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Objective The aim of this study was to compare the perceived oral health of elderly persons and the clinical reality of their oral status. Background Persons aged over 60 have considerable need for oral health care; a need that increases over time. However, this population appears to be unaware of their state of oral health, and this may be a further obstacle to professional management. We thought it useful to examine the objective and the perceived oral health of these patients. Understanding what may influence their perception can help us to improve their management. Methods The data analyzed in this work are the findings of a field survey carried out in elderly nursing home residents. Their objective oral health was evaluated by using two variables: oral profile, determined by clinical examination, and the oral health index determined using the Oral Health Assessment Tool (OHAT). Perceived oral health was evaluated using the various categories and fields of the General Oral Health Assessment Index (GOHAI). Results Our clinical study showed a discrepancy between perceived oral health and the clinical reality: although a significant association can be demonstrated between the OHAT and the GOHAI, there are considerable variations. It also appeared that the number of teeth and total edentation considerably influence perceived oral health and that findings vary according to different situations. Conclusion Numerous factors influence elderly persons' perception of their true oral health. In order to improve our elders' quality of life, the necessary measures must be taken for the follow-up and regular monitoring of their oral health. At the same time, all possible means should be used and awareness should be raised to improve the health behavior and perception of patients and their entourage.

Gérald Maille,1,2 Bérengère Saliba-Serre,1 Anne-Marie Ferrandez,1 Michel Ruquet1,2 1UMR 7268 ADÉS, Aix-Marseille Université–EFS–CNRS, Faculté de Médecine Nord, 2Faculté d’Odontologie, Aix-Marseille Université, Marseille Cedex, France Objective: We aimed to analyze, from the data in a national survey, the use of oral care and the oral health status of patients living at home or in an institution.Background: Patients aged 60 years and older have important oral health needs, but their oral management may differ according to their immediate environment. The fact of living at home or in an institution can influence the use of care and alter the patients’ perception of their oral health status.Methods: The data analyzed were taken from a survey on disability and health carried out in 2008–2009, which is representative of the population living in France. It consists of two sections, one centered on disability and health among home-dwellers and the other on patients living in an institution. In each of these two populations, we carried out descriptive analysis of three themes: use of care, forgoing of care, and oral health.Results: Although visits to physicians and specialists were frequent, visits to dentists were lower in both populations. While a minority of patients forwent care, it was dental care that was mainly forgone by both home-dwellers and institutionalized patients. The cost factor remained the principal reason, but other factors such as fear or accessibility problems were cited. Use of a dental appliance was considerably more frequent among institutionalized patients than among home-dwellers, with just over half the institutionalized population wearing a dental appliance. Perceived state of oral health remained difficult to interpret.Conclusion: To improve access to oral care for the elderly, the patients, their entourage and health providers need increased awareness and information on the importance of good oral health. Better information must be associated with regular clinical examination. Keywords: dental care, health care access, elderly, home-dwellers, community-dwellers, institution, national Disability and Health Survey, France

Background:Participation bias in exercise studies is poorly understood among older adults. This study was aimed at looking into whether older persons who volunteer to participate in an exercise study differ from nonvolunteers.Methods:A self-reported questionnaire on physical activity and general health was mailed out to 1000 persons, aged 60 or over, who were covered by the medical insurance of the French National Education System. Among them, 535 answered it and sent it back. Two hundred and thirty-three persons (age 69.7 ±7.6, 65.7% women) said they would volunteer to participate in an exercise study and 270 (age 71.7 ±8.8, 62.2% women) did not.Results:Volunteers were younger and more educated than nonvolunteers, but they did not differ in sex. They had less physical function decline and higher volumes of physical activity than nonvolunteers. Compared with volunteers, nonvolunteers had a worse self-reported health and suffered more frequently from chronic pain. Multiple logistic regressions showed that good self-reported health, absence of chronic pain, and lower levels of physical function decline were associated with volunteering to participate in an exercise study.Conclusions:Volunteers were fitter and healthier than nonvolunteers. Therefore, caution must be taken when generalizing the results of exercise intervention studies.

