The "Stroop Walking Task": An innovative dual-task for the early detection of executive function impairment.

AIMS OF THE STUDY: To evaluate a dual-task named the "Stroop Walking Task", which is similar to the task of making a decision of whether to cross a street based on a pedestrian traffic light. PATIENTS AND METHODS: Fifty-one subjects (15 young adults, 21 subjectively healthy old subjects and 15 old subjects with mild cognitive impairment) had to respond to a visual signal (pictogram) with an appropriate motor response (walk or stop). We used an electronic walkway system to record the gait parameters and performed a cluster analysis on the obtained data. RESULTS: This dual-task enables the early detection of executive function impairment with 89% sensitivity and 87% specificity. CONCLUSION: The use of a dual-task that is inspired by an everyday event as an evaluation tool seems to facilitate the detection of ageing subjects' cognitive impairment, which is not detectable with traditional psychometric tests.

The Functional Reach Test: strategies, performance and the influence of age.

BACKGROUND: The Functional Reach Test (FRT) is a clinical assessment of the risk of falls in elderly or disabled subjects. However, the FRT is complex (involving the leg, hip and trunk joints) and previous studies have shown that several different strategies can be used to complete the test. OBJECTIVES: To describe the strategies used by healthy, adult subjects when performing the FRT and to assess the influence of age on choice of the strategy. METHOD: This was a pilot study in which 29 non-fallers (18 under-50s and 11 over-75s) were asked to perform the FRT on a force platform in a motion analysis laboratory. A total of 18 reflective markers were placed on the body. The main outcome measures were the FRT score, the centre of pressure (CoP) excursion, and kinetic and kinematic test data. The two age groups were compared using a non-parametric, two-sample Mann-Whitney U test. A cluster analysis of the entire population grouped subjects together according to their functional similarities. RESULTS: The older subjects displayed a smaller CoP anteroposterior displacement (P<0.01), greater backwards displacement of the pelvis (P<0.05) and less trunk rotation during the FRT (P=0.024) than the younger subjects. The cluster analysis split the population into two groups, which differed in terms of age, FRT score, pelvis translation, and CoP displacement. CONCLUSION: Our results suggest that at the moment of trunk flexion, elderly subjects use pelvic translation in order to limit forward displacement of the CoP and prevent forward imbalance.

Concomitant changes in clinical and posturographic data in elderly fallers during the course of an in-home anti-falling multimodal program--a preliminary investigation.

AIM OF THE STUDY: The objective of this preliminary study was to evaluate the effectiveness, in terms of fall reduction, of an in-home strategy that we have developed for elderly fallers. We also aimed at finding links between the expected changes in the data obtained in static posturography and in clinical balance tests through our program. PATIENTS AND METHODS: Twelve elderly patients living at home who were diagnosed as fallers (5 males and 7 females; 77.9±4.1 years) participated in the study. Our multimodal intervention lasted 6 months. Before this period, and one year later, an evaluation was conducted using cognitive (MMSE), clinical balance tests (i.e. Berg Balance Scale, Balance One leg, Timed Up and Go, and Functional Reach tests) and static posturography (where the area of body sway, velocity and medio-lateral and antero-posterior amplitudes were recorded twice, first with eyes open and then with eyes closed). RESULTS: Among the 12 patients who were diagnosed as fallers, eight became non-fallers. When comparing data obtained after the intervention with those obtained beforehand, we found significant changes in all of the clinical balance tests and in the posturographic-derived variables indicating improvements in the balance control in our group of subjects. We also found significant correlations between the changes in the Berg Balance Scale scores and the changes in the area of body sway data, in antero-posterior amplitude both with eyes open and with eyes closed, and also in the medio-lateral amplitude in the eyes closed condition. CONCLUSIONS: We prospectively demonstrated the relevance of our anti-falling intervention at home and of the use of posturography for clinical follow-up.

Crosswalk time estimation and time perception: an experimental study among older female pedestrians.

