressive symptoms, and concern about falling were independently associated with falls.

CONCLUSIONS

Deficits in cognition (executive function) and affect (depressive symptoms) and concern about falling are as important as sensorimotor function for fall prediction. These domains should be included in fall risk assessments for older people and clinical groups.

Associations Between Gait Speed and Cognitive Domains in Older People with Cognitive Impairment

BACKGROUND

While gait has been linked with cognition, few studies have contrasted the strength of the relationships between gait speed and cognitive domains in people with cognitive impairment (CI).

OBJECTIVES

Investigate the association between gait speed and global cognitive function and cognitive domains in older people with CI.

METHOD

Three-hundred-and-nine community-dwelling people with CI (mean age 82 years, 47% female, and mean gait speed 0.62±0.23 m/s) were included using baseline data from the Intervention-Falls in Older Cognitively Impaired Study (iFOCIS). Usual gait speed (m/s) was measured over 2.4 m. Global cognitive function and individual cognitive domains (attention; memory; verbal fluency; language; visuospatial ability) were assessed using the Addenbrooke's Cognitive Examination-III (ACE-III). Additionally, executive function was assessed using the Frontal Assessment Battery (FAB).

RESULTS

Participants mean±standard deviation ACE-III and FAB scores were 62.8±19.3 and 11.4±4.6, respectively. In separate multiple linear regression analyses adjusting for confounders, global cognitive function, and each cognitive domain, was significantly associated with gait speed. Executive function demonstrated the strongest association (FAB: standardized β= 0.278, p < 0.001, adjusted R2 = 0.431), and remained significantly associated with gait speed when adjusted for attention, memory, language, and visuospatial ability.

CONCLUSION

In this large study of older people with CI, global cognition and each cognitive domain were associated with gait speed. Executive function had the strongest association, possibly reflecting the higher-level cognitive processes and complex motor task responses required for gait control. Future longitudinal studies are needed to explore the temporal relationships between declines in executive function and gait, and whether the facilitation of executive function lessens gait decline.

Tailored Exercise and Home Hazard Reduction Program for Fall Prevention in Older People With Cognitive Impairment: The i-FOCIS Randomized Controlled Trial

Background

The evidence to support effective fall prevention strategies in older people with cognitive impairment (CI) is limited. The aim of this randomized controlled trial (RCT) was to determine the efficacy of a fall prevention intervention in older people with CI.

Method

RCT involving 309 community-dwelling older people with CI. The intervention group (n = 153) received an individually prescribed home hazard reduction and home-based exercise program during the 12-month study period. The control group (n = 156) received usual care. The primary outcome was rate of falls. Secondary outcomes included faller/multiple faller status, physical function, and quality of life.

Results

Participants’ average age was 82 years (95% CI 82–83) and 49% were female. There was no significant difference in the rate of falls (incidence rate ratio [IRR] 1.05; 95% confidence interval [95% CI] 0.73–1.51). A sensitivity analysis, controlling for baseline differences and capping the number of falls at 12 (4 participants), revealed a nonsignificant reduction in fall rate in the intervention group (IRR 0.78; 95% CI 0.57–1.07). Analyses of secondary outcomes indicated the intervention significantly reduced the number of multiple fallers by 26% (RR 0.74; 95% CI 0.54–0.99) when adjusting for baseline differences. There was a differential impact on falls in relation to physical function (interaction term p-value = .023) with a significant reduction in fall rate in intervention group participants with better baseline physical function (IRR 0.60; 95% CI 0.37–0.98). There were no significant between-group differences for other secondary outcomes.

Conclusions

This intervention did not significantly reduce the fall rate in community-dwelling older people with CI. The intervention did reduce the fall rate in participants with better baseline physical function.

Clinical Trials Registration Number

Australian and New Zealand Trials Registry ACTRN12614000603617.

Pilot feasibility study of a home-based fall prevention exercise program (StandingTall) delivered through a tablet computer (iPad) in older people with dementia

OBJECTIVE

To assess the feasibility and safety of StandingTall-an individually tailored, progressive exercise program delivered through tablet computers-in community-dwelling older people with dementia.

