Maxime Lussier

An Investigation of Response and Stimulus Modality Transfer Effects after Dual-Task Training in Younger and Older

It has been shown that dual-task training leads to significant improvement in dual-task performance in younger and older adults. However, the extent to which training benefits to untrained tasks requires further investigation. The present study assessed (a) whether dual-task training leads to cross-modality transfer in untrained tasks using new stimuli and/or motor responses modalities, (b) whether transfer effects are related to improved ability to prepare and maintain multiple task-set and/or enhanced response coordination, (c) whether there are age-related differences in transfer effects. Twenty-three younger and 23 older adults were randomly assigned to dual-task training or control conditions. All participants were assessed before and after training on three dual-task transfer conditions; (1) stimulus modality transfer (2) response modality transfer (3) stimulus and response modalities transfer task. Training group showed larger improvement than the control group in the three transfer dual-task conditions, which suggests that training leads to more than specific learning of stimuli/response associations. Attentional costs analyses showed that training led to improved dual-task cost, only in conditions that involved new stimuli or response modalities, but not both. Moreover, training did not lead to a reduced task-set cost in the transfer conditions, which suggests some limitations in transfer effects that can be expected. Overall, the present study supports the notion that cognitive plasticity for attentional control is preserved in late adulthood.

Effect of overreaching on cognitive performance and related cardiac autonomic control.

The purpose of this study was to characterize the effect of a 2‐week overload period immediately followed by a 1‐week taper period on different cognitive processes including executive and nonexecutive functions, and related heart rate variability. Eleven male endurance athletes increased their usual training volume by 100% for 2 weeks, and decreased it by 50% for 1 week. A maximal graded test, a constant speed test at 85% of peak treadmill speed, and a Stroop task with the measurement of heart rate variability were performed at each period. All participants were considered as overreached. We found a moderate increase in the overall reaction time to the three conditions of the Stroop task after the overload period (816 ± 83 vs 892 ± 117 ms, P = 0.03) followed by a return to baseline after the taper period (820 ± 119 ms, P = 0.013). We found no association between cognitive performance and cardiac parasympathetic control at baseline, and no association between changes in these measures. Our findings clearly underscore the relevance of cognitive performance in the monitoring of overreaching in endurance athletes. However, contrary to our hypothesis, we did not find any relationship between executive performance and cardiac parasympathetic control.

Reduced pain inhibition is associated with reduced cognitive inhibition in healthy aging.

Summary Pain inhibitory descending control efficiency decreases with healthy aging, and it is significantly correlated with a decrease in the efficacy of cognitive inhibition. ABSTRACT The analgesic effect of heterotopic noxious counter‐stimulation (HNCS; “pain inhibits pain”) has been shown to decrease in older persons, while some neuropsychological studies have suggested a reduction in cognitive inhibition with normal aging. Taken together, these findings may reflect a generalized reduction in inhibitory processes. The present study assessed whether the decline in the efficacy of pain inhibition processes is associated with decreased cognitive inhibition in older persons. Healthy young (18‐46 years old; n = 21) and older (56‐75 years old; n = 23) adult volunteers participated in one experimental session to assess the effect of HNCS (cold pain applied on the left forearm) on shock pain and RIII reflex induced by transcutaneous electrical stimulation of the right sural nerve. In the same session, participants also performed a modified Stroop task, including a target condition requiring the frequent switching between inhibition and no inhibition of the meaning of color words. The analgesic effect induced by HCNS was significantly smaller in older participants for both shock‐pain ratings (P < 0.001) and RIII‐reflex amplitude (P < 0.05). The Stroop effect was significantly larger in elderly participants in the inhibition trials of the switching condition. Increased cognitive interference (ie, larger Stroop effect) correlated with smaller inhibition of the RIII reflex by HNCS across groups (r = −.34, P = 0.025). This association was independent from the age‐related slowing observed in control reading and naming tasks. These results suggest a generalized age‐related reduction in inhibitory processes affecting both executive functions and cerebrospinal processes involved in the regulation of pain‐related responses induced by competing nociceptive threats.

