Laboratory Visits Research Articles

Gait variability, fractal dynamics, and statistical regularity of treadmill and overground walking recorded with a smartphone

BackgroundThe nonlinear variability present during steady-state gait may provide a signature of health and showcase one’s walking adaptability. Although treadmills can capture vast amounts of walking data required for estimating variability within a small space, gait patterns may be misrepresented compared to an overground setting. Smartphones may provide a low-cost and user-friendly estimate of gait patterns among a variety of walking settings. However, no study has investigated differences in gait patterns derived from a smartphone between treadmill walking (TW) and overground walking (OW). Research questionThis study implemented a smartphone accelerometer to compare differences in temporal gait variability and gait dynamics between TW and OW. MethodsSixteen healthy adults (8F; 24.7 ± 3.8 years) visited the laboratory on three separate days and completed three 8-minute OW and three TW trials, at their preferred speed, during each visit. The inter-stride interval was calculated as the time difference between right heel contact events located within the vertical accelerometery signals recorded from a smartphone while placed in participants front right pant pocket during walking trials. The inter-stride interval series was used to calculate stride time standard deviation (SD) and coefficient of variation (COV), statistical persistence (fractal scaling index), and statistical regularity (sample entropy). Two-way analysis of variance compared walking condition and laboratory visits for each measure. ResultsCompared to TW, OW displayed significantly (p < 0.01) greater stride time SD (0.014 s, 0.020 s), COV (1.26 %, 1.82 %), fractal scaling index (0.70, 0.79) and sample entropy (1.43, 1.63). No differences were found between visits for all measures. SignificanceSmartphone-based assessment of gait provides the ability to distinguish between OW and TW conditions, similar to previously established methodologies. Furthermore, smartphones may be a low-cost and user-friendly tool to estimate gait patterns outside the laboratory to improve ecological validity, with implications for free-living monitoring of gait among various populations.

“Encephalapp Stroop”: Validity and reliability of a smartphone app to measure cognitive performance in physically active subjects

This study aimed to analyze the validity and reliability of a smartphone app (i.e., Encephalapp Stroop) to measure cognitive performance. Ten physically active individuals (mean age: 25.2 ± 4.3 years) participated in three laboratory visits. In a randomized sequence, subjects completed cognitive assessments using the app and a computer separately. The response times from 100 measurements for congruent and incongruent stimuli were compared between the two devices (app and computer) using the intraclass correlation coefficient, Pearson product-moment correlation coefficient (r), Cronbach’s alpha (α), and Bland-Altman plots. There was excellent agreement between the computerized Stroop and the app version for response times for congruent (ICC = 0.806, p < 0.001; Bland-Altman bias = 41.3 ± 56.4 ms, p < 0.001) and incongruent stimuli (ICC = 0.755, p < 0.001; Bland-Altman bias = 76.4 ± 75.1 ms, p < 0.001). In comparison to the computerized version, the app demonstrated a moderate correlation for response times of congruent (r = 0.678, p < 0.001) and incongruent (r = 0.623, p < 0.001) stimuli. The results of the present study indicate that the response times of congruent and incongruent stimuli can be easily, accurately, and reliably evaluated using a mobile app.

Energy Expenditure Validation of an Exergame Platform: Ring Fit Adventure Use in Adults with Overweight and Obesity.

Objective: This study aims at comparing the energy expenditure (EE) and heart rate (HR) data from Ring Fit Adventure (RFA) with those from indirect calorimetry (COSMED) and a heart rate monitor (Polar FT7). A secondary goal is to evaluate self-reported enjoyment and perceived effort levels. Materials and Methods: Thirty participants (age = 21.8 ± 2.2; body mass index = 31.8 ± 4.4) were recruited for two laboratory visits. The first visit involved baseline measurements. In the second visit, participants performed a 55-minute ad libitum exercise session with the RFA in adventure mode with moderate difficulty. During this session, EE, HR, perceived effort, and enjoyment of physical activity were recorded. Results: Although no statistically significant overestimation of EE was found between the RFA and the metabolic cart, two-way analysis of variance results show a main effect of condition (RFA vs. Polar FT7) on HR (122.8 ± 20.1 bpm and 129.0 ± 18.6 bpm; P = 0.007; ᶯp2 = 0.235). Based on comprehensive statistical evaluations, including the mean absolute percent error, intraclass correlations, typical error of measurement, and limits of agreement, the data suggest that the RFA provides reliable estimates for EE and HR. Overall, participants enjoyed the game considerably (71.3 ± 5.9/80 arbitrary units), and their reported perceived exertion was low. Conclusion: This study underscores that the RFA values are relatively accurate and precise, and thus it can be safely suggested for individuals with overweight and obesity to adopt an active lifestyle.