METHODS

Fifteen community-dwelling older people with dementia (mean age = 83 ± 8 years; Montreal Cognitive Assessment 16 ± 5) received StandingTall for 12 weeks with caregiver assistance. Feasibility and safety were assessed using the System Usability Scale (SUS; scores = 0-100; a priori target >65), Physical Activity Enjoyment Scale (PACES-8; scores = 8-56), adherence (exercise minutes) and adverse events.

RESULTS

Mean SUS scores were 68 ± 21/69 ± 15 (participants/caregivers). The mean PACES-8 score was 44 ± 8. In week 2, week 7 and week 12, mean (bias-corrected and accelerated 95% CI) exercise minutes were 37 (25-51), 49 (30-69) and 65 (28-104), respectively. In week 12, five participants exercised >115 minutes. One participant fell while exercising, without sustained injury.

CONCLUSIONS

StandingTall had acceptable usability, scored well on enjoyment and was feasible for participants. These results provide support for further evaluation of StandingTall in a randomised controlled trial with falls as the primary outcome.

The role of cognitive function and physical activity in physical decline in older adults across the cognitive spectrum

OBJECTIVES

The aim of this study was to investigate physical decline over 1-year in a cohort of older people across the cognitive spectrum.

METHODS

Physical function was assessed using the Physiological Profile Assessment (PPA) in 593 participants (cognitively normal [CN]: n = 342, mild cognitive impairment [MCI]: n = 77, dementia: n = 174) at baseline and in 490 participants available for reassessment 1-year later. Neuropsychological performance and physical activity (PA) were assessed at baseline.

RESULTS

Median baseline PPA scores for CN, MCI and dementia groups were 0.41 (IQR = -0.09-1.02), 0.66 (IQR = -0.06-1.15) and 2.37 (IQR = 0.93-3.78) respectively. All baseline neuropsychological domains and PA were significantly associated with baseline PPA. There were significant interaction terms (Time × Cognitive Group, Global Cognition, Processing Speed, Executive Function and PA) in the models investigating PPA decline. In multivariate analysis the Time × Executive Function and PA interaction terms were significant, indicating that participants with poorer baseline executive function and reduced PA demonstrated greater physical decline when compared to individuals with better executive function and PA respectively.

DISCUSSION

Having MCI or dementia is associated with greater physical decline compared to CN older people. Physical inactivity and executive dysfunction were associated with physical decline in this sample, which included participants with MCI and dementia. Both factors influencing physical decline are potentially amenable to interventions e.g. exercise.

Dementia

Dementia is a syndrome seen most commonly in older people and characterized by a decline in cognitive performance which impacts on the person's ability to function. There are approximately 47 million people worldwide with dementia and there are 10 million new cases every year. It is a major cause of disability and dependence and impacts on the physical, psychologic, and social well-being of families and carers. Alzheimer's disease is the most common form of dementia. Gait and balance impairments are common in people with dementia and contribute to the significantly elevated risk of falls. Older people with dementia are at increased risk of injury, institutionalization, hospitalization, morbidity, and death after a fall. There is preliminary evidence, predominantly from relatively small studies, that falls and disability can be prevented in this population. However, more good-quality research is needed, both to provide some certainty around the existing evidence base as well as to explore alternate approaches to prevention, including combined cognitive-motor training and cognitive pharmacotherapy.

Slow gait speed is associated with executive function decline in older people with mild to moderate dementia: A one year longitudinal study

OBJECTIVES

This study aimed to document change in neuropsychological, physical and functional performance over one year and to investigate the relationship between baseline gait speed and cognitive decline in this period in older people with dementia.

METHODS

One hundred and seventy-seven older people with dementia (Mini-Mental State Examination 11-23; Addenbrooke's Cognitive Examination-Revised <83) residing in the community or low level care facility completed baseline neuropsychological, physical and functional assessments. Of these, 134 participants agreed to reassessment of the above measures one year later.

RESULTS

Overall, many neuropsychological, physical and functional performance measures declined significantly over the one year study period. Baseline gait speed was significantly associated with decline in verbal fluency (B(109)=2.893, p=0.046), specifically phonemic/letter fluency (B(109)=2.812, p=0.004) while controlling for age, education, dementia drug use and baseline cognitive performance. There was also a trend for an association between baseline gait speed and decline in clock drawing performance (B(107)=0.601, p=0.071).

CONCLUSIONS

Older people with mild to moderate dementia demonstrate significant decline in neuropsychological, physical and functional performance over one year. Baseline gait speed is associated with decline in executive function over one year, suggesting shared pathways/pathology between gait and cognition.

