Using dual task walking as an aid to assess executive dysfunction ecologically in neurological populations: A narrative review

Toward Development of a Novel Proprioceptive Trail-Making Test: Comparing Healthy Dancers and Non-Dancers

There is a pressing need for ecologically valid versions of traditional neuropsychological tests indexing executive function (EF), such as the Trail-Making Task (TMT), that incorporate movement and bodily awareness in healthy participants with varying abilities. We designed a proprioceptive version of the TMT (pTMT) that involved coordinated gross motor movement and proprioceptive awareness to investigate whether this measure of visual attention, task switching, and working memory positively correlated with a computerized version of the TMT (the dTMT). We aimed to establish the initial validity of our proprioceptive TMT (pTMT) by comparing performances on the dTMT and pTMT among a cohort of 36 healthy participants (18 dancers, 18 non-dancers; M age = 22, SD = 5.27; 64% female) anticipating that dancers would express higher intrinsic bodily awareness than non-dancers. Results revealed a mild to moderate but statistically significant positive correlation between dTMT and pTMT completion times [part A: r (36) = .33, p = .04; part B: r (36) = .37, p = .03] and numbers of errors [part B: r (36) = .41, p = .01] across both participant groups. These data suggest partial measurement convergence between these two TMT versions. Relative to non-dancers, dancers exhibited a higher level of performance (likely due to their better proprioceptive ability) through their faster completion times on dTMT-B [t (34) = 3.81, p = .006, d = 1.27] and pTMT-B [t (34) = 2.97, p = .005, d = .99], and their fewer errors on dTMT-B [t (34) = 2.93, p = .006, d = 1.0]. By identifying cognitive differences between these different groups of healthy individuals, our data contribute to both a theoretical understanding and the initial development of gross motor movement-based cognitive assessments, providing a path toward the further refinement of an ecologically valid full-body TMT.

The impact of music making on neural efficiency & dual-task walking performance in healthy older adults

Music making is linked to improved cognition and related neuroanatomical changes in children and adults; however, this has been relatively under-studied in aging. The purpose of this study was to assess neural, cognitive, and physical correlates of music making in aging using a dual-task walking (DTW) paradigm. Study participants (N = 415) were healthy adults aged 65 years or older, including musicians (n = 70) who were identified by current weekly engagement in musical activity. A DTW paradigm consisting of single- and dual-task conditions, as well as portable neuroimaging (functional near-infrared spectroscopy), was administered. Outcome measures included neural activation in the prefrontal cortex assessed across task conditions by recording changes in oxygenated hemoglobin, cognitive performance, and gait velocity. Linear mixed effects models examined the impact of music making on outcome measures in addition to moderating their change between task conditions. Across participants (53.3% women; 76 ± 6.55 years), neural activation increased from single- to dual-task conditions (p < 0.001); however, musicians demonstrated attenuated activation between a single cognitive interference task and dual-task walking (p = 0.014). Musicians also displayed significantly smaller decline in behavioral performance (p < 0.001) from single- to dual-task conditions and faster gait overall (p = 0.014). Given evidence of lower prefrontal cortex activation in the context of similar or improved behavioral performance, results indicate the presence of enhanced neural efficiency in older adult musicians. Furthermore, improved dual-task performance in older adult musicians was observed. Results have important clinical implications for healthy aging, as executive functioning plays an essential role in maintaining functional ability in older adulthood.

Virtual Reality and Lower Limb Rehabilitation: Effects on Motor and Cognitive Outcome-A Crossover Pilot Study

