Cognitive and Tactile Factors Affecting Human Haptic Performance in Later Life

Background: Vision and haptics are the key modalities by which humans perceive objects and interact with their environment in a target-oriented manner. Both modalities share higher-order neural resources and the mechanisms required for object exploration. Compared to vision, the understanding of haptic information processing is still rudimentary. Although it is known that haptic performance, similar to many other skills, decreases in old age, the underlying mechanisms are not clear. It is yet to be determined to what extent this decrease is related to the age-related loss of tactile acuity or cognitive capacity. Methodology/Principal Findings: We investigated the haptic performance of 81 older adults by means of a cross-modal object recognition test. Additionally, we assessed the subjects ’ tactile acuity with an apparatus-based two-point discrimination paradigm, and their cognitive performance by means of the non-verbal Raven-Standard-Progressive matrices test. As expected, there was a significant age-related decline in performance on all 3 tests. With the exception of tactile acuity, this decline was found to be more distinct in female subjects. Correlation analyses revealed a strong relationship between haptic and cognitive performance for all subjects. Tactile performance, on the contrary, was only significantly correlated with male subjects ’ haptic performance. Conclusions: Haptic object recognition is a demanding task in old age, especially when it comes to the exploration o

Heterothermy and seasonal patterns of metabolic rate in the southern African hedgehog (Atelerix frontalis)

Animals that inhabit unfavourable habitats and experience seasons where the cost of maintenance exceeds the available energy resources have over time developed behavioural and physiological mechanisms to survive. These adaptations include changes in activity, improvement of cold tolerance by using nonshivering thermogenesis (NST), improvement of thermal conductance, reduction of body mass, or acclimation to colder temperatures (reduction of metabolic requirement). In addition some species exhibit heterothermy, in the form of either daily torpor or longer-term hibernation. The southern African hedgehog (Atelerix frontalis) is an excellent candidate to investigate the phenomenon of heterothermy because it is a small insectivore (summer body mass ca. 300 to 400g), burrows, inhabits harsh habitats and is not easy to find during the winter months. In this study I aimed to investigate whether A. frontalis exhibits seasonal differences in metabolic rate and furthermore if this species exhibits heterothermy. The study was carried out in the Northern Cape Province, South Africa. Hedgehogs were hand captured and their metabolic rates were measured using indirect calorimetry. Individuals were implanted with temperature dataloggers for a summer period (November 2009-January 2010) and a winter period (May-August 2009). The summer BMR of adult A. frontalis (0.448 ±0.035 mlO2/g/h, n=4) was significantly lower than their winter BMR (0.811 ±0.073 mlO2/g/h, n=4) and statistical analyses revealed that this was an affect caused by seasonal changes in the ambient environment. Individuals spent up to 84 percent of time during the measurement period torpid (-8°C <Ta<21°C). Body mass appears to be an important factor in determining the pattern of heterothermy (daily torpor versus hibernation) used in this species. To my knowledge the extremely low body temperature (Tb min) of 1.0°C recorded for A. frontalis is the lowest Tb min recorded for a mainland Afrotropical mammal. This species displays classic up-regulation in metabolic rate during winter, resulting in an increase in the energetic requirements of the species. As a result, heterothermy appears to play a significant role in the energy balance of this species during winter, contributing to energy saving. Heterothermy may enable this species to survive in the face of global climate change

Effects of combined physical and cognitive training on fitness and neuropsychological outcomes in healthy older adults

