A. Perrochon

Walking Stroop carpet: an innovative dual-task concept for detecting cognitive impairment

Background Several 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. Methods Forty-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. Results Cluster 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. Conclusion The 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.

The Walking Trail-Making Test is an early detection tool for mild cognitive impairment

Background Executive 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. Methods Fifty 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. Results Following 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. Conclusion The WTMT is of interest in that it can help provide early detection of dysexecutive cognitive impairment.

Cognitive Impairment Assessment through Visuospatial Memory Can Be Performed with a Modified Walking Corsi Test Using the 'Magic Carpet'

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.

Should the concept of MCI be revised in order to improve detection of dementia

The development of the concept of mild cognitive impairment (MCI) has prompted the need to identify individuals at high risk of dementia in order to provide immediate therapy. The conversion rate to dementia for MCI subjects is 15% per year whereas it is only 1—2% in healthy elderly subjects at the same age. In clinical practice, detection in subjects at high risk is currently based on neuropsychological tests. However, there are strong concerns about the ability of these clinical tests to objectify and evaluate cognitive decline due to inappropriate reference values, absence of clear decision limits and low sensitivity and specificity of these tests. In parallel, several studies have revealed the interest of using cerebral imagery and biomarkers for early identification of subjects at high risk of dementia. However, the use of cerebrospinal fluid or imaging biomarkers of amyloid deposition, structural magnetic resonance imaging markers of neuronal loss as well as testing for genetic predisposition are not readily available to the general population in the early phases of the disease. These limitations could explain the fact that dementia is still too often diagnosed in the later stages of the illness (the blue line in Fig. 1). In order to perform early detection of subjects at high risk of dementia, clinicians should resort to new and relevant infra-clinical markers of severe cognitive decline that could be measured through sensitive, specific and simple clinical tests. Interestingly, a reduction in walking performances in elderly subjects has been associated with the appearance of cognitive impairment or with the development of dementia. Indeed, walking requires complex integration of sensory, motor, and cognitive functions, which can be affected in the

Predictors of Rapid Cognitive Decline in Patients with Mild-to-Moderate Alzheimer Disease: A Prospective Cohort Study with 12-Month Follow-Up Performed in Memory Clinics

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.

Effects of a Multicomponent Exercise Program on Spatiotemporal Gait Parameters, Risk of Falling and Physical Activity in Dementia Patients

Background: Exercise programs are presumed to rehabilitate gait disorders and to reduce the risk of falling in dementia patients. This study aimed to analyze the specific effects of multicomponent exercise on gait disorders and to determine the association between gait impairments and the risk of falling in dementia patients before and after intervention. Methods: We conducted an 8-week multicomponent exercise program in 16 dementia patients (age 86.7 ± 5.4 years). All participants were assessed several times for gait analysis (Locométrix®), Tinetti score and physical activity (Body Media SenseWear® Pro armband). Results: After 8 weeks of the exercise program, the mean gait speed was 0.12 m/s faster than before the intervention (0.55 ± 0.17 vs. 0.67 ± 0.14 m/s). The multicomponent exercise program improved gait performance and Tinetti score (p < 0.05). Gait performance (gait speed, stride length) was correlated with the Tinetti score (p < 0.05). Conclusion: Analysis of spatiotemporal gait parameters using an accelerometer method provided a quick and easy tool to estimate the benefits of an exercise program and the risk of falling.