Metacognitions about suicidal thoughts.

BACKGROUND: Rumination about suicide has recently been identified as a risk factor for suicidal behavior. According to the metacognitive model of emotional disorders, the activation and maintenance of rumination is dependent on specific metacognitive beliefs. On this background, the current study is concerned with the development of a questionnaire to assess suicide-specific positive and negative metacognitive beliefs. METHODS: Factor structure, reliability and validity of the Scales for Suicide-related Metacognitions (SSM) were investigated in two samples comprised of participants suffering from lifetime suicide ideation. Participants of sample 1 (N = 214; 81.8% female; Mage = 24.9, SDage = 4.0) took part in a single assessment using an online survey. Participants of sample 2 (N = 56; 71.4% female; Mage = 33.2, SDage = 12.2) took part in two online assessments within a two week time-period. To establish convergent validity questionnaire-based assessments of suicidal ideation, general and suicide specific rumination and depression were used. Furthermore, it was analyzed whether suicide-related metacognitions predict suicide-specific rumination cross-sectionally and prospectively. RESULTS: Factor analyses revealed a two-factor structure of the SSM. Results indicated good psychometric properties, and provided evidence for construct validity and stability of the subscales. Positive metacognitions predicted concurrent and prospective suicide-specific rumination beyond the effect of suicide ideation and depression and rumination predicted concurrent and prospective negative metacognitions. CONCLUSION: Taken together the results provide initial evidence that the SSM is a valid and reliable measure of suicide-related metacognitions. Furthermore, findings are in line with a metacognitive conceptualization of suicidal crises and provide first indications of factors that might be relevant for the activation and maintenance of suicide-specific rumination.

Causes and Consequences of Interindividual Response Variability: A Call to Apply a More Rigorous Research Design in Acute Exercise-Cognition Studies.

The different responses of humans to an apparently equivalent stimulus are called interindividual response variability. This phenomenon has gained more and more attention in research in recent years. The research field of exercise-cognition has also taken up this topic, as shown by a growing number of studies published in the past decade. In this perspective article, we aim to prompt the progress of this research field by (i) discussing the causes and consequences of interindividual variability, (ii) critically examining published studies that have investigated interindividual variability of neurocognitive outcome parameters in response to acute physical exercises, and (iii) providing recommendations for future studies, based on our critical examination. The provided recommendations, which advocate for a more rigorous study design, are intended to help researchers in the field to design studies allowing them to draw robust conclusions. This, in turn, is very likely to foster the development of this research field and the practical application of the findings.

Cortical hemodynamics as a function of handgrip strength and cognitive performance: a cross-sectional fNIRS study in younger adults.

BACKGROUND: There is growing evidence for a positive correlation between measures of muscular strength and cognitive abilities. However, the neurophysiological correlates of this relationship are not well understood so far. The aim of this study was to investigate cortical hemodynamics [i.e., changes in concentrations of oxygenated (oxyHb) and deoxygenated hemoglobin (deoxyHb)] as a possible link between measures of muscular strength and cognitive performance. METHODS: In a cohort of younger adults (n = 39, 18-30 years), we assessed (i) handgrip strength by a handhold dynamometer, (ii) short-term working memory performance by using error rates and reaction times in the Sternberg task, and (iii) cortical hemodynamics of the prefrontal cortex (PFC) via functional near-infrared spectroscopy (fNIRS). RESULTS: We observed low to moderate negative correlations (rp = ~ - 0.38 to - 0.51; p < 0.05) between reaction time and levels of oxyHb in specific parts of the PFC. Furthermore, we noticed low to moderate positive correlations (rp = ~ 0.34 to 0.45; p < 0.05) between reaction times and levels of deoxyHb in distinct parts of the PFC. Additionally, higher levels of oxyHb (rp (35) = 0.401; p = 0.014) and lower levels of deoxyHb (rp (34) = - 0.338; p = 0.043) in specific parts of the PFC were linked to higher percentage of correct answers. We also found low to moderate correlations (p < 0.05) between measures of handgrip strength and levels of oxyHb (rp = ~ 0.35; p < 0.05) and levels of deoxyHb (rp = ~ - 0.25 to - 0.49; p < 0.05) in specific parts of the PFC. However, there was neither a correlation between cognitive performance and handgrip strength nor did cortical hemodynamics in the PFC mediate the relationship between handgrip strength and cognitive performance (p > 0.05). CONCLUSION: The present study provides evidence for a positive neurobehavioral relationship between cortical hemodynamics and cognitive performance. Our findings further imply that in younger adults higher levels of handgrip strength positively influence cortical hemodynamics although the latter did not necessarily culminate in better cognitive performance. Future research should examine whether the present findings can be generalized to other cohorts (e.g., older adults).

