scholarly journals Lower Extremity Long-Latency Reflexes Differentiate Walking Function After Stroke

2019 ◽  
Author(s):  
Caitlin L. Banks ◽  
Virginia L. Little ◽  
Eric R. Walker ◽  
Carolynn Patten
Keyword(s):  
Lower Extremity ◽  
System Level ◽  
Healthy Controls ◽  
Motor Impairments ◽  
Post Stroke ◽  
Long Latency ◽  
Walking Recovery ◽  
Long Latency Reflex ◽  
Walking Speeds ◽  
The Relationship

AbstractThe neural mechanisms of walking impairment after stroke are not well characterized. There is a need for a neurophysiologic marker that can unambiguously differentiate functional status and potential for walking recovery. The long-latency reflex (LLR) is a supraspinally-mediated response that integrates sensorimotor information during movement. It is hypothesized that lower extremity LLRs contribute to regulation of motor output during walking in healthy individuals. The goal of the present study was to assess the relationship between lower extremity LLRs, measures of supraspinal drive, and walking function. Thirteen individuals with chronic post-stroke hemiparesis and thirteen healthy controls performed both isometric and dynamic plantarflexion. Transcranial magnetic stimulation (TMS) assessed supraspinal drive to the tibialis anterior. LLR activity was assessed during dynamic voluntary plantarflexion and individuals post-stroke were classified as either LLR present (LLR+) or absent (LLR-). All healthy controls and nine individuals post-stroke exhibited LLRs, while four did not. LLR+ individuals revealed higher clinical scores, walking speeds, and greater ankle plantarflexor power during walking compared to LLR- individuals. LLR- individuals exhibited exaggerated responses to TMS during dynamic plantarflexion relative to healthy controls. This LLR- subset revealed dysfunctional modulation of stretch responses and antagonist supraspinal drive relative to healthy controls and the higher functioning LLR+ individuals post-stroke. These abnormal responses allow for unambiguous differentiation between individuals post-stroke and are associated with multiple measures of motor function. These findings provide an opportunity to distinguish among the heterogeneity of lower extremity motor impairments present following stroke by associating them with responses at the nervous system level.

scholarly journals Influence of kinesthetic motor imagery and effector specificity on the long-latency stretch response

2019 ◽  
Vol 122 (5) ◽  
pp. 2187-2200 ◽  
Author(s):  
Christopher J. Forgaard ◽  
Ian M. Franks ◽  
Dana Maslovat ◽  
Romeo Chua
Keyword(s):  
Motor Imagery ◽  
Voluntary Control ◽  
Overt Response ◽  
Voluntary Response ◽  
Long Latency ◽  
Early Portion ◽  
Extensive Body ◽  
Long Latency Reflex ◽  
The Relationship ◽  
Wrist Flexors

The long-latency “reflexive” response (LLR) following an upper limb mechanical perturbation is generated by neural circuitry shared with voluntary control. This feedback response supports many task-dependent behaviors and permits the expression of goal-directed corrections at latencies shorter than voluntary reaction time. An extensive body of literature has demonstrated that the LLR shows flexibility akin to voluntary control, but it has not yet been tested whether instruction-dependent LLR changes can also occur in the absence of an overt voluntary response. The present study used kinesthetic motor imagery ( experiment 1) and instructed participants to execute movement with the unperturbed contralateral limb ( experiment 2) to explore the relationship between the overt production of a voluntary response and LLR facilitation. Activity in stretched right wrist flexors were compared with standard “do not-intervene” and “compensate” conditions. Our findings revealed that on ~40% of imagery and ~50% of contralateral trials, a response occurred during the voluntary epoch in the stretched right wrist flexors. On these “leaked” trials, the early portion of the LLR (R2) was facilitated and displayed a similar increase to compensate trials. The latter half of the LLR (R3) showed further modulation, mirroring the patterns of voluntary epoch activity. By contrast, the LLR on “non-leaked” imagery and contralateral trials did not modulate. We suggest that even though a hastened voluntary response cannot account for all instruction-dependent LLR modulation, the overt execution of a response during the voluntary epoch in the same muscle(s) as the LLR is a prerequisite for instruction-dependent facilitation of this feedback response. NEW & NOTEWORTHY Using motor imagery and contralateral responses, we provide novel evidence that facilitation of the long-latency reflex (LLR) requires the execution of a response during the voluntary epoch. A high proportion of overt response “leaks” were found where the mentally simulated or mirrored response appeared in stretched muscle. The first half of the LLR was categorically sensitive to the appearance of leaks, whereas the latter half displayed characteristics closely resembling activity in the ensuing voluntary period.

