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Background/Aims: Alzheimer disease (AD) is particularly devastating, with no cure, no means of prevention, and no proven way to slow progression. AD is associated with the worsening of cognitive function attributable to a variety of factors of which little is known. Our main objective was to determine factors associated with rapid cognitive decline (RCD) in older AD patients. Methods: We conducted a 12-month, prospective, multi-centre cohort study. Community-living individuals aged ≥65 years with mild-to-moderate AD were included. RCD was defined as the loss of ≥3 points/year in the Mini-Mental State Examination (MMSE) score. Potential individual-level predictors were collected at baseline. Results: A total of 521 individuals were included. The mean age was 80.8 ± 9.0 years and 66.0% were females. The average baseline MMSE score was 20.5 ± 4.5. The incidence of RCD was 40.9% (95% confidence interval [CI], 36.7–45.1). RCD was more common in patients with moderate (53.5%) than mild (22.3%) AD. The factors associated with RCD were: a parental history of dementia (odds ratio [OR], 2.32 [95% CI, 1.24–4.21], p = 0.011), psychotic symptoms (OR, 2.06 [95% CI, 1.22–3.48], p = 0.007), malnutrition (OR, 1.61 [95% CI, 1.06–2.63], p = 0.028), and the female gender (OR, 1.48 [95% CI, 1.03–2.15], p = 0.036). An MMSE score < 20 at treatment onset was also associated with RCD (p < 0.001). Conclusion: The factors associated with RCD were an MMSE score < 20 at treatment onset, female gender, psychotic symptoms, malnutrition, and a family history of dementia. These results may be directly relevant to patients, their families, and their physicians, enabling early anticipation of difficult clinical trajectories and poor functional outcomes.

Background: Subjects with mild cognitive impairment (MCI) have disturbances in their spatial navigation abilities and exhibit early deficits in visuospatial short-term memory. The purpose of the present study was to determine whether a quantitative (span score) and qualitative (evaluating navigation strategies used) analysis of the Corsi test (usual condition and complex navigation task) would be useful to reveal cognitive decline. Methods: We evaluated the performance of 15 young adults, 21 healthy elderly subjects and 15 subjects with MCI using the electronic version of the Corsi test (the Modified Corsi Block-Tapping Test, MCBT) and the complex navigation task (the Modified Walking Corsi Test, MWCT). The MWCT, which is an adaptation of the Corsi test, assesses spatial memory when the subject walks in a complex environment. We used Richard et al.'s model [Cogn Sci 1993;17:497-529] to investigate problem-solving strategies during the Corsi tests. Results: The span scores obtained on the MCBT and the MWCT were significantly lower in the healthy elderly subjects (MCBT = 5.0 ± 0.7; MWCT = 4.0 ± 0.7) and the subjects with MCI (MCBT = 4.7 ± 0.8; MWCT = 4.1 ± 0.9) than in the younger adults (MCBT = 6.2 ± 0.6; MWCT = 5.3 ± 1.0). The visuospatial working memory was more impaired in the complex navigation task (MWCT = 4.3 ± 0.9) than in the modified Corsi test (MCBT = 5.3 ± 0.8). Finally, the subjects with greater cognitive impairment were more likely to have inadequate or absence of problem-solving strategies. Conclusions: Investigating the problem-solving strategies used during the MWCT appears to be a promising way to differentiate between the subjects with MCI and the healthy elderly subjects.

Background: Walking represents a major component of physical activity (PA), and its restriction could degrade autonomy and quality of life. An important objective for preventive and/or rehabilitative strategies to improve balance and gait in normal and pathological aging conditions is to focus on physical activity. Activity monitors have recently been getting increasingly popular and represent a modern solution to measure—and communicate—PA notably in terms of steps/day. These activity monitors are well-suited for various populations as they can be worn on a variety of locations on the body, including the wrist and the hip (i.e., the two most common locations), in an undifferentiated way according to the manufacturer's instruction. The aim of this study was hence to verify potential differences in step count (SC) by comparing this parameter assessed using wrist- and hip-worn activity trackers over a 24-h period in free-living conditions in young and older adults.Methods: Young adults (n = 22) and older adults (n = 22) voluntarily participated in this study. They were required to wear two commercially-available Actigraph GT3X+ activity monitors simultaneously at two locations recommended by the manufacturer, i.e., one positioned around the wrist and one above the hip, over a 24-h period in free-living conditions. The manufacturer's software was used to obtain estimates of the SC.Results: For both groups, the wrist-worn activity tracker provided significantly higher SC than the hip-worn activity tracker did. For both placements on the body, older adults exhibited significantly lower SC than young adults. Interestingly, for both young and older participants, the difference between both measurements tended to decrease for longer distances.Conclusion: The different estimations of the step count provided by the comparison between two identical Actigraph GT3x on the wrist or the hip during the 24-h observation period in free-living conditions in young and older adults strongly suggests that caution is needed when using total step per day values as an outcome to quantify walking behavior. Probably we can suggest the same caution across implementation of different activity Tracker.