Effect of a Multimodal Movement Intervention in Patients With Neurogenic Claudication Based on Lumbar Spinal Stenosis and/or Degenerative Spondylolisthesis-A Pilot Study.

Chronic low-back pain is a major individual, social, and economic burden. The impairment ranges from deterioration of gait, limited mobility, to psychosocial distress. Due to this complexity, the demand for multimodal treatments is huge. Our purpose is to compare the effects of a multimodal movement intervention (MI) (coordinative-cognitive exercises and dancing program) with standard physical therapy (PT) on gait, physical function, and quality of life in patients with lumbar spinal stenosis (LSS). The study design is based on a 6-week intervention with a two (group: MI/PT) by two (measurement time points: pre-/post-test) parallel group design with random assignment. Twenty-four subjects (18 female/6 male, 70.8 ± 10.6 years old) diagnosed with LSS were included and randomly allocated to the MI or PT group. The primary outcomes are minimum toe clearance (MTC) and double step length (DSL) variability and the Timed "Up & Go" test (TUG). Secondary outcomes are the Brief Pain Inventory, the short Fall Efficacy Scale-International (sFES-I), and the Oswestry Disability Index. Nine subjects for each group could be analyzed. The MTC variability revealed a significant between-group difference in the posttest (p = 0.008) showing a lower MTC variability for the MI compared to the PT group. The MI group displayed an improved TUG (p = 0.031) and a reduced sFES-I (p = 0.044). The decreased MTC variability and fear of falling as well as the improved functional mobility may contribute to a reduced risk of falling. For the subsequent study, further kinematic and cognitive parameters should be analyzed, and the number of participants has to be increased. Clinical Trial Registration: German Clinical Trial Register (ID: DRKS00021026/URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00021026).

A consensus guide to using functional near-infrared spectroscopy in posture and gait research.

BACKGROUND: Functional near-infrared spectroscopy (fNIRS) is increasingly used in the field of posture and gait to investigate patterns of cortical brain activation while people move freely. fNIRS methods, analysis and reporting of data vary greatly across studies which in turn can limit the replication of research, interpretation of findings and comparison across works. RESEARCH QUESTION AND METHODS: Considering these issues, we propose a set of practical recommendations for the conduct and reporting of fNIRS studies in posture and gait, acknowledging specific challenges related to clinical groups with posture and gait disorders. RESULTS: Our paper is organized around three main sections: 1) hardware set up and study protocols, 2) artefact removal and data processing and, 3) outcome measures, validity and reliability; it is supplemented with a detailed checklist. SIGNIFICANCE: This paper was written by a core group of members of the International Society for Posture and Gait Research and posture and gait researchers, all experienced in fNIRS research, with the intent of assisting the research community to lead innovative and impactful fNIRS studies in the field of posture and gait, whilst ensuring standardization of research.

Inter-Session Reliability of Functional Near-Infrared Spectroscopy at the Prefrontal Cortex While Walking in Multiple Sclerosis.

Many established technologies are limited in analyzing the executive functions in motion, especially while walking. Functional near-infrared spectroscopy (fNIRS) fills this gap. The aim of the study is to investigate the inter-session reliability (ISR) of fNIRS-derived parameters at the prefrontal cortex while walking in people with multiple sclerosis (MS) and healthy control (HC) individuals. Twenty people with MS/HC individuals walked a 12 m track back and forth over 6 min. The primary outcomes were the absolute and relative reliability of the mean, slope coefficient (SC), and area under the curve (A) of the oxy-/deoxyhemoglobin concentrations (HbO/HbR) in the Brodmann areas (BA) 9/46/10. The SC and the A of HbO exhibited a fair ISR in BA10 in people with MS. For the mean and A of the HbR, almost all areas observed revealed a fair ISR. Overall, the ISR was better for HbR than HbO. A fair to excellent ISR was found for most BA of the prefrontal cortex in HC individuals. In total, the ISR of the analyzed fNIRS-derived parameters was limited. To improve the ISR, confounders such as fatigue and mind wandering should be minimized. When reporting the ISR, the focus should be on the mean/A rather than SC.

