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1.
Drug Discov Ther ; 14(6): 325-329, 2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33390568

RESUMO

New strategies for early diagnosis and careful follow-up of systemic sclerosis are urgently needed. We unconventionally used a video capillaroscopy system to measure the amount of sweating on finger pads, and investigated its clinical significance. Thirty-three Japanese patients who were diagnosed with typical or pre-clinical stage patients of systemic sclerosis were included in this study. Five healthy subjects were also included. Among twenty-one patients with typical systemic sclerosis that fulfilled ACR/EULAR 2013 classification criteria, seven had increased sweating levels. On the other hand, among twelve pre-clinical stage patients that did not fulfill the classification criteria, no patient showed increase in finger sweating. We found that there was statistically significant difference. The ratio of diffuse cutaneous systemic sclerosis was also found to be significantly higher in subjects with increased amounts of sweating than in subjects with normal levels. Furthermore, the positivity of topoisomerase I antibody was statistically higher in patients with increased sweating levels than in those without. These results indicated that measurement of finger sweating levels may be a useful tool for early diagnosis and clarification of pathogenesis in this disease.


Assuntos
Dedos/fisiologia , Angioscopia Microscópica/métodos , Escleroderma Sistêmico/diagnóstico por imagem , Sudorese , Adulto , Idoso , Estudos de Casos e Controles , DNA Topoisomerases Tipo I/metabolismo , Diagnóstico Precoce , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Escleroderma Sistêmico/metabolismo
2.
Nat Commun ; 12(1): 221, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431883

RESUMO

Dedicated maps for cognitive quantities such as timing, size and numerosity support the view that topography is a general principle of brain organization. To date, however, all of these maps were driven by the visual system. Here, we ask whether there are supramodal topographic maps representing cognitive dimensions irrespective of the stimulated sensory modality. We measured haptically and visually driven numerosity-selective neural responses using model-based analyses and ultra-high field (7T) fMRI. We found topographically organized neural populations tuned to haptic numerosity. The responses to visual or haptic numerosity shared a similar cortical network. However, the maps of the two modalities only partially overlap. Thus, although both visual and haptic numerosities are processed in a similar supramodal functional network, the underlying neural populations may be related, but distinct. Therefore, we hypothesize that overlap between modality-specific maps facilitates cross-modal interactions and supramodal representation of cognitive quantities.


Assuntos
Rede Nervosa/fisiologia , Tato/fisiologia , Adulto , Feminino , Dedos/fisiologia , Mãos/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Atividade Motora/fisiologia , Estimulação Luminosa , Percepção Visual/fisiologia
3.
Artigo em Inglês | MEDLINE | ID: mdl-33352653

RESUMO

The present study investigated the time course of repetitive maximal isometric grip strength, depending on the arm position, laterality (dominant vs. non-dominant side), and climbing level. The intervention aimed to provide a feasible indicator of maximal strength-endurance in climbing. Seventeen recreational (climbing level (CL): 6.8 (SD 0.5) on the Union Internationale des Associations d'Alpinisme (UIAA) metric scale) and eleven ambitious (CL: 8.7 (SD 0.6) UIAA metric scale) climbers (age: 27 (8) years; BMI: 21.6 (1.9) kg/m2; ape index (arm span divided by body height): 1.05 (0.18); training volume: 2.2 (1.0) h/week). Participants completed maximal isometric handgrip strength (Fmax) tests in four positions (left and right hand beside the trunk as well as left and right hand above the shoulder) plus twelve repetitive work-relief cycles, lasting 4 and 1 s where isometric strength, heart rate, and perceived exertion were recorded. Fmax differed between groups in nearly all positions. A large side × position × time × group interaction was observed for repetitive isometric grip strength (p = 0.009, ηp2 = 0.71). However, subsequent post-hoc tests did not reveal a significant difference between groups during each testing position. Additional correlation analysis between asymmetry and CL showed an inverse relationship for ambitious climbers (r = -0.71). In conclusion, the degree of grip strength decline did not relevantly differentiate between ambitious and recreational climbers. Thus, the time course of handgrip strength seems to mainly rely on maximal grip strength during the first contraction.