Normative data for phonemic and semantic verbal fluency test in the adult French–Quebec population and validation study in Alzheimer’s disease and depression

Abstract Objective: Verbal fluency tasks are principally used to assess lexical access and have shown usefulness for differential diagnosis. The purpose of Study 1 was to provide normative data in the adult French–Quebec population (Canada) for semantic verbal fluency (animals), for two sets of phonemic verbal fluency (TNP and PFL), and for letter P alone (60 seconds per category/letter). The objectives of Study 2 were to establish the diagnostic and predictive validity of the present tasks and normative data in Alzheimer’s disease (AD) and major depressive episode (MDE). Method: The normative sample consisted of 932 participants aged 19–91 years. Based on multiple linear regressions, equations to calculate Z-scores were provided. To assess validity, performance of 62 healthy participants was compared to 62 participants with AD and 41 with MDE aged over 50. Results: Age and education, but not gender, predicted performance on each verbal fluency task. Healthy adults aged 50 and younger had a better performance on semantic than phonemic verbal fluency. In comparison to MDE, AD participants had lower performance on animals and TNP, but not on letter P. Ninety percent of people with a Z-score ≤ −1.50 on semantic verbal fluency had AD and the global accuracy was 76.6%. Test–retest reliability over one year was high for both animals (r = .711) and TNP (r = .790) in healthy older participants, but dropped for animals in people with AD (r = .493). Conclusions: These data will strengthen accurate detection of verbal fluency deficits in French–Quebec adults.

Limited Benefits of Heterogeneous Dual-Task Training on Transfer Effects in Older Adults

Objectives It has often been reported that cognitive training has limited transfer effects. The present study addresses training context variability as a factor that could increase transfer effects, as well as the manifestation through time of transfer effects. Method Fifty-eight older adults were assigned to an active placebo or two dual-task training conditions, one in which the training context varies between sessions (heterogeneous training) and the other in a fixed training context (homogeneous training). Transfer was assessed with near and far-modality transfer tasks. Results Results show that heterogeneous and homogeneous training led to larger near-modality transfer effects than an active placebo (computer lessons). Transfer effects were roughly comparable in both training groups, but heterogeneous training led to a steeper improvement of the dual-task coordination learning curve within training sessions. Also, results indicated that dual-task cost did not improve in the active placebo group from the pre- to the post-training sessions. Discussion Heterogeneous training showed modest advantages over homogeneous training. Results also suggest that transfer effects on dual-task cost induced by training take place early on in the post-training session. These findings provide valuable insights on benefits arising from variability in the training protocol for maximizing transfer effects.

Does Combined Physical and Cognitive Training Improve Dual-Task Balance and Gait Outcomes in Sedentary Older Adults?

Everyday activities like walking and talking can put an older adult at risk for a fall if they have difficulty dividing their attention between motor and cognitive tasks. Training studies have demonstrated that both cognitive and physical training regimens can improve motor and cognitive task performance. Few studies have examined the benefits of combined training (cognitive and physical) and whether or not this type of combined training would transfer to walking or balancing dual-tasks. This study examines the dual-task benefits of combined training in a sample of sedentary older adults. Seventy-two older adults (≥60 years) were randomly assigned to one of four training groups: Aerobic + Cognitive training (CT), Aerobic + Computer lessons (CL), Stretch + CT and Stretch + CL. It was expected that the Aerobic + CT group would demonstrate the largest benefits and that the active placebo control (Stretch + CL) would show the least benefits after training. Walking and standing balance were paired with an auditory n-back with two levels of difficulty (0- and 1-back). Dual-task walking and balance were assessed with: walk speed (m/s), cognitive accuracy (% correct) and several mediolateral sway measures for pre- to post-test improvements. All groups demonstrated improvements in walk speed from pre- (M = 1.33 m/s) to post-test (M = 1.42 m/s, p < 0.001) and in accuracy from pre- (M = 97.57%) to post-test (M = 98.57%, p = 0.005).They also increased their walk speed in the more difficult 1-back (M = 1.38 m/s) in comparison to the 0-back (M = 1.36 m/s, p < 0.001) but reduced their accuracy in the 1-back (M = 96.39%) in comparison to the 0-back (M = 99.92%, p < 0.001). Three out of the five mediolateral sway variables (Peak, SD, RMS) demonstrated significant reductions in sway from pre to post test (p-values < 0.05). With the exception of a group difference between Aerobic + CT and Stretch + CT in accuracy, there were no significant group differences after training. Results suggest that there can be dual-task benefits from training but that in this sedentary sample Aerobic + CT training was not more beneficial than other types of combined training.