A Discussion on Different Approaches for Prescribing Physical Interventions - Four Roads Lead to Rome, but Which One Should We Choose?

It is well recognized that regular physical exercise has positive effects on physical and mental health. To use the beneficial health effects of physical exercise, there are worldwide movements encouraging health care providers to include physical exercise in their care and treatments strategies. However, a crucial point in administering the "exercise polypill" is the dosing and, in turn, the prescription of the physical intervention (PI). In this perspective article, we discuss the advantages and disadvantages of different approaches to prescribe PI. In this context, we also highlight outstanding questions and potential areas of opportunity for further investigations.

New Directions in Exercise Prescription: Is There a Role for Brain-Derived Parameters Obtained by Functional Near-Infrared Spectroscopy?

In the literature, it is well established that regular physical exercise is a powerful strategy to promote brain health and to improve cognitive performance. However, exact knowledge about which exercise prescription would be optimal in the setting of exercise-cognition science is lacking. While there is a strong theoretical rationale for using indicators of internal load (e.g., heart rate) in exercise prescription, the most suitable parameters have yet to be determined. In this perspective article, we discuss the role of brain-derived parameters (e.g., brain activity) as valuable indicators of internal load which can be beneficial for individualizing the exercise prescription in exercise-cognition research. Therefore, we focus on the application of functional near-infrared spectroscopy (fNIRS), since this neuroimaging modality provides specific advantages, making it well suited for monitoring cortical hemodynamics as a proxy of brain activity during physical exercise.

Does squatting need attention?-A dual-task study on cognitive resources in resistance exercise.

INTRODUCTION: Accumulating evidence shows that acute resistance exercises and long-term resistance training positively influence cognitive functions, but the underlying mechanisms have been rarely investigated. One explanatory approach assumes that the execution of resistance exercises requires higher cognitive processes which, in turn, lead to an 'indirect' training of higher cognitive functions. However, current knowledge on the engagement of higher cognitive functions during the execution of resistance exercises is relatively sparse. Hence, the purpose of this study was to examine to what extent cognitive resources are needed to perform a resistance exercise in the form of barbell back squatting. METHODS: Twenty-four young adults performed a cognitive task (serial subtraction of 7's) during standing and during barbell back squatting on a Smith machine. The total number and the number of correct responses were analyzed and taken as indicators of the cognitive load imposed by the experimental condition (squatting) and the control condition (standing). Additionally, participants' perceived exertion, mean heart rate, and the number of squats they were able to perform were assessed. RESULTS: While accuracy scores were found not to be significantly different between conditions, the numbers of total and of correct responses were significantly lower during squatting than during standing. Additionally, during squatting a higher number of total answers was given in the fifth set compared to the first set. We attribute this phenomenon to a learning effect. Furthermore, there was no statistically significant correlation between cognitive measures and perceived exertion. CONCLUSION: Results suggest that perceived exertion cannot explain the higher dual-task costs observed during squatting. They rather reflect that more cognitive resources are needed to perform low-load barbell back squats than during standing. However, further research is necessary to confirm and generalize these findings.

Dose-response relationship of intermittent normobaric hypoxia to stimulate erythropoietin in the context of health promotion in young and old people.

