Profiling older community-dwellers with hypovitaminosis D: A classification tree analysis.

Despite the high prevalence of hypovitaminosis D in older adults, universal vitamin D supplementation is not recommended due to potential risk of intoxication. Our aim here was to determine the clinical profiles of older community-dwellers with hypovitaminosis D. The perspective is to build novel strategies to screen for and supplement those with hypovitaminosis D. A classification tree (CHAID analysis) was performed on multiple datasets standardizedly collected from 1991 older French community-dwelling volunteers ≥ 65 years in 2009-2012. Hypovitaminosis D was defined as serum 25-hydroxyvitamin D ≤ 50 nmol/L. CHAID analysis retained 5 clinical profiles of older community-dwellers with different risks of hypovitaminosis D up to 87.3%, based on various combinations of the following characteristics: polymorbidity, obesity, sadness and gait disorders. For instance, the probability of hypovitaminosis D was 1.42-fold higher [95CI: 1.27-1.59] for those with polymorbidity and gait disorders compared to those with no polymorbidity, no obesity and no sadness. In conclusion, these easily-recordable measures may be used in clinical routine to identify older community-dwellers for whom vitamin D supplementation should be initiated.

The influence of fear of falling on gait variability: results from a large elderly population-based cross-sectional study.

OBJECTIVE: To compare gait variability among older community-dwellers with and without fear of falling and history of falls, and 2) to examine the association between gait variability and fear of falling while taking into account the effect of potential confounders. METHODS: Based on a cross-sectional design, 1,023 French community-dwellers (mean age ± SD, 70.5 ± 5.0 years; 50.7% women) were included in this study. The primary endpoints were fear of falling, stride-to-stride variability of stride time and walking speed measured using GAITRite® system. Age, gender, history of falls, number of drugs daily taken per day, body mass index, lower-limb proprioception, visual acuity, use of psychoactive drugs and cognitive impairment were used as covariables in the statistical analysis. P-values less than 0.05 were considered as statistically significant. RESULTS: A total of 60.5% (n=619) participants were non-fallers without fear of falling, 19% (n=194) fallers without fear of falling, 9.9% (n=101) non-fallers with fear of falling, and 10.7% (n=109) fallers with fear of falling. Stride-to-stride variability of stride time was significantly higher in fallers with fear of falling compared to non-fallers without fear of falling. Full adjusted linear regression models showed that only lower walking speed value was associated to an increase in stride-to-stride variability of stride time and not fear of falling, falls or their combination. While using a walking speed ≥ 1.14 m/s (i.e., level of walking speed that did not influence stride-to-stride variability of stride time), age and combination of fear of falling with history of previous falls were significantly associated with an increased stride-to-stride variability of stride time. CONCLUSIONS: The findings show that the combination of fear of falling with falls increased stride-to-stride variability of stride time. However, the effect of this combination depended on the level of walking speed, increase in stride-to-stride variability of stride time at lower walking speed being related to a biomechanical effect overriding fear of falling-related effects.

Early detection of memory impairment in people over 65 years old consulting at Health Examination Centers for the French health insurance: the EVATEM protocol.

BACKGROUND: Only half of those living with Alzheimer's disease in France are currently diagnosed, and only one patient in three is supported during the early stages of dementia. This study aims to evaluate three cognitive tests for their predictive ability to diagnose mild cognitive impairments and Alzheimer's disease and related disorders. For people aged 65 years or over, presenting with a memory complaint, these tests can be performed easily during a preventative consultation. METHOD/DESIGN: The EVATEM (évaluation des troubles de l'équilibre et de la mémoire (evaluation of balance and memory problems)) cohort study was designed to prospectively assess the predictive value of tests for the diagnosis of mild cognitive impairments and Alzheimer's disease in elderly subjects aged 65 years or over. Subjects were recruited from three health examination centers that are part of the French health insurance system. If a memory complaint was identified (using a dedicated questionnaire), the five-word test, the cognitive disorders examination test and the verbal fluency test were administered during a preventative consultation. A memory consultation was performed at a University Hospital to diagnosis any potential cognitive disorder and a one-year follow-up consultation was also scheduled. We recorded 2041 cases of memory complaint at our Health Examination Centers. Cognitive tests were refused by 33.6% of people who had a memory complaint. The number of subjects sent to a University Hospital memory consultation was 832 and 74.5% of them completed this consultation. The study population therefore includes 620 subjects. DISCUSSION: Tests for the early diagnosis of a mild cognitive impairment or Alzheimer's disease and related disorders should be used in centers dedicated to disease prevention. These should guide subjects with memory impairment to full memory consultations at hospitals and improve the access to early medical and behavioral support. TRIAL REGISTRATION: ClinicalTrials.gov:NCT01316562.

