Background and objective: Duration of rehabilitation and active participation are crucial for gait rehabilitation in the early stage after stroke onset. Virtual reality (VR) is an innovative tool ...providing engaging and playful environments that could promote intrinsic motivation and higher active participation for non-ambulatory stroke patients when combined with robot-assisted gait training (RAGT). We have developed a new, fully immersive VR application for RAGT, which can be used with a head-mounted display and wearable sensors providing real-time gait motion in the virtual environment. The aim of this study was to validate the use of this new device and assess the onset of cybersickness in healthy participants before testing the device in stroke patients. Materials and Methods: Thirty-seven healthy participants were included and performed two sessions of RAGT using a fully immersive VR device. They physically walked with the Gait Trainer for 20 min in a virtual forest environment. The occurrence of cybersickness, sense of presence, and usability of the device were assessed with three questionnaires: the Simulator Sickness Questionnaire (SSQ), the Presence Questionnaire (PQ), and the System Usability Scale (SUS). Results: All of the participants completed both sessions. Most of the participants (78.4%) had no significant adverse effects (SSQ < 5). The sense of presence in the virtual environment was particularly high (106.42 ± 9.46). Participants reported good usability of the device (86.08 ± 7.54). Conclusions: This study demonstrated the usability of our fully immersive VR device for gait rehabilitation and did not lead to cybersickness. Future studies should evaluate the same parameters and the effectiveness of this device with non-ambulatory stroke patients.
Working memory (WM) capacity declines with advancing age, which impacts the ability to carry out complex cognitive activities in everyday life. Updating and inhibition processes have been identified ...as some of the most critical attentional control processes of WM and are linked to age-related WM decline. The general aim of the Attentional Control Training in Older People (ACTOP) study was to perform a side-by-side comparison of updating and inhibition training to examine their respective efficacy and transfer in cognitively healthy older adults.
The study was a three-arm, double-blind, randomized controlled trial registered with the US National Institutes of Health clinical trials registry. Ninety older adults were randomly assigned to 12 half-hour sessions of updating (N-back type exercises), inhibition (Stroop-like exercises) computerized training or active control (general knowledge quiz game). A group of thirty younger adults completed all proximal and WM transfer tasks without training to assess age-related deficits prior to training and whether training reduces these deficits.
Piecewise mixed models show quick improvement of performance during training for both updating and inhibition training. During updating training, the progression was more pronounced for the most difficult (3-back) than for the least (1-back) difficult level until the ninth session. Updating and inhibition training groups improved performance on all proximal and WM transfer measures but these improvements did not differ from the active control group. Younger adults outperformed older ones on all transfer tasks prior to training. However, this was no longer the case following training for two transfer tasks regardless of the training group.
The overall results from this study suggest that attentional control training is effective in improving updating and inhibition performance on training tasks. The optimal dose to achieve efficacy is ~9 half-hour sessions and the dose effect was related to difficulty level for updating training. Despite an overall improvement of older adults on all transfer tasks, neither updating nor inhibition training provided additional improvements in comparison with the active control condition. This suggests that the efficacy of process-based training does not directly affect transfer tasks.
www.ClinicalTrials.gov, identifier: NCT03532113.
The aim of this study was to highlight the underlying process responsible for the age-related deficit in recollection. Through two experiments using the Remember-Know-Guess procedure (Gardiner, J. ...M., & Richardson-Klavehn, A. 2000. Remembering and knowing. In The Oxford handbook of memory (pp. 229-244). New York, NY: Oxford University Press) in recognition, we manipulated the opportunity to update bindings between target items and their encoding context, in young and older adults. In the first experiment we impaired the binding updating process during the encoding of items, while in the second we supported this process. The results indicated that the "Remember" responses in the younger group were specifically reduced by the impairment of the binding updating process (Exp. 1), suggesting that this ability is useful for them to encode a specific episode. Conversely, only the "Remember" responses in the older group were improved in accuracy by supporting the binding updating process (Exp. 2), suggesting that their weakness in this ability is the source of their failure to improve the accuracy of their memories. The overall results support the hypothesis that the age-related decline in episodic memory is partly due to a greater vulnerability to interference on bindings, impairing the ability to update content-context bindings as and when events occur.