Assuntos
Braço , Dedos/fisiologia , Força da Mão/fisiologia , Montanhismo/fisiologia , Músculo Esquelético/fisiologia , Resistência Física/fisiologia , Recreação/fisiologia , Adulto , Braço/anatomia & histologia , Braço/fisiologia , Feminino , Mãos , Humanos , Masculino , Ombro/fisiologia
4.
J Sports Med Phys Fitness ; 60(8): 1057-1064, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32955831

RESUMO

BACKGROUND: Rock climbers are characterized by enhanced forearm fatigue resistance. This study compared the forearm isometric force of rock climbers (RC), strength-matched power lifters (PL) and aerobically trained (AT) athletes to determine the contribution of muscle oxygen desaturation during ischemia. METHODS: Aerobically trained athletes (N.=6, 23±1 years, 77±1 kg), power lifters (N.=7, 24±1 years, 80±3 kg) and rock climbers (N.=8, 25±2 years, 74±2 kg) took part in a controlled forearm ischemic occlusion (5 min) assessment using near infrared spectroscopy. In addition, three fatigue protocols were completed: protocol 1, sustained maximal voluntary contraction (MVC) until exhaustion; protocol 2, sustained 40% MVC for 3 mins duration; protocol 3, an intermittent 40% MVC (5-s contraction, 5-s recovery) for a duration of 3 mins. Forearm contractile fatigue was quantified as the reduction in MVC. RESULTS: MVC was equivalent between groups (P>0.05). Sustained MVC force (time to decline 50% MVC) was longer in the RC versus AT (AT: 35±5, PL: 46±6, RC: 54±4 s, P<0.05) and both AT and PL for sustained 40% MVC (AT: 56±9, RT: 62±8, RC: 87±7 s, P<0.05). Reduction in MVC was less in RC post intermittent 40% contractions (P<0.05). Oxygen desaturation half-time was longer in the RC versus AT (AT: 65±9, RT: 86±7, RC: 99±7 s, P<0.05) and this was associated with time to 50% MVC (P<0.05, r2=0.53) and time to 40% MVC task failure (P<0.05, r2=0.32). CONCLUSIONS: Rock climbers' enhanced isometric fatigue-resistance and ability to maintain MVC was associated with a lower oxygen consumption of the forearm flexors during the ischemic state. This suggests a training adaptation involving intracellular oxygen consumption.


Assuntos
Antebraço/fisiologia , Montanhismo/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Adaptação Fisiológica , Adulto , Dedos/fisiologia , Antebraço/irrigação sanguínea , Antebraço/diagnóstico por imagem , Humanos , Contração Isométrica/fisiologia , Masculino , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/diagnóstico por imagem , Consumo de Oxigênio , Condicionamento Físico Humano/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho , Levantamento de Peso/fisiologia , Adulto Jovem
5.
PLoS One ; 15(7): e0236416, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735572

RESUMO

Proprioception acquires a crucial role in estimating the configuration of our body segments in space when visual information is not available. Proprioceptive accuracy is assessed by asking participants to match the perceived position of an unseen body landmark through reaching movements. This task was also adopted to study the perceived hand structure by computing the relative distances between averaged proprioceptive judgments (hand Localization Task). However, the pattern of proprioceptive errors leading to the misperceived hand structure is unexplored. Here, we aimed to characterize this pattern across different hand landmarks, having different anatomo-physiological properties and cortical representations. Furthermore, we sought to describe the error consistency and its stability over time. To this purpose, we analyzed the proprioceptive errors of 43 healthy participants during the hand Localization Task. We found larger but more consistent errors for the fingertips compared to the knuckles, possibly due to poorer proprioceptive signal, compensated by other sources of spatial information. Furthermore, we found a shift (overlap effect) and a temporal drift of the hand perceived position towards the shoulder of origin, which was consistent within and between subjects. The overlap effect had a greater influence on lateral compared to medial landmarks, leading to the hand width overestimation. Our results are compatible with domain-general and body-specific spatial biases affecting the proprioceptive localization of the hand landmarks, thus the apparent hand structure misperception.