Association between vitamin D deficiency and long hospital stay in geriatric acute care unit: results from a pilot cohort study.

Finding a biomarker of long length-of-stay (LOS) would provide a simple solution to target frail older inpatients at such risk. The aim of this study was to determine whether serum 25-hydroxyvitamin D (25OHD) deficiency, defined as serum concentration <25 nmol/L, was associated with long LOS among inpatients admitted to a geriatric acute care unit. Three hundred and six older inpatients (mean age 84.6 ± 6.4 years, 61.8% women) were consecutively included in this longitudinal prospective cohort study. Patients were separated into two groups according to LOS tertiles: highest tertile (≥14 days; n = 120) versus the other two tertiles combined (<14 days; n = 186). Serum 25OHD deficiency (58.3 vs. 38.7%, P = 0.001) and the prevalence of male gender (58.3 vs. 28.5%, P < 0.001) were higher among inpatients with the highest LOS compared with those with lower LOS. Serum 25OHD deficiency [odds ratio (OR) = 2.22, P = 0.001 for unadjusted model; OR = 1.87, P = 0.012 for fully adjusted model) and male gender (OR = 2.87, P < 0.001 for unadjusted model; OR = 2.64, P = 0.001 for full model) were associated with a high LOS. Vitamin D deficiency and male gender were risk factors for a long LOS in this pilot study. Using these risk factors to identify inpatients at risk of long LOS may be helpful in adapting early care plans, and thus improving inpatients' health and shortening LOS.

Screening for elderly patients admitted to the emergency department requiring specialized geriatric care.

BACKGROUND: There is a need for a brief geriatric assessment (BGA) tool to screen elderly patients admitted to the Emergency Department (ED) for their risk of a long hospital stay. OBJECTIVE: To examine whether a BGA administered to elderly patients admitted to the ED may predict the risk of a long hospital stay in the geriatric acute care unit. METHODS: This study had a prospective cohort study design, enrolling 424 elderly patients (mean age 84.0 ± 6.5 years, 31.6% male) who were evaluated in the ED using a BGA composed of the following items: age, gender, number of medications taken daily, history of falls during the past 6 months, Mini-Mental State Examination (MMSE) score, and non-use of home-help services (i.e., living alone without using any formal or informal home services or social help). The length of stay (LOS) was calculated in days. Patients were separated into three groups based on LOS: low (<8 days), intermediate (8-13 days), and high (>13 days). RESULTS: The prevalence of male gender was higher among patients with the longest LOS compared to those with intermediate LOS (p = 0.002). There were more patients with a history of falls in the high LOS group compared to the intermediate LOS group (p = 0.001) and the low LOS group (p < 0.001). The classification tree showed that male patients with an MMSE score <20 who fell with age under 85 years formed the end node with the greatest relative risk (RR) of a long hospital stay (RR = 14.3 with p < 0.001). CONCLUSIONS: The combination of a history of falls, male gender, cognitive impairment, and age under 85 years identified elderly ED patients at high risk of a long hospital stay.

Effectiveness of the combination of memantine plus vitamin D on cognition in patients with Alzheimer disease: a pre-post pilot study.