Comparison of two cognitive interventions for adults experiencing executive dysfunction post-stroke: a pilot study

Abstract Purpose This pilot partially randomised controlled trial compared the feasibility and preliminary efficacy of two promising interventions for persons with executive dysfunction post-stroke: (1) occupation-based strategy training using an adapted version of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach; and (2) Computer-based EF training (COMPUTER training). Method Participants received 16 h of either CO-OP or COMPUTER training. We assessed feasibility and acceptability of each intervention, and change in intervention outcomes at baseline, post-intervention and one-month follow-up. Performance and satisfaction with performance in self-selected everyday life goals were measured by the participant and the significant other-rated Canadian Occupational Performance Measure (COPM). Other intervention outcomes included changes in EF impairment, participation in daily life and self-efficacy. Results Six participants received CO-OP and five received COMPUTER training: one in each group discontinued the intervention for medical reasons unrelated to the intervention. The remaining nine participants completed all 16 sessions. Participants expressed high levels of satisfaction with both interventions. Both treatment groups showed large improvements in self and significant other-rated performance and satisfaction with performance on their goals immediately post-intervention and at follow-up (CO-OP: effect sizes (ES) = 1.6–3.5; COMPUTER: ES = 0.9–4.0), with statistically significant within-group differences in CO-OP (p < 0.05). The COMPUTER group also showed large improvements in some areas of EF impairment targeted by the computerised tasks (ES = 0.9–1.6); the CO-OP group demonstrated large improvements in self-efficacy for performing everyday activities (ES = 1.5). Conclusions Our findings provide preliminary evidence supporting the feasibility of using both CO-OP and COMPUTER training with patients with executive dysfunction post-stroke. Implications for Rehabilitation Computerised executive function training and occupation-based strategy training are feasible to deliver and acceptable to persons with executive dysfunction post-stroke. Preliminary evidence suggests that both interventions have a positive impact on real-world outcomes; and, that CO-OP might have a greater impact on improving self-efficacy for performing everyday activities.

Executive functions in men and postmenopausal women

Introduction. This study was designed to assess sex differences in older adults (55–65 years old) in executive functions and to examine the influence of hormone therapy (HT) in postmenopausal women. Method. We have assessed task performance in memory, visuospatial, and executive functions in 29 women using HT, 29 women who never used HT, and 30 men. Results. Men outperformed never users in task switching and updating. HT users outperformed never users in updating. HT users outperformed never users and men in visual divided attention. Discussion. The present study support previous findings that sex and HT impact cognition and bring new insights on sex and HT-related differences in executive functions.

Are stress and mixed urinary incontinence associated with impaired executive control in community-dwelling older women?

Objectives: To assess whether stress or mixed urinary incontinence (UI) is associated with deficits in executive functioning among community-dwelling women. Design: An observational study comparing the performance, using multivariate analyses of variance (MANOVAs) and Bonferroni post hoc test, of continent women and women with stress or mixed UI during executive control tasks. Setting: The research center of the Institut universitaire de gériatrie de Montréal. Participants: One hundred and fifty-five community-dwelling women aged 60 and older participated in the study. Measurements: Based on the Urogenital Distress Inventory (UDI), participants were split into three groups: 35 continent women, 43 women with stress UI, and 78 women with mixed UI. Participants completed a battery of neuropsychological tests and a computerized dual-task test. Results: Women with mixed UI showed poorer performances than continent and stress UI women in executive control functions. Deficits were specific to tests involving switching and sharing/dividing attention between two tasks. Conclusion: Results of this study suggest that mixed UI can be associated with executive control deficits in community-dwelling older women. Future intervention studies in the treatment of UI should take the higher risk of an executive control deficit in women with UI under consideration.

Specific transfer effects following variable priority dual-task training in older adults.

PURPOSE Past divided attention training studies in older adults have suggested that variable priority training (VPT) tends to show larger improvement than fixed priority training (FPT). However, it remains unclear whether VPT leads to larger transfer effects. METHODS In this study, eighty-three older adults aged between 55 and 65 received five 1-hour sessions of VPT, FPT or of an active placebo. VPT and FPT subjects trained on a complex dual-task condition with variable stimulus timings in order to promote more flexible and self-guided strategies with regard to attentional priority devoted to the concurrent tasks. Real-time individualized feedback was provided to encourage improvement. The active placebo group attended computer classes. Near and far modality transfer tasks were used to assess the generalization of transfer effects. RESULTS Results showed that VPT induced significantly larger transfer effects than FPT on a near modality transfer task. Evidence for larger transfer effects in VPT than FPT on a far modality transfer task was also observed. Furthermore, the superiority of VPT on FPT in transfer effects was specific to the ability to coordinate two concurrent tasks. CONCLUSIONS Results of this study help better understand the benefits of VPT attentional training on transfer effects, which is an essential outcome for cognitive training effectiveness and relevancy.