The effectiveness of virtual reality (VR) in the motor and cognitive rehabilitation of patients with severe acquired brain injury (sABI) is unclear. This randomized, controlled, crossover, single-blinded, pilot study investigates the cognitive and motor effects of lower limb robotic therapy with and without VR visual feedback in a group of patients with ABI. A total of 23 patients with ABI were randomized into two groups: one group (VR-NVR) underwent a 2-week rehabilitation for the lower limbs training with a robotic device (Omego^®) with VR feedback, followed by 2 weeks without VR; the other group (NVR-VR) performed the protocol in the opposite order. Patients were evaluated at baseline, after two and four weeks of treatment using the Level of Cognitive Functioning scale (LCF), Disability Rating Scale (DRS), and Motricity Index for Lower Limb (MI-LL) in the most affected limb. At the end of the intervention, both groups significantly improved in all the outcomes. A significant difference was found between VR treatment versus non-VR treatment for LCF (p = 0.024) and for DRS (p = 0.043) after the second week, while no significant differences were found in the group NVR-VR at T1. Our study indicates how the combination of robotic treatment with VR is effective in enhancing the recovery of cognitive function in patients with ABI, also improving disability and muscular function. Further, VR seems to enhance the early recovery process of motor and cognitive functions.

Patients Surviving Critical COVID-19 have Impairments in Dual-task Performance Related to Post-intensive Care Syndrome

Objective

The purpose was to examine Dual Task (DT) performance in patients surviving severe and critical COVID-19 compared to patients with chronic lung disease (CLD). Secondarily, we aimed to determine the psychometric properties of the Timed Up and Go (TUG) test in patients surviving COVID-19.

Design

Prospective, cross-sectional, observational study.

Setting

Academic medical center within United States.

Patients

Ninety-two patients including 36 survivors of critical COVID-19 that required mechanical ventilation (critical-COVID), 20 patients recovering from COVID-19 that required supplemental oxygen with hospitalization (severe-COVID), and 36 patients with CLD serving as a control group.

Measurements and Main Results

Patients completed the TUG, DT-TUG, Short Physical Performance Battery (SPPB), and Six Minute Walk Test (6MWT) 1-month after hospital discharge. A subset of patients returned at 3-months and repeated testing to determine the minimal detectable change (MDC). Critical-COVID group (16.8 ± 7.3) performed the DT-TUG in significantly slower than CLD group (13.9 ± 4.8 s; P = .024) and Severe-COVID group (13.1 ± 5.1 s; P = .025). Within-subject difference between TUG and DT-TUG was also significantly worse in critical-COVID group (−21%) compared to CLD (−10%; P = .012), even despite CLD patients having a higher comorbid burden (P < .003) and older age (P < .001). TUG and DT-TUG demonstrated strong to excellent construct validity to the chair rise test, gait speed, and 6MWT for both COVID-19 groups (r = −0.84to 0.73, P < .05). One- and 3-months after hospital discharge there was a floor effect of 14% (n = 5/36) and 5.2% (n = 1/19), respectively for patients in the critical-COVID group. Ceiling effects were noted in four (11%) critical-COVID, six (30%) severe-COVID patients for the TUG and DT-TUG at 1-month.

Conclusion

The ability to maintain mobility performance in the presence of a cognitive DT is grossly impaired in patients surviving critical COVID-19. DT performance may subserve the understanding of impairments related to Post-intensive care syndrome (PICS) for survivors of critical illness.

Greater Cognitive-Motor Interference in Individuals Post-Stroke During More Complex Motor Tasks

BACKGROUND AND PURPOSE

Dual-task (DT) walking assessments allow for the simultaneous evaluation of cognitive and motor performance. During DT walking, individuals may experience interference in one or both tasks, known as cognitive-motor interference (CMI). The primary purpose of this study was to compare CMI between individuals post-stroke and healthy persons group during single- and dual-motor and cognitive tasks, using 2 distinct walking tasks.

METHODS

Motor performance was quantified as the total time for the Timed Up and Go (TUG) and gait speed for the 90-second walk (90W). Cognitive performance was measured as the correct response rate (CRR) during serial 7 subtractions. Participants performed the motor and cognitive tasks in isolation for the single-task (ST) and simultaneously for DT conditions, TUG-DT and 90W-DT. A repeated-measures analysis of variance assessed group (poststroke and healthy) by condition (ST and DT) interactions for the TUG, 90W, and CRR.

