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.

Depressive symptoms increase fall risk in older people, independent of antidepressant use, and reduced executive and physical functioning.

Depressive symptoms and antidepressant use are associated with greater fall risk in older people. This prospective study investigated interactions between depressive symptoms, antidepressant use and physical and cognitive function measures in relation to injurious or multiple falls in a large sample of community-living older people. Four-hundred and eighty-eight community-dwelling older people aged 70 years and over, underwent a comprehensive psychological, cognitive and physiological assessment and were prospectively monitored for falls over a 12-month follow up period. Substantial depressive symptoms were defined by a Geriatric Depression Scale (GDS) (15-item) score ≥5 and fallers were defined as people who had at least one injurious or two non-injurious falls during follow-up. In univariate analyses, the presence of depressive symptoms (RR=1.50; 95% CI=1.06-2.11), antidepressant use (RR=1.56; 95% CI=1.08-2.27), high physiological fall risk (RR=1.61; 95% CI=1.20-2.15) and poorer executive functioning (RR=1.40; 95% CI=1.05-1.88) were significant risk factors for falls. Multivariate models revealed that depressive symptomatology and antidepressant use were independent of each other, and independent of the presence of a high physiological fall risk and poorer executive functioning in the prediction of falls. Fall risk increased with the number of risk factors present: i.e. by 55% in participants with any two risk factors (RR=1.55; 95% CI=1.17-2.04) and by 144% in participants with three or four risk factors (RR=2.44; 95% CI=1.75-3.43). The study findings indicate that higher depressive symptoms and antidepressant use predict falls over 12-months, independent of reduced executive and physical functioning. Treatment of depressive symptoms using non-pharmacological approaches should be considered as part of fall prevention programs, especially in populations at high risk of falls.

Transcranial Doppler to measure cerebral blood flow in delirium superimposed on dementia. A cohort study.

OBJECTIVE: Delirium superimposed on dementia (DSD) is frequently not diagnosed, at great cost. Both delirium and dementia are associated with cerebral hypoperfusion. A switch to anaerobic glycolysis in the central nervous system during delirium compared to Alzheimer's dementia (AD) suggests greater hypoperfusion in DSD. The main aims of this study were to investigate whether cerebral hypoperfusion could differentiate DSD from related entities, and the characteristics of that hypoperfusion. METHODS: Prospective cohort study of 44 Geriatric Medicine patients in 4 groups: (1) delirium, no history of dementia; (2) DSD; (3) acute illness without delirium or dementia; and (4) AD, no delirium. We measured CBF using transcranial Doppler to assess flow velocity (FV) and pulsatility index in the middle cerebral artery (MCA). RESULTS: DSD has lower FV than either AD or delirium alone, or acute illness (28.2 ± 4.7 vs AD: 41.3 ±15.7; P = .040; vs delirium 37.7 ± 8.2; P =.009; vs acute illness 43.0 ± 8.3; P <.001). A mean MCA FV cut-off of 32.25 cm/s diagnoses DSD with a sensitivity of 0.875 and specificity of 0.788, area under the curve 0.884; P = .001. Resolution of delirium improves FV (P = .005). FV correlates with delirium severity (delirium index R = -0.39; P = .009) and dementia (Mini-Mental State Examination, R = 0.33; P = .029, and Informant Questionnaire on Cognitive Decline in the Elderly, R = -0.41; P = .005). CONCLUSIONS: Transcranial Doppler is a potential diagnostic and monitoring test for DSD. Correlation with clinical indicators of delirium suggests pathophysiological significance.

Depressive symptomatology as a risk factor for falls in older people: systematic review and meta-analysis.

OBJECTIVES: To conduct a systematic literature review and meta-analysis to evaluate studies that have addressed depressive symptoms as a risk factor for falls in older people. DESIGN: Systematic review with meta-analysis. SETTING: Community and residential care. PARTICIPANTS: Individuals aged 60 and older. MEASUREMENTS: Depressive symptoms, incidence of falls. RESULTS: Twenty-five prospective studies with a total of 21,455 participants met inclusion criteria for the systematic review. Twenty studies met criteria for the meta-analyses. Recruitment of participants was conducted randomly or by approaching groups with identified healthcare needs. Eleven measures were used to assess depressive symptoms, and length of follow-up for falls ranged from 90 days to 8 years. Reporting of antidepressant use was variable across studies. The pooled effect of 14 studies reporting odds ratios (ORs) indicated that a higher level of depressive symptoms at baseline resulted in a greater likelihood of falling during follow-up (OR = 1.46, 95% confidence interval (CI) = 1.27-1.67, P < .001, I(2) = 77.2%). In six studies reporting relative risks (RRs) or hazard ratios, a higher level of depressive symptoms at baseline resulted in a greater likelihood of falling during follow-up (RR = 1.52, 95% CI = 1.19-1.84, P < .001). There was no difference between community samples and those with identified healthcare needs with respect to depressive symptoms being a risk factor for falls. CONCLUSION: Depressive symptoms were found to be consistently associated with falls in older people, despite the use of different measures of depressive symptoms and falls and varying length of follow-up and statistical methods. Clinicians should consider management of depression when implementing fall prevention initiatives, and further research on factors mediating depressive symptoms and fall risk in older people is needed.

Cerebrospinal fluid in long-lasting delirium compared with Alzheimer's dementia.

BACKGROUND: Delirium is a common syndrome affecting older people in hospital, whose pathophysiology is poorly understood, but sequelae of increased cognitive and functional impairment suggest neuronal loss. METHODS: Cohort study comparing cerebrospinal fluid, blood, and clinical markers of delirium and neuronal cell death in 20 older hospitalized patients with delirium and 20 outpatients with Alzheimer's dementia. RESULTS: Compared with participants with dementia, patients with delirium demonstrated higher CSF lactate (1.87 vs 1.48 mmol/L, p < .001) and protein levels (0.62 vs 0.44 g/L, p = .036) and lower levels of neuron-specific enolase (4.84 vs 8.98 ng/mL, p < .001) but no difference in S100B. The changes correlated with clinical indices and outcomes. CONCLUSION: Older patients with delirium experience significant metabolic disturbance in the brain, which requires further investigation.

Physiological and cognitive mediators for the association between self-reported depressed mood and impaired choice stepping reaction time in older people.

BACKGROUND: The aim of the study was to use path analysis to test a theoretical model proposing that the relationship between self-reported depressed mood and choice stepping reaction time (CSRT) is mediated by psychoactive medication use, physiological performance, and cognitive ability. METHODS: A total of 280 retirement village residents, aged 62-95 years, undertook tests of CSRT, which required them to step onto one of four panels that were illuminated in a random order. Depressed mood was assessed using the 30-item Geriatric Depression Scale (GDS). The participants were also tested on physiological and cognitive performance, including quadriceps strength, balance, complex attention (Trail Making Test [TMT] B), simple reaction time, reported level of exercise, and use of psychoactive medications. RESULTS: A total of 51 participants (18%) showed mild to severe depression. Those with higher GDS scores had significantly increased CSRT and worse performance on all physiological and cognitive parameters. CSRT was also significantly associated with all other measures. The final path analysis model revealed an association between self-reported depression and CSRT that was mediated by two paths, one through quadriceps strength and the other through TMT B with both mediating variables then influencing CSRT via simple reaction time and balance. CONCLUSIONS: The findings suggest that self-reported depressed mood is related to slowed performance on a CSRT task and that this relationship is explained by underlying physiological and cognitive impairments.