Assuntos
Mãos/fisiologia , Movimento/fisiologia , Propriocepção/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Dedos/fisiologia , Corpo Humano , Humanos , Julgamento , Aprendizagem/fisiologia , Masculino , Polegar/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
6.
J Vis Exp ; (161)2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32804156

RESUMO

Passive tactile perception is the ability to passively and statically perceive stimulus information coming from the skin; for example, the ability to sense spatial information is the strongest in the skin on the hands. This ability is termed tactile spatial acuity, and is measured by the tactile threshold or discrimination threshold. At present, the two-point threshold is extensively used as a measure of tactile spatial acuity, although many studies have indicated that critical deficits exist in two-point discrimination. Therefore, a computer-controlled tactile stimulus system was developed, the tactile semiautomated passive-finger angle stimulator (TSPAS), using the tactile angle discrimination threshold as a new measure for tactile spatial acuity. The TSPAS is a simple, easily operated system that applies raised angle stimuli to a subject's passive fingerpad, while controlling movement speed, distance, and contact duration. The components of the TSPAS are described in detail as well as the procedure to calculate the tactile angle discrimination threshold.


Assuntos
Dedos/fisiologia , Percepção do Tato/fisiologia , Humanos
7.
Motor Control ; 24(3): 365-382, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663389

RESUMO

The authors examined how the stability of the current total isometric force (FT) produced by four fingers is influenced by previous and expected voluntary changes in FT. The authors employed the synergy index obtained from the across-trial uncontrolled manifold analysis to quantify the stability of FT. The authors compared two tasks with similar histories of FT changes; one in which participants expected changes in FT in the future, and one in which they expected no changes in FT. The stability of FT was lower in the former task, indicating the existence of a novel type of anticipatory synergy adjustment. Disparate histories of FT changes yield inconsistent changes in stability, driven by individual differences in the covariation in the finger forces that leave FT invariant. Future research should focus on exploring these individual differences to better understand how previous and expected behavior changes influence the stability of the current motor behavior.


Assuntos
Dedos/fisiologia , Força da Mão/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
8.
Wilderness Environ Med ; 31(3): 312-316, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32482519

RESUMO

INTRODUCTION: Cold-induced vasodilation (CIVD) is seen in the extremities during exposure to cold. A strong vasodilation response has been associated with a decreased risk of cold injury. Increasing CIVD might further decrease this risk. The calcium-channel blocker nifedipine causes vasodilation and is used to treat Raynaud's syndrome and chilblains. Nifedipine is also used for high altitude pulmonary edema and could potentially serve a dual purpose in preventing frostbite. The effects of nifedipine on CIVD have not been studied. METHODS: A double-blind crossover study comparing nifedipine (30 mg SR (sustained release) orally twice daily) to placebo was designed using 2 sessions of 4 finger immersion in 5°C water, with 24 h of medication pretreatment before each session. Finger temperatures were measured via nailbed thermocouples. The primary outcome was mean finger temperature; secondary outcomes were mean apex and nadir temperatures, first apex and nadir temperatures, subjective pain ranking, and time of vasodilation onset (all presented as mean±SD). RESULTS: Twelve volunteers (age 29±3 [24-34] y) completed the study. No significant difference in finger temperature (9.2±1.1°C nifedipine vs 9.0±0.7°C placebo, P=0.38) or any secondary outcome was found. Pain levels were similar (2.8±1.6 nifedipine vs 3.0±1.5 placebo, P=0.32). The most common adverse event was headache (32% of nifedipine trials vs 8% placebo). CONCLUSIONS: Pretreatment with 30 mg of oral nifedipine twice daily does not affect the CIVD response in healthy individuals under cold stress.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Temperatura Baixa/efeitos adversos , Dedos/fisiologia , Nifedipino/farmacologia , Vasodilatação/fisiologia , Vasodilatadores/farmacologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Utah , Vasodilatação/efeitos dos fármacos , Adulto Jovem
9.
J Vis Exp ; (160)2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32568217

RESUMO

The purpose of the protocol is to indirectly evaluate the direction of the finger force during manipulation of a handheld object based on the biomechanical relationships in which deviated force direction causes center of pressure (COP) replacement. To evaluate this, a thin, flexible, and high spatial resolution pressure sensor sheet is used. The system allows measurement of the COP trajectory in addition to the force amplitude and its temporal regulation. A series of experiments found that increased trajectory length reflected a sensorimotor deficit in stroke patients, and that decreased COP trajectory reflects a compensatory strategy to avoid an object slipping from the hand grip in the elderly. Moreover, the COP trajectory could also be decreased by dual task interference. This article describes the experimental procedure and discusses how finger COP contributes to an understanding of the physiology and pathophysiology of grasping.


