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Olivier Beauchet

Publications and source records attributed to Olivier Beauchet.

13 recordsLinked to original sources
PubMed2006

Relationships between dual-task related changes in stride velocity and stride time variability in healthy older adults.

Dual-task related gait changes have been previously reported for healthy older adults, suggesting that gait control requires attention. Compared to balance control, the involvement of attention in the control of the rhythmic stepping mechanism, as reflected by stride time variability, is not well known. In particular, under dual-task, the relative contributions of a second, attention-demanding task and changes in walking speed remain unclear. Thus, the aims of this study were (1) to assess whether walking with a slow-selected speed or walking while performing an attention-demanding task affected stride time variability in a sample of healthy older participants, and (2) to establish whether stride time variability under dual-task conditions is related either to the decrease of walking speed or the simultaneous attention-demanding task, or to both. Forty-five healthy older participants performed four experimental conditions: (1) walking at a normal self-selected speed, (2) walking at a slow self-selected speed, (3) performing a verbal fluency task when sitting on a chair, and (4) performing the verbal fluency task while walking at self-selected walking speed. Gait parameters were recorded across 15 meters, using Physilog. Results showed a significant dual-task related decrease in mean values of stride velocity, as well as a significant increase in mean values and coefficients of variation of stride time. These dual-task related changes in stride time were explained by the simultaneous performance of the verbal fluency task, the decrease of gait speed and the variability between participants. Although a relationship exists between decreased walking speed and increased stride time variability, the dual-task related increase of stride time variability was also significantly associated with the attention-demanding task, suggesting some attentional control for the rhythmic stepping mechanism of walking in healthy older adults.

Aged↗
PubMed2006

Guidelines for clinical applications of spatio-temporal gait analysis in older adults.

Quantifying spatio-temporal gait parameters in stationary and ambulatory geriatric settings may aid the early identification of potential fallers, as well as the documentation of illness-specific gait disorders and intervention-related changes in rehabilitative medicine. Bringing gait analysis out of the laboratory and into a clinical setting is the goal of the European GAITRite network group, initiated in 2003 in Geneva. To enhance reproducibility of gait measures and for better comparability of outcomes in clinical environments, a consensus on data collection was formulated and presented at the 2nd European GAITRite Meeting in Marseilles. The guidelines presented here are intended to facilitate network collaborations and to provide guidance to clinicians who wish to implement spatio-temporal gait analysis in clinical settings.

Accidental Falls↗
PubMed2006

Testosterone and cognitive function: current clinical evidence of a relationship.

BACKGROUND: Testosterone levels decline as men age, as does cognitive function. Whether there is more than a temporal relationship between testosterone and cognitive function is unclear. Chemical castration studies in men with prostate cancer suggest that low serum testosterone may be associated with cognitive dysfunction. Low testosterone levels have also been observed in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). This paper reviews the current clinical evidence of the relationship between serum testosterone levels and cognitive function in older men. METHODS: A systematic literature search was conducted using PubMed and EMBASE to identify clinical studies and relevant reviews that evaluated cognitive function and endogenous testosterone levels or the effects of testosterone substitution in older men. RESULTS: Low levels of endogenous testosterone in healthy older men may be associated with poor performance on at least some cognitive tests. The results of randomized, placebo-controlled studies have been mixed, but generally indicate that testosterone substitution may have moderate positive effects on selective cognitive domains (e.g. spatial ability) in older men with and without hypogonadism. Similar results have been found in studies in patients with existing AD or MCI. CONCLUSIONS: Low endogenous levels of testosterone may be related to reduced cognitive ability, and testosterone substitution may improve some aspects of cognitive ability. Measurement of serum testosterone should be considered in older men with cognitive dysfunction. For men with both cognitive impairment and low testosterone, testosterone substitution may be considered. Large, long-term studies evaluating the effects of testosterone substitution on cognitive function in older men are warranted.

Androgens↗
PubMed2006

[Gait and dual-task: definition, interest, and perspectives in the elderly].