Rhisaa (Recherche qualitative exploratoire sur les handicaps, les incapacites, la sante et l’aide pour l’autonomie), a notamment mis en evidence la place centrale des auxiliaires de vie dans l’accompagnement et le suivi des personnes en besoin d’aide a l’autonomie, quel que soit leur âge, et leur participation a des actions de prevention (notamment au cours des repas et des soins corporels realises lors de la toilette) aupres des beneficiaires qu’elles accompagnent. Au-dela d’un besoin de reconnaissance lie a un flou identitaire, ces travaux ont permis d’identifier en particulier certaines insuffisances (formation, supervision et encadrement) pour que ces auxiliaires de vie soient des acteurs de prevention de premiere ligne a part entiere.

International audience; In this study, long ( approximately 1,300 ms) and short duration ( approximately 450 ms) estimation trials in an event-related functional MRI (fMRI) study were contrasted in order to reveal the regions within a time estimation network yielding increased activation with the increase of the duration to be estimated. In accordance with numerous imaging studies, our results showed that the presupplementary motor area (preSMA), the anterior cingulate, the prefrontal and parietal cortices, and the basal ganglia were involved in the estimation trials whatever the duration to be estimated. Moreover, only a subset of the regions within this distributed cortical and subcortical network yielded increased activation with increasing time, namely, the preSMA, the anterior cingulate cortex, the right inferior frontal gyrus (homolog to Broca's area), the bilateral premotor cortex, and the right caudate nucleus. This suggests that these regions are directly involved in duration estimation. We propose that the caudate-preSMA circuit, the anterior cingulate, and the premotor-inferior frontal regions may support a clock mechanism, decision and response-related processes, and active maintenance of temporal information, respectively.

Brain imaging studies on duration perception usually report the activation of a network that includes the frontal and mesiofrontal cortex (supplementary motor area, SMA), parietal cortex, and subcortical areas (basal ganglia, thalamus, and cerebellum). To address the question of the specific involvement of these structures in temporal processing, we contrasted two visual discrimination tasks in which the relevant stimulus dimension was either its intensity or its duration. Eleven adults had to indicate (by pressing one of two keys) whether they thought the duration or the intensity of a light (LED) was equal to (right hand) or different from (left hand) that of a previously presented standard. In a control task, subjects had to press one of the two keys at random. A similar broad network was observed in both the duration-minus-control and intensity-minus-control comparisons. The intensity-minus-duration comparison pointed out activation in areas known to participate in cognitive operations on visual stimuli: right occipital gyrus, fusiform gyri, hippocampus, precuneus, and intraparietal sulcus. In contrast, the duration-minus-intensity comparison indicated activation of a complex network that included the basal ganglia, SMA, ventrolateral prefrontal cortex, inferior parietal cortex, and temporal cortex. These structures form several subnetworks, each possibly in charge of specific time-coding operations in humans. The SMA and basal ganglia may be implicated in the time-keeping mechanism, and the frontal-parietal areas may be involved in the attentional and mnemonic operations required for encoding and retrieving duration information.