OBJECTIVE: To determine whether treatment with memantine plus vitamin D is more effective than memantine or vitamin D alone in improving cognition among patients with Alzheimer disease (AD). METHODS: We studied 43 white outpatients (mean 84.7 ± 6.3 years; 65.1% women) with a new diagnosis of AD, who had not taken anti-dementia drugs or vitamin D supplements. We prescribed memantine alone (n = 18), vitamin D alone (n = 17), or memantine plus vitamin D (n = 8) for an average of 6 months. We assessed cognitive change with the Mini-Mental State Examination (MMSE). We used age, sex, pre-treatment MMSE score, and duration of treatment as covariables. RESULTS: Before treatment, the 3 groups had comparable MMSE scores. At 6 months, participants taking memantine plus vitamin D increased their MMSE score by 4.0 ± 3.7 points (P = 0.034), while participants taking memantine alone remained stable (change of 0.0 ± 1.8 points; P = 0.891), as did those taking vitamin D alone (-0.6 ± 3.1 points; P = 0.504). Treatment with memantine plus vitamin D was associated with improvement in the MMSE score compared to memantine or vitamin D alone after adjustment for covariables (P < 0.01). Mixed regression analysis showed that the visit by combined treatments (memantine plus vitamin D) interaction was significant (P = 0.001), while memantine or vitamin D alone showed no effect. CONCLUSIONS: Patients with AD who took memantine plus vitamin D for 6 months had a statistically and clinically relevant gain in cognition, underlining possible synergistic and potentiating benefits of the combination.

Gait control: a specific subdomain of executive function?

BACKGROUND: Few studies looked at the association between gait variability and executive subdomains (ESD). The aim of this study was to examine the association between ESD (i.e., information updating and monitoring) and stride time variability among healthy older adults. METHODS: Seventy-eight healthy older adults (mean age 69.9 ± 0.9 years, 59% women) were divided into 3 groups according to stride time variability (STV) tertiles while steady state walking. Coefficient of variation of stride time was used as a marker of STV. Scores on cognitive tests evaluating information updating and monitoring (Digit Span test), mental shifting (Trail Making Test part A and part B) and cognitive inhibition (Stroop Color Word test) were used as measures of ESD. RESULTS: The full adjusted and the stepwise backward logistic regression models showed that the highest tertile (i.e., the worst performance) of STV was only associated with lower Digit Span performance (Odds ratio = 0.78 with P = 0.020 and Odds ratio = 0.81 with P = 0.019). CONCLUSIONS: Information updating and monitoring are associated with STV in the sample of studied participants, suggesting that walking may be a complex motor task depending specifically of this subdomain of executive functions.

Development of a short form of Mini-Mental State Examination for the screening of dementia in older adults with a memory complaint: a case control study.

BACKGROUND: Primary care physicians need a brief and accurate screening test of dementia. The objective of this study was to determine whether a short form of Mini-Mental State Examination (SMMSE) was as accurate as the Mini-Mental State Examination (MMSE) in screening dementia. METHODS: Based on case control design study, SMMSE and MMSE were assessed in 184 community-dwelling older adults (mean age 81.3 ± 6.5 years, 71.7% women) with memory complaint sent by their primary care physician to a memory clinic. Included participants were separated into two groups: cognitively healthy individuals and demented individuals. RESULTS: The trade-off between sensitivity and specificity of the SMMSE for clinically diagnosed dementia was 4. Based on the cut-off value ≤ 4 for SMMSE and a cut-off value ≤ 24 for MMSE, the sensitivity of both tests was similar (89.5% for SMMSE versus 90.0% for MMSE), whereas the specificity, the positive predictive values (PPV) and the negative predictive values (NPV) were higher for SMMSE compared to MMSE (85.4 versus 75.5% for specificity; 95.5% versus 92.8% for PPV; 70.0 versus 68.9 for NPV). The positive and negative Likehood Ratio (LR) of SMMSE were higher than those of MMSE (respectively, 6.1 versus 3.7; 8.1 versus 7.7). In addition, odds ratio (OR) for dementia was higher for the SMMSE compared to the MMSE (OR = 49.8 with 95% confident interval (CI) [18.0; 137.8] versus OR = 28.6 with 95% CI [11.6; 70.3]). CONCLUSIONS: SMMSE seems to be an efficient short screening test for dementia among community-dwelling older adults with a memory complaint. Further research is needed to confirm its predictive values among unselected primary care older patients.

Fall prevention and vitamin D in the elderly: an overview of the key role of the non-bone effects.

