Diabetic older women without peripheral neuropathy amplify body sway but are capable of improving postural stability during a saccadic gaze task.

BACKGROUND: Diabetic older people tend to present deteriorated performance in balance and locomotion activities, even those without peripheral neuropathy. There is evidence that saccadic eye movements are used to reduce body sway in young and older healthy adults, but it has not been shown that diabetic older people preserve this visuomotor adaptation capacity. RESEARCH QUESTION: Are diabetic older women without peripheral neuropathy capable of improving postural stability during a saccadic gaze task? METHODS: Seventeen type 2 diabetic older women (68.2 ± 10.7 years old) and seventeen healthy women, age-matched controls (66.0 ± 8.4 years old) voluntarily participated in the study. All participants were instructed to stand upright, barefoot, as stable as possible, for 30 s. Participants maintained their feet parallel to each other, at standard and narrow bases of support, while either fixating on a stationary target (fixation condition) or performing horizontal saccadic eye movements to follow a target (eccentricity of 11° of visual angle), which continuously disappeared and reappeared immediately on the opposite side (saccade 0.5 Hz and saccade 1.1 Hz conditions). RESULTS: Results indicated that the diabetic group clearly had deteriorated postural control, as shown by increased values of mean sway amplitude and mean sway velocity. However, diabetic and control groups were similarly capable of using saccadic eye movements to improve their postural stability, reducing their sway velocity compared to a gaze fixation condition. SIGNIFICANCE: Diabetes per se (without peripheral neuropathy) amplifies postural sway of older women as compared to their healthy age-matched controls. However, diabetic older women without peripheral neuropathy are capable of improving postural stability during a saccadic gaze task.

Does joint impedance improve dynamic leg simulations with explicit and implicit solvers?

The nervous system predicts and executes complex motion of body segments actuated by the coordinated action of muscles. When a stroke or other traumatic injury disrupts neural processing, the impeded behavior has not only kinematic but also kinetic attributes that require interpretation. Biomechanical models could allow medical specialists to observe these dynamic variables and instantaneously diagnose mobility issues that may otherwise remain unnoticed. However, the real-time and subject-specific dynamic computations necessitate the optimization these simulations. In this study, we explored the effects of intrinsic viscoelasticity, choice of numerical integration method, and decrease in sampling frequency on the accuracy and stability of the simulation. The bipedal model with 17 rotational degrees of freedom (DOF)-describing hip, knee, ankle, and standing foot contact-was instrumented with viscoelastic elements with a resting length in the middle of the DOF range of motion. The accumulation of numerical errors was evaluated in dynamic simulations using swing-phase experimental kinematics. The relationship between viscoelasticity, sampling rates, and the integrator type was evaluated. The optimal selection of these three factors resulted in an accurate reconstruction of joint kinematics (err < 1%) and kinetics (err < 5%) with increased simulation time steps. Notably, joint viscoelasticity reduced the integration errors of explicit methods and had minimal to no additional benefit for implicit methods. Gained insights have the potential to improve diagnostic tools and accurize real-time feedback simulations used in the functional recovery of neuromuscular diseases and intuitive control of modern prosthetic solutions.

Does joint impedance improve dynamic leg simulations with explicit and implicit solvers?

The nervous system predicts and executes complex motion of body segments actuated by the coordinated action of muscles. When a stroke or other traumatic injury disrupts neural processing, the impeded behavior has not only kinematic but also kinetic attributes that require interpretation. Biomechanical models could allow medical specialists to observe these dynamic variables and instantaneously diagnose mobility issues that may otherwise remain unnoticed. However, the real-time and subject-specific dynamic computations necessitate the optimization these simulations. In this study, we explored the effects of intrinsic viscoelasticity, choice of numerical integration method, and decrease in sampling frequency on the accuracy and stability of the simulation. The bipedal model with 17 rotational degrees of freedom (DOF)-describing hip, knee, ankle, and standing foot contact-was instrumented with viscoelastic elements with a resting length in the middle of the DOF range of motion. The accumulation of numerical errors was evaluated in dynamic simulations using swing-phase experimental kinematics. The relationship between viscoelasticity, sampling rates, and the integrator type was evaluated. The optimal selection of these three factors resulted in an accurate reconstruction of joint kinematics (err < 1%) and kinetics (err < 5%) with increased simulation time steps. Notably, joint viscoelasticity reduced the integration errors of explicit methods and had minimal to no additional benefit for implicit methods . Gained insights have the potential to improve diagnostic tools and accurize real-time feedback simulations used in the functional recovery of neuromuscular diseases and intuitive control of modern prosthetic solutions.