scholarly journals Influence of chronotype on daily mood fluctuations: pilot study in patients with depression

BJPsych Open ◽  
2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Konstantin F. Brückmann ◽  
Jürgen Hennig ◽  
Matthias J. Müller ◽  
Stanislava Fockenberg ◽  
Anne-Marthe Schmidt ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Pilot Study ◽  
Negative Affect ◽  
Clinical Setting ◽  
Early Morning ◽  
Healthy Controls ◽  
Patient Subgroup ◽  
Depression Risk ◽  
Gender And Age ◽  
The Relationship

Summary Depression risk is associated with a late chronotype pattern often described as an ‘evening chronotype’. Fluctuations in mood over consecutive days have not yet been measured according to chronotype in in-patients with depression. A total of 30 in-patients with depression and 32 healthy controls matched for gender and age completed a chronotype questionnaire and twice-daily ratings on mood for 10 consecutive days (registered in the German Clinical Trials Register: DRKS00010215). The in-patients had Saturdays and Sundays as hospital-leave days. The relationship between chronotype and daily mood was mediated by the weekday–weekend schedule with higher levels of negative affect in the evening-chronotype patient subgroup at weekends. Results are discussed with respect to a probably advantageous standardised clinical setting with early morning routines, especially for patients with evening chronotypes.

scholarly journals Eliciting and Recording Event Related Potentials (ERPs) in Behaviourally Unresponsive Populations: A Retrospective Commentary on Critical Factors

2021 ◽  
Vol 11 (7) ◽  
pp. 835
Author(s):  
Alexander Rokos ◽  
Richard Mah ◽  
Rober Boshra ◽  
Amabilis Harrison ◽  
Tsee Leng Choy ◽  
...  
Keyword(s):  
Event Related Potentials ◽  
Stimulus Presentation ◽  
Event Related Potential ◽  
Critical Factors ◽  
Healthy Elderly ◽  
States Of Consciousness ◽  
Long Latency ◽  
Eeg Data ◽  
Related Potentials ◽  
The Relationship

A consistent limitation when designing event-related potential paradigms and interpreting results is a lack of consideration of the multivariate factors that affect their elicitation and detection in behaviorally unresponsive individuals. This paper provides a retrospective commentary on three factors that influence the presence and morphology of long-latency event-related potentials—the P3b and N400. We analyze event-related potentials derived from electroencephalographic (EEG) data collected from small groups of healthy youth and healthy elderly to illustrate the effect of paradigm strength and subject age; we analyze ERPs collected from an individual with severe traumatic brain injury to illustrate the effect of stimulus presentation speed. Based on these critical factors, we support that: (1) the strongest paradigms should be used to elicit event-related potentials in unresponsive populations; (2) interpretation of event-related potential results should account for participant age; and (3) speed of stimulus presentation should be slower in unresponsive individuals. The application of these practices when eliciting and recording event-related potentials in unresponsive individuals will help to minimize result interpretation ambiguity, increase confidence in conclusions, and advance the understanding of the relationship between long-latency event-related potentials and states of consciousness.

scholarly journals Mediating effects of lower extremity function on the relationship between night sleep duration and cardiovascular disease risk: a cross-sectional study in elderly Chinese without cardiovascular diseases

BMJ Open ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. e046015
Author(s):  
Hui Zhang ◽  
Xiaoyu Chen ◽  
Peipei Han ◽  
Weibo Ma ◽  
Yuanyuan Zhang ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Sleep Duration ◽  
Physical Performance ◽  
Indirect Effect ◽  
Night Sleep ◽  
Lower Extremity Function ◽  
Cvd Risk ◽  
Extremity Function ◽  
Elderly Chinese ◽  
The Relationship