Preventing falls and fall-related fractures in the elderly is an objective yet to be reached. There is increasing evidence that a supplementation of vitamin D and/or of calcium may reduce the fall and fracture rates. A vitamin D-calcium supplement appears to have a high potential due to its simple application and its low cost. However, published studies have shown conflicting results as some studies failed to show any effect, while others reported a significant decrease of falls and fractures. Through a 15-year literature overview, and after a brief reminder on mechanism of falls in older adults, we reported evidences for a vitamin D action on postural adaptations - i.e., muscles and central nervous system - which may explain the decreased fall and bone fracture rates and we underlined the reasons for differences and controversies between published data. Vitamin D supplementation should thus be integrated into primary and secondary fall prevention strategies in older adults.

The self-reported Montgomery-Asberg Depression Rating Scale is a useful evaluative tool in Major Depressive Disorder.

BACKGROUND: The use of Patient-reported Outcomes (PROs) as secondary endpoints in the development of new antidepressants has grown in recent years. The objective of this study was to assess the psychometric properties of the 9-item, patient-administered version of the Montgomery-Asberg Depression Rating Scale (MADRS-S). METHODS: Data from a multicentre, double-blind, 8-week, randomised controlled trial of 278 outpatients diagnosed with Major Depressive Disorder were used to evaluate the validity, reliability and sensitivity to change of the MADRS-S using psychometric methods. A Receiver Operating Characteristic (ROC) curve was plotted to identify the most appropriate threshold to define perceived remission. RESULTS: No missing values were found at the item level, indicating good acceptability of the scale. The construct validity was satisfactory: all items contributed to a common underlying concept, as expected. The correlation between MADRS-S and physicians' MADRS was moderate (r = 0.54, p < 0.001) indicating that MADRS-S is complementary rather than redundant to the MADRS. Cronbach's alpha was 0.84, and the stability over time of the scale, estimated on a sub-sample of patients whose health status did not change during the first week of the study, was good (intraclass correlation coefficient of 0.78). MADRS-S sensitivity to change was shown. Using a threshold value of 5, the definition of "perceived remission" reached a sensitivity of 82% and a specificity of 75%. CONCLUSION: Taking account of patient's perceptions of the severity of their own symptoms along with the psychometric properties of the MADRS-S enable its use for evaluative purposes in the development of new antidepressant drugs.

Vitamin D and Subjective Memory Complaint in Community-Dwelling Older Adults.

BACKGROUND: Older adults with hypovitaminosis D report more often subjective cognitive complaints, especially with regards to memory. This raises prospects that vitamin D may improve older adults' subjective experience of memory disorders. OBJECTIVE: To determine among older community-dwellers whether higher serum 25- hydroxyvitamin D (25OHD) concentrations were associated with fewer memory complaints, while considering different subtypes of memory complaints. METHOD: One hundred eighty Caucasian community-dwellers with memory complaint and no dementia (mean±standard deviation, 71.1±3.4years; 33.3%female) from the French 'EVATEM study' were included in this analysis. Subjective memory complaints regarding memory lapses, problems learning new information, problems finding words, problems calculating and problems concentrating were assessed using a standardized questionnaire. Participants were categorized according to the highest tertile of serum 25OHD (i.e., ≥68nmol/L). Age, gender, body mass index, morbidities burden, use of vitamin D supplements, cognitive performance, mood, serum concentrations of calcium, parathyroid hormone and vitamin B12, creatinine clearance, and season of evaluation were used as potential confounders. RESULTS: Compared to participants with 25OHD<68nmol/L (n=121), those with 25OHD≥68nmol/L had less often problems learning new information (P=0.027). There were no between-group differences for the other memory complaints. The highest 25OHD tertile was cross-sectionally associated with fewer problems learning new information (odds ratio (OR)=0.48, P=0.029), even after adjustment for potential confounders (OR=0.32, P=0.039). CONCLUSION: Higher vitamin D status was associated with reduced problems memorizing new information in older community-dwellers. This novel finding provides a scientific base for vitamin D replacement trials attempting to improve older patients' subjective experience of cognitive decline.

Cost-effectiveness of escitalopram vs. citalopram in major depressive disorder.