Daily physical activity in children enrolled in extracurricular activity / Atividade física diária em crianças participantes de atividade extrecurricular

ABSTRACT This study aimed to verify and compare the physical activity practices of children enrolled and non-enrolled on different days of week in a specific program offered at school. Seventy-eight children comprised two groups: children with extra physical activity (EPA; n=39; 15 females and 24 males; age: 9.2±0.8 years) and those with no involvement in extra physical activity (NPA; n=39; 21 females and 18 males; age: 9.0±0.4 years). To infer caloric expenditure, number of steps per day, and total distance traveled, children were monitored with pedometers during three nonconsecutive days: a day with a physical education class at school, a normal activity weekday, and a weekend day. Children enrolled in extra activities at school presented higher levels of caloric expenditure (EPA=132±61, NPA=61±25), performed more steps per day (EPA=7742±2473, NPA=5245±2306) and traveled longer distances (EPA=4201±1318, NPA=2799±1269), with boys (calories=154.1±91.6; steps=9763±3804; traveled distance=5114±2205) more active than girls (calories=94.4±46.7; steps=6691±2394; traveled distance=3726±1387). In the extracurricular physical activity day, children expended more calories (155.8±88.3), performed mores steps (10133±3724) and traveled longer distance (5442±2118) than in the physical education day (calories=127.2±79.3; steps=8409±3283; traveled distance=4478±1864) and in the weekend (calories=96.8±58.8; steps=6493±2687; traveled distance=3500±1466). Extracurricular physical activity at school leads to an increase of physical activity of boys and girls, even on days when the extracurricular activity is not offered.

RESUMO O objetivo deste estudo foi verificar e comparar a prática de atividade física de crianças em diferentes dias da semana envolvidas e não envolvidas em um programa de atividade física extracurricular. Setenta e oito crianças formaram dois grupos: crianças com atividade física extracurricular (CAF; n=39; 15 meninas e 24 meninos; idade: 9,2±0,8 anos) e crianças sem atividade física extracurricular (NAF; n=39; 21 meninas e 18 meninos; idade: 9,0±0,4 anos). Foram estimados o dispêndio calórico, o número de passos por dia e a distância percorrida, por meio de pedômetros em dias não consecutivos: um dia com aula de educação física, um dia com atividades cotidianas e um dia de final de semana. Crianças envolvidas em atividades extracurriculares na escola apresentaram maior dispêndio calórico (CAF=132±61, NAF=61±25), número de passos (CAF=7742±2473, NAF=5245±2306) e distância percorrida (CAF=4201±1318, NAF=2799±1269), sendo ainda meninos (calorias=154,1±91,6; passos=9763±3804; distância=5114±2205) mais ativos que meninas (calorias=94,4±46,7; passos=6691±2394; distância=3726±1387). No dia de atividade extracurricular, crianças dispendem mais calorias (155,8±88,3), realizam mais passos (10133±3724) e percorrem maior distância (5442±2118) do que nos dias de educação física (calorias=127,2±79,3; passos=8409±3283; distância=4478±1864) e final de semana (calorias=96,8±58,8; passos=6493±2687; distância=3500±1466). Atividade física extracurricular na escola promove aumento de atividade física de meninos e meninas, mesmo nos dias em que a atividade física extracurricular não foi oferecida.

A multiple domain postural control assessment in people with Parkinson's disease: traditional, non-linear, and rambling and trembling trajectories analysis.

BACKGROUND: Postural impairment is one of the most debilitating symptoms in people with Parkinson's disease (PD), which show faster and more variable oscillation during quiet stance than neurologically healthy individuals. Despite the center of pressure parameters can characterize PD's body sway, they are limited to uncover underlying mechanisms of postural stability and instability. RESEARCH QUESTION: Do a multiple domain analysis, including postural adaptability and rambling and trembling components, explain underlying postural stability and instability mechanisms in people with PD? METHOD: Twenty-four individuals (12 people with PD and 12 neurologically healthy peers) performed three 60-s trials of upright quiet standing on a force platform. Traditional and non-linear parameters (Detrended Fluctuation Analysis- DFA and Multiscale Entropy- MSE) and rambling and trembling trajectories were calculated for anterior-posterior (AP) and medial-lateral (ML) directions. RESULTS: PDG's postural control was worse compared to CG, displaying longer displacement, higher velocity, and RMS. Univariate analyses revealed largely longer displacement and RMS only for the AP direction and largely higher velocity for both AP and ML directions. Also, PD individuals showed lower AP complexity, higher AP and ML DFA, and increased AP and ML displacement, velocity, and RMS of rambling and trembling components compared to neurologically healthy individuals. SIGNIFICANCE: Based upon these results, people with PD have a lower capacity to adapt posture and impaired both rambling and trembling components compared to neurologically healthy individuals. These findings provide new insights to explain the larger, faster, and more variable sway in people with PD.