A proof-of-concept study testing the factor structure of the Stop Signal Task: overlap with substance use and mental health symptoms

ABSTRACT Background: Research utilizing experimental tasks usually does not report estimates of internal reliability of measurement. However, modern measurement theories conceptualize reliability as sample dependent indicating that reliability should be empirically demonstrated in the samples used to make inferences. Objectives: Test whether confirmatory factor analytic (CFA) estimates of reliability can be applied to a commonly used task measuring response inhibition (the Stop Signal Task) to predict substance use (alcohol and cannabis) and mental health symptoms. Methods: Thirty-seven participants between the ages of 18–20 (72% female; 16% Asian, 3% Native American, 11% Black or African American, 59% White; 32% Latino/a/x) were recruited via social media advertisement and attended a laboratory visit. The Stop Signal Reaction Time (SSRT) was calculated as the outcome for three experimental blocks and used as indicators in a CFA. Results: CFA suggests the task yields reliable scores; factor loadings were statistically significant (p < .05) and substantial (standardized loadings ranged from .74 to .94). However, reliability increased across experimental blocks and error was non-trivial (ranging from 50% to 12% of the variance). The inhibition factor predicted higher maximum number of drinks consumed (β = .37, p < .05), higher frequency of cannabis use (β = .39, p < .05), and more cannabis use occasions within using days (β = .40, p < .05), as well as facets of mental health (anxious/depression, attention, and anxiety problems; all p’s < .05). Conclusion: Results support the utility of CFA to test for reliability of measurement, with the ability to inhibit dominant responses serving as a transdiagnostic correlate of substance use and mental health problems.

The effect of attentional cues on mechanical efficiency and movement smoothness in running gait: An interdisciplinary investigation

ABSTRACT The aim was to examine the effect of focus of attention cues on foot angle for retraining movement purposes. Twenty (females: 8) rearfoot-striking recreational runners (mass: 72.5 ± 11.8 kg; height: 1.73 ± 0.09 m; age: 32.9 ± 11.3 years) were randomly assigned to an internal focus (IF) (n = 10) or external focus (EF) (n = 10) verbal cue group. Participants performed 5 × 6 minute blocks of treadmill running (control run, 3 × cued running, retention run) at a self-selected running velocity (9.4 ± 1.1 km∙h−1) during a single laboratory visit. Touchdown foot angle, mechanical efficiency, internal and external work were calculated and, centre of mass (COM) and foot movement smoothness was quantified. Linear-mixed effect models showed an interaction for foot angle (p < 0.001, ηp 2 = 0.35) and mechanical efficiency (p < 0.001, ηp 2 = 0.40) when comparing the control to the cued running. Only the IF group reduced foot angle and mechanical efficiency during cued running, but not during the retention run. The IF group produced less external work during the 1st cued run than the control run. COM and foot smoothness were unaffected by cueing. Only an IF produced desired technique changes but at the cost of reduced mechanical efficiency. Movement smoothness was unaffected by cue provision. Changes to foot angle can be achieved within 6 minutes of gait retraining.

Remotely prescribed and monitored home-based gait-and-balance therapeutic exergaming using augmented reality (AR) glasses: protocol for a clinical feasibility study in people with Parkinson’s disease