Clinical trials have shown better efficacy of escitalopram over citalopram, and review-based economic models the cost-effectiveness of escitalopram vs. citalopram (brand and generic). No head-to-head clinical trial has, however, evaluated the cost-effectiveness of both drugs so far. The aim of this study was to assess the relative cost-effectiveness of escitalopram compared with citalopram in patients with major depressive disorder. An economic evaluation was conducted alongside a double-blind randomized clinical trial conducted by general practitioners and psychiatrists comparing fixed doses of escitalopram (20 mg/day) or citalopram (40 mg/day) over 8 weeks in ambulatory care patients with major depressive disorder (baseline Montgomery-Asberg Depression Rating Scale score > or =30). Resources use was recorded using a standardized form recording use of healthcare services and days of sick leave for the 2-month prestudy period and for the 8-week study period. Statistically significant improvements were observed in patients treated with escitalopram. Mean per-patient costs for the escitalopram group, compared with the citalopram group, were 41% lower (96 euro vs. 163 euro; P<0.05) from a healthcare perspective. Differences were mostly related to lower hospitalization costs for escitalopram compared with citalopram recipients, assuming a parity price between escitalopram and citalopram. Bootstrapped distributions of the cost-effectiveness ratios also showed better effectiveness and lower costs for escitalopram compared with citalopram. Escitalopram is significantly more effective than citalopram, and is associated with lower healthcare costs. This prospective economic analysis demonstrated that escitalopram is a cost-effective first-line treatment option for major depressive disorder.

The cost of multiple sclerosis in Australia.

Multiple sclerosis (MS) represents a significant economic burden both to the patient and to society. This study aims to provide information about direct and indirect costs of MS in Australia. Detailed questionnaires were completed for 100 patients over a 6-month period (12 months for hospitalization costs). Overall, the average annual direct and indirect costs per patient were AU$20 396 and AU$15 085, respectively. The greatest uses of resources were for immunomodulating drugs, consultations and district nursing. Various factors significantly increased overall direct costs, including secondary progressive MS, severe MS symptoms and higher Expanded Disability Status Scale scores. This study confirms that MS is a costly disease with a high economic burden on society. In order to minimize MS costs and improve quality of life, the ideal aim of MS treatment should be to stabilize patients on a low disability (low cost) level at an early stage of the disease utilising a cost-effective therapy.

[Perspectives of general practitioners on the role of patients' caregivers in the process of consultation and treatment]. / Représentations par les médecins généralistes du rôle de l'entourage accompagnant le patient.

The aim of this study is to describe, from the perspective of general practitioners, the role of relatives and caregivers who accompany a patient in their consultation and treatment processes. 435 general practitioners filled out two questionnaires: the first was self administered and the second described specific clinical situations and the possible role of the family caregiver in the case of a patient with Alzheimer's diseases, Parkinson's disease, depression, epilepsy, asthma, cardiovascular disease, or type II diabetes. General practitioners think that overall they offer satisfactory responses to relatives' requests and concerns regarding the disease itself and its treatment. However, they do not feel skilled or qualified enough to answer them with regard to administrative or social questions. The relative's role is for the most part, perceived as positive, and seems to contribute to the efficacy of the care provided. This description corresponds to a new trend in modern medical practice, dominated by the burden of chronic and disabling diseases which implies, and in some cases requires, the need to involve a relative's presence and on-going support.

Falling in the elderly: Do statistical models matter for performance criteria of fall prediction? Results from two large population-based studies.

OBJECTIVE: To compare performance criteria (i.e., sensitivity, specificity, positive predictive value, negative predictive value, area under receiver operating characteristic curve and accuracy) of linear and non-linear statistical models for fall risk in older community-dwellers. METHODS: Participants were recruited in two large population-based studies, "Prévention des Chutes, Réseau 4" (PCR4, n=1760, cross-sectional design, retrospective collection of falls) and "Prévention des Chutes Personnes Agées" (PCPA, n=1765, cohort design, prospective collection of falls). Six linear statistical models (i.e., logistic regression, discriminant analysis, Bayes network algorithm, decision tree, random forest, boosted trees), three non-linear statistical models corresponding to artificial neural networks (multilayer perceptron, genetic algorithm and neuroevolution of augmenting topologies [NEAT]) and the adaptive neuro fuzzy interference system (ANFIS) were used. Falls ≥1 characterizing fallers and falls ≥2 characterizing recurrent fallers were used as outcomes. Data of studies were analyzed separately and together. RESULTS: NEAT and ANFIS had better performance criteria compared to other models. The highest performance criteria were reported with NEAT when using PCR4 database and falls ≥1, and with both NEAT and ANFIS when pooling data together and using falls ≥2. However, sensitivity and specificity were unbalanced. Sensitivity was higher than specificity when identifying fallers, whereas the converse was found when predicting recurrent fallers. CONCLUSIONS: Our results showed that NEAT and ANFIS were non-linear statistical models with the best performance criteria for the prediction of falls but their sensitivity and specificity were unbalanced, underscoring that models should be used respectively for the screening of fallers and the diagnosis of recurrent fallers.