The capacity to perceive and produce rhythmic patterns accurately is an important element of musical skill. As people age, deficits in some cognitive functions may lead to less accurate rhythmic performance. This article reviews studies on age-related changes concerning slowing of an internal timekeeping mechanism, effects of attentional and memory deficits on temporal processing, and effects of practice in preserving accurate rhythmic performance. The assumption of a slower pacemaker in older people is supported by experiments using isochronous tasks. Slowing in polyrhythmic tasks, implicating the role of attentional workload factors, suggests that timing in music involves more than automatic processes. Studies of the estimation of short temporal intervals generally converge to show that temporal judgments of elderly are less accurate than those of young adults, particularly in attentional sharing conditions. Mere changes in the rate of the internal timekeeping mechanisms are insufficient to explain those results and suggest an interaction between more general changes in cognitive processes, such as reduction in attentional resources, and deficits in working-memory. Studies of the benefits of continued practice in older professional musicians demonstrate that high levels of experience and practice preserve accurate rhythmic performance, thus partially compensating for age-related decline in processing speed and memory. Temporal and Nontemporal Information Processing in Music Music often is considered the "art of time." Indeed, "time enters into both the production and perception of musical events" (Jones, 1990, p. 213). Music perception and performance as cognitively demanding activities require that several categories of information be simultaneously processed. Some of them are more related to temporal processes than others, for example, rhythm versus melody. Musical time speaks to traditional psychological issues that are concerned with the production and perception of time. A number of researchers studying psychological time (Church, 1984;Michon, 1972;Treisman, 1963) have proposed that temporal information processing in humans is subserved by an internal clock-like mechanism. According to the internal clock model, time perception relies on an accumulation process, activated when the subject attends to time, and which counts the number of pulses produced by means of an internal time base during the interval to be evaluated. This model accounts principally for perception of the duration of external stimuli. Wing and Kristofferson (1973) proposed a two-process model to account for the performance of rhythmic tapping: An internal timekeeper emits pulses (timing process), each of which triggers a motor response (motor process). Thus the production of time intervals depends not only on actual physical duration but also on a variety of nontemporal factors, such as those related to motor implementation, Similarly, duration judgments cannot center on use of abstracted and isolated time intervals. For example, the so-called "filled interval effect" reveals that two identical time intervals may be perceived as different because of the information that fills them. This effect emphasizes the influence of nontemporal information on time judgments. Generally, studies examining the relationship between nontemporal factors and time perception and production often lead to different and contradictory results. The great variety of methodological approaches often makes the comparison of findings difficult. Nevertheless, good agreement exists between researchers that the judgment of duration cannot only be accounted for in terms of biological clocks or pacemakers and that a number of cognitive variables could affect a putative biological mechanism. As stressed by Craik and Hay ( 1999), a reasonable middle ground can be found in current models that embrace both biological and psychological factors. Thus, "attentional" models, which are basically extensions of models postulating the existence of an internal timer (pacemaker-accumulator), add an attentional component, assuming that the internal timer requires attention to operate (B lock & Zakay, 1996; Zakay, 1989). …

A B S T R A C T Studies that investigated stability of PA in older populations are scarce. Moreover, no studies used dynamic indicators to predict PA trajectories. The purpose of the present study were to investigate PA stability overtime, and to examine if changes in self-reported physical function (dynamic indicator) are better predictors of trajectories of PA than baseline measures of physical function (static indicator). This is a prospective postal survey with two time-point follow-ups: 12 and 38 months. Participants were older adults aged 60 years, and members of the medical insurance scheme of the French national education system. They responded to a self-report questionnaire on PA and general health status at three different times: baseline, 12- and 38-month follow-ups (n = 243 for the 12-month follow-up; n = 164 for the 38-month follow-up). Overtime analyses of PA showed a moderate-to-good stability with regard to both duration and volume of PA; however, a decrease in stability for vigorous PA was found between 12and 38-month follow-ups. Both baseline measure and changes in physical function predicted PA trajectories, but magnitudes of associations were stronger for the dynamic indicator. Moreover, change in physical function was the only predictor of both becoming active compared with Inactive (reduced probability) and becoming inactive compared to Active (increased probability). In conclusion, a dynamic indicator of physical function is a better predictor of PA variation than static indicators.