RESULTS

There were significant main effects of group and condition for both the TUG and the 90W (P < 0.05). There was also an interaction effect for the TUG, with individuals post-stroke demonstrating a larger decrement in TUG-DT performance compared with healthy persons (P < 0.05). Furthermore, a significant interaction effect was observed for the CRR, in which healthy individuals exhibited a greater decrement in performance from the ST to the 90W-DT (P < 0.05).

DISCUSSION AND CONCLUSIONS

Individuals post-stroke were susceptible to greater motor interference during the more complex motor task, the TUG-DT. However, the only decrements observed in cognitive performance from the ST to DT occurred in healthy individuals during the 90W-DT.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A367).

Gait Variability and Complexity during Single and Dual-Task Walking on Different Surfaces in Outdoor Environment

Nowadays, gait assessment in the real life environment is gaining more attention. Therefore, it is desirable to know how some factors, such as surfaces (natural, artificial) or dual-tasking, influence real life gait pattern. The aim of this study was to assess gait variability and gait complexity during single and dual-task walking on different surfaces in an outdoor environment. Twenty-nine healthy young adults aged 23.31 ± 2.26 years (18 females, 11 males) walked at their preferred walking speed on three different surfaces (asphalt, cobbles, grass) in single-task and in two dual-task conditions (manual task-carrying a cup filled with water, cognitive task-subtracting the number 7). A triaxial inertial sensor attached to the lower trunk was used to record trunk acceleration during gait. From 15 strides, sample entropy (SampEn) as an indicator of gait complexity and root mean square (RMS) as an indicator of gait variability were computed. The findings demonstrate that in an outdoor environment, the surfaces significantly impacted only gait variability, not complexity, and that the tasks affected both gait variability and complexity in young healthy adults.

Virtual reality-based assessment of cognitive-locomotor interference in healthy young adults

BACKGROUND

A recent literature review emphasized the importance of assessing dual-task (DT) abilities with tasks that are representative of community ambulation. Assessing DT ability in real-life activities using standardized protocols remains difficult. Virtual reality (VR) may represent an interesting alternative enabling the exposure to different scenarios simulating community walking. To better understand dual-task abilities in everyday life activities, the aims of this study were (1) to assess locomotor and cognitive dual-task cost (DTC) during representative daily living activities, using VR, in healthy adults; and 2) to explore the influence of the nature and complexity of locomotor and cognitive tasks on DTC.

METHODS

Fifteen healthy young adults (24.9 ± 2.7 years old, 8 women) were recruited to walk in a virtual 100 m shopping mall corridor, while remembering a 5-item list (DT condition), using an omnidirectional platform and a VR headset. Two levels of difficulty were proposed for the locomotor task (with vs. without virtual agent avoidance) and for the cognitive task (with vs. without items modification). These tasks were also performed in single task (ST) condition. Locomotor and cognitive DTC were measured by comparing performances in ST and DT conditions. Locomotor performance was characterized using walking speed, walking fluidity, and minimal distance between the participant and the virtual agent during avoidance. Cognitive performance was assessed with the number of items correctly recalled. Presence of DTC were determined with one-sample Wilcoxon signed-rank tests. To explore the influence of the tasks' complexity and nature on DTC, a nonparametric two-way repeated measure ANOVA was performed.

RESULTS

No locomotor interference was measured for any of the outcomes. A cognitive DTC of 6.67% was measured (p = .017) while participants performed simultaneously both complex locomotor and cognitive tasks. A significant interaction between locomotor task complexity and cognitive task nature (p = .002) was identified on cognitive DTC.

CONCLUSIONS

In challenging locomotor and cognitive conditions, healthy young adults present DTC in cognitive accuracy, which was influenced by the locomotor task complexity task and the cognitive task nature. A similar VR-based protocol might be used to investigate DT abilities in older adults and individuals with a stroke.