BackgroundClinical guidelines for people with Parkinson’s disease (pwPD) stress that, complementary to pharmacological treatment, exercise and physiotherapy should be given a central role in disease management. Adhering to regular exercise of the right type, and with high repetition, remains a challenge for pwPD. Exergaming has the potential to increase adherence through play and personalised interventions, both in clinic and at home. Reality DTx® is an augmented-reality (AR) home-based gait-and-balance exergaming intervention specifically designed for pwPD as an extension of supervised physiotherapy. The primary objective of this study is to evaluate the feasibility and potential efficacy of Reality DTx®.MethodsTwenty-four pwPD (Hoehn and Yahr stages 2–4) with self-reported gait and/or balance impairments will participate in this study. The study comprises a 6-week waitlist-controlled AR home-based therapeutic gait-and-balance exergaming intervention. Reality DTx® will initially be prescribed remotely for a minimum of 5 days a week for 30 min per day. We will remotely set and adjust the frequency, difficulty, type of games, and/or duration weekly, based on objective and subjective data from the AR glasses and participant, respectively. In addition to the home-based gait-and-balance exergaming intervention, the study comprises three laboratory visits: before the 6-week waitlist period (t0; baseline), before the 6-week intervention period (t1; pre-intervention), and after the 6-week intervention period (t2; post-intervention). The primary study parameters are feasibility (in terms of safety, adherence, and user experience) and potential efficacy for improving gait and balance (using standard clinical gait-and-balance tests and a targeted walking-related fall-risk assessment). Recruitment started in December 2022 and the final post-intervention assessment will be according to planning in July 2023.ConclusionsThis clinical feasibility trial is the first remotely prescribed and monitored home-based AR gait-and-balance exergaming intervention for pwPD. The results in terms of clinical feasibility (i.e. safety, adherence, and user experience) and potential efficacy (gait, balance, and fall-risk outcomes) form the basis for future randomised controlled studies on the effectiveness of home-based AR gait-and-balance exergaming interventions for pwPD.Trial registrationClinicalTrials.gov, NCT05605249. Registered on 4 November 2022.

Abstract P334: The Impact of Cardiovascular Risk Factors on Cognition in Adults With Down Syndrome

Introduction: Most adults with Down Syndrome (DS) will develop Alzheimer's disease. Evidence in the general population suggests that factors associated with cardiovascular health including, moderate to vigorous physical activity (MVPA), cardiorespiratory fitness, and systolic blood pressure, are associated with better cognitive outcomes and decreased risk of Alzheimer's disease. Studies supporting these associations in adults with DS are limited. The purpose of this study was to examine the associations between systolic blood pressure, cardiorespiratory fitness, and MVPA on cognition in adults with DS. Methods: This is a cross-sectional analysis using baseline data from a trial in adults with DS. Participants attended a laboratory visit where resting blood pressure, cardiorespiratory fitness (VO 2 Peak ) and cognitive function (CANTAB ® DS Battery) were obtained. The cognitive battery included tests measuring multitasking, episodic memory, and reaction time. Physical activity (accelerometer) was collected over the week following the laboratory visit. Pearson correlations and linear regressions were used to measure the impact of systolic blood pressure, cardiorespiratory fitness, and MVPA on cognitive outcomes. Results: Complete data was available for 72 adults with DS (26.8 ± 9.3 years of age, 57% female). At baseline, VO 2 Peak (21.1 ± 4.2 ml/kg/min) and MVPA were low (14.4 ±14.4 min/day), and systolic blood pressure was 118.3 ± 13.3 mmHg. VO 2 Peak was correlated with simple movement time (rho = -0.28, p=0.03) but was not significant using a linear regression controlling for age and sex. Systolic blood pressure was significantly associated with episodic memory (first attempt memory score: β = -0.11, p=0.002; total errors: β = 0.58, p = 0.001) and reaction time (five-choice movement time: β = 4.11, p = 0.03; simple movement time: β = 6.14, p = 0.005) using age-and sex-adjusted linear regressions. No associations were observed between MVPA and multitasking, episodic memory, or reaction time. Conclusion: Cardiovascular risk factors, including cardiorespiratory fitness and systolic blood pressure, were associated with cognition in adults with DS. Given the high prevalence of Alzheimer's disease in adults with DS, future research examining cardiovascular health and Alzheimer's disease risk is warranted.

Leukocytes and lactate responses to cycling and running at the same target heart rate

AbstractHeart Rate (HR) is widely used for erobic exercise intensity prescriptions and/or studies of exercise training. It is often assumed that exercising at a given HR results in similar physiological response, regardless of exercise modality. This study aimed to gauge cellular immune mobilization to submaximal exercise at a given target HR on a cycle ergometer (CE) and treadmill (TM). Thirteen healthy male adults (23.2 ± 3.5 y.o) completed 4 laboratory visits. Participants performed two graded exercise tests to exhaustion on CE and TM and two 30‐min constant exercise challenges at 70% HR reserve on CE or TM in random order. Rating of Perceived Exertion (RPE) was recorded every 5 min, and blood was drawn before and after exercise to measure leukocytes subpopulation levels, lactate, and IL‐6. HR was successfully “clamped” during the exercise in CE and TM (CE 156.7 ± 1.1; TM 159.3 ± 1.6 bpm). Cycling was perceived as more strenuous than running and was accompanied by a greater increase in lactate post‐exercise (p &lt; 0.0001; 6.2 ± 0.3 vs. 2.9 ± 0.3 mmol/L). IL‐6 and leukocytes subpopulations were significantly elevated post‐exercise (p &lt; 0.003) with no difference between exercise modalities (monocytes; CE 57.6% TM 61.2%, granulocytes; CE 41.37%, TM 50.1%, lymphocytes; CE 91.03%, TM 78.8%). The findings revealed that HR is not sufficient in and of itself to fully assess the metabolic stress associated with a given exercise modality. However, despite different metabolic and subjective stress, the IL‐6 and leukocyte counts relative changes were similar in the two modalities.