Prospective, multicentre, randomized, double-blind study of the efficacy of escitalopram versus citalopram in outpatient treatment of major depressive disorder.

Pre-clinical studies, active-control clinical trials and meta-analyses indicate that escitalopram (S-citalopram) might be more effective than citalopram, the racemic mixture of S- and R-citalopram. The present study aimed to confirm the superior efficacy of escitalopram over citalopram. A double-blind, randomized clinical trial was performed in which general practitioners and psychiatrists compared fixed doses of escitalopram (20 mg/day) with citalopram (40 mg/day) over 8 weeks in outpatients with major depressive disorder (MDD) [baseline Montgomery-Asberg Depression Rating Scale (MADRS) score > or =30]. Primary efficacy parameter was change from baseline to last assessment in the MADRS total score. Out of 138 (aged 44.1+/-10.9 years; initial MADRS score 36.3+/-4.8) and 142 (aged 46.2+/-11.1 years; initial MADRS score 35.7+/-4.4) evaluable patients who were randomized to escitalopram and citalopram, respectively, six and 15 withdrew prematurely (P=0.05). The MADRS score decreased more in the escitalopram than in the citalopram arm (-22.4+/-12.9 versus -20.3+/-12.7; P<0.05). There were more treatment responders with escitalopram (76.1%) than with citalopram (61.3%, P<0.01). Adjusted remitter rates were 56.1% and 43.6%, respectively (P<0.05). Tolerability was similar in both groups. This randomized double-blind trial confirms that escitalopram has a superior effect to citalopram in MDD.

Derivation and validation of a clinical diagnostic tool for the identification of older community-dwellers with hypovitaminosis D.

OBJECTIVES: Hypovitaminosis D is highly prevalent among seniors. Although evidence is insufficient to recommend routine vitamin D screening in seniors, universal vitamin D supplementation is not desirable either. To rationalize vitamin D determination, our objective was to elaborate and test a clinical diagnostic tool for the identification of seniors with hypovitaminosis D without using a blood test. DESIGN: Derivation of a clinical diagnostic tool using artificial neural networks (multilayer perceptron; MLP) in randomized training subgroup of Prévention des Chutes, Réseau 4' cohort, and validation in randomized testing subgroup. SETTING: Health Examination Centers of health insurance, Lyon, France. PARTICIPANTS: A total of 1924 community-dwellers aged ≥ 65 years without vitamin D supplements, consecutively recruited between 2009 and 2012. MEASUREMENTS: Hypovitaminosis D defined as serum 25-hydroxyvitamin (25OHD) concentration ≤ 75 nmol/L, ≤ 50 nmol/L, or ≤ 25 nmol/L. A set of clinical variables (age, gender, living alone, individual deprivation, body mass index, undernutrition, polymorbidity, number of drugs used daily, psychoactive drugs, biphosphonates, strontium, calcium supplements, falls, fear of falling, vertebral fractures, Timed Up and Go, walking aids, lower-limb proprioception, handgrip strength, visual acuity, wearing glasses, cognitive disorders, sad mood) were recorded. Several MLPs, based on varying amounts of variables according to their relative importance, were tested consecutively. RESULTS: A total of 1729 participants (89.9%) had 25OHD ≤ 75 nmol/L, 1288 (66.9%) had 25OHD ≤ 50 nmol/L, and 525 (27.2%) had 25OHD ≤ 25 nmol/L. MLP using 16 clinical variables was able to diagnose hypovitaminosis D ≤ 75 nmol/L with accuracy = 96.3%, area under curve (AUC) = 0.938, and κ = 79.3 indicating almost perfect agreement. It was also able to diagnose hypovitaminosis D ≤ 50 nmol/L with accuracy = 81.5, AUC = 0.867, and κ = 57.8 (moderate agreement); and hypovitaminosis D ≤ 25 nmol/L with accuracy = 82.5, AUC = 0.385, and κ = 55.0 (moderate agreement). CONCLUSIONS: We elaborated an algorithm able to identify, from 16 clinical variables, seniors with hypovitaminosis D.