Mobile EEG reveals functionally dissociable dynamic processes supporting real-world ambulatory obstacle avoidance: Evidence for early proactive control

The ability to safely negotiate the world on foot takes humans years to develop, reflecting the extensive cognitive demands associated with real-time planning and control of walking. Despite the importance of walking, methodological limitations mean that surprisingly little is known about the neural and cognitive processes that support ambulatory motor control. Here, we report mobile EEG data recorded from 32 healthy young adults during real-world ambulatory obstacle avoidance. Participants walked along a path while stepping over expected and unexpected obstacles projected on the floor, allowing us to capture the dynamic oscillatory response to changes in environmental demands. Compared to obstacle-free walking, time-frequency analysis of the EEG data revealed clear neural markers of proactive and reactive forms of movement control (occurring before and after crossing an obstacle), visible as increases in frontal theta and centro-parietal beta power respectively. Critically, the temporal profile of changes in frontal theta allowed us to arbitrate between early selection and late adaptation mechanisms of proactive control. Our data show that motor plans are updated as soon as an upcoming obstacle appears, rather than when the obstacle is reached. In addition, regardless of whether motor plans required updating, a clear beta rebound was present after obstacles were crossed, reflecting the resetting of the motor system. Overall, mobile EEG recorded during real-world walking provides novel insight into the cognitive and neural basis of dynamic motor control in humans, suggesting new routes to the monitoring and rehabilitation of motor disorders such as dyspraxia and Parkinson's disease.

Performance during dual-task walking in a corridor after mild traumatic brain injury: A potential functional marker to assist return-to-function decisions

Objective: To compare the performance of participants with mTBI and healthy control on locomotor-cognitive dual-tasks in a corridor with limited technology.Design: Prospective study of twenty participants with mTBI (10 women; 22.10 ± 2.97 years; 70.9 ± 22.31 days post-injury), and 20 sex- and age-matched control participants (10 women; 22.55 ± 2.72 years).Methods: Participants performed six different dual-tasks combining locomotor tasks (level-walking, obstacle-crossing, and tandem gait) and cognitive tasks (counting backwards and verbal fluency). Symptoms and neuropsychological performance were also assessed.Results: No differences between groups were found for symptoms and neuropsychological measures. For gait speed, the group effect was not significant, but a significant group X cognitive task interaction was found, revealing a tendency toward slower gait speed in the mTBI group during dual-task conditions. A significantly greater dual-task cost for gait speed was found for the mTBI group. Although no statistically significant differences in cognitive performance were observed during dual-tasks, the mTBI group subjectively reported being significantly less concentrated.Conclusion: The present study revealed that in persons who seem to have well recovered after mTBI, on average 71 days post-injury, alterations in gait are detectable using a simple, "low-tech," corridor-based dual-task walking assessment.

Effects of adding a concurrent cognitive task on manual dexterity in people with schizophrenia: Implications for performance of daily life activities

This study investigated the effect of dual task performance of hand dexterity tasks and the relationship to daily functioning in 40 people with chronic schizophrenia and 35 healthy participants. Participants performed the Purdue Pegboard Test, O'Connor Finger Dexterity Test, and the Serial Subtracting Seven Task as the secondary task under single- and dual-task conditions and completed the Activities of Daily Living Rating Scale-III (ADLRS-III). The hand dexterity of all participants declined from the single to the dual tasks, and the discrepancy between single- and dual-task performance was significantly greater in the schizophrenia group than in the control group. Significant condition and group effects were found for both hand dexterity tests. People with schizophrenia who took longer time in performing hand dexterity tasks had significantly worse daily life function. Negative correlations were noted between discrepancy of dual tasking and the ADLRS-III score in the schizophrenic group. Deficits in dual-task performance of hand dexterity is significant in people with schizophrenia and is related to daily life performance. Occupational therapy practitioners can consider using dual tasks as a therapeutic activity for people with schizophrenia to promote functional abilities in real-world environments.

Differences between two types of dual tasks according to the educational level in older adults

INTRODUCTION

For dual-task paradigms, the timed up and go (TUG) test along with other cognitive or motor tasks has been used to evaluate and predict the risk of falling in older adults. However, the interference between motor-cognitive tasks can differ by the cognitive task.