ObjectiveThe purpose of this study is to investigate the mediating effect of physical performance on the relationship between night sleep duration and risk of cardiovascular disease (CVD) in elderly Chinese without CVD.Methods782 participants without CVD over 65 years (average: 70.82±3.86 years, 448 women) were included in this study. CVD risk was calculated by the Framingham Risk Score and participants were divided into four groups of night sleep duration (in hours): <7 hours, ≥7–8 hours, >8–9 hours and >9 hours. Upper extremity function was measured by grip strength and lower extremity function was measured by the Short Physical Performance Battery (SPPB), consisting of balance, 4 m walk and chair stands tests.ResultsAfter adjusting for covariates, long night sleep duration (>9 hours) and CVD risk were significantly positively associated compared with moderate night sleep duration (≥7–8 hours) (β=1.152; 95% CI 0.05 to 2.25). SPPB total score (indirect effect ab=−0.122; 95% CI −0.291 to –0.0008) rather than grip strength partially mediated the relationship between long night sleep duration and CVD risk, in which chair stands played a major mediating role (indirect effect ab=−0.171; 95% CI −0.040 to –0.0006), while balance (indirect effect ab=−0.016; 95% CI −0.100 to 0.063) and 4 m walk (indirect effect ab=0.048; 95% CI −0.066 to 0.201) did not.ConclusionsLower extremity function, especially lower limb muscle strength, partially mediates a positive association between long night sleep duration and CVD risk in the elderly without CVD. Suitable interventions for physical performance and sleep may minimise the risk of subsequent CVD.

Significance of Lower Body Postures in Chair Design

2021 ◽  
pp. 001872082110270
Author(s):  
Seulgi Kim ◽  
Ilseok Lee ◽  
Sang Hyeon Kang ◽  
Sangeun Jin
Keyword(s):  
Lower Extremity ◽  
Lumbar Lordosis ◽  
System Level ◽  
Lumbar Region ◽  
Muscle Recruitment ◽  
Knee Angle ◽  
Activity Measures ◽  
Head Flexion ◽  
Kinematic Measures ◽  
The Cost

Objective This study examined a system-level perspective to investigate the changes in the whole trunk and head postures while sitting with various lower extremity postures. Background Sitting biomechanics has focused mainly on the lumbar region only, whereas the anatomy literature has suggested various links from the head and lower extremity. Method Seventeen male participants were seated in six lower extremity postures, and the trunk kinematics and muscle activity measures were captured for 5 s. Results Changes in the trunk-thigh angle and the knee angle affected the trunk and head postures and muscle recruitment patterns significantly, indicating significant interactions between the lower extremity and trunk while sitting. Specifically, the larger trunk-thigh angle (T135°) showed more neutral lumbar lordosis (4.0° on average), smaller pelvic flexion (1.8°), smaller head flexion (3.3°), and a less rounded shoulder (1.7°) than the smaller one (T90°). The smaller knee angle (K45°) revealed a more neutral lumbar lordosis (6.9°), smaller pelvic flexion (9.2°), smaller head flexion (2.6°), and less rounded shoulder (2.4°) than the larger condition (K180°). The more neutral posture suggested by the kinematic measures confirmed significantly less muscular recruitment in the trunk extensors, except for a significant antagonistic co-contraction. Conclusion The lower and upper back postures were more neutral, and back muscle recruitment was lower with a larger trunk-thigh angle and a smaller knee angle, but at the cost of antagonistic co-contraction. Application The costs and benefits of each lower extremity posture can be used to design an ergonomic chair and develop an improved sitting strategy.

scholarly journals Glutamate connectivity associations converge upon the salience network in schizophrenia and healthy controls

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Robert A. McCutcheon ◽  
Toby Pillinger ◽  
Maria Rogdaki ◽  
Juan Bustillo ◽  
Oliver D. Howes
Keyword(s):  
Functional Connectivity ◽  
Frontal Cortex ◽  
Network Connectivity ◽  
Resonance Spectroscopy ◽  
Salience Network ◽  
Healthy Controls ◽  
1H Mrs ◽  
Before And After ◽  
Functional Brain Networks ◽  
The Relationship