Reaction Time and Postural Sway Modify the Effect of Executive Function on Risk of Falls in Older People with Mild to Moderate Cognitive Impairment

OBJECTIVES

To explore the relationship between cognitive performance and falls in older people with mild to moderate cognitive impairment (CI) by investigating the mediational effects of medical, medication, neuropsychological, and physiological factors.

DESIGN

Secondary analysis, prospective cohort study.

SETTING

Community and low-level care.

PARTICIPANTS

177 older people (aged 82 ± 7 years) with mild to moderate CI (MMSE 11-23; ACE-R < 83).

MEASUREMENTS

Global cognition and six neuropsychological domains (memory, language, visuospatial, processing speed, executive function [EF], and affect) were assessed. Participants also underwent sensorimotor and balance assessments. Falls were recorded prospectively for 12 months.

RESULTS

The EF domain was most strongly associated with multiple falls (relative risk [RR]: 1.50, 95% CI: 1.18-1.91). Global cognition was not associated with falls (RR: 1.09, 95% CI: 0.92-1.30). Additional analyses showed that participants with poorer EF (median cutpoint) were more likely to be taking centrally acting medications and were less physically active. They also had significantly worse vision, reaction time, knee extension strength, balance (postural sway, controlled leaning balance), and higher physiological fall risk scores. Participants with poorer EF were 1.5 times (RR: 1.50, 95% CI: 1.03-2.18) more likely to have multiple falls. Mediational analyses demonstrated that reaction time and postural sway reduced the relative risk of EF on multiple falls by 31% (RR: 1.19, 95% CI: 0.81-1.74).

CONCLUSIONS

Within this sample of older people with mild to moderate CI, poorer EF increased the risk of multiple falls. This relationship was mediated by reaction time and postural sway,suggesting cognitively impaired older people with poorer EF may benefit from fall prevention programs targeting these mediating factors.

Physiological fall risk factors in cognitively impaired older people: a one-year prospective study

BACKGROUND/AIMS

Cognitively impaired older people are at twice the risk of falls compared to cognitively intact, with approximately 60% falling once or more per year. This study aimed to investigate sensorimotor and balance risk factors for falls in cognitively impaired older people.

METHODS

177 community-dwelling older people with mild to moderate cognitive impairment (Mini-Mental State Examination < 24, Addenbrooke's Cognitive Examination-Revised < 83) were assessed using the Physiological Profile Assessment (PPA). Falls were recorded prospectively for 12 months using monthly calendars with the assistance of carers.

RESULTS

Seventy-one participants (43%) fell ≥2 times in the follow-up period. Impaired simple reaction time, postural sway, leaning balance and increased PPA fall risk score were significantly associated with multiple falls. The area under the receiver-operating characteristic curve for the PPA model including tests of vision, proprioception, knee extension strength, reaction time, postural sway and leaning balance was 0.75 (95% confidence interval: 0.68-0.83).

CONCLUSION

These findings indicate poor performance on physiological fall risk factors, particularly balance, increases the risk of falls in older cognitively impaired people.

Gait parameter risk factors for falls under simple and dual task conditions in cognitively impaired older people

Impaired gait may contribute to the increased rate of falls in cognitively impaired older people. We investigated whether gait under simple and dual task conditions could predict falls in this group. The study sample consisted of 64 community dwelling older people with mild to moderate cognitive impairment. Participants walked at their preferred speed under three conditions: (a) simple walking, (b) walking while carrying a glass of water and (c) walking while counting backwards from 30. Spatiotemporal gait parameters were measured using the GAITRite(®) mat. Falls were recorded prospectively for 12months with the assistance of carers. Twenty-two (35%) people fell two or more times in the 12month follow-up period. There was a significant main effect of gait condition and a significant main effect of faller status for mean value measures (velocity, stride length, double support time and stride width) and for variability measures (swing time variability and stride length variability). Examination of individual gait parameters indicated that the multiple fallers walked more slowly, had shorter stride length, spent longer time in double support, had a wider support width and showed more variability in stride length and swing time (p<0.05). There was no significant interaction between gait condition and faller status for any of the gait variables. In conclusion, dual task activities adversely affect gait in cognitively impaired older people. Multiple fallers performed worse in each gait condition but the addition of a functional or cognitive secondary task provided no added benefit in discriminating fallers from non-fallers with cognitive impairment.