ERPs were recorded from 12 subjects performing duration and intensity visual discrimination tasks which have been previously used in a PET study. PET data showed that the same network was activated in both tasks (P. Maquet et al., NeuroImage 3:119 -126, 1996). Different ERP waveforms were observed for the late latency components depending on the dimension of the stimulus to be processed: frontal negativity (CNV) for the duration task and parieto-occipital positivity (P300) for the intensity task. Using BESA software, the sources were first modelled with a "PET dipolar model" (right prefrontal, right parietal, anterior cingulate, left and right fusiforms). To obtain a better fit for ERPs recorded in each task, two sources (cuneus, left prefrontal area) had to be added. Consistently with PET findings, dipole modelling indicates that duration and intensity dimensions of a visual stimulus are processed in the same areas. However, ERPs also reveal prominent differences between the time course of the dipole activations for each task, particularly for sources contributing to the late latency ERP components. In the intensity task, dipoles located in the cuneus, the anterior cingulate, and the left prefrontal area yield largest activity within the P300 interval, then activity diminishes rapidly as the stimulus ends, whereas in the duration task, the cuneus and anterior cingulate are still active several hundred milliseconds following stimulus offset. Moreover, in the duration task, the activity of the right frontal dipole parallels the CNV waveform, whereas in the intensity task, this dipole is largely inactive. We assume that the right frontal area plays a specific role in the formation of temporal judgments. Hum. Brain Mapping 10:49 - 60, 2000. © 2000 Wiley-Liss, Inc.

The aim of this research was to better understand how gait slows with age. We analyzed the kinematic parameters of locomotion (velocity, stride length, cycle duration, and double support duration) and their interrelationships both in the slowing process due to aging and in intentional modulations of velocity. The experiments were carried out on a group of 67 elderly adults (aged 60 to 92) walking with a free gait and a fast gait. This group was compared to a young population in equivalent situations. The results show that the main characteristics of the elderly gait are the shortening of strides and the increasing of the double support phase. However, these properties seem to be due to the slowness of the elderly gait more than to more specific alterations affecting this population since identical features were also observed in the slow gait of the young subjects. Furthermore, the ability to intentionally modulate velocity observed in this study was not altered by aging. These results suggest that elderly gait can be said to be normal if one takes the velocity into account., Le but de cette recherche est de tenter de mieux comprendre comment la marche ralentit avec le vieillissement. Les paramètres cinématiques de la locomotion (vitesse, longueur d'enjambée, durée du cycle et du double appui) et leurs relations à la fois dans le ralentissement lié à l'âge et dans les modulations volontaires de vitesse ont été analysés. Les expériences ont porté sur un groupe de 67 sujets âgés (de 60 à 92 ans) et un groupe contrôle de sujets jeunes dans une marche normale et une marche rapide. Les résultats montrent que le vieillissement entraîne une diminution de la vitesse et de la longueur d'enjambée et une augmentation de la durée du double appui. Celle-ci cependant semble due plus à la lenteur qu'au vieillissement lui-même, puisque les mêmes caractéristiques ont aussi été observées dans la marche lente des sujets jeunes. Déplus la capacité de moduler volontairement sa vitesse n'est pas altérée par le vieillissement. On peut donc considérer la marche des sujets âgés comme normale, si l'on tient compte de leur vitesse., Ferrandez Anne-Marie, Durup M., Pailhous J. Effets du vieillissement sur les capacités adaptatives locomotrices. In: Enfance, n°2, 1995. Aspects actuels de recherches sur la Psychologie du Développement. pp. 147-154.

Purpose: The purpose of this study was to design and validate a self-reported assessment tool for the identification of frailty. Materials and methods: A thousand community-dwelling older adults (� 60 years), users of the medical insurance of the French national education system, received (Year 1) a postal questionnaire requesting information about health and socio-demographic characteristics. Among those who responded to the questionnaire (n = 535), 398 individuals were classified as frail, pre-frail, or robust. One year later (Year 2), the same questionnaire was sent to this group and n = 309 were returned. Frailty was operationalized using four criteria: low body mass index (BMI), low level of physical activity, and dissatisfaction with both muscle strength and endurance. Results: Frailty constituted a single entity, different from physical limitation and co-morbidity. Compared with robust individuals, frail persons were older, had more chronic diseases, higher levels of disability and physical function decline. Pre-frail individuals had an intermediate distribution. Those people classified as either frail or pre-frail had higher frequency of hospitalization, and a higher probability of co-morbidity than robust. Frailty was also associated with higher mortality. Conclusions: Our screening tool for frailty was able to evidence important characteristics of this syndrome, i.e., it is a single entity with grades of severity which are associated with health problems. Detecting and categorizing frailty may lead to early therapeutic interventions to combat this condition.