Saccadic eye movement performance reduces visual manipulation influence and center of pressure displacements in older fallers.

This study examined changes in postural control and gaze performance of faller and non-faller older adults under conditions of visual tasks and optical flow manipulations. Fifteen older non-fallers (69.8 years, ± 3.2) and fifteen older fallers (71.1 years, ± 6.4) stood on a force platform inside a moving room wearing an eye tracker. Four tasks were performed: gaze fixation; predictable saccades; unpredictable saccades; and free-viewing. The stimuli appeared at a frequency of 1.1 Hz during conditions of predictable and unpredictable saccades. Sixteen trials were divided into two blocks. In the first block, the room remained stationary. In the second block, the room oscillated, without the participant's awareness, with a 0.6 cm amplitude and 0.2 Hz frequency. Results showed postural sway attenuation in older fallers during the saccadic tasks compared to gaze fixation and free-viewing tasks, in both stationary and moving room conditions. Both groups showed increased center of pressure (CoP) magnitude during the moving room condition and CoP displacements strongly coupled to the room's movement. The influence of the moving room on the postural sway was reduced during the saccadic tasks for both older groups. Older fallers exhibited higher variability compared to older non-fallers. Gaze behavior differences between groups were dependent on the goals of the visual tasks. Therefore, CoP displacements of older adults are reduced during saccadic tasks regardless of their falling history. However, postural and gaze performance of older fallers suggests increased deterioration of postural and oculomotor control which may be used as a predictor of fall risk.

Compensatory Strategies Due to Knee Flexion Constraint during Gait of Non-Disabled Adults.

Constraining knee flexion of non-disabled individuals could further our understanding regarding the importance of knee joint during gait, which is a common disturbance in individuals with gait impairment. In this study we investigated whether a mechanical constraint of knee flexion in non-disabled adults would lead to compensatory strategies. Eleven non-disabled male adults walked without and with an orthosis that permitted full extension and limited knee flexion up to either 45° or 30°. We analyzed the temporal organization of lower limb kinematics and electromyograms of the rectus femoris, vastus medialis and lateralis, tibialis anterior, semitendinosus, biceps femoris, and gastrocnemius medialis and lateralis. Non-disabled adults compensated for the reduced knee flexion by increasing hip and ankle joint excursions and ankle flexor activation amplitude. Also, these adults shortened pre-swing and lengthened swing duration in the constrained limb and increased the activity of bifunctional hip extensor and knee flexor muscles in the constrained limb in relation to the unconstrained limb. The use of an orthosis that limited knee flexion in non-disabled adults leaded to compensatory strategies in the temporal organization of joint excursions and muscle activations in the constrained limb. The compensatory effects were correlated with the extent of knee flexion constraint.

Performance of postural balance in children and adolescents living with and without HIV.

RESEARCH QUESTION: The present study aimed to compare the postural control of children and adolescents with and without Human Immunodeficiency Virus (HIV). METHODS: A total of 32 children and adolescents (18 with HIV and 14 without) of both sexes, aged 6-18 years, were included in the present study. Participants in the HIV + group were infected through vertical transmission and received antiretroviral therapy. Participants maintained an erect, bipedal posture in the following conditions: with vision, without vision, and on a foam base. RESULTS: Concerning the evaluation of time variables, higher values ​​were observed in the HIV + group for mean anterior-posterior (AP) velocity, mean medial-lateral (ML) velocity, AP perimeter (p = 0.001), and ML perimeter (p = 0.001). Concerning the evaluation of conditions, a difference was observed in the mean AP mean sway amplitude (MSA) (p = 0.039), as the AP MSA was lower with vision than without vision or with foam. Concerning the evaluation of spectral domain variables, higher values ​​were observed in the HIV+ group for the predominant ML frequency (p = 0.04) and mean AP (p = 0.001) and ML frequencies (p = 0.001). Regarding the evaluation of conditions, a difference was found only in the predominant AP frequency (p = 0.001). Higher values ​​were found in the closed eye condition than in with foam (Δ = +103 %). CONCLUSION: The results of the present study indicated that children and adolescents living with HIV have poorer postural control performance than those without HIV.

Detection of passive movement in lower limb joints is impaired in individuals with Parkinson's disease.