The aim of this study was to highlight that episodic memory and working memory compete for the same resource, which would be diminished in aging. Using the remember/know paradigm, we compared the ...interference related to the retrieval of words on the parallel processing of preestablished relational bindings (Shifting condition) or newly established relational bindings (Updating condition). Within each age-group, participants had comparable performances in remembering across recognition conditions. However, the results showed that only updating activity was impaired after a remember response was given in the younger group. This specific interaction between updating and remembering - but not knowing - tends to indicate that both working memory and episodic memory rely on the ability to establish contextualized representations. In the older group, the performance in updating activity was impaired regardless of the kind of the competing retrieval. Limitations in terms of interference hypothesis and limited resource hypothesis are discussed.
This study investigates the relationship between inter-individual neurofunctional differences in older adults and cognitive training efficacy, with a specific focus on the association between ...youth-like task-related brain activation and improvements in working memory (WM) training. The data is part of the Attentional Control Training for Older People (ACTOP) study, 30 older adults completed 12 half-hour WM training sessions. The WM performance slope, assessed at the conclusion of sessions 1 through 6 and sessions 7 to 12, determined early- and late-stage training gains, respectively. Transfer measures were taken before (PRE), midway (MID), and after (POST) training, and the differences in MID-PRE and POST-MID on transfer tasks were used to determine early- and late-stage transfer effects, respectively. The Goodness of Fit (GOF) metric was used to quantify the similarity between each older adult's activation pattern, as measured with functional magnetic resonance imaging (fMRI), to that of a group of younger adults. GOF scores were calculated for activation during low-load (1-0back) and high-load (2-0back) N-back tasks. The results indicated that larger GOF scores in the low-load condition were associated with greater training gains in both the early and late learning stages, and that larger GOF scores in the high-load condition were associated with greater training gains during the late-stage. These findings suggest that a youth-like brain activation pattern in older adults is associated with greater cognitive training benefits, underscoring the role of inter-individual neurofunctional differences to account for variations in training outcomes among older adults.
ClinicalTrials.gov NCT03532113; https://clinicaltrials.gov/ct2/show/NCT03532113.
Background
Individuals with the Val/Val homozygous variation of the catechol‐O‐methyltransferase (COMT) gene possess lower prefrontal dopaminergic levels than Met/‐carriers and show more pronounced ...age‐related cognitive impairment (Papenberg et al., 2015). The aim of this study was to examine the impact of the COMT genotype profile on the transfer of working memory (WM) training effect in older adults.
Method
60 older adults were randomly assigned to inhibition or updating WM training conditions which were provided over 12 half‐hour sessions (3 sessions per week). Their COMT genotype was determined from a salivary sample collected using an Oragene OG‐500 collection kit. Transfer was measured with untrained complex WM tasks: Alpha‐span, Reading‐span, and a Virtual Reality dual‐task (VR‐WM) involving the detection of a visual road sign and a concurrent verbal memory task. Testing was done weekly, but to limit the bias of regression to the mean with small samples, the first two and the last two assessments were averaged.
Result
Mixed model analyses showed better performance for COMT Met/‐carriers (n = 43) than Val/Val carriers (n = 11) in the Reading‐Span task and improved performance on the three transfer tasks. There was a COMT x Time interaction on the VR‐WM task. Post‐hoc analyses showed that only the Val/Val group improved their performance following training, allowing them to reach levels similar to that observed in the Met/‐carriers group.
Conclusion
Our results indicate an effect of the COMT status on WM performance and training transfer. The observed pattern is similar to that previously reported in younger adults (Colzato et al., 2014) and emphasizes the role of dopaminergic regulation in WM and WM malleability. Colzato, L. S., van den Wildenberg, W. P. M., & Hommel, B. (2014). Cognitive control and the COMT Val158Met polymorphism: Genetic modulation of videogame training and transfer to task‐switching efficiency. Psychological Research, 78(5), 670–678. https://doi.org/10.1007/s00426‐013‐0514‐8. Papenberg, G., Lindenberger, U., & Bäckman, L. (2015). Aging‐related magnification of genetic effects on cognitive and brain integrity. Trends in Cognitive Sciences. Elsevier Ltd. https://doi.org/10.1016/j.tics.2015.06.008.
Abstract
Background
Individuals with the Val/Val homozygous variation of the catechol‐O‐methyltransferase (COMT) gene possess lower prefrontal dopaminergic levels than Met/‐carriers and show more ...pronounced age‐related cognitive impairment (Papenberg et al., 2015). The aim of this study was to examine the impact of the COMT genotype profile on the transfer of working memory (WM) training effect in older adults.