Methodological adjustments for experimental studies including neurodiverse participants: A checklist for before, during, and after laboratory visits

In this paper, we developed an experimental checklist for laboratory experiments including neurodiverse participants, particularly those with attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and dyslexia. The checklist suggests additions to the basic requirements for ethical laboratory-based studies with human participants. The suggestions emphasize physical comfort, the agency of participants concerning environmental adjustments, clarity of communication, and a focus on participants’ overall well-being. Those methodological guidelines aim to help researchers in facilitating inclusive and accessible laboratory environments for neurodiverse participants in order to:•Enhance research validity by minimizing the influence of factors that affect responses in neuroscience experiments.•Facilitate research recruitment by encouraging continued participation in future studies and increasing word-of-mouth.•Improve research dissemination by fostering a more positive perception of the research process amongst neurodiverse individuals and encouraging community involvement.

A Retrospective Comparison of Medication Recommendations Between a Cardiologist and ChatGPT-4 for Hypertension Patients in a Rural Clinic.

Background With ChatGPT demonstrating impressive abilities in solving clinical vignettes and medical questions, there is still a lack of studies assessing ChatGPT using real patient data. With real-world cases offering added complexity, ChatGPT's utility in treatment using such data must be tested to better assess its accuracy and dependability. In this study, we compared a rural cardiologist's medication recommendations to that of GPT-4 for patients with lab review appointments. Methodology We reviewed the lab review appointments of 40 hypertension patients, noting their age, sex, medical conditions, medications and dosage, and current and past lab values. The cardiologist's medication recommendations (decreasing dose, increasing dose, stopping, or adding medications) from the most recent lab visit, if any, were recorded for each patient. Data collected from each patient was inputted into GPT-4 using a set prompt and the resulting medication recommendations from the model were recorded. Results Out of the 40 patients, 95% had conflicting overall recommendations between the physician and GPT-4, with only 10.2% of the specific medication recommendations matching between the two. Cohen's kappa coefficient was -0.0127, indicating no agreement between the cardiologist and GPT-4 for providing medication changes overall for a patient. Possible reasons for this discrepancy can be differing optimal lab value ranges, lack of holistic analysis by GPT-4, and a need for providing further supplementary information to the model. Conclusions The study findings showed a significant difference between the cardiologist's medication recommendations and that of ChatGPT-4. Future research should continue to test GPT-4 in clinical settings to validate its abilities in the real world where more intricacies and challenges exist.

Symptom reduction in mal de débarquement syndrome with attenuation of the velocity storage contribution in the central vestibular pathways.

The velocity storage mechanism of the central vestibular system is closely associated with the vestibulo-ocular reflex (VOR), but also contributes to the sense of orientation in space and the perception of self-motion. We postulate that mal de débarquement syndrome (MdDS) is a consequence of inappropriate sensory adaptation of velocity storage. The premise that a maladapted velocity storage may be corrected by spatial readaptation of the VOR has recently been translated into the development of the first effective treatment for MdDS. However, this treatment's initial impact may be reversed by subsequent re-triggering events. Presently, we hypothesized that MdDS symptoms could alternatively be reduced by attenuating the velocity storage contribution in the central vestibular pathways. Forty-three patients with MdDS (aged 47 ± 14 yo; 36 women) were randomly assigned to two treatment groups and followed for 6 months. The horizontal VOR was tested with chair rotation during laboratory visits, and the strength of velocity storage was quantified with model-based parameters-the time constant (Tc) and the gain of coupling from the vestibular primary afferent signals (g0). To attenuate velocity storage, Group 1 underwent a progressively intensifying series of low-frequency earth-vertical oscillatory rotation coupled to conflicting visual stimuli. Group 2 underwent an established protocol combining head tilts and visual stimulation, designed to correct maladapted spatial orientation but not change the velocity storage strength. The symptom severity was self-rated on an 11-point scale and reported before and up to 6 months after the treatment. In Group 1, velocity storage was modified through reduction of g0 (p < 0.001) but not Tc. The symptom rating was at least halved initially in 43% of Group 1 (p = 0.04), the majority of whom retained a similar level of improvement during the 6-month follow-up period. In Group 2, no systematic change was induced in the parameters of velocity storage strength, as expected. The symptom rating was at least halved initially in 80% of Group 2 (p < 0.001), but paralleling previous findings, symptoms often returned subsequently. Attenuation of velocity storage shows promise as a lasting remedy for MdDS that can complement the VOR readaptation approach.