OBJECTIVE: Sensory information is crucial when performing daily activities, and Parkinson's disease may diminish sensitivity to sensory cues. This study aimed to examine the detection threshold of passive motion of knee and ankle joints in individuals with Parkinson's disease. METHODS: Eighteen individuals in the early stages of idiopathic Parkinson's disease (age: 62.7 ±â€¯7.3 years) and 18 healthy matched controls (age: 62.5 ±â€¯7.1 years) first performed a simple reaction time test. Participants were asked to perform ten trials, during which they had to watch a square on a screen and press a button as quickly as possible when the square lit up. Thereafter, the participants were tested for their detection threshold of passive motion of their lower limb joints. Participants were seated in a specially designed chair and their knee or ankle joint was passively moved at a velocity of 0.5º/s. Participants kept their eyes closed and were instructed to press a button as quickly as possible when any joint motion was detected. RESULTS: Individuals with Parkinson's disease needed more time to perform the reaction time test than did the control participants. Individuals with Parkinson's disease also needed larger angular displacement, even when reaction time was used as a covariate measure, to detect any passive motion, in both knee (0.70ºâ€¯±â€¯0.20º) and ankle (1.03ºâ€¯±â€¯0.23º) joints than did the control participants [(0.57ºâ€¯±â€¯0.20º) and (0.84ºâ€¯±â€¯0.27º), respectively]. CONCLUSION: Impaired joint proprioception can be observed in the early stages of Parkinson's disease, which may compromise the use of proprioception cues from lower limbs.

Parkinson's disease delays predictable visual cue processing without affecting complex and unpredictable visual cue processing in postural control.

This study examined the influence of visual information of different complexities and predictability on the body sway of individuals with Parkinson's disease (PD) during upright stance. Twenty-one individuals at initial stages of PD (62.1 ± 7.2 years), under dopaminergic medication, and 21 controls (62.3 ± 7.1 years) stood inside a moving room, performing 10 trials of 60 s. In the first trial, the room remained motionless. Then, the room oscillated in an anterior-posterior direction. There were three blocks of three trials. In the first block, the room oscillated at 0.2 Hz (periodic simple condition); in the second block, periodic frequencies of 0.1, 0.3, and 0.5 Hz were combined (periodic complex condition); in the third block, non-periodic frequencies of 0.1, 0.3, and 0.5 Hz were combined (non-periodic complex condition). Participants were not informed about the room movement. The displacement of the room and trunk were registered using an OPTOTRAK system. Postural sway was examined using mean sway amplitude, and the relationship between visual information and body sway used coherence, gain, and phase. There was no group difference when the room remained motionless. Upon visual manipulation, the PD group displayed larger sway magnitude in the non-periodic complex condition. Individuals with PD also lagged behind the moving room (lower phase values) compared to controls, only in the periodic simple condition. In the remaining measures, there was no group difference. These results suggest that individuals with PD use complex and unpredictable visual information, similar to controls, during upright stance. However, PD might affect the predictable visual cues processing.

Kinesiotaping Diminishes Delayed Muscle Soreness but does not Improve Muscular Performance.

This study aimed at determining the effect of kinesio-taping (KT) on muscle performance and delayed onset muscle soreness (DOMS) after exercise induced muscle damaged. Sixty-six healthy men volunteered to participate (age:18-25 y/o), who performed 200 isokinetic lengthening contractions of the dominant quadriceps. Then subjects were randomized to either control (no treatment), sham (no tape tension), or KT (10% tape tension) groups. Muscle performance was assessed by peak torque and muscular work during maximal isometric and concentric isokinetic contractions. DOMS intensity was assessed using a visual analog scale. Measurements were taken pre-exercise (Pre), 48 h and 96 h post-exercise. Repeated measures ANOVA was used for comparisons within group, and ANCOVA for comparisons among groups. Muscle damage was confirmed in all participants by an increase in CK activity level (p<0.01). Decrease in isometric and isokinetic peak torque was detected at 48 h in the control and sham groups (p<0.01). Muscular work decreased in all groups at 48 h (p<0.01). No differences between groups were detected in muscular performance variables. Increase in DOMS intensity was determined in all groups at 48 h. Comparisons between groups showed lower DOMS intensity in the KT group at 48 h. KT decreased DOMS intensity perception after exercise-induced muscle damage; however, it did not impact muscular performance.

Dyslexic children need more robust information to resolve conflicting sensory situations.