Assuntos
Força da Mão/fisiologia , Fenômenos Mecânicos , Adulto , Idoso , Fenômenos Biomecânicos , Feminino , Dedos/fisiologia , Dedos/fisiopatologia , Humanos , Masculino , Acidente Vascular Cerebral/fisiopatologia
10.
PLoS One ; 15(6): e0234354, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530942

RESUMO

Soft robot fabrication by casting liquid elastomer often requires multiple steps of casting or skillful manual labor. We present a novel soft robotic fabrication technique: negshell casting (negative-space eggshell casting), that reduces the steps required for fabrication by introducing 3D-printed thin-walled cores for use in casting that are meant to be left in place instead of being removed later in the fabrication process. Negshell casting consists of two types of cores: sacrificial cores (negshell cores) and structural cores. Negshell cores are designed to be broken into small pieces that have little effect on the mechanical structure of the soft robot, and can be used for creating fluidic channels and bellows for actuation. Structural cores, on the other hand, are not meant to be broken, and are for increasing the stiffness of soft robotic structures, such as endoskeletons. We describe the design and fabrication concepts for both types of cores and report the mechanical characterization of the cores embedded in silicone rubber specimens. We also present an example use-case of negshell casting for a single joint soft robotic finger, along with an experiment to demonstrate how negshell casting concepts can aid in force transmission. Finally, we present real-world usage of negshell casting in a 6 degree-of-freedom three-finger soft robotic gripper, and a demonstration of the gripper in a robotic pick-and-place task. A companion website with further details about fabrication (as well as an introduction to molding and casting for those who are unfamiliar with the terms), engineering file downloads, and experimental data is provided at https://negshell.github.io/.


Assuntos
Desenho Assistido por Computador/instrumentação , Impressão Tridimensional/instrumentação , Robótica/instrumentação , Biomimética/instrumentação , Elasticidade , Elastômeros , Desenho de Equipamento , Dedos/fisiologia , Força da Mão/fisiologia , Humanos , Fenômenos Mecânicos , Elastômeros de Silicone
11.
Acta Psychol (Amst) ; 208: 103090, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32485337

RESUMO

Recent studies have demonstrated that mental representations of the hand dorsum are distorted even for healthy participants. Perceptual hand maps estimated by pointing to specific landmarks (e.g., knuckles and tips of fingers) is stretched and shrunk along the medio-lateral and the proximo-distal axes, respectively. Similarly, tactile distance perception between two touches is longer along the medio-lateral axis than the proximo-distal axis. The congruency of the two types of distortions suggests that common perceptual and neural representations may be involved in these processes. Prolonged stimulation by two simultaneous touches having a particular distance can bias subsequent perception of tactile distances (e.g., adaptation to a long distance induces shorter stimuli to be perceived even shorter). This tactile distance adaptation aftereffect has been suggested to occur based on the modulations of perceptual and neural responses at low somatosensory processing stages. The current study investigated whether tactile distance adaptation aftereffects affect also the pattern of distortions on the perceptual hand maps. Participants localized locations on the hand dorsum cued by tactile stimulations (Experiment 1) or visually presented landmarks on a hand silhouette (Experiment 2). Each trial was preceded by adaptation to either a small (2 cm) or large (4 cm) tactile distance. We found clear tactile distance aftereffects. However, no changes were observed for the distorted pattern of the perceptual hand maps following adaptation to a tactile distance. Our results showed that internal body representations involved in perceptual distortions may be distinct between tactile distance perception and the perceptual hand maps underlying position sense.