The Acute Effects of a Commercially Available Caffeinated and Caffeine-Free Thermogenic Dietary Supplement on Resting Energy Expenditure, Hunger, and Hemodynamic Responses

There has been a rise in popularity of “stimulant-free” or caffeine-free fat loss supplements, but it is not well understood whether those fat loss supplements are effective at enhancing thermogenesis without caffeine’s influence. The purpose of this study was to examine the effects of a caffeinated and non-caffeinated commercially available fat loss supplement on resting energy expenditure (REE), hunger, and hemodynamic variables in healthy adults. Twenty-five healthy male and female participants completed three separate laboratory visits after overnight fasts. Baseline assessments of REE, subjective hunger, heart rate (HR), and blood pressure (BP) were followed by ingestion of a caffeinated (Phoenix, Legion®; CAF), non-caffeinated (Phoenix Caffeine-Free, Legion®; NCAF), or placebo (PL) fat loss supplement. REE, hunger, HR, and BP assessments were repeated at 60-, 120-, and 180-min post-ingestion. CAF, but not NCAF, significantly elevated REE greater than PL at all time points (p &lt; 0.05). NCAF significantly reduced hunger compared to CAF and PL at the 120-min time point (p = 0.006). CAF significantly increased diastolic BP 60-min post-ingestion and significantly increased systolic BP 120- and 180-min post-ingestion compared to NCAF and PL. Further research is warranted with respect to investigating non-caffeinated ingredients and their effects on REE.

Successful Powerlifting in a Unilateral, Transtibial Amputee: A Descriptive Case Series.

Beausejour, JP, Guinto, G, Artrip, C, Corvalan, A, Mesa, MF, Lebron, MA, and Stock, MS. Successful powerlifting in a unilateral, transtibial amputee: A descriptive case series. J Strength Cond Res 38(5): e243-e252, 2024-There are no reports in the literature of powerlifting success after amputation. We had the unique opportunity to characterize functional outcomes, strength, muscle contractility and size, and corticospinal excitability in an accomplished, competitive powerlifter (best competition squat = 205.0 kg, deadlift = 262.7 kg) with a unilateral, transtibial amputation relative to amputee controls. Four men (age range = 23-49 years) with unilateral, lower-limb amputation (3 transtibial, 1 transfemoral) participated in 1 laboratory visit. We assessed 10-m gait speed, the timed up and go (TUG) test, 5-time sit-to-stand performance (5TSTS), contractile properties of the vastus lateralis (VL) and medial gastrocnemius by tensiomyography, and VL cross-sectional area (CSA) by ultrasonography. Unilateral assessments for the intact limb included isokinetic knee extension and flexion torque and power and transcranial magnetic stimulation derived corticospinal excitability. An interview with the powerlifter provided contextual perspective. Compared with the control subjects, the powerlifter performed the 5TSTS faster (6.8%), exhibited faster VL contraction times (intact limb = 12.2%; residual limb = 23.9%), and showed larger VL CSA for the intact limb (46.7%). The powerlifter exhibited greater knee extension and flexion peak torque and mean power, particularly at 180°·s -1 , as well as greater corticospinal excitability for the intact VL (65.6%) and tibialis anterior (79.6%). By contrast, the control subjects were faster in the TUG (18.3%) and comfortable (13.0%) and fast (21.4%) in the 10-m walk test. The major themes of our interview included needing to modify lifting mechanics, persistence, and remarkable pain tolerance. Our findings highlight the impressive neuromuscular adaptations that are attainable after lower-limb amputation.

Assessing Functional Capacity in Directly and Remotely Monitored Home-Based Settings in Individuals With Chronic Respiratory Diseases: Protocol for a Multinational Validation Study.

