Working memory capacity and strategy use in single and dual-tasks

Research Objectives: A preliminary study (Collin, Patchay & Thompson, 2009) showed that strategy training could improve memory performance in single-tasks, but not in dual-tasks. Here the influence of working memory capacity (WMC) on the impact of strategy use on memory performance in single and dual-tasks is examined. In line with previous findings, it is hypothesised that participants with higher WMC will benefit from strategy use and perform better in both single and dual tasking. Design/Method: Participants completed a memory task and a secondary auditory discrimination task independently and together in a dual-task. They were divided into high and low WMC groups and received training in memory strategies (imagery/association). The number of words recalled on a word list and reaction time on the auditory discrimination task were measured pre- and post-strategy training. Results/Conclusion: In general, performance was better post strategy training. Interestingly, on average the low span group performed better (not all significantly different) on both tasks in single and dual tasking post strategy training. It is suggested that regardless of capacity, strategies impact on performance and could even compensate for reduced WMC

Fast learning and interference in motor memories for two consecutive different tasks

Research Objectives: Fast learning of a novel motor sequence occurs across trials for a given motor task (Karni et al., 1998). Furthermore, two similar motor sequences can interfere with each other when executed within a short delay because motor memories are unstable initially (e.g. Shadmehr & Brashers-Krug, 1997). With a longer delay, interference decreases because motor memory consolidation occurs. This study investigated whether fast learning and interference would occur with two consecutive different motor tasks. It was hypothesised that fast learning would be evident for both tasks across counterbalanced and blocked trials, and that there would be interference between the two tasks executed consecutively within a short delay only. Design/Method:The tasks consisted of drawing a square pyramid and doing a simple addition on a Chinese abacus, with three trials in each. The time taken to perform each trial was measured. One group of participants performed both tasks together in alternate trials (short delay). Another group completed each task separately on different days (longer delay). Results/Conclusion:Fast learning was elicited as a decreased execution time across trials for both tasks in both groups. Interference from the memory for the first task was observed only in group one

An object-centred reference frame for control of grasping: effects of grasping a distractor object on visuomotor control

Previous evidence based on perceptual integration and arbitrary responses suggests extensive cross-modal links in attention across the various modalities. Attention typically shifts to a common location across the modalities, despite the vast differences in their initial coding of space. An issue that remains unclear is whether or not these effects of multisensory coding occur during more natural tasks, such as grasping and manipulating three-dimensional objects. Using kinematic measures, we found strong effects of the diameter of a grasped distractor object on the aperture used to grasp a target object at both coincident and non-coincident locations. These results suggest that interference effects can occur between proprioceptive and visuomotor signals in grasping. Unlike other interference effects in cross-modal attention, these effects do not depend on the spatial relation between target and distractor, but occur within an object-based frame of reference

Gait initiation and falls: exploration of motor-related cortical potentials and anticipatory postural adjustments

Abstract: Ageing seems to affect the gait initiation phase thus increasing the risk of falls. Electroencephalography and force platforms were used to simultaneously measure motor cortical activity and vertical ground reaction force variations under both feet during gait initiation under single-task and dual-task conditions. Supporting summary: Gait initiation is a risky activity for older adults (Polcyn et al., 1998). Gait initiation is made possible by the variation of muscle-induced vertical ground reaction forces (VGRF) under both feet. In addition, motor imagery studies have found an increased activity in the motor cortex during GI (e.g. Sahyoun, Floyer-Lea, Johansen-Berg & Matthews, 2004). However, those studies have overlooked older adults with a history of falling. The current study used electroencephalography (EEG) and two force platforms to measure EEG activity and VRGF under both feet during the physical execution of the first step. Participants included 10 healthy older adults (aged 65 and above) and 10 age-matched older adults who have experienced at least one fall in the past year (fallers). Participants were required to stand still with two feet on separate force platforms and initiate gait. Results show no significant differences in EEG activity and patterns of VGRF in fallers in comparison to non-fallers. The discussion focuses on the possible implications in the risk of falls. Cau, N., Cimolin, V., Galli, M., Precilios, H., Tacchini, E., Santovito, C., & Capodaglio, P. (2014). Center of pressure displacements during gait initiation in individuals with obesity. Journal of Neuroengineering and Rehabilitation, 11(1), 82. Patchay, S., & Gahéry, Y. (2003). Effect of asymmetrical limb loading on early postural adjustments associated with gait initiation in young healthy adults. Gait & Posture, 18(1), 85-94. Sahyoun, C., Floyer-Lea, A., Johansen-Berg, H., & Matthews, P. M. (2004). Towards an understanding of gait control: brain activation during the anticipation, preparation and execution of foot movements. Neuroimage, 21(2), 568-575

Exploration of motor cortical activity and anticipatory postural adjustments during gait initiation in young and older adults

Gait initiation is made possible by muscle-induced variations in vertical ground reaction forces (VGRF) under both feet (e.g. Patchay & Gahery, 2003). In addition, neuroimaging studies (e.g. Sahyoun, Floyer-Lea, Johansen-Berg & Matthews, 2004) have shown that the motor cortex is activated when participants imagined gait preparation and execution. However, VGRF studies and neuroimaging studies have essentially employed single-task conditions and overlooked dual-task conditions. The current study aimed to examine motor cortical EEG activity and VGRF variations under both feet during gait initiation in healthy young and older participants. Twelve young (mean age= 23, SD=6.7) and thirteen older adults (mean age = 74.15, SD= 6.69) were required to initiate gait according to two different protocols (i) initiating gait only (simple gait initiation task); and (ii) initiating gait while carrying a full glass of water (complex gait initiation task). Results show that older adults displayed reduced MRCP amplitudes in the simple gait initiation task but increased amplitudes in the complex gait initiation task in comparison to young adults. In addition, no significant group differences were observed in the patterns of VGRF during both, the simple and complex gait initiation tasks. References Sahyoun, C., Floyer-Lea, A., Johansen-Berg, H., & Matthews, P. M. (2004). Towards an understanding of gait control: brain activation during the anticipation, preparation and execution of foot movements. Neuroimage, 21(2), 568-575. Patchay, S., & Gahéry, Y. (2003). Effect of asymmetrical limb loading on early postural adjustments associated with gait initiation in young healthy adults. Gait & Posture, 18(1), 85-94

Living well with chronic illness: a 10-minute summary video of the Knowledge Exchange event

On 3rd May the Centre for Chronic Illness and Ageing at the University of Greenwich held a hybrid dissemination event: Living well with Chronic Illness as we age. It was partly funded by the British Society of Gerontology and supported by the Institute for Lifecourse Development, which is the Centre for Chronic Illness and Ageing is part of. Around 35 attendees took part offline and online. Attendees were from service user networks, health care providers, and individuals living with chronic illness and they contributed with questions, commentary and feedback. For further question please contact: Lesley Dibley = [email protected] - IBD Sandhiran Patchay = [email protected] - Falls / gait Dharinee Hansjee = [email protected] - Swallowing difficulties Omo Ojo = [email protected] - Diabetes Kafui Adjaye-Gbewonyo = [email protected] - Cardio Vascular Marianne Markowski = [email protected] - User involvemen