Assuntos
Mãos/fisiologia , Percepção do Tato/fisiologia , Adaptação Fisiológica , Dedos/fisiologia , Humanos , Tato
12.
Nat Commun ; 11(1): 2183, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366821

RESUMO

Coupling myoelectric and mechanical signals during voluntary muscle contraction is paramount in human-machine interactions. Spatiotemporal differences in the two signals intrinsically arise from the muscular excitation-contraction process; however, current methods fail to deliver local electromechanical coupling of the process. Here we present the locally coupled electromechanical interface based on a quadra-layered ionotronic hybrid (named as CoupOn) that mimics the transmembrane cytoadhesion architecture. CoupOn simultaneously monitors mechanical strains with a gauge factor of ~34 and surface electromyogram with a signal-to-noise ratio of 32.2 dB. The resolved excitation-contraction signatures of forearm flexor muscles can recognize flexions of different fingers, hand grips of varying strength, and nervous and metabolic muscle fatigue. The orthogonal correlation of hand grip strength with speed is further exploited to manipulate robotic hands for recapitulating corresponding gesture dynamics. It can be envisioned that such locally coupled electromechanical interfaces would endow cyber-human interactions with unprecedented robustness and dexterity.


Assuntos
Eletromiografia/métodos , Força da Mão/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Amplitude de Movimento Articular/fisiologia , Membros Artificiais , Bioengenharia/instrumentação , Bioengenharia/métodos , Fenômenos Biomecânicos , Eletrônica Médica/instrumentação , Eletrônica Médica/métodos , Dedos/fisiologia , Antebraço/fisiologia , Mãos/fisiologia , Humanos , Desenho de Prótese/instrumentação , Desenho de Prótese/métodos
13.
Sci Rep ; 10(1): 8470, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32439947

RESUMO

Balancing the body in upright standing and balancing a stick on the fingertip are two examples of unstable tasks that, in spite of strong motor and sensory differences, appear to share a similar motor control paradigm, namely a state-space intermittent feedback stabilization mechanism. In this study subjects were required to perform the two tasks simultaneously, with the purpose of highlighting both the coordination between the two skills and the underlying interaction between the corresponding controllers. The experimental results reveal, in particular, that upright standing (the less critical task) is modified in an adaptive way, in order to facilitate the more critical task (stick balancing), but keeping the overall spatio-temporal signature well known in regular upright standing. We were then faced with the following question: to which extent the physical/biomechanical interaction between the two independent intermittent controllers is capable to explain the dual task coordination patterns, without the need to introduce an additional, supervisory layer/module? By comparing the experimental data with the output of a simulation study we support the former hypothesis, suggesting that it is made possible by the intrinsic robustness of both state-space intermittent feedback stabilization mechanisms.


Assuntos
Dedos/fisiologia , Modelos Teóricos , Equilíbrio Postural/fisiologia , Postura/fisiologia , Desempenho Psicomotor/fisiologia , Posição Ortostática , Adulto , Retroalimentação , Feminino , Humanos , Masculino , Análise e Desempenho de Tarefas , Adulto Jovem
14.
World Neurosurg ; 140: 303-307, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32428719

RESUMO

BACKGROUND: Malformations of cortical development (MCDs) often result in mental retardation, intractable epilepsy, neurodevelopmental delay, and contralateral hemiparesis. We describe herein a rare patient with MCD who had developed normally in spite of diffuse hemispheric anomaly of the brain. CASE DESCRIPTION: We report a left-handed 20-year-old healthy man. A magnetic resonance image scan revealed congenital left cerebral hemispheric dysplasia and deficit of the normal anatomical primary motor cortices although he was normally developed without hemiparesis nor aphasia. Diffusion tensor tractography showed unusual fiber radiation from the left cerebral peduncle to the much more rostral and lateral cerebral cortices compared with normal anatomy. Right finger flexion-extension task showed activation in that area on functional magnetic resonance imaging. CONCLUSIONS: Even in a congenital hemispheric dysplasia, the contralateral fine finger movement may still depend on the dysplastic hemisphere. On the other hand, speech and the other gross movements including leg, foot, and arm can be compensated with the ipsilateral normal cerebral cortices.


Assuntos
Dedos/fisiologia , Lateralidade Funcional/fisiologia , Córtex Motor/fisiopatologia , Movimento/fisiologia , Imagem de Tensor de Difusão , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Motor/diagnóstico por imagem , Adulto Jovem
15.
Sci Rep ; 10(1): 7851, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398669