Since the sense of time is strongly influenced by advancing age, this laboratory study aimed to find out more about older pedestrians' decisions to cross the road, focusing on their estimates of how long it would take them to cross. The walking times of older female adults with or without any walking impairment and of healthy young adults were recorded on a walkway representing a road section. Participants also performed actual and imagined crossings of this "road" as well as a duration production task. Results showed that misestimated crossing times were related to the individual time base, with stronger time distortions in some older participants. A comparison between the older participants with disabilities and their age-paired counterparts without disabilities revealed an overestimation of crossing time in the former, affording them a bigger safety margin.

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.

Physiological responses in handcycling. Preliminary study.

INTRODUCTION: In the field of sports for the disabled, this last decade has been marked by the development of handcycling. Although assessment of maximal capacity during arm exercises in cases of spinal cord injury (SCI) has been widely investigated, investigations of maximal capacity in handcyclists remain less frequent. OBJECTIVE: The aim of this study was to investigate the physiological parameters of an incomplete quadriplegic athlete (cervical lesion C5-C6; ASIA-D) during an adapted incremental handcycling test and to judge the appropriateness of the test. Using such a test, it will then be possible to determine the individualized training program intensity needed to improve the athlete's aerobic capacity. METHODS: The athlete completed an incremental hand cycling test (i.e., an adapted Léger-Boucher test), with the handbike mounted on an ergotrainer. The athlete's physiological parameters were recorded during the test, and the pedalling rate and the perceived exertion rate were estimated. Given the athlete's pathology, ergonomic adaptations were necessary in order to improve comfort and propulsion quality. RESULTS: The maximum values recorded (VO2peak = 1.16l/min; [La]=7.7 mmol/l; heart rate peak=133 beats/min; maximum respiratory frequency=85 cycles/min and averaged pedaling rate=95 tours/min) indicate that the incremental test, adapted for handcycling, is maximal, and consequently, it should be possible to individualize the training intensity. CONCLUSION: This test is innovative and potentially applicable in a booming discipline garnering more and more interest. However, first it is necessary to extend this test to a larger population and to test the extended application in field.

Thymocognitive input and postural regulation: a study on obsessive-compulsive disorder patients.

CONTEXT: To show that emotional and cognitive information acts upon the postural balance system in a way comparable to that of the other known inputs (vision, vestibular, proprioception). METHOD: Controlled case study on 90 subjects. One group was composed of 45 subjects suffering from obsessive-compulsive disorder (OCD) in accordance with the Yale-Brown scale, while the other was the control group. All of the subjects underwent recording of their orthostatic posture on a force platform with eyes open and eyes closed. RESULTS: As regards to the postural findings, the two groups appear to be quite different. The OCD patients present a considerably reduced area and velocity of sway regardless of whether their eyes are open or closed. CONCLUSION: These results are coherent with regard to those of other studies establishing the link between postural balance and psychological status. Recent morphological studies likewise tend to confirm the existence of neuronal networks common to postural regulation and cognitive and emotional functioning. When interpreting symptoms, these interactions should be taken into account.

Identification of healthy elderly fallers and non-fallers by gait analysis under dual-task conditions.

OBJECTIVE: We compared falling and non-falling healthy elderly subjects to identify balance disorders associated with falling. Gait parameters were determined when carrying out single and dual tasks. DESIGN: Case comparison study. SETTING: Subjects were studied in the gait laboratory at Hôpital Roger Salengro, Lille, France. SUBJECTS: A group of 40 healthy elderly women were assigned to one of two groups according to their falling history: 21 fallers aged 70.4 +/- 6.4 years and 19 non-fallers aged 67.0 +/- 4.8 years. All subjects performed first a single leg balance test with two conditions (eyes open/closed). Then, gait parameters were analysed under single-task and dual motor-task conditions (walking with a glass of water in the hand). MAIN MEASURES: Falls, number of times suspended foot touched the floor during the single leg balance test, cadence, speed, stride time, step time, single-support time, stride length and step length during walking under single- and dual-task conditions. RESULTS: During the single leg balance test, fallers placed their feet on the floor three times more often than non-fallers under eyes open conditions (P < 0.05) and twice as often under eyes closed conditions (P < 0.05). In the single-task condition, no significant difference in gait parameters was reported between fallers and non-fallers. There was a significant difference (P < 0.05) in the gait parameters (cadence, speed, stride and step time, single-support time) between fallers and non-fallers under dual-task conditions. CONCLUSIONS: Dual tasks perturb walking in fallers, who exhibit deteriorated static balance. Consequently, walking under dual-task conditions plus a single leg balance test could be helpful in detecting walking disorders and planning physiotherapy to prevent falls.