The study involved investigating dyslexic children's postural control responses when visual and somatosensory cues were separately manipulated. Twenty dyslexic and 19 nondyslexic children performed a trial by standing upright inside a moving room and another by lightly touching a moving bar. Both trials lasted 240 s with the following three different stimulus characteristics: low (pretransition), high (transition), and low amplitude (posttransition). Body sway magnitude and the relationship between the movement of the room/bar surface and body sway were examined. When compared to nondyslexic children, dyslexic children oscillated with higher magnitude in the transition and posttransition under visual and somatosensory manipulation; their sway was more influenced by visual manipulation in the transition and posttransition, and they used higher applied force levels in the somatosensory modality in all conditions. The results suggest that dyslexic children could not efficiently reweight visual cues when compared to nondyslexic children. The same was not observed in the somatosensory cues when dyslexic children reduced the influence of the somatosensory stimulus. The proper use of somatosensory information was related to stronger acquired cues and higher applied forces as observed for dyslexic children. Dyslexic children experience difficulties in dynamically reweighting sensory cues although these types of difficulties are overcome when more informative sensory cues are provided.

Relationship between postural control in upright stance and virtual reality in post-stroke individuals / Relação entre desempenho do controle postural em pé e em realidade virtual em indivíduos pós-AVC

Abstract Introduction: Considered the second leading cause of death worldwide, stroke leads to several consequences resulting from the injury in regions responsible for the processing of sensorimotor information, leading to deficits in the maintenance and performance of postural control. Objective: To relate the performance of postural control during upright stance and a virtual reality task in post-stroke individuals. Method: Nine post-stroke individuals, aged 30 to 76 years, characterized by the Berg balance scale, Fugl - Meyer scale and Mini Mental State Examination participated in this study. Postural performance was measured by the center of pressure under bipedal conditions, in anteroposterior and mediolateral directions and unipedal with the affected and unaffected sides, using a force platform. Virtual reality performance was measured by distance and time required to perform a task in the Nintendo Wii®. Results: Revealed significant correlations between distance and displacement time of the affected side (distance x disc_affected = 0.667 - p = 0.025; time x disc_affected = 0.683 - p = 0.021) and between variables time and mean amplitude of mediolateral oscillation (time x amo_ml = -0.733 - p = 0.012), time and mediolateral and anteroposterior mean velocity (time x vm_ml = -0.617 - p = 0.038; time x vm_ap = -0.833 - p = 0.003) and between time and area (time x area = -0.633 - p = 0.034). Conclusion: the performance of standing postural control in post-stroke individuals, represented by measures of weight discharge and variables of postural control, presented a significant relation with the variables of virtual reality.

Resumo Introdução: Tido como a segunda maior causa de morte no mundo, o Acidente Vascular Cerebral tem suas consequências resultantes da lesão em regiões responsáveis pelo processamento das informações sensório-motoras, acarretando déficits na manutenção e desempenho do Controle Postural. Objetivo: Relacionar o desempenho do controle postural em pé e uma tarefa em realidade virtual em indivíduos pós-AVC. Método: Participaram 9 indivíduos em condição de pós-AVC com idades entre 30 a 76 anos, caracterizados por meio da escala de equilíbrio de Berg, Escala de Fugl-Meyer e Mini-Exame de Estado Mental. O desempenho postural foi medido através do deslocamento do centro de pressão nas condições bipodal, nas direções ântero-posterior e médio-lateral, e unipodal, com o lado afetado e não afetado, por meio de uma plataforma de força. O desempenho em realidade virtual, medido por distância e tempo, foi realizado por meio do console Nintendo Wii®. Resultados: Revelaram correlações significativas entre as variáveis distância e tempo de deslocamento do lado afetado (distância x desc_afetado=0,667 - p=0,025; tempo x desc_afetado=0,683 - p=0,021) e entre as variáveis tempo e amplitude média de oscilação médio-lateral (tempo x amo_ml= -0,733 - p=0,012), tempo e velocidade média médio-lateral e ântero-posterior (tempo x vm_ml= -0,617 - p=0,038; tempo x vm_ap= -0,833 - p=0,003) e entre tempo e área (tempo x área= -0,633 - p=0,034). Conclusão: Há relação entre o desempenho do controle postural, mensurado quantitativamente a partir de uma plataforma de força, e o desempenho em tarefa virtual pé em indivíduos pós-AVC.

Effects of water immersion on quasi-static standing exploring center of pressure sway and trunk acceleration: a case series after incomplete spinal cord injury.