BackgroundSeveral studies have reported the potential value of the dual-task concept during locomotion in clinical evaluation because cognitive decline is strongly associated with gait abnormalities. However, current dual-task tests appear to be insufficient for early diagnosis of cognitive impairment.MethodsForty-nine subjects (young, old, with or without mild cognitive impairment) underwent cognitive evaluation (Mini-Mental State Examination, Frontal Assessment Battery, five-word test, Stroop, clock-drawing) and single-task locomotor evaluation on an electronic walkway. They were then dual-task-tested on the Walking Stroop carpet, which is an adaptation of the Stroop color–word task for locomotion. A cluster analysis, followed by an analysis of variance, was performed to assess gait parameters.ResultsCluster analysis of gait parameters on the Walking Stroop carpet revealed an interaction between cognitive and functional abilities because it made it possible to distinguish dysexecutive cognitive fragility or decline with a sensitivity of 89% and a specificity of 94%. Locomotor abilities differed according to the group and dual-task conditions. Healthy subjects performed less well on dual-tasking under reading conditions than when they were asked to distinguish colors, whereas dysexecutive subjects had worse motor performances when they were required to dual task.ConclusionThe Walking Stroop carpet is a dual-task test that enables early detection of cognitive fragility that has not been revealed by traditional neuropsychological tests or single-task walking analysis.

Stroke patients often exhibit difficulties performing a cognitive task while walking, defined as a dual task (DT). Their prefrontal cortex (PFC) activity is higher in DT than in single task (ST). The effects of an increasing load on PFC activity during DT in subacute stroke patients remains unexplored. Our objective was to assess the effects of N-back tasks (low/high load) on cerebral activity, gait parameters, and cognitive performances. Eleven subacute stroke patients (days post-stroke 45.8 ± 31.6) participated in this pilot study (71.4 ± 10 years, BMI 26.7 ± 4.8 kg.m −2 , Barthel index 81.8 ± 11.0). Patients completed a ST walk , and 4 conditions with 1-back (low load) and 2-back (high load): ST low , ST high , DT low , and DT high . Overground walking was performed at a comfortable pace and -N-back conditions were carried out verbally. Both gait (speed, stride variability) and cognitive (rate of correct answers) performances were recorded. Changes in PFC oxyhemoglobin (ΔO 2 Hb) and deoxyhemoglobin (ΔHHb) were measured by functional near infrared spectroscopy (fNIRS). Results showed an increase of ΔO 2 Hb while walking, which was not augmented by cognitive loads in DT. Walking speed was reduced by low and high cognitive loads in DT compared to ST walk ( P < 0.05), but was not different between DT low and DT high . Cognitive performances were negatively impacted by both walking ( P < 0.05) and cognitive load (between “low” and “high,” P < 0.001). These data highlight a “ceiling” effect in ΔO 2 Hb levels while walking, leaving no available resources for simultaneous cognitive tasks, during the early recovery period following stroke. In these patients, cognitive, but not motor, performances declined with a higher cognitive load.

BackgroundExecutive function impairment (in particular, mental flexibility) in the elderly, and in patients with mild cognitive impairment (MCI), is strongly correlated with difficulties in performing complex walking tasks. The aim of this study was to determine if the adaptation of a neuropsychological test (the Trail-Making Test), to evaluate executive functions during walking, can be an early detection tool for cognitive impairment.MethodsFifty subjects (15 young, 20 older, presumably healthy, and 15 MCI) were first evaluated for cognitive functions (Mini-Mental State Examination, Frontal Assessment Battery, and Trail-Making Test) and motor functions (10-meter walking test). All subjects then performed a spatial navigation, or a complex walking test (the Walking Trail-Making Test: [WTMT]), and their spatiotemporal walking variables were analyzed using cluster analysis.ResultsFollowing evaluation of WTMT locomotor performance, cluster analysis revealed three groups that were distinctly different in age and cognitive abilities: a group of young subjects, a group of healthy older subjects, MCI subjects with amnestic impairment, and a group of MCI subjects with executive function impairment. The WTMT enabled early detection, (ie, borderline MCI) of dysexecutive impairment, with 78% sensitivity and 90% specificity.ConclusionThe WTMT is of interest in that it can help provide early detection of dysexecutive cognitive impairment.