Pulmonary rehabilitation is widely recommended to improve functional status and as secondary and tertiary prevention in individuals with chronic pulmonary diseases. Unfortunately, access to timely and appropriate rehabilitation remains limited. To help close this inaccessibility gap, telerehabilitation has been proposed. However, exercise testing is necessary for effective and safe exercise prescription. Current gold-standard tests, such as maximal cardiopulmonary exercise testing (CPET) and the 6-minute walk test (6MWT), are poorly adapted to home-based or telerehabilitation settings. This was an obstacle to the continuity of services during the COVID-19 pandemic. It is essential to validate tests adapted to these new realities, such as the 6-minute stepper test (6MST). This test, strongly inspired by 6MWT, consists of taking as many steps as possible on a "stepper" for 6 minutes. This study aims to evaluate the metrological qualities of 6MST by (1) establishing concurrent validity and agreement between the 6MST and CPET, as well as with the 6MWT; (2) determining test-retest reliability in a home-based setting with direct and remote (videoconferencing) monitoring; and (3) documenting adverse events and participant perspectives when performing the 6MST in home-based settings. Three centers (Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec in Québec, Groupement des Hôpitaux de l'Institut Catholique de Lille in France, and FormAction Santé in France) will be involved in this multinational project, which is divided into 2 studies. For study 1 (objective 1), 30 participants (Québec, n=15; France, n=15) will be recruited. Two laboratory visits will be performed to assess anthropometric data, pulmonary function, and the 3 exercise tolerance tests (CPET, 6MWT, and 6MST). Concurrent validity (paired sample t tests and Pearson correlations) and agreement (Bland-Altman plots with 95% agreement limits) will be evaluated. For study 2 (objectives 2 and 3), 52 participants (Québec, n=26; France, n=26) will be recruited. Following a familiarization trial (trial 1), the 6MST will be conducted on 2 separate occasions (trials 2 and 3), once under direct supervision and once under remote supervision, in a randomized order. Paired sample t test, Bland-Altman plots, and intraclass correlations will be used to compare trials 2 and 3. A semistructured interview will be conducted after the third trial to collect participants' perspectives. Ethical approval was received for this project (October 12, 2023, in Québec and September 25, 2023, in France) and the first participant was recruited in February 2024. This study innovates by validating a new clinical test necessary for the development and implementation of new models of rehabilitation adapted to home and telerehabilitation contexts. This study also aligns with the United Nations Sustainable Development Goals by contributing to augmenting health care service delivery (goal 3) and reducing health care access inequalities (goal 11). ClinicalTrials.gov NCT06447831; https://clinicaltrials.gov/study/NCT06447831. DERR1-10.2196/57404.

Glycemic Management Around Postprandial Exercise in People With Type 1 Diabetes: Challenge Accepted.

The precise glycemic impact and clinical relevance of postprandial exercise in type 1 diabetes (T1D) has not been clarified yet. This work aimed to examine acute, subacute, and late effects of postprandial exercise on blood glucose (BG). A randomized, controlled trial comprised 4 laboratory visits, with 24-hour follow-up at home. Participants included adults with T1D (n = 8), aged 44 ± 13 years, with body mass index of 24 ± 2.1. Intervention included 30 minutes of rest (CONTROL), walking (WALK), moderate-intensity (MOD), or intermittent high-intensity (IHE) exercise performed 60 minutes after a standardized meal. Main outcome measures included BG change during exercise/control (acute), and secondary outcomes included the subacute (≤2 h after) and late glycemic effects (≤24 h after). Exercise reduced postprandial glucose (PPG) excursion compared to CONTROL, with a consistent BG decline in all patients for all modalities (mean declines -45 ± 24, -71 ± 39, and -35 ± 21 mg/dL, during WALK, MOD, and IHE, respectively (P < .001). For this decline, clinical superiority was demonstrated separately for each exercise modality vs CONTROL. Noninferiority of WALK vs MOD was not demonstrated, noninferiority of WALK vs IHE was demonstrated, and equivalence of IHE vs MOD was not demonstrated. Hypoglycemia did not occur during exercise. BG increased in the hour after exercise (more than after CONTROL; P < .001). More than half of participants showed hyperglycemia after exercise necessitating insulin correction. There were more nocturnal hypoglycemic events after exercise vs CONTROL (P < .05). Postprandial exercise of all modalities is effective, safe, and feasible if necessary precautions are taken (ie, prandial insulin reductions), as exercise lowered maximal PPG excursion and caused a consistent and clinically relevant BG decline during exercise while there was no hypoglycemia during or shortly after exercise. However, there seem to be 2 remaining challenges: subacute postexercise hyperglycemia and nocturnal hypoglycemia.