Managing falls in older patients with cognitive impairment

With an aging population, both dementia and fall-related injury pose an international health challenge. Individuals with dementia fall twice as often as cognitively intact people and are more likely to have injurious falls. Higher morbidity and rates of mortality and institutionalization after falls have also been reported in this group. There is limited but emerging literature that is attempting to define and explain why fall risk is increased in this population. This will allow for targeted fall prevention programs. Currently, there are no published randomized controlled trials that have prevented falls in community-dwelling cognitively impaired older people, and conflicting evidence is reported in hospital and residential care trials. Recent exercise interventions have demonstrated significant benefits, such as improved gait speed, strength and balance in people with cognitive impairment/dementia, providing encouraging evidence for further research and clinical interventions.

Gait impairment and falls in cognitively impaired older adults: an explanatory model of sensorimotor and neuropsychological mediators

OBJECTIVES

to explore the associations between spatiotemporal gait parameters and falls in cognitively impaired older people and to investigate whether sensorimotor and neuropsychological factors mediate the association between gait performance and falls.

DESIGN

prospective cohort study with a 1 year follow-up.

SETTING

community-dwelling sample.

PARTICIPANTS

sixty-four participants (62-96 years of age) with cognitive impairment.

MEASUREMENTS

gait analysis and sensorimotor and neuropsychological functions were assessed in all participants. Falls were identified prospectively for 1 year.

RESULTS

multiple fallers (≥2 falls) had significantly slower gait velocity, shorter stride length, greater double support time and increased step length variability in univariate analyses. Multivariate logistic regression indicated that the relationship between gait and falls was mediated primarily by sensorimotor function and to a lesser extent by neuropsychological performance.

CONCLUSION

the findings indicate that slow and variable gait patterns increase the risk of falls in cognitively impaired older adults. Further, the association between gait and falls seems to be mediated in large by reduced sensorimotor functioning. Further research is needed to investigate whether interventions aimed at improving gait and/or sensorimotor fall risk factors, such as strength and balance, can prevent falls in cognitively impaired older adults.

Complex encounters at the macrophage-mycobacterium interface: studies on the role of the mannose receptor and CD14 in experimental infection models with Mycobacterium avium

The initial interactions between mycobacterial cell wall components and receptor structures on the surface of macrophages may be critical in determining the outcome of infection. They may trigger the ingestion and digestion of microorganisms, but they may also promote the intracellular persistence and growth of mycobacteria. Using Mycobacterium avium as a model system, three approaches of different complexities were used to analyse some structural features and some functional consequences of M. avium interacting with the macrophage mannose receptor or CD14, a pattern recognition receptor. Binding specificities of a recombinant, truncated extracellular portion of the mannose receptor were assayed in a novel ELISA-formatted system using viable M. avium cells as ligands. Infection with M. avium strains differing in their virulence were performed in murine bone marrow-derived macrophages and in mice with a targeted deletion of the CD14 gene. These parallel and converging approaches not only help define the molecular basis for understanding early events in the pathogenesis of mycobacterial infections, but are also necessary to ultimately determine the relevance of in vitro findings in the context of actual manifestations of disease in vivo.

Bioassay and biochemical analyses of insecticide resistance in southern African Anopheles funestus (Diptera: Culicidae)

Anopheles funestus Giles has been implicated as a major malaria vector in sub-Saharan Africa where pyrethroid insecticides are widely used in agriculture and public health. Samples of this species from northern Kwazulu/Natal in South Africa and the Beluluane region of southern Mozambique showed evidence of resistance to pyrethroid insecticides. Insecticide exposure, synergist and biochemical assays conducted on A. funestus suggested that elevated levels of mixed function oxidases were responsible for the detoxification of pyrethroids in resistant mosquitoes in these areas. The data suggested that this mechanism was also conferring cross-resistance to the carbamate insecticide propoxur.