Walking is an automated rythmic motor behavior that is mostly controlled by subcortical brain regions. Automaticity implies that gait can be performed without attention. However, recent works highlight the involvement of attentional resources in gait, using a "dual-task" methodology in which performance on attention-demanding tasks such as spoken verbal response and walking is compared when they are performed separately and concurrently. Changes in gait patterns due to simultaneous performance of an attention-demanding task are interpreted as interference caused by competing demands for attentional resources involving the cortical level in gait control. Dual-task related gait changes are a new way to assess age-associated change in gait control. Furthermore, new screening tools of falling risk based on the dual-task paradigm have been developed, comparing walking performance alone to walking while performing a simultaneous attention-demanding task. However, the consistent prediction of falls by dual-task testing remains difficult. The recent availability and growing number of validated, user-friendly portable gait analysis systems allow simple objective gait measurement such as gait variability. The study of gait variability under dual-task represents a new challenge for the clinicians because high stride-to-stride variability is a powerful fall predictor in older adults. Because there is increasing evidence that age-related gait changes are associated with incidence of dementia, dual-task related gait changes could provide useful information about relationship between gait disorders and cognitive decline. Furthermore, dual-task could be a new approach of the gait disorders rehabilitation.

Accidental Falls↗
PubMed2005

Stride-to-stride variability while backward counting among healthy young adults.

BACKGROUND: Little information exists about the involvement of attention in the control of gait rhythmicity. Variability of both stride time and stride length is closely related to the control of the rhythmic stepping mechanism. We sought 1) to determine whether backward counting while walking could provoke significant gait changes in mean values and coefficients of variation of stride velocity, stride time and stride length among healthy young adults; and 2) to establish whether change in stride-to-stride variability could be related to dual-task related stride velocity change, attention, or both. METHODS: Mean values and coefficients of variation of stride velocity, stride time and stride length were recorded using the Physilog-system, at a self-selected walking speed in 49 healthy young adults (mean age 24.1 +/- 2.8 years, women 49%) while walking alone and walking with simultaneous backward counting. Performance on backward counting was evaluated by recording the number of figures counted while sitting alone and while walking. RESULTS: Compared with walking alone, a significant dual-task-related decrease was found for the mean values of stride velocity (p < 0.001), along with a small but significant increase for the mean values and coefficients of variation of stride time (p < 0.001 and p = 0.015, respectively). Stride length parameters did not change significantly between both walking conditions. Dual-task-related increase of coefficient of variation of stride time was explained by changing stride velocity and variability between subjects but not by backward counting. The number of figures counted while walking decreased significantly compared to backward counting alone. Further, the dual-task related decrease of the number of enumerated figures was significantly higher than the dual-task related decrease of stride velocity (p = 0.013). CONCLUSION: The observed performance-changes in gait and backward counting while dual tasking confirm that certain aspects of walking are attention-demanding in young adults. In the tested group of 49 young volunteers, dual tasking caused a small decrease in stride velocity and a slight increase in the stride-to-stride variability of stride time, while stride velocity variability was not affected by the attention-demanding task. The increase in stride time variability was apparently the result of a change in gait speed, but not a result of dual tasking. This suggests that young adults require minimal attention for the control of the rhythmic stepping mechanism while walking.

Journal Article↗
PubMed2005

Relationship between dual-task related gait changes and intrinsic risk factors for falls among transitional frail older adults.

BACKGROUND AND AIMS: Gait changes in dual-task conditions have been associated with an increased risk of falling in older adults, and become more important in increasingly frail older adults. We studied the relationship between commonly known intrinsic risk factors for falls and dual-task related gait changes among transitional frail older adults. METHODS: Walking time and number of steps were measured while walking alone and while walking with counting backward on a 10-m walkway in 66 transitional frail older adults (mean age 83.6+/-6.1, 84.9% women). Uni- and multiple linear regression analyses were performed to explore the relationship between dual-task related gait changes (walking time and number of steps) and age over 85 years, polymedication, psychoactive drugs, poor distance vision, abnormal mobility and cognitive impairment. RESULTS: Compared with walking alone, both walking time and number of steps increased significantly while counting backward (p<0.001). Polymedication and abnormal mobility were associated with a significant increase of walking time and number of steps (p<0.01 for unadjusted change, p<0.05 for adjusted change). CONCLUSIONS: Dual-task related gait changes were closely correlated with polymedication and impaired mobility in our sample of transitional frail older adults. These findings give some insight into the complexity of performing attention-demanding tasks while walking and accentuate the need for multi-factorial, personalized intervention strategies, to prevent decline in dual-task performance in this fall-prone population.

Accidental Falls↗
PubMed2005

Decreased trunk angular displacement during sitting down: an early feature of aging.