Objective: This article examines the predictors of body satisfaction among older men and women. Method: A self-reported questionnaire on body satisfaction (focused on body appearance and functioning), health, physical activity, and sociodemographic characteristics was completed by 384 older adults twice, at a year’s interval. Women ( n = 243) were on average 70.3 ± 7.9 years old, and men 70.9 ± 7.5 years old. Results: Body mass index was found to be the strongest predictor of satisfaction with body appearance for both genders, along with body functioning in the case of men. Regarding satisfaction with body functioning, functional limitations were women’s most important predictor of satisfaction, whereas for men body appearance was more important. Discussion: Men seemed to link satisfaction with body appearance more closely to body functioning than did women. Gender differences suggest that interventions to improve body satisfaction must be gender specific, particularly those relating to body functioning.

Objectif.--Les questionnaires sont des outils fréquemment utilisés pour mesurer le niveau d'activité physique. Cependant, peu d'entre eux ont été écrits en franc¸ais. L'objectif de cette étude est de proposer un instrument de mesure de l'activité physique des personnes de 60 ans et plus, le Questionnaire d'activité physique pour les personnes âgées (QAPPA), et d'en discuter les données psychométriques. Patients et méthodes.--Cinquante-six personnes, dont 13 hommes, de 56 à 87 ans, ont répondu au QAPPA, à des questions concernant la santé et les limitations fonctionnelles, et à l'International Physical Activity Questionnaire (IPAQ). Le QAPPA a été administré de nouveau une semaine après. Résultats.--Le QAPPA a présenté une répétabilité acceptable (r = 0,58 ; p < 0,001) et une bonne reproductibilité ( = 0,714) test-retest. La validité concurrente par rapport à l'IPAQ a donné une corrélation de r = 0,31 (p < 0,05). L'âge a été un élément important dans la détermination du niveau d'activité physique (validité de construit ; p < 0,05). De plus le QAPPA a permis de réduire la surestimation que présente l'IPAQ en ce qui concerne les activités physiques modérées (Z =−3,211, p = 0,001). Conclusions.--Les qualités psychométriques du QAPPA soutiennent la validité de cet outil. Néanmoins, une étude de validation de critère s'avère nécessaire pour comparer le QAPPA à une mesure objective de l'activité physique.