[Parkinson's disease as a model of aging: prospective analysis of gait discorders]. / Maladie de Parkinson comme modèle de vieillissement: analyse prospective des troubles de la marche.

Falls are a dramatic consequence of the age-related gait disorders. There are few prospective studies on falls predictive of the biomechanical features of gait. According to the literature, there are similarities between the gait observed in older people and in parkinsonian subjects. The objective of this study was to apply multiparametric gait analysis to demonstrate changes of the neuromotor gait pattern connected with falls. This prospective study included two groups of 16 subjects aged more than 60 years, who had not fallen during the previous year. One group included 16 minimally disabled parkinsonian patients off drugs, and the other group 16 healthy people. Gait recordings were obtained with a three-dimensional optoelectronic movement analysis system coupled with 2 force platforms in all persons who were followed for 1 year to collect data on all new events, particularly falls. Data analysis concerned spatiotemporal stride and three-dimensional power peaks developed in each lower limb joint. Cluster analysis of the 32 persons was used to determine various infraclinic neuromotor gait patterns. A post hoc analysis of variance was then applied to identify discriminating parameters. Three groups of subjects were identified with 3 different neuromotor gait patterns, independently of the presence of Parkinson disease. There were no fallers in first group (n=18). The second group (n=8) had 20 p.cent fallers and the third group (n=4) 100 p.cent fallers. The groups differed by 4 spatiotemporal parameters and 3 joint power peaks in the sagittal plane. Functional capacity was good in the first group with no falls recorded. This group of subjects had characteristics reported in the literature corresponding to a category of persons who compensate well for the phenomena of aging. Functional capacity was intermediary in the second group (20 p. cent were fallers). The kinematic pattern appeared to be less successful, revealing a tendency for stiff posture. The third group (100 p. cent fallers) exhibited inferior functional capacity. In this group, the kinematic pattern appeared to be disrupted. The subjects were unable to adapt satisfactorily to situations other than by stereotypical neuromotor reactions. In conclusion this study demonstrated a close determinism between physiological neuromotor aging and Parkinson's disease. The prospective follow-up demonstrated that falls that occurred were related to changes in neuromotor gait patterns. Three phases of gait pattern were also identified from minimal to major risk of falls.

[Postural strategies and falls in elderly and in parkinsonism]. / Stratégies posturales et chutes chez la personne âgée et le sujet parkinsonien.

OBJECTIVE: To use a posture analysis to show the evolution of postural pattern connected with falls. MATERIAL AND METHOD: It is a prospective study on two groups of 16 persons of more than 60 years. A group concerns 16 small disability off drug parkinsonian patients, a group concerns 16 healthy witnesses. All the persons benefited from a posture recording by means of a force platform and were followed during 1 year. RESULTS: Data analysis underlines three groups of persons corresponding to three postural patterns, independently of the presence of Parkinson disease. A group (n = 18) did not contain fallers, the second (n = 10 ) contained 20% of fallers, the third (n = 4) contained 100% of fallers. Differences between the groups were identified on 16 posturographic parameters. DISCUSSION: A group has a good functional value and one does not record any fall. Its characteristics, which correspond to a category of persons who compensate well for the phenomena of ageing, are found in the literature. A group has an intermediate functional value and regrets 20% of fallers. Kinetic profile reveals a tendency to the stiffness of the posture. This group is going to operate rather ankle strategies. A group has an inferior functional value and regrets 100% of fallers. Kinetic profile seems disrupted and not to be able to adapt itself in a satisfactory way to the situation otherwise than by stereotypical reactions. This group is going to operate systematically much less stabilizing hip strategies. CONCLUSION: A close determinism between physiological neuromotor ageing and Parkinson disease does exist. We showed with a prospective follow-up, the arisen of fall and showed the evolution of postural patterns related to fall. It appears as well that evolution mainly follows three stages leading from a small risk of fall gait pattern to a major risk of fall gait pattern.