PURPOSE: Erythropoietin (EPO) has multifactorial positive effects on health and can be increased by intermittent normobaric hypoxia (IH). Recommendations about the intensity and duration of IH to increase EPO exist, but only for young people. Therefore, the aim of the study was to investigate the dose-response relationship regarding the duration of hypoxia until an EPO expression and the amount of EPO expression in old vs. young cohorts. METHODS: 56 young and 67 old people were assigned to two separate investigations with identical study designs (3-h hypoxic exposure) but with different approaches to adjust the intensity of hypoxia: (i) the fraction of inspired oxygen (FiO2) was 13.5%; (ii) the FiO2 was individually adjusted to an oxygen saturation of the blood of 80%. Age groups were randomly assigned to a hypoxia or control group (normoxic exposure). EPO was assessed before, during (90 and 180 min), and 30 min after the hypoxia. RESULTS: EPO increased significantly after 180 min in both cohorts and in both investigations [old: (i) + 16%, p = 0.007 and (ii) + 14%, p < 0.001; young: (i) + 27%, p < 0.001 and (ii) + 45%, p = 0.007]. In investigation (i), EPO expression was significantly higher in young than in old people after 180 min of hypoxic exposure (p = 0.024) and 30 min afterwards (p = 0.001). CONCLUSION: The results indicate that after a normobaric hypoxia of 180 min, EPO increases significantly in both age cohorts. The amount of EPO expression is significantly higher in young people during the same internal intensity of hypoxia than in old people.

Towards the Neuromotor Control Processes of Steady-State and Speed-Matched Treadmill and Overground Walking.

The neuromotor control of walking relies on a network of subcortical and cortical structures. While kinematic differences between treadmill and overground walking are extensively studied, the neuromotor control processes are still relatively unknown. Hence, this study aims to investigate cortical activation during steady-state treadmill and overground walking using functional near-infrared spectroscopy, inertial measurement units and a heart rate monitor. We observed a higher concentration of oxygenated hemoglobin in prefrontal cortices, premotor cortices and supplementary motor areas during treadmill walking. Therefore, our results suggest that treadmill walking requires higher demands on cortical neuromotor control.

The Effect of a Cognitive Dual Task on the Control of Minimum Toe Clearance While Walking.

The aim of the current study was to evaluate the effect of a cognitive dual task on minimum toe clearance (MTC) variability while walking. In a randomized cross-over design, gait kinematics of 25 older (70 ± 6 years) and 45 younger adults (25 ± 2 years) were captured during normal walking and dual-task walking. Variability of stride time, stride length, and MTC were calculated. Differences between normal versus dual-task walking were assessed using Wilcoxon tests. Compared with normal walking, dual-task walking caused an increase in stride time variability (older adults: p < .001 and younger adults: p < .001), while the variability of MTC decreased (older adults: p = .032 and younger adults: p = .012). MTC seems to be a task-relevant gait parameter that is controlled with high priority to preserve its variability under challenging conditions.

Strengthening the Brain-Is Resistance Training with Blood Flow Restriction an Effective Strategy for Cognitive Improvement?

Aging is accompanied by a decrease in physical capabilities (e.g., strength loss) and cognitive decline. The observed bidirectional relationship between physical activity and brain health suggests that physical activities could be beneficial to maintain and improve brain functioning (e.g., cognitive performance). However, the exercise type (e.g., resistance training, endurance training) and their exercise variables (e.g., load, duration, frequency) for an effective physical activity that optimally enhance cognitive performance are still unknown. There is growing evidence that resistance training induces substantial brain changes which contribute to improved cognitive functions. A relative new method in the field of resistance training is blood flow restriction training (BFR). While resistance training with BFR is widely studied in the context of muscular performance, this training strategy also induces an activation of signaling pathways associated with neuroplasticity and cognitive functions. Based on this, it seems reasonable to hypothesize that resistance training with BFR is a promising new strategy to boost the effectiveness of resistance training interventions regarding cognitive performance. To support our hypothesis, we provide rationales of possible adaptation processes induced by resistance training with BFR. Furthermore, we outline recommendations for future studies planning to investigate the effects of resistance training with BFR on cognition.

Effects of physical exhaustion on local dynamic stability and automaticity of walking.

BACKGROUND: While the effects of diseases, performance of proprioceptors, anxiety or pain on gait stability or automaticity of walking are well-explored, physical fatigue might be another relevant factor whose consequences are not sufficiently investigated, yet. RESEARCH QUESTION: The aim of the current study was to evaluate the effect of physical exhaustion on local dynamic stability (LDS) and automaticity of gait. METHODS: In a randomized controlled trial, 30 young and healthy adults were randomly assigned to either a passive control group or a fatigue group. The participants assigned to the fatigue group passed a shuttle-run test which finished at maximal exhaustion while those of the control group rested in sitting position for 15 min. Immediately before and after the intervention, local dynamic gait stability as well as the cognitive (serial seven subtractions) and motor dual-task costs, as a measure of automaticity, were registered. RESULTS: While there was no effect of fatigue on LDS during single-task walking, we observed an interaction effect for LDS in the dual-task condition (p = .034) and for the motor dual-task costs (p = .031). Lower dual-task costs were found in the fatigued group in the post-test compared to the pre-test while the control group increased their costs at the same time. SIGNIFICANCE: In conclusion, gait automaticity might increase after total exhaustion in young adults. Still, the underlying mechanisms are not completely resolved and further research incorporating measurements of cortical gait control might be promising.