Study design: This work is a case series. Objectives: We assessed the influence of the aquatic environment on quasi-static posture by measuring center of pressure (COP) sway and trunk acceleration parameters after incomplete spinal cord injury (iSCI) in water and on land. Setting: Tertiary Rehabilitation Hospital, Ontario, Canada. Methods: Six adult participants with iSCI (4 cervical/2 thoracic injuries, AIS D) were enrolled. Baseline balance was assessed by the Berg Balance Scale and Mini-Balance Evaluation System Test. Participants stood on a waterproof force plate for one minute per trial on land and in water; participants completed testing with their eyes open or closed in random order over 10 trials. Individuals' perceptions of their standing balance were obtained. COP and trunk acceleration parameters were analyzed in the time-domain. Results: COP sway and upper to lower trunk acceleration ratios in the AP direction increased in water, which was in contrast to standing on land in both visual conditions for 5/6 participants. Three participants (P1, P3 & P4) with greater sensorimotor deficits had larger COP sway in water with the eyes closed. Two (P1 & P4) of six participants reported more discomfort standing in water than standing on land. Conclusions: Increased COP sway seemed to reflect the balance and sensorimotor impairments of the participants, especially when standing with eyes closed in water. Although most participants (4/6) perceived that they swayed more in water in contrast to on land, 5 out of 6 participants reported that water felt like a safer environment in which to stand.

Correlation between eccentric training and functional tests in subjects with reconstructed acl / Correlação entre treino excêntrico e testes funcionais em sujeitos com lca reconstruído / Correlación entre entrenamiento excéntrico y pruebas funcionales en sujetos con lca reconstruido

INTRODUCTION: Eccentric training and jump tests are widely used to recover and measure deficits in knee strength and functionality after anterior cruciate ligament (ACL) reconstruction. OBJECTIVE: To correlate knee extension and flexion torque generated by eccentric isokinetic training, with functional jump tests in subjects with reconstructed ACL. METHOD: Sixteen men with unilateral ACL reconstruction were assessed before and after 12 weeks of eccentric isokinetic training of knee flexors and extensors (3×10 MVC, 2x/week) at 30°/s for extension and flexion torque (isometric; concentric and eccentric at 30 and 120°/s) and functional jump tests (single, triple, cross and figure of 8). Inter- and intra-limb pre- and post-training mean peak torque (MPT), distance and jump test times were compared along with the correlations between these variables, considering P<0.05. RESULTS: The affected limb (AL) showed significant gain of extension and flexion torque (P<0.01) in the different test categories and velocities evaluated. In the non-affected limb (NAL), this only occurred in the eccentric category (30 and 120°/s), in the extension (P<0.01) and flexion (P<0.05 and P<0.01) torques, respectively. In the jumps, there was an increase in distance (single and triple; P<0.05) and a decrease in time (crossed and figure of 8; P<0.01), however, MPT x Jump correlations were weak (r<0.3) in the pre and post-training period in both limbs. CONCLUSION: Despite the gain in knee extension and flexion torque and jumping performance, the expected correlation was not satisfactory, suggesting that knee functionality involves other variables inherent to motor control. Level of Evidence IV; Type of study: Case series.

INTRODUÇÃO: O treino excêntrico e testes de saltos são muito utilizados para recuperar e aferir déficits de força e funcionalidade do joelho, após reconstrução do ligamento cruzado anterior (LCA). OBJETIVO: Correlacionar o torque extensor e flexor do joelho, gerados pelo treino isocinético excêntrico, com testes funcionais de saltos em sujeitos com LCA reconstruído. MÉTODO: Foram avaliados 16 homens, com reconstrução unilateral do LCA, antes e depois de 12 semanas de treino isocinético excêntrico de extensores e flexores do joelho (3 × 10 CEVM, 2x/semana) a 30°/s, quanto ao torque extensor e flexor (isométrico; concêntrico e excêntrico a 30°/s e 120°/s) e aos testes funcionais de saltos (simples, triplo, cruzado e figura em 8). As médias dos picos de torque (MPT), a distância e os tempos dos testes de salto inter e intramembros, pré e pós-treino foram comparados, além das correlações entre essas variáveis, considerando P< 0,05. RESULTADOS: O membro acometido (MA) mostrou ganho significativo de torque extensor e flexor (P< 0,01) nos modos e velocidades avaliados. No membro não acometido (MNA), isso ocorreu apenas para o modo excêntrico (30°/s e 120°/s), do torque extensor (P< 0,01) e flexor (P< 0,05 e P<0,01), respectivamente. Nos saltos, houve aumento da distância (simples e triplo; P< 0,05) e diminuição do tempo (cruzado e figura em 8; P< 0,01), porém, as correlações entre MPT e saltos mostraram-se fracas nos dois membros (r< 0,3) antes e depois do treino. CONCLUSÃO: Apesar do ganho no torque extensor e flexor do joelho e no rendimento dos saltos, a correlação esperada não foi satisfatória, sugerindo que a funcionalidade do joelho envolve outras variáveis inerentes ao controle motor. Nível de evidência IV; Tipo de estudo: Série de casos.