RESUMO

A simple motor behaviour or a more complex behaviour is the result of the neural activity of those neural networks responsible for the behaviour. To understand how the network activity is transformed into human behaviours, it is necessary to identify task-specific networks and analyse the dynamic network activity that changes with time. Here we report a novel task-fMRI technique to identify task-specific networks and analyse their dynamic activity. Nine subjects participated in a task-fMRI study in which the subjects were cued to perform three different tasks of word-reading, pattern-viewing and finger-tapping. A functional area of unitary pooled activity (FAUPA) is defined as an area in which the temporal variation of the activity is the same across the entire area, and a task-associated FAUPA plays the role of a functional unit for the task. A novel method is presented to (1) identify FAUPAs that are associated with each task as well as their functional groupings; (2) identify the three task-specific networks; and (3) analyse the network activity from trial to trial. Task-associated FAUPAs were identified for each task and each subject. A task-specific large-scale neural network across the whole brain consisted of all FAUPAs that were activated each time the task was performed, and all three task-specific networks were identified for each individual subject. The temporal changes of activation and functional connectivity of the FAUPAs within each network from trial to trial characterized the dynamic activity of the network. The results demonstrated a one-to-one relation between the network activity and the task performance from trial to trial, offering a means of testing the causal relationship between network activity and human task performance by systematically manipulating task performance and measuring corresponding network activity change.


Assuntos
Encéfalo/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Dedos/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Córtex Motor/diagnóstico por imagem , Córtex Motor/fisiologia , Movimento , Córtex Somatossensorial/diagnóstico por imagem , Córtex Somatossensorial/fisiologia , Adulto Jovem
16.
Hum Mov Sci ; 71: 102625, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32452441

RESUMO

While much has been learned about the visual pursuit and motor strategies used to intercept a moving object, less research has focused on the coordination of gaze and digit placement when grasping moving stimuli. Participants grasped 2D computer generated square targets that either encouraged placement of the index finger and thumb along the horizontal midline (Control targets) or had narrow "notches" in the top and bottom surfaces of the target, intended to discourage digit placement near the midline (Experimental targets). In Experiment 1, targets remained stationary at the left, middle, or right side of the screen. Gaze and digit placement were biased toward the closest side of non-central targets, and toward the midline of center targets. These locations were shifted rightward when grasping Experimental targets, suggesting participants prioritized visibility of the target. In Experiment 2, participants grasped horizontally translating targets at early, middle, or late stages of travel. Average gaze and digit placement were consistently positioned behind the moving target's horizontal midline when grasping. Gaze was directed farther behind the midline of Experimental targets, suggesting the absence of a flat central grasp location pulled participants' gaze toward the trailing edge. Participants placed their digits at positions closer to the horizontal midline of leftward moving targets, suggesting participants were compensating for the added mechanical constraints associated with grasping targets moving in a direction contralateral to the grasping hand. These results suggest participants minimize the effort associated with reaching to non-central targets by grasping the nearest side when the target is stationary, but grasp the trailing side of moving targets, even if this means placing the digits at locations on the far side of the target, potentially limiting visibility of the target.


Assuntos
Dedos/fisiologia , Fixação Ocular , Movimento , Desempenho Psicomotor , Polegar/fisiologia , Adolescente , Adulto , Fenômenos Biomecânicos , Feminino , Força da Mão , Humanos , Masculino , Adulto Jovem
17.
JAMA Netw Open ; 3(4): e202064, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32242908