OBJECTIVE

To evaluate the performance of the TUG test under a single task condition and two dual-task conditions in older adults and to explore the effect of educational level on task performance.

METHODS

A total of 418 older adults (328 females) voluntarily participated in this study. The TUG test was administered as a single task and a dual task with one secondary simultaneous task: counting aloud backward from 100 or naming animals. Comparisons were performed to determine the interference caused by each cognitive task on the motor task, and correlation analysis was performed to explore the role of educational level.

RESULTS

The animal task led to a poorer TUG performance and a higher dual-task cost than did the counting task. Furthermore, the motor task led to a higher percentage of errors and cognitive stops in the animal task. Educational level plays a significant role in the interaction between tasks.

CONCLUSIONS

Between-task interference differs by the type of cognitive task performed and the educational level of the participants. The results of the present study should be considered when dual-task assessments are planned for older adults.

The association between dual-task walking and counting responses and cognitive function and disability after severe head injury: A preliminary study

Adverse outcomes after severe head injury (SHI) can be difficult to detect in primary care and other settings where there is not specialist expertise for interpretation. Walking and counting dual-task (DT) measures are strongly associated with cognitive impairment and dementia and this preliminary study investigates whether performance on DT walking and counting tasks are associated with cognitive function and disability in 125 participants who sustained a SHI on average 26 years before. Single Task (ST) walking (speed over 6 metres) and ST counting (Serial 3s) and DT performance of concurrent walking and Serial 3s were compared with neuropsychological, wellbeing and disability tests for strength of association. The strongest correlations were between ST Correct Cognitive Responses (CCRs) and MMSE (rho = 0.435), DT CCRs and Short-term Memory Binding Tests (STMBT) binding accuracy (rho = 0,409) and DT CCRs and STROOP (rho = 0.420), but associations were less strong with disability. Developing this test, as a cost-efficient screening tool for triage to onward referral for neuropsychological assessment, holds promise, but requires further research.

Influence of a Cell-Phone Conversation on Balance Performance in Women with Fibromyalgia: A Cross-Sectional Descriptive Study

Background

Altered balance is a common and debilitating symptom of fibromyalgia. Previous studies have investigated balance under single-task conditions that do not reflect real-life situations. The present study evaluated the impact of a simultaneous cell-phone conversation on balance performance in a case-control cohort from Spain.

Methods

A cross-sectional case-control study was performed in 34 women recruited from local self-help organizations and university facilities (n = 18 fibromyalgia cases; n = 16 healthy, pain-free controls). Participants performed the 30 s postural stability test, as implemented in the Biodex Balance System, under two conditions: (a) as a single task and (b) as a dual task, i.e., while holding a simultaneous cell-phone conversation with a technician. Intergroup differences in dual task costs were calculated.

Findings

Compared with controls, women with fibromyalgia showed higher dual-task costs in balance variables, such as overall sway (pp value = 0.039) and anterior/posterior sway (p value = 0.007). In the dual-task condition, overall (p value = 0.004) and anterior/posterior (p value = 0.012) sway indices significantly decreased in women with fibromyalgia but not in controls.

Interpretation

In women with fibromyalgia, balance performance was adversely impacted by the holding of a simultaneous cell-phone conversation. The inability to conduct two tasks simultaneously may be related to reduced attention and may increase the risk of falling in this population.

Assessment of cognitive instrumental activities of daily living: a systematic review

PURPOSE

Cognitive instrumental activities of daily living are particularly related to executive functions, such as scheduling appointments, monthly payments, managing the household economy, shopping or taking the bus. The aim of this systematic review was to determine the available tests for the assessment of executive functions with ecological validity to predict individuals' functioning.

MATERIALS AND METHODS

An electronic search was conducted in MEDLINE, Cochrane Central, PsyCInfo and IEEE Xplore until May 2019, in addition to a manual search. The PRISMA criteria and the Covidence platform were used to select articles and extract data.