INTRODUCCIÓN: El entrenamiento excéntrico y las pruebas de saltos son muy utilizados para recuperar y medir los déficits de fuerza y funcionalidad de la rodilla, después de la reconstrucción del ligamento cruzado anterior (LCA). OBJETIVO: Correlacionar el torque extensor y flexor de la rodilla, generados por el entrenamiento isocinético excéntrico, con pruebas funcionales de saltos en sujetos con LCA reconstruido. MÉTODO: Fueron evaluados 16 hombres, con reconstrucción unilateral del LCA, antes y después de 12 semanas de entrenamiento isocinético excéntrico de extensores y flexores de la rodilla (3x10 CEVM, 2x/semana) a 30°/s, cuanto al torque extensor y flexor (isométrico, concéntrico y excéntrico a 30 y 120°/s) y a las pruebas funcionales de saltos (simple, triple, cruzado y figura en 8). Se compararon promedios de los picos de torque (MPT), distancia y tiempos de las pruebas de salto, inter e intra-miembros, pre y post-entrenamiento, además de las correlaciones entre estas variables, considerando P<0,05. RESULTADOS: El miembro acometido (MA) mostró aumento significativo del torque extensor y flexor (P<0,01) en los modos y velocidades evaluados. En el miembro no acometido (MNA), eso ocurrió sólo para el modo excéntrico (30 y 120°/s), del torque extensor (P<0,01) y flexor (P<0,05 y P<0,01), respectivamente. En los saltos, hubo aumento en la distancia (simple y triple; P<0,05) y disminución del tiempo (cruzado y figura en 8; P<0,01), sin embargo, las correlaciones MPT x saltos se mostraron débiles (r<0,3) en el pre y post-entrenamiento, en los dos miembros. CONCLUSIÓN: A pesar del aumento en el torque extensor y flexor de la rodilla y en el rendimiento de los saltos, la correlación esperada no fue satisfactoria, sugiriendo que la funcionalidad de la rodilla involucra otras variables inherentes al control motor. Nivel de evidencia IV; Tipo de estudio: Serie de casos

Parkinson's disease does not alter automatic visual-motor coupling in postural control.

This study examined the coupling between visual information and body sway in patients with Parkinson's disease (PD) compared with healthy controls. Postural control performance was compared between 14 patients with PD (age: 69.6 ±â€¯8.8 years - stages 1-3 of the Hoehn and Yahr scale) and 14 healthy control participants (age: 68.6 ±â€¯3.0 years). Participants stood upright in a moving room that remained motionless or continuously oscillated in the anterior-posterior direction. Ten trials were performed in the following conditions: no movement of the room (1 trial) and with the room moving at frequencies of 0.1, 0.17, and 0.5 Hz (3 trials each frequency). Body sway and moving room displacement were recorded. The results indicated that patients with PD displayed larger body sway magnitude in the stationary room condition. Body sway of patients with PD was induced by visual manipulation in all three visual stimulus frequencies, but body sway of patients with PD was less coherent compared to that of the control participants. However, no difference was observed in the visual-body sway coupling structure. These results indicate that patients with PD can unconsciously couple body sway to visual information in order to control postural sway in a similar manner to healthy participants with intact visual-motor coupling for posture control. However, this coupling is marked by greater variability, indicating that people with PD have a motor system with greater inherent noise leading to a more varied behavior.

Eye movement and postural sway in dyslexic children during sitting and standing.

In this study, we investigated the eye movement and postural control performance in dyslexic children while reading text and performing Landolt reading when sitting and standing. Fifteen dyslexic and 15 non-dyslexic children were asked to sit in a chair while the eye movements were recorded, and were then asked to stand on an unstable platform while eye movements and postural sway were recorded simultaneously at the time of Landolt reading and text reading. Eye movements were recorded binocularly by Mobile EyeBrain Tracker (MobileT2®, SuriCog) and center of pressure excursions were recorded by Multitest Equilibre (by Framiral®). The dependent variables for visual performance in the reading tasks were: total reading time, mean duration of fixation, number of pro- and retro-saccades, and amplitude of pro-saccades. The dependent variable for postural performance was the center of pressure area. The results showed that dyslexic children spent more time reading the text compared to non-dyslexic children (p < 0.02). However, no difference was observed for the Landolt reading task (p > 0.05). Dyslexic children performed longer fixations in the sitting condition as compared to the standing (p < 0.03), namely, higher number of pro- (p < 0.001) and retro- saccades (p < 0.001), and smaller pro-saccades amplitude (p < 0.001). Therefore, when the linguistic and semantic requirements are not involved in the reading task, dyslexic children perform similar to non-dyslexic children even in different task requirements (p > 0.05). Finally, postural performance was poorer in dyslexic children than in non-dyslexic children in both the reading tasks (p < 0.02). However, postural control performance, which was poor in dyslexic children, is not related to lexical and semantic reading requirements.