Laurence Desjardins-Cr&eacute;peau,1,2 Nicolas Berryman,2,3 Sarah A Fraser,4 Thien Tuong Minh Vu,5,6 Marie-Jeanne Kergoat,2,6 Karen ZH Li,7 Laurent Bosquet,8 Louis Bherer2,7 1Department of Psychology, University of Quebec at Montreal, Montreal, QC, Canada; 2Research Center, Institut universitaire de g&eacute;riatrie de Montr&eacute;al, Montreal, QC, Canada; 3Department of Sports Studies, Bishop&rsquo;s University, Sherbrooke, QC, Canada; 4Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, ON, Canada; 5Research Center, Centre hospitalier de l&rsquo;Universit&eacute; de Montr&eacute;al, Montreal, QC, Canada; 6Faculty of Medicine, Universit&eacute; de Montr&eacute;al, Montreal, QC, Canada; 7Department of Psychology and PERFORM Centre, Concordia University, Montr&eacute;al, QC, Canada; 8Facult&eacute; des sciences du sport, Universit&eacute; de Poitiers, Poitiers, France Purpose: Physical exercise and cognitive training have been shown to enhance cognition among older adults. However, few studies have looked at the potential synergetic effects of combining physical and cognitive training in a single study. Prior trials on combined training have led to interesting yet equivocal results. The aim of this study was to examine the effects of combined physical and cognitive interventions on physical fitness and neuropsychological performance in healthy older adults.Methods: Seventy-six participants were randomly assigned to one of four training combinations using a 2&times;2 factorial design. The physical intervention was a mixed aerobic and resistance training program, and the cognitive intervention was a dual-task (DT) training program. Stretching and toning exercises and computer lessons were used as active control conditions. Physical and cognitive measures were collected pre- and postintervention.Results: All groups showed equivalent improvements in measures of functional mobility. The aerobic&ndash;strength condition led to larger effect size in lower body strength, independently of cognitive training. All groups showed improved speed of processing and inhibition abilities, but only participants who took part in the DT training, independently of physical training, showed increased task-switching abilities. The level of functional mobility after intervention was significantly associated with task-switching abilities.Conclusion: Combined training did not yield synergetic effects. However, DT training did lead to transfer effects on executive performance in neuropsychological tests. Both aerobic-resistance training and stretching-toning exercises can improve functional mobility in older&nbsp;adults. Keywords: aging, combined intervention, physical performance, cognitive performance, dual task, executive function

The interplay between cognitive and motor functioning in healthy older adults: findings from dual-task studies and suggestions for intervention

Reaching late adulthood is accompanied by losses in physical and mental resources, but lifestyle choices seem to have a considerable influence on the aging trajectory. This review deals with the interplay of cognitive and motor functioning in old age, focusing on two different lines of research, namely (a) dual-task studies requiring participants to perform a cognitive and a motor task simultaneously, and (b) intervention studies investigating whether increases in physical fitness also lead to improvements in cognitive performance. Dual-task studies indicate that healthy older adults show greater performance reductions in both domains than young adults when performing a cognitive and a motor task simultaneously. In addition, older adults often tend to protect their motor functioning at the expense of the cognitive task when the situation involves a threat to balance. This can be considered an adaptive behavior, since fall-related injuries can have severe consequences. Fitness intervention studies which increased the aerobic fitness of previously sedentary older adults have demonstrated impressive performance improvements in the cognitive domain, especially for tasks involving executive control processes. These findings are interesting in light of cognitive intervention studies, which often fail to find significant transfer effects to tasks that have not been trained directly. The authors argue that future research should compare the effects of cognitive and aerobic fitness interventions in older adults, and they present a study design in which cognition and fitness are trained sequentially as well as simultaneously. Finally, methodological issues involved in this type of research and potential applications for applied settings are discussed

The interplay between posture control and memory for spatial locations

Three experiments examined interactions between posture control in upright stance and a concurrent location memory task. Healthy young participants stood upright and memorized the locations of dots presented on a computer screen. In the retrieval phase, they indicated whether arrows presented on the screen would pass through any of the memorized locations. Postural sway variability was measured either during the retention period or during retrieval. Relative to not performing the memory task, postural sway variability increased in the retention period when the eyes were closed, but remained unaffected when the eyes were open. During retrieval, postural sway variability was reduced relative to the no-memory-task condition. Results were interpreted in terms of dual-task costs associated with maintaining multiple frames of reference