Gait speed or gait variability, which one to use as a marker of risk to develop Alzheimer disease? A pilot study.

BACKGROUND: Previous literature demonstrates the interest of gait analysis to predict cognitive decline in old people. AIMS: This pilot study aims to determine if gait speed or gait variability is a marker able to early identify, among mild cognitive impairment (MCI) subjects, those at risk to develop Alzheimer's disease (AD) in the future. METHODS: 13 MCI subjects were included in 2007. Their gait parameters (walking speed, stride length and gait frequency, regularity and symmetry) were measured in 2007 and 2008 in simple task (ST) and in dual task (DT) using a triaxial accelerometer (Locometrix(®)). Among the 13 MCI subjects included in 2007, 10 were assessed in 2008. So, 23 (13 in 2007 + 10 in 2008) gait tests were collected. In 2011, MCI people were considered as "MCI+" when they developed AD (between baseline and 2011) and as "MCI-" if they did not. Among the 23 gait tests, 15 were from MCI+ (9 gait tests in 2007 and 6 in 2008) and 8 from MCI- (4 gait tests in 2007 and 4 gait tests in 2008). Mann-Whitney non-parametric U test was used to compare gait parameters of MCI+ and MCI-. RESULTS: Gait speed, symmetry and regularity were lower in MCI+ than in MCI-. DISCUSSION: Despite the small sample size, the results presented in this original pilot study are in line as the infrequent previous literature related to this topic. The authors discuss lacks and strengths of this work. CONCLUSIONS: These results suggest that both gait speed and gait variability could be markers to early identify MCI at risk to develop AD.

Gait analysis in elderly adult patients with mild cognitive impairment and patients with mild Alzheimer's disease: simple versus dual task: a preliminary report.

UNLABELLED: SUMMARY BACKGROUND/AIMS: The aim of this study was to assess gait characteristics during simple and dual task in patients with mild cognitive impairment (MCI) and compare them with those of healthy elderly subjects and mild Alzheimer's disease (AD) patients. METHODS: We proposed a gait analysis to appreciate walking (simple task and dual task) in 14 MCI, 14 controls and six AD subjects who walked at their preferred speed. A 20-second period of stabilized walking was used to calculated stride frequency, stride length, symmetry and regularity. Speed walking was measured by electrical photocells. RESULTS: Variables measured during simple and dual tasks showed an alteration of motor function as well in mild AD patients as in MCI patients. CONCLUSION: At the end of this preliminary study, we defined a specific gait pattern for each cognitive profile. Further researches appear necessary to enlarge the study cohort.

A grid for a precise analysis of daily activities.

Assessment of daily living activities is essential in patients with Alzheimer's disease. Most current tools quantitatively assess overall ability but provide little qualitative information on individual difficulties. Only a few tools allow therapists to evaluate stereotyped activities and record different types of errors. We capitalised on the Kitchen Activity Assessment to design a widely applicable analysis grid that provides both qualitative and quantitative data on activity performance. A cooking activity was videotaped in 15 patients with dementia and assessed according to the different steps in the execution of the task. The evaluations obtained with our grid showed good correlations between raters, between versions of the grid and between sessions. Moreover, the degree of independence obtained with our analysis of the task correlated with the Kitchen Activity Assessment score and with a global score of cognitive functioning. We conclude that assessment of a daily living activity with this analysis grid is reproducible and relatively independent of the therapist, and thus provides quantitative and qualitative information useful for both evaluating and caring for demented patients.

The value of instrumental gait analysis in elderly healthy, MCI or Alzheimer's disease subjects and a comparison with other clinical tests used in single and dual-task conditions.

In the elderly, gait disorders and cognitive frailty may influence each other and increase the risk of falling. The aim of the present study was to determine gait parameters in elderly people with different cognitive profiles (controls, individuals with mild cognitive impairment [MCI] and Alzheimer's disease [AD] patients) with the Locometrix three-axis accelerometer and establish whether or not this tool is more useful than conventional clinical tests (the timed "get up and go" test, the pull test and the single-leg balance test). Study subjects were all over 65, living at home and free of known gait impairments. A neuropsychological battery was applied to 14 control subjects, 14 MCI subjects and six AD patients. A motor evaluation (in single- and dual-task paradigms) was performed with three conventional clinical tests and the Locometrix (standardized gait). Our results showed that in a single-task paradigm, the Locometrix was more accurate than validated, conventional tests and generated a characteristic gait profile for each of the three cognitive profiles. In a dual-task paradigm, the gait of MCI subjects more closely resembled that of AD patients than that of control subjects. We conclude that the Locometrix is a high-performance tool for defining gait profiles, which correspond to given cognitive profiles. The use of a dual-task paradigm is a good way to screen for gait abnormalities in MCI.

Effects of incidental and intentional feature binding on recognition: a behavioural and PET activation study.

Using Positron Emission Tomography (PET), we investigated cerebral regions associated with the episodic recognition of words alone and words bound to contextual colours. Two modes of colour encoding were tested: incidental and intentional word-to-colour binding. Word-only recognition was associated with brain activation in a lexico-semantic left middle temporal region and in the cerebellum following an incidental colour encoding, and with brain activation in the left posterior middle frontal gyrus, right anterior cingulate and right inferior frontal gyrus following an intentional encoding. Recognition of bound features was associated with activation in left prefrontal and superior parietal regions following an incidental colour encoding, and with preferential right prefrontal cortex activation following an intentional colour encoding. Our results are in line with the hypothesis of a parietal involvement in context processing, and prefrontal areas in monitoring retrieval processes. Our results also support the hypothesis of a 'cortical asymmetry for reflective activity' (CARA).

[A day care center for management of early stage Alzheimer's disease]. / Un centre de jour pour une prise en charge de patients Alzheimer à un stade débutant.

Alzheimer's disease represents an important problem for our societies, both in social and economical dimensions. Built in July 1997, the day care center of Liège aims at practicing strategic cognitive interventions in early Alzheimer patients or when pathological memory impairments occur. By means of an interdisciplinary work (by neuropsychologists and occupational therapists), the ultimate goal of the interventions is to facilitate the patient's autonomy in activities of daily living. Because of the variability of clinical symptoms of the disease, the goal of these cognitive interventions is to optimize the performance of each patient by making the most of its preserved abilities. Moreover, another goal of the day care center is also to support the caregivers, by giving them advices in order to adequately face with difficulties presented by the patient.

Deep dysphasia: Further evidence on the relationship between phonological short-term memory and language processing impairments.

We report a cognitive investigation of a case of deep dysphasia appearing in the context of primary progressive aphasia. Over a period of 5 years, patient CO presented progressive difficulties in word finding and in oral comprehension, while nonverbal cognitive functions remained preserved. As in other deep dysphasic patients, CO's repetition performance showed marked imageability and lexicality effects, and semantic paraphasias. The same effects were observed in writing-to-dictation. Regularisation errors occurred in word reading. CO's short-term memory span was less than two words. A cognitive analysis of language processing revealed difficulties in phoneme identification and rhyme judgement, in detecting grammatical class for orally presented words, and in oral and written naming. The interpretation of CO's deep dysphasic symptoms within interactive models of language processing confirmed the importance of a phonological short-term storage impairment as an explanatory factor of deep dysphasia.