The purpose of this study was threefold: (1) to assess older exercisers’ functional fitness (FF), (2) to study the relationships between FF and psychosocial variables among older exercisers, and (3) to compare levels of body mass index (BMI), handgrip strength, and psychosocial variables, between exercisers and non-exercisers. Older women who were exercisers (Es, n = 17, age 59-86) and non-exercisers (NEs, n = 41, age 61-85) were tested on self-esteem, aesthetic body care, BMI and handgrip strength. Es were also tested for functional fitness using the Senior Fitness Test battery. High levels of self-esteem and aesthetic body care were observed in both groups. Handgrip strength was higher for the Es than for the NEs. In Es, FF was high (especially in lower-body strength and dynamic balance/agility) and BMI was correlated with self-esteem. Although the results indicated high levels of FF, self-esteem, and aesthetic body care for Es, further research, especially exercise-controlled trials, is needed to confirm the impact of bodily expression on physical function and well-being in the elderly. Cette recherche avait un triple objectif : 1) évaluer la capacité physique fonctionnelle (CPF) chez des aînées qui pratiquent un exercice physique, 2) étudier les relations entre CPF et variables psychosociales chez ces personnes, et 3) comparer les niveaux d’indice de masse corporelle (IMC), de force de préhension de la main, et les variables psychosociales de celles-ci à des personnes qui ne pratiquent pas d’exercice physique. On a testé l’estime de soi, l’attention portée à l’esthétique du corps (APEC), l’IMC, et la force de préhension de la main chez des femmes âgées, les unes (groupe E, n = 17, 59-86 ans) pratiquant une activité physique, les autres ne pratiquant pas d’activité physique (groupe NE, n = 41, 61-85 ans). On a aussi évalué dans le groupe E la CPF au moyen de la batterie « Senior Fitness Test ». Des niveaux élevés d’estime de soi et d’APEC ont été observés dans les deux groupes. La force de préhension de la main était plus élevée dans le groupe E que dans le groupe NE. Le groupe E présentait des scores élevés de CPF (en particulier pour la force de l’hémicorps inférieur et l’équilibre dynamique). Dans ce groupe, l’IMC était corrélé à l’estime de soi. Bien que les résultats aient montré des niveaux élevés de CPF, d’estime de soi, et d’APEC dans le groupe E, des recherches ultérieures, en particulier des recherches d’intervention, sont nécessaires pour évaluer directement l’impact, chez les personnes âgées, de l’expression corporelle sur l’aptitude physique et le bien-être.

The aims of the present study were to analyze how L-Dopa allows parkinsonian patients to increase their gait velocity and to compare these L-Dopa-induced modifications with those achieved by consciously attempting to walk as fast as possible (intentional modulations). The 'intentional modulations' of velocity were also compared with those of healthy elderly subjects. The results showed that parkinsonian patients walked more slowly, with shorter strides and shorter durations of swing phase, and longer durations of stance and double support phases, although no differences were observed for cycle duration. The mechanisms involved in increasing gait velocity were found to differ according to whether this was achieved through the action of L-Dopa, or by intentional increases in velocity. Intentional increases in velocity were greater than those caused by the effect of L-Dopa. The patients, however, used efficient strategies to increase their velocity when under the influence of L-Dopa. As L-Dopa leads to a ceiling effect on stride length, the patients can increase their velocity by modifying the cycle to such an extent that it compensates for the limitation in stride length. This strategy effectively increases velocity, despite the L-Dopa ceiling effect. The effects of L-Dopa on locomotion and, more generally, on motor control aspects are discussed.

The purpose of this study was to assess changes in cerebral activity in middle-aged adults (MA: 50 years) compared to young adults (YA: 20 years). Subjects had to compare the duration or the intensity of a visual stimulus with a previously memorized standard. Evoked potentials were recorded, and a dipole model (obtained from PET data on young adults) was applied for fitting late-latency components. MA performance was poorer than YA performance. Task-specific ERP late components were found (P3 in intensity, CNV in duration), but P3 had a lower amplitude and CNV was less frontal in MAs compared to YAs. The activity of the dipoles that generate late components - cuneus in the intensity task, right frontal in the duration task, and anterior cingulate in both tasks–was less ample or less peaked in MAs than in YAs. This study characterizes neurobiological effects of aging that may already be visible during midlife.

School children often experience difficulty in mastering the concept of proportionality (Hart, 1981; Inhelder & Piaget, 1970; Noelting, 1980a, 1980b, 1983; Piaget, 1946; Vergnaud, 1980, 1983). Its development results from the quantification of a two-fold qualitative relation (lnhelder & Piaget, 1970; Sinclair, 1968). Vergnaud (1980) and Karplus, Pulos, and Stage (1983a, 1983b) have studied the distinction between two types of relationships (within and between) among variables, and Vergnaud and Ricco (1977) have observed the between comparison to be more “natural.”