The order of running shoes and how it influences the perception of effort and comfort

Introduction High performance modern shoes reduce energy expenditure and improve performance, however, these gains may also stem from differences in perceived effort. Humans tend to weigh negative information more heavily than positive information, which could influence perception of effort when different shoes are tested sequentially. This study aimed to determine the existence of negativity bias on different measures of perception when alternating running shoes. Methods Eleven well-trained male athletes [age: 28 ± 6 years, weight: 68 ± 5 kg, height: 179 ± 5 cm, peak oxygen consumption: 65 ± 4 ml O2･kg-1･min-1] performed three lab visits: a familiarization day with an incremental test followed by two experimental days (track and treadmill, in balanced order). On each day, participants performed four sets of two 5-min runs at 16km･h-1 (5-min breaks in-between) alternating between On Cloudrunner (entry-level, EL) and Cloudboom Echo 3 (high-performance, HP). The order of the shoes was changed every set (i.e, EL-HP or HP-EL). After each run, participants reported their perception of effort (both on a 100-mm Visual Analog Scale [VAS] and on a 1-10 Borg Scale) and shoe comfort (VAS). Heart rate and gas exchange were monitored using a chest sensor and a metabolic cart. Differences in ratings between EL-HP and HP-EL were compared using paired t-tests. Results In combined data of track and treadmill, the physiological response and perception of effort were significantly lower while perception of comfort was significantly higher with HP compared to EL. On the treadmill, the absolute value of the change in perceived effort (VAS) was lower for EL-HP compared with HP-EL (0.6 ± 0.5 mm vs. 1.0 ± 0.7 mm, p = 0.013), but not on the track (EL-HP 0.5 ± 0.5 mm vs. HP-EL 0.6 ± 0.3 mm, p = 0.602). Absolute changes of effort (Borg) were neither affected by shoe order on the treadmill (EL-HP 0.7 ± 0.4 pts vs. HP-EL 0.8 ± 0.7 pts, p = 0.699) nor on the track (EL-HP 0.5 ± 0.4 pts vs. HP-EL 0.7 ± 0.6 pts, p = 0.452). Similarly, ratings of shoe comfort were neither affected by shoe order on the treadmill (EL-HP 1.8 ± 1.1 mm vs. HP-EL 1.4 ± 1.0 mm, p = 0.086) nor on the track (EL-HP 1.5 ± 1.1 mm vs. HP-EL 1.6 ± 1.0 mm, p = 0.674). Discussion/Conclusion Changes in perceived effort (VAS) assessed during treadmill running were nearly two times larger when switching from EL to HP than vice-versa, supporting the presence of a negativity bias in this specific condition, which could be related to the higher resolution of VAS scales compared with Borg. Possibly, the lack of negativity bias on the track resulted from an overall reduced rating of effort compared with treadmill, which left less room for differences. These findings suggest that it would be beneficial to include a control shoe worn before and between the tested shoes of interest to mitigate any potential negativity bias in tests when determining perceived effort on a treadmill with different shoes.

Interoceptive beliefs moderate the link between physiological and emotional arousal during an acute stressor.

Growing work suggests that interoception, that is, representations of one's internal bodily changes, plays a role in shaping emotional experiences. Past studies primarily examine how behavioral accuracy in detecting interoceptive signals (interoceptive ability) relates to emotional states, with less work examining self-reported interoceptive facets such as the characterizations of one's interoceptive abilities (interoceptive sensibility) or evaluative beliefs about the value versus danger of interoceptive signals (interoceptive beliefs). However, existing studies rarely examine physiological reactivity, behavioral, and self-reported dimensions of interoception together in the same sample. As such, it remains unclear whether and how much individual differences in interoceptive facets uniquely and in interaction with physiological reactivity may matter for emotional experience. Herein, 250 healthy young adults completed a heartbeat detection task assessing interoceptive ability and questionnaire measures of interoceptive sensibility and beliefs during an initial laboratory visit. At a follow-up session, 227 participants returned to undergo an acute psychosocial stressor. Measures of physiological arousal such as preejection period (PEP) and heart rate variability were acquired throughout the stressor with self-reported emotions acquired immediately after. Linear regressions revealed that greater sympathetic nervous system reactivity (i.e., PEP), poorer interoceptive ability (i.e., accuracy), and less positive interoceptive beliefs were related to more intense high arousal emotions during the stressor. Importantly, across models, interoceptive beliefs was the only interoceptive facet to moderate the concordance between physiological and emotional arousal. Implications for psychological theories of emotion, stress, and interoception are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Neural complexity is increased after low doses of LSD, but not moderate to high doses of oral THC or methamphetamine.