Effect of colored filters on reading capabilities in dyslexic children.

AIM: The aim of the present study was to examine the effects of colored filters on reading performance and eye movement control in children with and without dyslexia. METHODS: Eighteen children with dyslexia and 18 children without dyslexia were seated on a chair with their heads stabilized by a forehead and chin support. The children read different texts under the following three filter conditions: no filter, yellow filter, and green filter. The children's eye movements were recorded with a Mobile EyeBrain Tracker. Reading total time, duration of fixation between two successive saccades, pro-saccades amplitude and number of pro- and retro-saccades were obtained. RESULTS: Children with dyslexia read the fastest and had the shortest fixation time in the green filter condition compared with the other conditions. Furthermore, children with dyslexia showed the shortest fixation time in the green filter condition with respect to the other conditions. CONCLUSIONS: Taken together, these results suggested that the green filter improved reading performance in children with dyslexia because the filter most likely facilitated cortical activity and decreased visual distortions.

Eye movements and postural control in dyslexic children performing different visual tasks.

The aim of this study was to examine eye movements and postural control performance among dyslexic children while reading a text and performing the Landolt reading task. Fifteen dyslexic and 15 non-dyslexic children were asked to stand upright while performing two experimental visual tasks: text reading and Landolt reading. In the text reading task, children were asked to silently read a text displayed on a monitor, while in the Landolt reading task, the letters in the text were replaced by closed circles and Landolt rings, and children were asked to scan each circle/ring in a reading-like fashion, from left to right, and to count the number of Landolt rings. Eye movements (Mobile T2®, SuriCog) and center of pressure excursions (Framiral®, Grasse, France) were recorded. Visual performance variables were total reading time, mean duration of fixation, number of pro- and retro-saccades, and amplitude of pro-saccades. Postural performance variable was the center of pressure area. The results showed that dyslexic children spent more time reading the text and had a longer duration of fixation than non-dyslexic children. However, no difference was observed between dyslexic and non-dyslexic children in the Landolt reading task. Dyslexic children performed a higher number of pro- and retro-saccades than non-dyslexic children in both text reading and Landolt reading tasks. Dyslexic children had smaller pro-saccade amplitude than non-dyslexic children in the text reading task. Finally, postural performance was poorer in dyslexic children than in non-dyslexic children. Reading difficulties in dyslexic children are related to eye movement strategies required to scan and obtain lexical and semantic meaning. However, postural control performance, which was poor in dyslexic children, is not related to lexical and semantic reading requirements and might not also be related to different eye movement behavior.

The Effect of Dual Task on Attentional Performance in Children With ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is a common psychiatric disorder without validated objective markers. Oculomotor behavior and executive motor control could potentially be used to investigate attention disorders. The aim of this study was to explore an oculomotor and postural dual task in children with ADHD. Forty-two children were included in the study, gathering children with ADHD (n = 21) (mean 8.15 age ± years 0.36) and sex-, age-, and IQ-matched typically developing children (TD). Children performed two distinct fixation tasks in three different postural conditions. Eye movements and postural body sway were recorded simultaneously, using an eye tracker and a force platform. Results showed that children with ADHD had poor fixation capability and poor postural stability when compared to TD children. Both groups showed less postural control on the unstable platform and displayed more saccades during the fixation task. Surprisingly, in the dual unstable platform/fixation with distractor task, the instability of children with ADHD was similar to that observed in TD children. "Top-down" dys-regulation mediated by frontal-striatal dysfunction could be at the origin of both poor inhibitory oculomotor deficits and impaired body stability reported in children with ADHD. Finally, we could assume that the fact both groups of children focused their attention on a secondary task led to poor postural control. In the future it could be interesting to explore further this issue by developing new dual tasks in a more ecological situation in order to gain more insight on attentional processes in children with ADHD. HIGHLIGHTS - Children with ADHD showed poor fixation capability when compared to TD children. - "Top-down" dys-regulation mediated by frontal-striatal dysfunction could be at the origin of both poor inhibitory oculomotor deficits and impaired body stability reported in children with ADHD. - Both groups of children focused their attention on the visual fixation task leading to poor postural control. - In the future it could be interesting to develop new dual tasks in an ecological situation in order to gain more insight on attentional processes in children with ADHD.