Thinking While Moving or Moving While Thinking - Concepts of Motor-Cognitive Training for Cognitive Performance Enhancement.

The demographic change in industrial countries, with increasingly sedentary lifestyles, has a negative impact on mental health. Normal and pathological aging leads to cognitive deficits. This development poses major challenges on national health systems. Therefore, it is necessary to develop efficient cognitive enhancement strategies. The combination of regular physical exercise with cognitive stimulation seems especially suited to increase an individual's cognitive reserve, i.e., his/her resistance to degenerative processes of the brain. Here, we outline insufficiently explored fields in exercise-cognition research and provide a classification approach for different motor-cognitive training regimens. We suggest to classify motor-cognitive training in two categories, (I) sequential motor-cognitive training (the motor and cognitive training are conducted time separated) and (II) simultaneous motor-cognitive training (motor and cognitive training are conducted sequentially). In addition, simultaneous motor-cognitive training may be distinguished based on the specific characteristics of the cognitive task. If successfully solving the cognitive task is not a relevant prerequisite to complete the motor-cognitive task, we would consider this type of training as (IIa) motor-cognitive training with additional cognitive task. In contrast, in ecologically more valid (IIb) motor cognitive training with incorporated cognitive task, the cognitive tasks are a relevant prerequisite to solve the motor-cognitive task. We speculate that incorporating cognitive tasks into motor tasks, rather than separate training of mental and physical functions, is the most promising approach to efficiently enhance cognitive reserve. Further research investigating the influence of motor(-cognitive) exercises with different quantitative and qualitative characteristics on cognitive performance is urgently needed.

Functional near-infrared spectroscopy in movement science: a systematic review on cortical activity in postural and walking tasks.

Safe locomotion is a crucial aspect of human daily living that requires well-functioning motor control processes. The human neuromotor control of daily activities such as walking relies on the complex interaction of subcortical and cortical areas. Technical developments in neuroimaging systems allow the quantification of cortical activation during the execution of motor tasks. Functional near-infrared spectroscopy (fNIRS) seems to be a promising tool to monitor motor control processes in cortical areas in freely moving subjects. However, so far, there is no established standardized protocol regarding the application and data processing of fNIRS signals that limits the comparability among studies. Hence, this systematic review aimed to summarize the current knowledge about application and data processing in fNIRS studies dealing with walking or postural tasks. Fifty-six articles of an initial yield of 1420 publications were reviewed and information about methodology, data processing, and findings were extracted. Based on our results, we outline the recommendations with respect to the design and data processing of fNIRS studies. Future perspectives of measuring fNIRS signals in movement science are discussed.

Motor-cognitive dual-tasking under hypoxia.

Hypoxic conditions diminish motor performance and cognitive functions, especially when the motor task and the cognitive task are conducted simultaneously. Hypoxia does further increase prefrontal cortex activity which provokes a reduced capability of efficient resource utilisation. This, again, might evoke that the capacity of the limited mental resources of a dual task will be reached at an earlier stage of task complexity. The purpose of our study was to examine whether a cognitive task would increase gait variability to a higher extent under hypoxic as compared to normoxic conditions. 18 young subjects walked on a treadmill with and without performing a cognitive task under normoxic vs. normobar hypoxic conditions. The variability of stride times was calculated and a two-way ANOVA with repeated measurements was performed to compare single-task walking with a dual task under both environmental conditions. Furthermore, we compared the cognitive performance while walking in different conditions with Wilcoxon tests. An interaction effect (F 1,34 = 6.178; p = 0.018; η p2  = 0.154) was observed indicating that in the dual-task condition, there was a greater increase in gait variability in hypoxic conditions as compared to normoxic conditions. We further observed that under hypoxic conditions, each participant performed worse in the cognitive task while walking (p < 0.001). Hypoxia might decrease the ability of performing a motor-cognitive dual task. We speculate that performing a dual task under hypoxia requires a shift of resources away from prefrontal regions. However, future research should verify this assumption examining prefrontal cortex activity while dual-task walking under normoxic conditions to analyse the haemodynamic responses of the brain.