An extended conformation of the macrophage mannose receptor

The macrophage mannose receptor mediates phagocytosis of pathogenic microorganisms and endocytosis of potentially harmful soluble glycoproteins by recognition of their defining carbohydrate structures. The mannose receptor is the prototype for a family of receptors each having an extracellular region consisting of 8-10 domains related to C-type carbohydrate recognition domains (CRDs), a fibronectin type II repeat and an N-terminal cysteine-rich domain. Hydrodynamic analysis and proteolysis experiments performed on fragments of the extracellular region of the receptor have been used to investigate its conformation. Size and shape parameters derived from sedimentation and diffusion coefficients indicate that the receptor is a monomeric, elongated and asymmetric molecule. Proteolysis experiments indicate the presence of close contacts between several pairs of domains and exposed linker regions separating CRDs 3 and 6 from their neighboring domains. Hydrodynamic coefficients predicted for modeled receptor conformations are consistent with an extended conformation with close contacts between three pairs of CRDs. The N-terminal cysteine-rich domain and the fibronectin type II repeat appear to increase the rigidity of the molecule. The rigid, extended conformation of the receptor places domains with different functions at distinct positions with respect to the membrane.

Structure of a C-type carbohydrate recognition domain from the macrophage mannose receptor

The mannose receptor of macrophages and liver endothelium mediates clearance of pathogenic organisms and potentially harmful glycoconjugates. The extracellular portion of the receptor includes eight C-type carbohydrate recognition domains (CRDs), of which one, CRD-4, shows detectable binding to monosaccharide ligands. We have determined the crystal structure of CRD-4. Although the basic C-type lectin fold is preserved, a loop extends away from the core of the domain to form a domain-swapped dimer in the crystal. Of the two Ca(2+) sites, only the principal site known to mediate carbohydrate binding in other C-type lectins is occupied. This site is altered in a way that makes sugar binding impossible in the mode observed in other C-type lectins. The structure is likely to represent an endosomal form of the domain formed when Ca(2+) is lost from the auxiliary calcium site. The structure suggests a mechanism for endosomal ligand release in which the auxiliary calcium site serves as a pH sensor. Acid pH-induced removal of this Ca(2+) results in conformational rearrangements of the receptor, rendering it unable to bind carbohydrate ligands.

Multiple interactions between pituitary hormones and the mannose receptor

The macrophage mannose receptor, which has a well-documented role in the innate immune system, has an additional function in the clearance of pituitary hormones. Clearance is mediated by the recognition of sulphated terminal N-acetylgalactosamine residues (SO(4)-4GalNAc) on the hormones. Previous studies with an SO(4)-4GalNAc-containing neoglycoprotein suggest that the SO(4)-4GalNAc-binding site is localized to the N-terminal cysteine-rich domain of the receptor, distinct from the mannose/N-acetylglucosamine/fucose-specific C-type carbohydrate-recognition domains (CRDs). The present study characterizes the binding of natural pituitary hormone ligands to a soluble portion of the mannose receptor consisting of the whole extracellular domain and to a truncated form containing the eight CRDs but lacking the N-terminal cysteine-rich domain and the fibronectin type II repeat. Both forms of the receptor show high-affinity saturable binding of lutropin and thyrotropin. Binding to the full-length receptor is dependent on pH and ionic strength and is inhibited effectively by SO(4)-4GalNAc but only partly by mannose. In contrast, binding to the truncated form of the receptor, which is also dependent on pH and ionic strength, is inhibited by mannose but not by SO(4)-4GalNAc. The results are consistent with the presence of an SO(4)-4GalNAc-specific binding site in the cysteine-rich domain of the mannose receptor but indicate that interactions between other sugars on the hormones and the CRDs are also important in hormone binding.

Detection of glycopeptide-resistant enterococci in routine diagnostic faeces specimens

Faeces received in a diagnostic laboratory were screened for glycopeptide-resistant enterococci (GRE) on modified Lewisham medium, with and without enrichment in Enterococcosel broth. Colonization by GRE was detected in 102/838 patients (12.2%). In 74 (73%) of colonized patients GRE were detected by both methods and in 28 (27%) they were detected only after enrichment. The carriage rate in hospitalized patients was 32% (93/289) compared with 2.3% (11/425) in the community (GP patients and food-handlers). Carriage of GRE increased with age. Clostridium difficile isolation was associated with GRE colonization, odds ratio 6.76 (P<0.001). Fifty-nine percent (60/102) of the GRE had the VanA phenotype and 41% (42/102) had the VanB phenotype. In the community VanA predominated (91%), whereas 64% (57/89) of the isolates from hospitalised patients were of the VanB phenotype.