AbstractAlterations in cortical inter-areal functional connectivity, and aberrant glutamatergic signalling are implicated in the pathophysiology of schizophrenia but the relationship between the two is unclear. We used multimodal imaging to identify areas of convergence between the two systems. Two separate cohorts were examined, comprising 195 participants in total. All participants received resting state functional MRI to characterise functional brain networks and proton magnetic resonance spectroscopy (1H-MRS) to measure glutamate concentrations in the frontal cortex. Study A investigated the relationship between frontal cortex glutamate concentrations and network connectivity in individuals with schizophrenia and healthy controls. Study B also used 1H-MRS, and scanned individuals with schizophrenia and healthy controls before and after a challenge with the glutamatergic modulator riluzole, to investigate the relationship between changes in glutamate concentrations and changes in network connectivity. In both studies the network based statistic was used to probe associations between glutamate and connectivity, and glutamate associated networks were then characterised in terms of their overlap with canonical functional networks. Study A involved 76 individuals with schizophrenia and 82 controls, and identified a functional network negatively associated with glutamate concentrations that was concentrated within the salience network (p < 0.05) and did not differ significantly between patients and controls (p > 0.85). Study B involved 19 individuals with schizophrenia and 17 controls and found that increases in glutamate concentrations induced by riluzole were linked to increases in connectivity localised to the salience network (p < 0.05), and the relationship did not differ between patients and controls (p > 0.4). Frontal cortex glutamate concentrations are associated with inter-areal functional connectivity of a network that localises to the salience network. Changes in network connectivity in response to glutamate modulation show an opposite effect compared to the relationship observed at baseline, which may complicate pharmacological attempts to simultaneously correct glutamatergic and connectivity aberrations.

scholarly journals Colonic Volume Changes in Paediatric Constipation Compared to Normal Values Measured Using MRI

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 974
Author(s):  
Hayfa Sharif ◽  
Caroline L. Hoad ◽  
Nichola Abrehart ◽  
Penny A. Gowland ◽  
Robin C. Spiller ◽  
...  
Keyword(s):  
Linear Regression ◽  
Physiological State ◽  
Functional Constipation ◽  
Initial Study ◽  
Healthy Controls ◽  
Volume Changes ◽  
Additional Information ◽  
Symptom Reports ◽  
Magnetic Resonance Imaging Mri ◽  
The Relationship

Background: Functional constipation in children is common. Management of this condition can be challenging and is often based on symptom reports. Increased, objective knowledge of colonic volume changes in constipation compared to health could provide additional information. However, very little data on paediatric colonic volume is available except from methods that are invasive or require unphysiological colonic preparations. Objectives: (1) To measure volumes of the undisturbed colon in children with functional constipation (FC) using magnetic resonance imaging (MRI) and provide initial normal range values for healthy controls, and (2) to investigate possible correlation of colonic volume with whole gut transit time (WGTT). Methods: Total and regional (ascending, transverse, descending, sigmoid, and rectum) colon volumes were measured from MRI images of 35 participants aged 7–18 years (16 with FC and 19 healthy controls), and corrected for body surface area. Linear regression was used to explore the relationship between total colon volume and WGTT. Results: Total colonic volume was significantly higher, with a median (interquartile range) of 309 mL (243–384 mL) for the FC group than for the healthy controls of 227 mL (180–263 mL). The largest increase between patients and controls was in the sigmoid colon–rectum region. In a linear regression model, there was a positive significant correlation between total colonic volume and WGTT (R = 0.56, p = 0.0005). Conclusions: This initial study shows increased volumes of the colon in children with FC, in a physiological state, without use of any bowel preparation. Increased knowledge of colonic morphology may improve understanding of FC in this age group and help to direct treatment.

scholarly journals Decision making under ambiguity and risk in adolescent-onset schizophrenia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dandan Li ◽  
Fengyan Zhang ◽  
Lu Wang ◽  
Yifan Zhang ◽  
Tingting Yang ◽  
...  
Keyword(s):  
Decision Making ◽  
Executive Function ◽  
Iowa Gambling Task ◽  
Clinical Symptoms ◽  
Healthy Controls ◽  
Syndrome Scale ◽  
Significant Difference ◽  
Abnormal Pattern ◽  
Negative Syndrome ◽  
The Relationship