Neural complexity correlates with one's level of consciousness. During coma, anesthesia, and sleep, complexity is reduced. During altered states, including after lysergic acid diethylamide (LSD), complexity is increased. In the present analysis, we examined whether low doses of LSD (13 and 26 µg) were sufficient to increase neural complexity in the absence of altered states of consciousness. In addition, neural complexity was assessed after doses of two other drugs that significantly altered consciousness and mood: delta-9-tetrahydrocannabinol (THC; 7.5 and 15 mg) and methamphetamine (MA; 10 and 20 mg). In three separate studies (N = 73; 21, LSD; 23, THC; 29, MA), healthy volunteers received placebo or drug in a within-subjects design over three laboratory visits. During anticipated peak drug effects, resting state electroencephalography (EEG) recorded Limpel-Ziv complexity and spectral power. LSD, but not THC or MA, dose-dependently increased neural complexity. LSD also reduced delta and theta power. THC reduced, and MA increased, alpha power, primarily in frontal regions. Neural complexity was not associated with any subjective drug effect; however, LSD-induced reductions in delta and theta were associated with elation, and THC-induced reductions in alpha were associated with altered states. These data inform relationships between neural complexity, spectral power, and subjective states, demonstrating that increased neural complexity is not necessary or sufficient for altered states of consciousness. Future studies should address whether greater complexity after low doses of LSD is related to cognitive, behavioral, or therapeutic outcomes, and further examine the role of alpha desynchronization in mediating altered states of consciousness.

Intraindividual variability in post-stroke cognition and its relationship with activities of daily living and social functioning: an ecological momentary assessment approach

ABSTRACT Introduction Ecological momentary assessment (EMA) is a methodological approach to studying intraindividual variation over time. This study aimed to use EMA to determine the variability of cognition in individuals with chronic stroke, identify the latent classes of cognitive variability, and examine any differences in daily activities, social functioning, and neuropsychological performance between these latent classes. Methods Participants (N = 202) with mild-to-moderate stroke and over 3-month post-stroke completed a study protocol, including smartphone-based EMA and two lab visits. Participants responded to five EMA surveys daily for 14 days to assess cognition. They completed patient-reported measures and neuropsychological assessments during lab visits. Using latent class analysis, we derived four indicators to quantify cognitive variability and identified latent classes among participants. We used ANOVA and Chi-square to test differences between these latent classes in daily activities, social functioning, and neuropsychological performance. Results The latent class analysis converged on a three-class model. The moderate and high variability classes demonstrated significantly greater problems in daily activities and social functioning than the low class. They had significantly higher proportions of participants with problems in daily activities and social functioning than the low class. Neuropsychological performance was not statistically different between the three classes, although a trend approaching statistically significant difference was observed in working memory and executive function domains. Discussion EMA could capture intraindividual cognitive variability in stroke survivors. It offers a new approach to understanding the impact and mechanism of post-stroke cognitive problems in daily life and identifying individuals benefiting from self-regulation interventions.

When crying turns to hitting: Examining maternal responses to negative affect

Physical aggression in toddlerhood is empirically linked to anger and often conceptualized as a byproduct of frustration and related negative affect. Further, parenting is the major environmental construct implicated in the development of aggressive behaviors. Given parents’ role as “external regulators,” parents’ responses to their toddlers’ negative affect may serve to escalate or de-escalate their toddlers’ affective experience, thereby impacting the likelihood of subsequent aggression. In the present study, we examined whether parents’ negative affect, harsh, soothing, and distracting responses to their toddlers’ negative affect mediated the relation between toddlers’ negative affect and their aggressive behavior in brief conflict episodes. During a laboratory visit, a community sample of 69 mother-toddler dyads was observed in a structured interaction task. We found that child negative affect is associated with subsequent aggressive behavior by way of maternal harsh responses to negative affect. Negative emotional expression, soothing, and distraction neither facilitated or hindered children’s escalation from negative affect to aggression. Our findings support a dyadic intervention in which patterns of coercive parent-child interactions are targets for prevention and intervention of toddler aggression.