Method
60 older adults were randomly assigned to inhibition or updating WM training conditions which were provided over 12 half‐hour sessions (3 sessions per week). Their COMT genotype was determined from a salivary sample collected using an Oragene OG‐500 collection kit. Transfer was measured with untrained complex WM tasks: Alpha‐span, Reading‐span, and a Virtual Reality dual‐task (VR‐WM) involving the detection of a visual road sign and a concurrent verbal memory task. Testing was done weekly, but to limit the bias of regression to the mean with small samples, the first two and the last two assessments were averaged.
Result
Mixed model analyses showed better performance for COMT Met/‐carriers (
n
= 43) than Val/Val carriers (
n
= 11) in the Reading‐Span task and improved performance on the three transfer tasks. There was a COMT x Time interaction on the VR‐WM task. Post‐hoc analyses showed that only the Val/Val group improved their performance following training, allowing them to reach levels similar to that observed in the Met/‐carriers group.
Conclusion
Our results indicate an effect of the COMT status on WM performance and training transfer. The observed pattern is similar to that previously reported in younger adults (Colzato et al., 2014) and emphasizes the role of dopaminergic regulation in WM and WM malleability. Colzato, L. S., van den Wildenberg, W. P. M., & Hommel, B. (2014). Cognitive control and the COMT Val158Met polymorphism: Genetic modulation of videogame training and transfer to task‐switching efficiency.
Psychological Research
,
78
(5), 670–678.
https://doi.org/10.1007/s00426‐013‐0514‐8
. Papenberg, G., Lindenberger, U., & Bäckman, L. (2015). Aging‐related magnification of genetic effects on cognitive and brain integrity.
Trends in Cognitive Sciences
. Elsevier Ltd.
https://doi.org/10.1016/j.tics.2015.06.008
.
Background
To prevent age-related cognitive impairment, many intervention programs offer exercises targeting different central cognitive processes. However, the effects of different process-based ...training programs are rarely compared within equivalent experimental designs.
Objective
Using a randomized double-blind controlled trial, this project aims to examine and compare the impact of 2 process-based interventions, inhibition and updating, on the cognition and brain of older adults.
Methods
A total of 90 healthy older adults were randomly assigned to 1 of 3 training conditions: (1) inhibition (Stroop-like exercises), (2) updating (N-back-type exercises), and (3) control active (quiz game exercise). Training was provided in 12 half-hour sessions over 4 weeks. First, the performance gain observed will be measured on the trained tasks. We will then determine the extent of transfer of gain on (1) untrained tasks that rely on the same cognitive process, (2) complex working memory (WM) measurements hypothesized to involve 1 of the 2 trained processes, and (3) virtual reality tasks that were designed to mimic real-life situations that require WM. We will assess whether training increases cortical volume given that the volume of the cortex is determined by cortical area and thickness in regions known to be involved in WM or changes task-related brain activation patterns measured with functional magnetic resonance imaging. Dose effects will be examined by measuring outcomes at different time points during training. We will also determine whether individual characteristics moderate the effect of training on cognitive and cerebral outcomes. Finally, we will evaluate whether training reduces the age-related deficit on transfer and brain outcomes, by comparing study participants to a group of 30 younger adults.
Results
The project was funded in January 2017; enrollment began in October 2017 and data collection was completed in April 2019. Data analysis has begun in June 2020 and the first results should be published by the end of 2020 or early 2021.
Conclusions
The results of this study will help understand the relative efficacy of 2 attentional control interventions on the cognition and the brain of older adults, as well as the moderating role of individual characteristics on training efficiency and transfer.
Trial Registration
ClinicalTrials.gov NCT03532113; https://clinicaltrials.gov/ct2/show/NCT03532113
International Registered Report Identifier (IRRID)
DERR1-10.2196/20430
Selective fluorophores are seminal for the development of fluorescent cell imaging allowing the simultaneous monitoring of several biological parameters. Mitochondria are one of the main targets of ...optical microscopy as their dynamics are related to many biological events. One of the best strategy to target them, is to design cationic dyes which accumulate preferentially in their membranes due to their high electrochemical potential. In this work, indazole scaffold was explored to build new cationic merocyanine dyes and compared with indole scaffold. This nitrogen heteroaromatic structure is still very uncommon in dyes chemistry; therefore, a lot has to be discovered about the effects of pH, solvent polarity and methylation in cyclic nitrogen on their optical properties. Finally, fluorescent imaging revealed that a red shift occurred in the emission of these molecules inside the mitochondria.
Display omitted
•Fluorescent indazole-based cationic merocyanines were developed to probe mitochondria and compared to their indole analogues.•pH and viscosity response was studied.•In vivo, these compounds featured a red-shifted emission.•This red-shift was attributed to aggregation formation inside of mitochondria.
PDF