RESUMO

Importance: Atrial fibrillation (AF) affects more than 6 million people in the United States; however, much AF remains undiagnosed. Given that more than 265 million people in the United States own smartphones (>80% of the population), smartphone applications have been proposed for detecting AF, but the accuracy of these applications remains unclear. Objective: To determine the accuracy of smartphone camera applications that diagnose AF. Data Sources and Study Selection: MEDLINE and Embase were searched until January 2019 for studies that assessed the accuracy of any smartphone applications that use the smartphone's camera to measure the amplitude and frequency of the user's fingertip pulse to diagnose AF. Data Extraction and Synthesis: Bivariate random-effects meta-analyses were constructed to synthesize data. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) of Diagnostic Test Accuracy Studies reporting guideline. Main Outcomes and Measures: Sensitivity and specificity were measured with bivariate random-effects meta-analysis. To simulate the use of these applications as a screening tool, the positive predictive value (PPV) and negative predictive value (NPV) for different population groups (ie, age ≥65 years and age ≥65 years with hypertension) were modeled. Lastly, the association of methodological limitations with outcomes were analyzed with sensitivity analyses and metaregressions. Results: A total of 10 primary diagnostic accuracy studies, with 3852 participants and 4 applications, were included. The oldest studies were published in 2016 (2 studies [20.0%]), while most studies (4 [40.0%]) were published in 2018. The applications analyzed the pulsewave signal for a mean (range) of 2 (1-5) minutes. The meta-analyzed sensitivity and specificity for all applications combined were 94.2% (95% CI, 92.2%-95.7%) and 95.8% (95% CI, 92.4%-97.7%), respectively. The PPV for smartphone camera applications detecting AF in an asymptomatic population aged 65 years and older was between 19.3% (95% CI, 19.2%-19.4%) and 37.5% (95% CI, 37.4%-37.6%), and the NPV was between 99.8% (95% CI, 99.83%-99.84%) and 99.9% (95% CI, 99.94%-99.95%). The PPV and NPV increased for individuals aged 65 years and older with hypertension (PPV, 20.5% [95% CI, 20.4%-20.6%] to 39.2% [95% CI, 39.1%-39.3%]; NPV, 99.8% [95% CI, 99.8%-99.8%] to 99.9% [95% CI, 99.9%-99.9%]). There were methodological limitations in a number of studies that did not appear to be associated with diagnostic performance, but this could not be definitively excluded given the sparsity of the data. Conclusions and Relevance: In this study, all smartphone camera applications had relatively high sensitivity and specificity. The modeled NPV was high for all analyses, but the PPV was modest, suggesting that using these applications in an asymptomatic population may generate a higher number of false-positive than true-positive results. Future research should address the accuracy of these applications when screening other high-risk population groups, their ability to help monitor chronic AF, and, ultimately, their associations with patient-important outcomes.


Assuntos
Fibrilação Atrial/diagnóstico , Confiabilidade dos Dados , Determinação da Frequência Cardíaca/instrumentação , Smartphone/instrumentação , Adulto , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/epidemiologia , Coleta de Dados/métodos , Feminino , Dedos/fisiologia , Humanos , Hipertensão/epidemiologia , Hipertensão/fisiopatologia , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Aplicativos Móveis/estatística & dados numéricos , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Estados Unidos/epidemiologia
18.
J Neurosci ; 40(20): 3933-3948, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32245828

RESUMO

In an uncertain external environment, the motor system may need to respond rapidly to an unexpected stimulus. Limb displacement causes muscle stretch; the corrective response has multiple activity bursts, which are suggested to originate from different parts of the neuraxis. The earliest response is so fast, it can only be produced by spinal circuits; this is followed by slower components thought to arise from primary motor cortex (M1) and other supraspinal areas. Spinal cord (SC) contributions to the slower components are rarely considered. To address this, we recorded neural activity in M1 and the cervical SC during a visuomotor tracking task, in which 2 female macaque monkeys moved their index finger against a resisting motor to track an on-screen target. Following the behavioral trial, an increase in motor torque rapidly returned the finger to its starting position (lever velocity >200°/s). Many cells responded to this passive mechanical perturbation (M1: 148 of 211 cells, 70%; SC: 67 of 119 cells, 56%). The neural onset latency was faster for SC compared with M1 cells (21.7 ± 11.2 ms vs 25.5 ± 10.7 ms, respectively, mean ± SD). Using spike-triggered averaging, some cells in both regions were identified as likely premotor cells, with monosynaptic connections to motoneurons. Response latencies for these cells were compatible with a contribution to the muscle responses following the perturbation. Comparable fractions of responding neurons in both areas were active up to 100 ms after the perturbation, suggesting that both SC circuits and supraspinal centers could contribute to later response components.SIGNIFICANCE STATEMENT Following a limb perturbation, multiple reflexes help to restore limb position. Given conduction delays, the earliest part of these reflexes can only arise from spinal circuits. By contrast, long-latency reflex components are typically assumed to originate from supraspinal centers. We recorded from both spinal and motor cortical cells in monkeys responding to index finger perturbations. Many spinal interneurons, including those identified as projecting to motoneurons, responded to the perturbation; the timing of responses was compatible with a contribution to both short- and long-latency reflexes. We conclude that spinal circuits also contribute to long-latency reflexes in distal and forearm muscles, alongside supraspinal regions, such as the motor cortex and brainstem.