Respective and combined effects of impairments in sensorimotor systems and cognition on gait performance: a population-based cross-sectional study.

BACKGROUND: Respective and combined effects of impairments in sensorimotor systems and cognition on gait performance have not been fully studied. This study aims to describe the respective effects of impairments in muscle strength, distance vision, lower-limb proprioception and cognition on the Timed Up & Go (TUG) scores (i.e., performed TUG [pTUG], imagined TUG [iTUG] and the time difference between these two tests [delta TUG]) in older community-dwellers; and to examine their combined effects on TUG scores. METHODS: Based on a cross-sectional design, 1792 community-dwellers (70.2 ± 4.8 years; 53.6% female) were recruited. Gait performance was assessed using pTUG, iTUG and delta TUG. Participants were divided into healthy individuals and 15 subgroups of individuals according to the presence of impairment in one or more subsystems involved in gait control (i.e., muscle strength and/or distance vision and/or lower-limb proprioception and/or cognition [episodic memory and executive performance]). Impairment in muscle strength, distance vision and lower-limb proprioception was defined as being in the lowest tertile of performance. Impairment in cognition was defined as abnormal episodic memory and executive tests. RESULTS: A total of 191 (10.7%) exhibited impairment in muscle strength, 188 (10.5%) in distance vision, 302 (16.9%) in lower-limb proprioception, and 42 (2.3%) in cognition. Linear regressions showed that cognitive impairment as well as dual combinations of impairments were associated with increased pTUG (P<0.02). Impairment in lower-limb proprioception was associated with decreased iTUG (P=0.015). All combinations of impairments, except those including muscle strength and the combinations of the 4 subsystems, were associated with increased delta TUG (P<0.04). CONCLUSION: Cognitive integrity is central for efficient gait control and stability, whereas lower-limb proprioception seems to be central for gait imagery.

Episodic memory and executive function impairments in non-demented older adults: which are the respective and combined effects on gait performances?

Gait control depends in part on cognition. This study aims to examine the separate and combined effects of episodic memory and executive function impairments on the mean value and the coefficient of variation (CoV) of stride time among non-demented older community dwellers. Based on a cross-sectional design, 1458 older community dwellers without dementia (70.6 ± 4.9 years; 49.2 % female) were recruited and separated into cognitively healthy individuals (CHI) and individuals with cognitive impairment. A score ≤5/6 on the Short Mini-Mental State Examination defined episodic memory impairment. Impaired executive function was defined by errors on the clock-drawing test. Mean value and CoV of stride time were measured by the GAITRite® system. A total of 517 participants (35.5 %) had cognitive impairment in at least one cognitive domain. Participants with memory impairment (P = 0.006) and those with combined cognitive impairments (P < 0.001) had greater (i.e., worse gait performance) mean value of stride time (P = 0.006) compared to CHI. Participants with combined cognitive impairment had a greater CoV of stride time (i.e., worse gait performance) compared to CHI (P = 0.004) and to those with separate memory impairment (P = 0.037). Among participants with combined cognitive impairments, mean value and CoV of stride time had the highest effect size (respectively, effect size = 0.49 [95 % confidence interval (CI) 0.27;0.71] and effect size = 0.40 [95 %CI 0.18;0.62]). Participants with episodic memory or executive impairments had a greater mean value and CoV of stride time compared to those with no cognitive impairment. Combined episodic memory and executive impairments exceeded the sum of separate impairments on gait performances, suggesting a complex interplay going beyond a simple additive effect.