Simultaneous superficial hyperthermia and external radiotherapy: report of thermal dosimetry and tolerance to treatment

BACKGROUND

In vitro and animal studies indicate that a moderate temperature of 41 degrees C maintained for approximately 1 h will provide radiosensitization if radiation (RT) and hyperthermia (HT) are delivered simultaneously, but not with sequential treatment. A minimum tumour temperature of 41 degrees C is a more feasible goal than the goal of >42 degrees C needed for sequential treatment.

METHODS AND MATERIALS

Forty-four patients with 47 recurrent superficial cancers received simultaneous external beam radiotherapy and superficial hyperthermia on successive IRB approved phase I/II studies. All lesions had failed previous therapy, 35 were previously irradiated (mean dose 52.7 Gy). Hyperthermia was delivered with 915 MHz microwave or 1-3.5 MHz ultrasound using commercially available applicators. The average dimensions of 19 lesions treated with microwave were 4.7 x 3.6 x 1.7 cm and the average dimensions of 28 lesions treated with ultrasound were 8.0 x 6.1 x 2.9 cm. The most common sites were chest wall (15 cases) and head and neck (21 cases). Temperatures were monitored at an average of six intratumoral locations using multisensor probes. The median number of hyperthermia treatments was three and the median radiation dose 30 Gy. Radiation dose per fraction was 4 Gy with hyperthermia and 2 Gy or 4 Gy (depending on protocol) on non-hyperthermia days.

RESULTS

Six different measures of minimum monitored temperature and duration were found to be highly correlated with each other. There was nearly a one-to-one correspondence between minimum tumour time at or above 41 degrees C (Min t41) and minimum tumour Sapareto Dewey equivalent time at 42 degrees C (Min teq42). After four sessions 63% of cases had a per session average Sapareto Dewey equivalent time at 41 degrees C which exceeded 60 min in all monitored tumour locations. The complete and partial response rate in evaluable lesions were respectively 21/41 (51%) and 7/41 (17%) and were best correlated with site (chest wall showing best response). Toxicity consisted of 10/47 (21%) slow healing soft tissue ulcers which healed in all cases but required a median of 7 months. The most important predictors for chronic ulceration were cumulative radiation dose >80 Gy and complete response to treatment.

CONCLUSIONS

Minimum tumour temperatures maintained for durations compatible in vitro with thermal radiosensitization (if RT and HT are delivered simultaneously) are clinically feasible and tolerable for broad but superficial lesions amenable to externally applied ultrasound or microwave hyperthermia. The current in-house protocol is evaluating the impact of more than four hyperthermia sessions on the overall thermal dose distribution and toxicity.

Mature results from a phase II trial of accelerated induction chemoradiotherapy and surgery for poor prognosis stage III non-small-cell lung cancer

Mature results are reported from a phase II trial of accelerated induction chemoradiotherapy and surgical resection for stage III non-small-cell lung cancer whose prognosis is poor. Surgically staged patients with poor prognosis stage III non-small-cell lung cancer were eligible for this study. Four-day continuous intravenous infusions of cisplatin 20 mg/m2/day, 5-fluorouracil 1,000 mg/m2/day, and etoposide 75 mg/m2/day were given concurrently with accelerated fractionation radiation therapy, 1.5 Gy twice a day, to a total dose of 27 Gy. Surgical resection followed in 4 weeks. Identical postoperative chemotherapy and concurrent radiation to a total dose of 40 to 63 Gy was subsequently given. Between February 1991 and June 1994, 42 eligible and evaluable patients, 23 with stage IIIA disease and 19 with stage IIIB disease, were entered in this trial. Treatment was well tolerated. The pathologic response rate was 40%. This response was complete in 5%. With a median follow-up of 54 months, the Kaplan-Meier 4-year survival estimate is 19%: 26% for stage IIIA and 11% for stage IIIB patients. Patients with a pathologic response, resectable disease, or pathologic downstaging to stage 0, I, or II had a better survival. The 4-year estimates of locoregional and distant disease control are 70% and 19%, respectively. It is concluded that although the ultimate role of concurrent chemoradiotherapy and surgery in stage III non-small-cell lung cancer must await the results of phase III clinical trials, survival and locoregional control in this study appear improved in comparison with historical experience. There is a subset of patients, able to undergo resection with pathologic downstaging, who have a projected survival equivalent to that of patients with more limited disease. Clinical or pathologic tools to identify these patients before treatment would be highly useful.