Abstract Objective Numerous studies have identified impaired decision making (DM) under both ambiguity and risk in adult patients with schizophrenia. However, the assessment of DM in patients with adolescent-onset schizophrenia (AOS) has been challenging as a result of the instability and heterogeneity of manifestations. The Iowa Gambling Task (IGT) and Game of Dice Task (GDT), which are frequently used to evaluate DM respectively under ambiguity and risk, are sensitive to adolescents and neuropsychiatric patients. Our research intended to examine the performance of DM in a relatively large sample of patients with AOS using the above-mentioned two tasks. We also aimed to take a closer look at the relationship between DM and symptom severity of schizophrenia. Methods We compared the performance of DM in 71 patients with AOS and 53 well-matched healthy controls using IGT for DM under ambiguity and GDT for DM under risk through net scores, total scores and feedback ration. Neuropsychological tests were conducted in all participants. Clinical symptoms were evaluated by using Positive and Negative Syndrome Scale (PANSS) in 71 patients with AOS. Pearson’s correlation revealed the relationship among total score of DM and clinical and neuropsychological data. Results Compared to healthy controls, patients with AOS failed to show learning effect and had a significant difference on the 5th block in IGT and conducted more disadvantageous choices as well as exhibited worse negative feedback rate in GDT. Apart from DM impairment under risk, diminished DM abilities under ambiguity were found related to poor executive function in AOS in the present study. Conclusions Our findings unveiled the abnormal pattern of DM in AOS, mainly reflected under the risky condition, extending the knowledge on the performance of DM under ambiguity and risk in AOS. Inefficient DM under risk may account for the lagging impulse control and the combined effects of developmental disease. In addition, our study demonstrated that the performance on IGT was related to executive function in AOS.

scholarly journals The Relationship of Psychiatric Symptoms with Performance-Based and Self-Reported Cognitive Function After Ischemic Stroke

2021 ◽  
pp. 1-13
Author(s):  
Elisabeth Kliem ◽  
Elise Gjestad ◽  
Truls Ryum ◽  
Alexander Olsen ◽  
Bente Thommessen ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Executive Function ◽  
Depressive Symptoms ◽  
Cognitive Function ◽  
Psychiatric Symptoms ◽  
Post Stroke ◽  
Cognitive Difficulties ◽  
Memory And Attention ◽  
Relationship Of ◽  
The Relationship

Abstract Objective: Findings on the relationship of psychiatric symptoms with performance-based and self-reported cognitive function post-stroke are inconclusive. We aimed to (1) study the relation of depression and anxiety to performance-based cognitive function and (2) explore a broader spectrum of psychiatric symptoms and their association with performance-based versus self-reported cognitive function. Method: Individuals with supratentorial ischemic stroke performed neuropsychological examination 3 months after stroke. For primary analyses, composite scores for memory and attention/executive function were calculated based on selected neuropsychological tests, and the Hospital Anxiety and Depression Scale (HADS) was used. Psychiatric symptoms and self-reported cognitive function for secondary aims were assessed using the Symptom-Checklist-90 – Revised (SCL-90-R). Results: In a sample of 86 patients [mean (M) age: 64.6 ± 9.2; Mini-Mental State Examination (MMSE), 3–7 days post-stroke: M = 28.4 ± 1.7; National Institutes of Health Stroke Scale (NIHSS) after 3 months: M = 0.7 ± 1.6] depressive symptoms (HADS) were associated with poorer memory performance after controlling for age, sex, and education (p ≤ .01). In a subsample (n = 41; Age: M = 65.7 ± 8.1; MMSE: M = 28.4 ± 1.8; NIHSS: M = 1.0 ± 1.9), symptoms of phobic anxiety (SCL-90-R) were associated with poorer performance-based memory and attention/executive function, and symptoms of anxiety (SCL-90-R) with lower attention/executive function. Higher levels of self-reported cognitive difficulties were associated with higher scores in all psychiatric domains (p ≤ .05). Conclusion: Even in relatively well-functioning stroke patients, depressive symptoms are associated with poorer memory. The results also suggest that various psychiatric symptoms are more related to self-reported rather than to performance-based cognitive function. Screening for self-reported cognitive difficulties may not only help to identify patients with cognitive impairment, but also those who need psychological treatment.

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