RESULTS

After applying the search selection criteria, 76 studies were identified. They referred to 110 tools to assess instrumental activities of daily living. Those that have received most attention are related to menu preparation and shopping. Performance-based measures are the most widely used traditional methods. Most tests were aimed at the adult population with acquired brain damage, cognitive impairment or dementia. There was a predominance of tests based on the Multiple Errands Test paradigm.

CONCLUSIONS

In recent years, it has increased the number of tools that assess the instrumental activities of daily living based on technologies such as personal or environmental sensors and serious games.IMPLICATIONS FOR REHABILITATIONAssessment of Instrumental Activities of Daily Living through performance-based measures is especially useful for the early detection of dysfunctions or preclinical disability.Difficulties in performing instrumental activities of daily living are closely associated with deficits in executive functions and prospective memory.Activities of Daily Living can be understood as multitasks.The use of virtual reality-based tests was shown to be sensitive to the detection of cognitive deficits in Activities of Daily Living.An advantage of using virtual reality in assessments is that it can help to predict the level of personal autonomy in patients who are in an institutional environment and could be a first approximation to the real environment.

Alterations in dual-task walking persist two months after mild traumatic brain injury in young adults

Objectives

To compare dual-task performance involving different cognitive-locomotor combinations between healthy controls and participants with sub-acute mild traumatic brain injury (mTBI) and to correlate dual-task performances to history of prior head injuries.

Methods

Eighteen participants having recently sustained mTBI and 15 controls performed nine dual-tasks combining locomotor (level-walking, narrow obstacle, deep obstacle) and cognitive (Stroop task, Verbal fluency, Counting backwards) tasks. Previous history of concussion was also investigated.

Results

Slower gait speeds were observed in the mTBI group compared to controls during both single and dual-tasks. Longer response times to cognitive tasks in the mTBI group further suggested the presence of residual impairments two months following injury. No combination of dual-task was more sensitive. Correlations were observed between history of mTBI and several measures of dual-task performance, underlying the need to further consider the effects of multiple injuries in relation to dual-task walking.

Conclusion

Dual-tasks using simultaneously locomotor and cognitive functions represent an ecological way for clinicians to detect residual, but subtle, alterations post-mTBI. History of previous mTBI needs to be considered as a personal characteristic which may influence dual-task walking performance.

Walking speed changes in response to novel user-driven treadmill control

Implementing user-driven treadmill control in gait training programs for rehabilitation may be an effective means of enhancing motor learning and improving functional performance. This study aimed to determine the effect of a user-driven treadmill control scheme on walking speeds, anterior ground reaction forces (AGRF), and trailing limb angles (TLA) of healthy adults. Twenty-three participants completed a 10-m overground walking task to measure their overground self-selected (SS) walking speeds. Then, they walked at their SS and fastest comfortable walking speeds on an instrumented split-belt treadmill in its fixed speed and user-driven control modes. The user-driven treadmill controller combined inertial-force, gait parameter, and position based control to adjust the treadmill belt speed in real time. Walking speeds, peak AGRF, and TLA were compared among test conditions using paired t-tests (α = 0.05). Participants chose significantly faster SS and fast walking speeds in the user-driven mode than the fixed speed mode (p > 0.05). There was no significant difference between the overground SS walking speed and the SS speed from the user-driven trials (p < 0.05). Changes in AGRF and TLA were caused primarily by changes in walking speed, not the treadmill controller. Our findings show the user-driven treadmill controller allowed participants to select walking speeds faster than their chosen speeds on the fixed speed treadmill and similar to their overground speeds. Since user-driven treadmill walking increases cognitive activity and natural mobility, these results suggest user-driven treadmill control would be a beneficial addition to current gait training programs for rehabilitation.

Profiles of Cognitive-Motor Interference During Walking in Children: Does the Motor or the Cognitive Task Matter?