Evolving views of protein glycosylation

The composition, biosynthesis and known roles of oligosaccharides that are attached to glycoproteins suggest that multiple forces have driven the evolution of proteins that create and recognize these structures. The evolution of glycoprotein biosynthesis and recognition mechanisms can be best understood as a sequential development of functions associated with oligosaccharides.

Orientation of sugars bound to the principal C-type carbohydrate-recognition domain of the macrophage mannose receptor

The extracellular region of the macrophage mannose receptor, a protein involved in the innate immune response, contains eight C-type carbohydrate-recognition domains (CRDs). The fourth of these domains, CRD-4, is central to ligand binding by the receptor, and binds mannose, fucose and N-acetylglucosamine by direct ligation to Ca2+. Site-directed mutagenesis combined with NMR and molecular modelling have been used to determine the orientation of monosaccharides bound to CRD-4. Two resonances in the 1H NMR spectrum of CRD-4 that are perturbed on sugar binding are identified as a methyl proton from a leucine side chain in the core of the domain and the H-2 proton of a histidine close to the predicted sugar-binding site. The effects of mutagenesis of this histidine residue, a nearby isoleucine residue and a tyrosine residue previously shown to stack against sugars bound to CRD-4 show the absolute orientation of sugars in the binding site. N-Acetylglucosamine binds to CRD-4 of the mannose receptor in the orientation seen in crystal structures of the CRD of rat liver mannose-binding protein. Mannose binds to CRD-4 in the orientation seen in the CRD of rat serum mannose-binding protein and is rotated by 180 degrees relative to GlcNAc bound to CRD-4. Interaction of the O-methyl group and C-1 of alpha-methyl Fuc with the tyrosine residue accounts for the strong preference of CRD-4 for this anomer of fucose. Both anomers of fucose bind to CRD-4 in the orientation seen in rat liver mannose-binding protein.

The C-type lectin superfamily in the immune system

Protein-carbohydrate interactions serve multiple functions in the immune system. Many animal lectins (sugar-binding proteins) mediate both pathogen recognition and cell-cell interactions using structurally related Ca(2+)-dependent carbohydrate-recognition domains (C-type CRDs). Pathogen recognition by soluble collections such as serum mannose-binding protein and pulmonary surfactant proteins, and also the macrophage cell-surface mannose receptor, is effected by binding of terminal monosaccharide residues characteristic of bacterial and fungal cell surfaces. The broad selectivity of the monosaccharide-binding site and the geometrical arrangement of multiple CRDs in the intact lectins explains the ability of the proteins to mediate discrimination between self and non-self. In contrast, the much narrower binding specificity of selectin cell adhesion molecules results from an extended binding site within a single CRD. Other proteins, particularly receptors on the surface of natural killer cells, contain C-type lectin-like domains (CTLDs) that are evolutionarily divergent from the C-type lectins and which would be predicted to function through different mechanisms.

Hospital-acquired infection in elderly patients

Increasing numbers of elderly people are being treated in hospitals and are at particular risk of acquiring infections. The incidence, risk factors and types of hospital-acquired infection (HAI) in the elderly are reviewed. Special reference is made to urinary tract infections, respiratory tract infections, gastrointestinal infections including Clostridium difficile, bacteraemia, skin and soft tissue infections and infections with antibiotic-resistant organisms.

Ethical dilemmas in current planning for polio eradication

Intensification of polio eradication efforts worldwide raises concerns about costs and benefits for poor countries. A major argument for global funding is the high benefit-cost ratio of eradication; however, financial benefits are greatest for rich countries. By contrast, the greatest costs are borne by poor countries; the Pan American Health Organization has estimated that host countries bore 80% of costs for polio eradication in the Americas. The 1988 World Health Assembly resolution setting up the Polio Eradication Initiative carried the proviso that programs should strengthen health infrastructures. Drastic cuts in donor funding for health make this commitment even more important. Two international evaluations have reported both positive and negative effects of polio and Expanded Programme on Immunization programs on the functioning and sustainability of primary health care. Negative effects were greatest in poor countries with many other diseases of public health importance. If poor countries are expected to divert funds from their own urgent priorities, donors should make solid commitments to long-term support for sustainable health development.