Summary : The acquisition of the concept of inverse proportion in the task of balance equilibrium. The aim of this work is the study of the acquisition of the concept of inverse proportion within a physical task : the equilibrium of the balance. We led a genetic study, examining two aspects of knowledge : the initial knowledge through anticipation questions, and the knowledge in active manipulating, through realisation questions. 144 subjects from 3 to 14 years old were examined, in a situation allowing the subject to act freely. The results were interpreted according to the task analysis (derived from a rules model proposed by Siegler). A five steps model was determined, from the mere knowledge of the action of the weight in the desequilibrium, to the equilibrium by compensation between weight and distance. Key-words : Developmental psychology, concept of inverse proportion., Résumé Le but de ce travail est d'étudier l'acquisition de la notion de proportion inverse dans une tâche physique : l'équilibre de la balance. On a confronté, dans cette recherche, l'anticipation verbale avec la rétroaction que produit le résultat de manipulations actives sur un matériel concret. Une étude génétique a été effectuée avec l'examen de 144 enfants de 3 à 14 ans. L'analyse de la tâche fournit un cadre pour l'interprétation des résultats. On propose un modèle, dérivé de celui de Siegler, comportant 5 étapes, depuis la connaissance de l'action du poids (pour provoquer le déséquilibre) jusqu'à la compensation poids-distance. Mots clefs : Psychologie génétique, notion de proportion inverse., Ferrandez-Reinisch Anne-Marie. Elaboration de la notion de proportion inverse dans l'épreuve de l'équilibre de la balance. In: L'année psychologique. 1983 vol. 83, n°2. pp. 505-512.

The aim of this article was to observe how children (5, 6 and 7 years old subjects) perform in the problem of the balance equilibrium when it is presented through a proprioceptive situation. We observed adequation between the responses in the two situations : the extêroceptive one (visual situation) and the proprioceptive one. The U ish evolution in desequilibrium questions was discussed and interpreted as a type of cognitive reorganization., Nous avons examiné dans cette expérience des réactions d'enfants de 5, 6 et 7 ans face au problème de l'équilibre de la balance, quand celui-ci est présenté dans une situation proprioceptive. On montre une nette adéquation entre les réponses à la situation appréhendée de manière extêroceptive (vision) et proprioceptive. D'autre part l'évolution en U des sujets aux questions de déséquilibre est interprétée en terme de réorganisation cognitive., Ferrandez Anne-Marie, Cadopi Marielle. Rôle de l'expérience proprioceptive dans la compréhension de l'équilibre de la balance.. In: Enfance, tome 39, n°1, 1986. pp. 53-59.

The aim of this study was to investigate the modulations of locomotion induced by a rhythmic cognitive task (counting one's steps). Subjects (6- and 8-year-olds and adults) were requested to walk freely, and then to walk while counting their steps. Here a decrease in cadence values was observed in children only, with quasi-total repercussions on velocity at the age of 6 only. The spatiotemporal structuring of locomotion described here is already present at 6 years of age and is not altered in the step-counting situation: strong links were observed between cadence and velocity, and between stride length and velocity, and weak links between cadence and stride length.

National audience

School children often experience difficulty in mastering the concept of proportionality (Hart, 1981; Inhelder & Piaget, 1970; Noelting, 1980a, 1980b, 1983; Piaget, 1946; Vergnaud, 1980, 1983). Its development results from the quantification of a two-fold qualitative relation (Inhelder & Piaget, 1970; Sinclair, 1968). Vergnaud (1980) and Karplus, Pulos, and Stage (1983a, 1983b) have studied the distinction between two types of relationships (within and between) among variables, and Vergnaud and Ricco (1977) have observed the between comparison to be more "natural." No such thorough investigations have been devoted, however, to the case of inverse proportionality. The study conducted by Linn and Pulos (1983) gave more information on sex differences than on developmental acquisition. Siegler (1976, 1981) has analyzed the qualitative development of inverse proportionality without attending in any detail to the various quantificational stages involved. In this paper, a model is proposed in which the quantification of inverse proportionality is developed beyond the initial qualitative relation. This general model was based on a task analysis and was tested in a training experiment. The effects of training were assessed by means of a balance task (Inhelder & Piaget, 1970).