The evidence supporting the effects of age on the ability to coordinate a motor and a cognitive task show inconsistent results in children and adolescents, where the Dual-Task Effects (DTE) – if computed at all – range from either being lower or comparable or higher in younger children than in older children, adolescents and adults. A feasible reason for the variability in such findings is the wide range of cognitive tasks (and to some extend of motor tasks) used to study Cognitive-Motor Interference (CMI). Our study aims at determining the differences in CMI when performing cognitive tasks targeting different cognitive functions at varying walking pathways. 69 children and adolescents (boys, n = 45; girls, n = 24; mean age, 11.5 ± 1.50 years) completed higher-level executive function tasks (2-Back, Serial Subtraction, Auditory Stroop, Clock Task, TMT-B) in comparison to non-executive distracter tasks [Motor Response Task (MRT), TMT-A] to assess relative effects on gait during straight vs. repeated Change of Direction (COD) walking. DT during COD walking was assessed using the Trail-Walking-Test (TWT). The motor and cognitive DTE were calculated for each task. There were significant differences between 5th and 8th graders on single gait speed on the straight (p = 0.016) and the COD pathway (p = 0.023), but not on any of the DT conditions. The calculation of DTEs revealed that motor DTEs were lowest for the MRT and highest for the TWT in the numbers/letters condition (p < 0.05 for all comparisons). In contrast, there were cognitive benefits for the higher-order cognitive tasks on the straight pathways, but cognitive costs for both DT conditions on the COD pathway (p < 0.01 for all comparisons). Our findings demonstrate that DT changes in walking when completing a secondary task that involve higher-level cognition are attributable to more than low-level divided attention or motor response processes. These results specifically show the direct competition for higher-level executive function resources important for walking, and are in agreement with previous studies supporting the cognitive-motor link in relation to gait in children. This might be in line with the idea that younger children may not have adequate cognitive resources.

Obesity is associated with lack of inhibitory control and impaired heart rate variability reactivity and recovery in response to food stimuli

Recent theories compare obesity with addiction in terms of lack of inhibitory control in both clinical populations. The present study hypothesized impaired inhibition in obese patients reflected both in executive functions and reduced vagal tone (indexed by a decrease in heart rate variability; HRV) in response to food stimuli. Twenty-four inpatients with obesity (19 women) and 37 controls (24 women) underwent ECG monitoring during baseline, food stimuli viewing, and a recovery phase. Tests and questionnaires assessing inhibitory control and psychopathological dispositions were also administered. As hypothesized, patients were characterized by deficits in all the tests measuring inhibitory capacities. Results also show greater HRV reduction and impaired HRV recovery in response to food stimuli in obese patients compared to controls. The drive to eat experienced by obese patients in the absence of caloric need may rely on impairments in inhibitory and vagal functioning. Results are discussed in terms of implications for therapy.

Executive dysfunction following a mild traumatic brain injury revealed in early adolescence with locomotor-cognitive dual-tasks

OBJECTIVE

To compare gait parameters between children in early adolescence (EA) with and without a mild traumatic brain injury (mTBI) during dual-task walking (DTW).

METHODS

Children in EA with mTBI (n = 14; six girls) were compared to those without (n = 13; five girls) while walking in different combinations of obstacle avoidance and cognitive dual-tasks. Gait speed and fluidity and their related dual-task costs (DTC) were analysed along with foot clearance and proximity to the obstacle.

RESULTS

No group effects were found for gait speed, proximity or clearance, but were found for fluidity DTC, specifically during the dual Stroop task and when crossing the deeper obstacle. There were also group differences for fluidity during the planning of obstacle avoidance for the narrow obstacle combined with the verbal fluency task and the deep obstacle with no cognitive task. Finally, gait fluidity showed group differences across unobstructed dual-task situations.

CONCLUSIONS

Gait fluidity may be a more sensitive variable than gait speed for revealing executive dysfunction following mTBI in EA. Assessing DTW in level walking also seems to show a potential to reveal executive dysfunctions in this age group. These results provide direction for future research on clinical assessment using DTW post-mTBI in adolescents.