Intersession Reliability of Isokinetic Strength Testing in Knee and Elbow Extension and Flexion Using the BTE PrimusRS.

CONTEXT: The use of isokinetic dynamometers playing an important role in different settings of sports and medicine. Therefore, a high reliability of these devices is required. OBJECTIVE: The aim of this study was to examine the intersession reliability of the dynamometer BTE PrimusRS regarding to the isolated single-joint exercises extension/flexion of the knee and elbow for isokinetic testing DESIGN: Intersession reliability. SETTING: Clinical settings and sports science. PARTICIPANTS: 16 young male students. INTERVENTION: The testing protocol includes 5 consecutive repetitions (concentric/concentric) at a velocity of 60°/s for the exercises. MAIN OUTCOME MEASURES: Raw data of torque curves were used to determine the peak torque. Reliability was evaluated with the intraclass correlation coefficient (ICC), the limits of agreement (LoA), and the bias and the variability of measurements (V). RESULTS: High ICC values (.954-.991) were found for the used exercises. However, the LoAs yielded up to over 16 Nm and the V yielded up to nearly 9 % in several testing exercises, indicating poor absolute reliability. CONCLUSION: The BTE PrimusRS shows good to excellent reliability. However, regarding the absolute measures of reliability, the users must decide as experts in their fields whether this reliability is sufficient for their purposes.

Exploring phase dependent functional gait variability.

Gait variability is frequently used to evaluate the sensorimotor system and elderly fallers compared to non-fallers exhibit an altered variability in gait parameters during unchanged conditions. While gait variability is often interpreted as movement error, it is also necessary to change the gait pattern in order to react to internal and external perturbations. This phenomenon has been described as functional variability and ensures the stability of gait motor control. The aim of the current study is to explore the functional variability in relation to the different phases of the gait cycle (phase-dependent gait variability). Kinematics of the foot, shank and thigh were registered with inertial sensors (MTw2, Xsens Technologies B.V) in 25 older participants (70±6years) during normal overground walking. Phase-dependent variability was defined as the standard deviation of the Euclidean norm of the angular velocity data. To assess differences with respect to the variability of different body segments (foot, shank, and thigh), the statistical parametric mapping method was applied. In normal walking, the variability of the time-continuous foot kinematics during parts of the swing phase was higher compared to the shank (9-14% of swing phase, p<0.000) and to the thigh (3-43%, p<0.000 and 92%, p=0.024 of swing phase). Compared to the thigh, the shank kinematics was less variable at 62-64% (p=0.013) of the swing phase. The magnitudes of the variability were comparable regarding all three body segments during mid swing. Furthermore, those magnitudes of variability were smallest during mid swing where the minimum toe clearance was identified. In conclusion, we found signs of phase-dependent functional variability particularly in the swing phase of gait. In fact, we found reduced variability in the time-continuous foot kinematics in mid swing during normal walking where also the minimum toe clearance event occurs.

Between-day test-retest reliability of gait variability in older individuals improves with a familiarization trial.

Gait variability is an important measure in clinical settings to diagnose older individuals with fall risk. This study examines whether a familiarization trial improves test-retest reliability of gait variability. Twenty-two older participants walked twice at 1 day and twice 7 days later. The standard deviations of stride length, swing time, stance time, stride time and minimum foot clearance were calculated. The test-retest reliability of (1) between-day comparison of the first trials and (2) between-day comparison of the second trials of all gait variability measures was quantified with the intraclass-correlation coefficient (ICC), the smallest detectable differences (SDD) and the bias and the limits of agreement (LoA). The between-day comparison of the second trials per day showed higher ICC values, lower LoA values and lower SDD values in all analyzed parameters. Our data suggest that the reliability of gait variability in an older population can be considerably improved just with the aid of one familiarization trial.