BACKGROUND AND PURPOSE: Trunk motion plays an important role in achieving both sit-to-stand and stand-to-sit transfers. However, these 2 body transfers depend on different postural and mechanical constraints. Although the effects of aging on sit-to-stand transfers have been widely studied, there is a lack of information concerning stand-to-sit transfers. The aim of this study was to determine how angular displacements of the trunk and shank are affected by aging during sit-to-stand and stand-to-sit transfers. SUBJECTS: Ten community-dwelling older adults (mean age=75.9 years, SD=3.2) and 9 young adults (mean age=26.8 years, SD=4.7) volunteered to participate. METHODS: Maximal angular displacements of the trunk and shank with respect to the vertical (ie, orientation angles) were measured, during standing up and sitting down, using an optoelectronic movement analyzer. RESULTS: For standing up, there was no difference between the young and older adults with regard to both maximal orientation angles. During sitting down, the maximal shank orientation angle was not affected by age, whereas the older adults had a smaller trunk motion compared with the young adults (approximately 10 degrees less). DISCUSSION AND CONCLUSION: The results showed that older adults tended to minimize the forward body displacement during sitting down. This strategy could be seen as an adaptive mechanism to decrease the risk of anterior disequilibrium. The authors suggest that this feature could be used as an early marker of aging on postural control.

Adult↗
PubMed2003

[Streptococcus suis bacteremia].

INTRODUCTION: Streptococcus suis infection is recognised despite it rareness as a zoonotic occupational disease in humans, and is often associated with meningitis, more rarely with bacteremia. OBSERVATION: A Streptococcus suis bacteremia occurred in a hunter and was complicated by septic shock with disseminated intravascular coagulation, rhabdomyolysis and purpura fulminans. Contamination had occurred through inoculation of a cut on the thumb when the hunter was slaughtering a wild boar. The blood cultures isolated Streptococcus suis. The patient died 36 hours after admission, despite intensive care and adapted antibiotic treatment with penicillin A and macrolide. CONCLUSION: Streptococcus suis bacteremia are uncommon but serious in humans. Despite adapted treatment, evolution may be fatal, so their conditions of occurrence must be well known by hunters and practitioners.

Anti-Bacterial Agents↗
PubMed2003

[T'ai chi in the elderly: practical aspects].

New approaches to health promotion for the growing geriatric population are needed. Low to moderately intense exercise programs, such as T'ai Chi seem particularly appropriate for older individuals because of many worthwhile physiological and psychological long-term benefits. T'ai Chi reduces falls and improves postural stability in older adults. It also has a positive impact on muscle strength and cardiovascular fitness and can improve mobility in patients with rheumatoid arthritis. It imparts a sense of well-being and confidence, and can reduce fear of falling in older adults. This article reviews the current medical literature regarding the multiple effects of T'ai Chi. Historical aspects of T'ai Chi and its current adaptation for practice by healthy older adults are presented. Finally, a set of modified exercises is proposed that is based on underlying principles of T'ai Chi and can be applied to patients with mild to moderate cognitive impairment.

Aged↗
PubMedDate not supplied

Dual-task-related gait changes in transitionally frail older adults: the type of the walking-associated cognitive task matters.

BACKGROUND: Changes in gait patterns due to a simultaneously performed cognitive task have been reported previously and associated with an increased falling risk among older adults. Little is known whether the type of cognitive task performed while walking is important concerning possible gait interference in older fall-prone individuals. OBJECTIVE: To quantify and compare the effects of two different cognitive tasks on gait in transitionally frail older adults. MEASUREMENTS: Gait was tested in 30 transitionally frail older adults (mean age 82.6 +/- 7.1 years, 90% female) while either walking alone, performing a simple arithmetic task, or performing a task of verbal fluency. Walking time in seconds, number of steps, frequency of lateral line stepping-over, and stops were recorded. Health status was assessed using standard instruments of geriatric assessment. The classification of Speechley and Tinetti was used to define the participants' degree of frailty. RESULTS: Walking time and number of steps increased significantly under both dual-task conditions compared to walking alone (p < 0.001) without reaching a significant difference between the two dual-task conditions (respectively, p = 0.131 and p = 0.407), whereas lateral gait instability (frequency of lateral line stepping-over) increased significantly in association with counting backward (p = 0.006) but not with the verbal fluency task (p = 1). CONCLUSION: Among the studied sample of transitional older adults, a walking- associated arithmetic task significantly interfered with lateral gait stability, whereas no lateral gait deviations were seen in association with a verbal fluency task. We, therefore, suggest that the choice of the attention-splitting task in dual-task gait assessment among older adults must be made carefully.

Aged↗