Assuntos
Dedos/inervação , Dedos/fisiologia , Medula Espinal/fisiologia , Animais , Fenômenos Biomecânicos , Eletromiografia , Feminino , Cinética , Macaca mulatta , Córtex Motor/fisiologia , Neurônios Motores/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Estimulação Física , Desempenho Psicomotor/fisiologia , Tempo de Reação , Reflexo de Estiramento/fisiologia , Torque
19.
Sci Rep ; 10(1): 6341, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286380

RESUMO

The ratio between the length of second and fourth digits (2D:4D) is a putative biomarker for prenatal testosterone and estrogen exposure. The aim of the study was to examine the association between 2D:4D and women's general and reproductive health. This analysis was conducted within a prospective pregnancy cohort study. The study population included 187 women. 2D:4D was measured directly in both hands using a digital caliper. Multivariable linear and logistic models were used to study the associations between digit ratio and the studied health characteristics. Mean age of the participants was 30.7 ± 4.9 years. The mean age at menarche was 12.9 ± 1.4 years. Right hand 2D:4D mean ± SD was 0.965 ± 0.03. Left hand 2D:4D mean ± SD was 0.956 ± 0.03. An association was found between right 2D:4D and age at menarche, with older age in women with 2D:4D ≥ mean versus 2D:4D < mean (13.2 ± 1.5 and 12.8 ± 1.3 respectively, b = 0.48, 95%CI:0.06-0.91) while controlling for ethnicity. Higher 2D:4D was also associated with heavier menses bleeding and dysmenorrhea. There is an association between 2D:4D and sub optimal reproductive characteristics, including later age at menarche, heavier menses bleeding and dysmenorrhea. These findings support the association between the intrauterine period and reproductive characteristics. Further studies are required to support our findings.


Assuntos
Dedos/fisiologia , Menarca/fisiologia , Reprodução/fisiologia , Adolescente , Adulto , Idoso , Antropometria/métodos , Criança , Estudos de Coortes , Estrogênios/sangue , Feminino , Dedos/anatomia & histologia , Humanos , Menarca/sangue , Gravidez , Estudos Prospectivos , Reprodução/genética , Testosterona/sangue
20.
PLoS One ; 15(3): e0230687, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32208443

RESUMO

AIM: This study was conducted to investigate the effect of resuscitation guideline terminology on the performance of infant cardiopulmonary resuscitation (CPR). METHODS: A total of 40 intern or resident physicians conducted 2-min CPR with the two-finger technique (TFT) and two-thumb technique (TT) on a simulated infant cardiac arrest model with a 1-day interval. They were randomly assigned to Group A or B. The participants of Group A conducted CPR with the chest compression depth (CCD) target of "approximately 4 cm" and those of Group B conducted CPR with the CCD target of "at least one-third the anterior-posterior diameter of the chest". Single rescuer CPR was performed with a 15:2 compression to ventilation ratio on the floor. RESULTS: In both chest compression techniques, the average CCD of Group B was significantly deeper than that of Group A (TFT: 41.0 [range, 39.3-42.0] mm vs. 36.5 [34.0-37.9] mm, P = 0.002; TT: 42.0 [42.0-43.0] mm vs. 37.0 [35.3-38.0] mm, P < 0.001). Adequacy of CCD also showed similar results (Group B vs. A; TFT: 99% [82-100%] vs. 29% [12-58%], P = 0.001; TT: 100% [100-100%] vs. 28% [8-53%], P < 0.001). CONCLUSIONS: Using the CCD target of "at least one-third the anterior-posterior diameter of the chest" resulted in deep and adequate chest compressions during simulated infant CPR in contrast to the CCD target of "approximately 4 cm". Therefore, changes in the terminology used in the guidelines should be considered to improve the quality of CPR. TRIAL REGISTRATION: Clinical Research Information Service; cris.nih.go.kr/cris/en (Registration number: KCT0003486).


Assuntos
Reanimação Cardiopulmonar/métodos , Médicos/psicologia , Adulto , Feminino , Dedos/fisiologia , Guias como Assunto , Humanos , Lactente , Internato e Residência , Masculino , Manequins , Parada Cardíaca Extra-Hospitalar/patologia , Parada Cardíaca Extra-Hospitalar/prevenção & controle , Pressão , Estudos Prospectivos , Tórax/fisiologia
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