Pelvic and lower limb compensatory actions of subjects in an early stage of hip osteoarthritis.

OBJECTIVE: To determine if compensatory actions take place at the pelvis and other joints of the affected lower limb in subjects who were in an early stage of hip osteoarthritis (OA). DESIGN: Nonrandomized, case-control study. SETTING: A gait laboratory. PARTICIPANTS: Seventeen patients with OA of the hip (clinical group) matched with 17 healthy elderly subjects (nonclinical group). INTERVENTIONS: Video data obtained while subjects walked a 10-meter walkway twice and stepped across a forceplate. MAIN OUTCOME MEASURES: Four phasic and temporal gait parameters (walking speed, stance phase relative duration, stride length, cadence) 10 pelvic (pelvic tilt, obliquity, rotation at push-off maximum range of motion for all 3) and hip (3 hip angles at push-off, maximum hip flexion) kinematic parameters, 3 hip moments, and twenty-seven 3-dimensional peak muscle powers (labeled by joint, peak power, plane) developed in the lower limb joints during the gait cycle. RESULTS: Subjects in the clinical group were characterized by a 12.4% slower walking speed. The pelvis was more upwardly tilted (2.5 times) at push-off in the clinical group than in the nonclinical group. Obliquity, measured in the frontal plane, revealed that the pelvis dropped more (2.4 times) on the unsupported limb of the clinical group at push-off. In the sagittal plane, subjects in the clinical group absorbed less energy in their second hip peak power for decelerating the thigh extension and generated less hip pull (third hip peak power) than the nonclinical group by 34% and 29%, respectively. In the sagittal plane, the clinical group had 57% lower second knee peak power to straighten the joint shortly after heel strike, and 43% less knee absorption (third peak power) at push-off. During the push-off phase, the clinical group developed more than twice their third peak knee power in the frontal plane and 5 times more their third peak knee power in the transversal plane than the peak knee power of the nonclinical group in an attempt to control knee adduction and to facilitate body-weight transfer by an internal rotation. At the end of the swing phase, the fourth peak power in the sagittal plane showed the absorption power required to decelerate the leg; it was reduced by 35% in the clinical group, representing a strategy to increase walking speed by lengthening the stride length. CONCLUSIONS: Even at an early stage of hip OA, joint degeneration was compensated by an increase in pelvis motion and muscle power generation or absorption modifications in other lower limb joints.

Gait pattern classification of healthy elderly men based on biomechanical data.

OBJECTIVES: To distinguish the gait patterns of young subjects from those of elderly men using three-dimensional (3D) gait data, to determine if elderly subjects displayed other than a typical gait pattern, and to identify which parameters best describe them. DESIGN: Nonrandomized study in which video and force plate data were collected at the subject's own free walking speed and used in a 3D inverse dynamic model. Cluster analysis was chosen to identify the gait families, and analyses of variance were performed to determine which parameters were different. SETTING: A gait laboratory. PARTICIPANTS: The sample of convenience involved a single but mixed group consisting of 16 able-bodied elderly subjects (mean age, 62yrs) and 16 able-bodied young subjects aged between 20 and 35 years. MAIN OUTCOME MEASURES: Phasic and temporal gait parameters, as well as the 3D muscle powers developed in the joints of the right lower limb during the gait cycle. RESULTS: The walking patterns in elderly subjects were found to be different from those of the young adults. Three elderly gait families or groups forming a specific gait pattern were identified, and differences were found in the phasic and temporal parameters as well as in 6 peak muscle powers. Four of the peak powers occurred in the sagittal plane, and half of them were related to the hip. CONCLUSIONS: Biomechanical parameters can be used to classify the gait patterns of young and elderly men using cluster analysis rather than age alone. The muscle powers in elderly subjects are perturbed throughout the gait cycle and not only at push-off. It appears that the plane in which the peak powers occurred was related to their occurrence in the gait cycle. Variability in the gait patterns of elderly subjects could reflect natural adaptations or compensations. These should not be indicative of a deficient gait or be misconstrued as some age-related pathology.