ali esteki

The impact of cognitive tasks on human movement is of practical significance; we hereby aim to demonstrate that a significant relationship exists between the dual task’s cognitive demand and the disruption caused in hand movement, with the hope to extend this experiment to subjects with disorders (MS, CP, stroke patients) in future studies. By doing so, we hope to be able to develop a metric for evaluating their disease levels using our method and minimize clinical interventions. While previous research has predominantly focused on lower body activities, this study explores the effect of dual tasks on hand movements in healthy individuals.A simulated finger-to-nose test combined with a standard reverse counting task, featuring four difficulty levels, was conducted. Utilizing SVM and decision tree classifiers, we analyzed various features to discern the impact of cognitive tasks on hand movements, including completed cycles and idle time at markers. Our findings reveal that features such as entropy and kurtosis effectively distinguish between task difficulty levels and hand movement disruption. The classifiers achieved accuracies of 70% and 74% for decision tree and SVM, respectively. We hope extending this research to diseased subjects could potentially provide a more accurate assessment of disease severity through the measurement of hand movements during cognitive tasks, offering a non-clinical alternative for disease evaluation.

The anterior cruciate ligament (ACL) is one of the most important factors in knee stability and motion control so that its injuries result in serious movement problems for patients. The present study clarifies the effect of unilateral ACLT on histological and biomechanical properties of articular cartilage of rabbit knee.

Ten skeletally mature Dutch white male rabbits were divided into 2 groups. In the surgery group, left anterior cruciate ligament was completely transected through midshaft. Histopathological properties, biomechanical charachteristics and thickness of femoral and tibial articular cartilage in left knee measured at 62nd day post surgery. Normal group underwent no intervention in the same period. Biomechanical characteristics of tibial medial plateau and femoral medial condyle studied by means of the ex vivo biphasic stress–relaxation test. Maximal force, elastic modulus, equilibrium force and aggregate modulus were extracted from these data. Data were statistically analyzed via Mann-Whitney U test. To avoid error in histological sample reading, histological study performed on tibial lateral plateau and femoral lateral condyle.

In ACLT group, both femoral and tibial cartilages deteriorated. In comparison to normal group, cartilage thickness in ACLT group decreased significantly only in femoral medial condyle (P = 0.009). All biomechanical parameters of femoral condyle were significantly less than normal group (P < 0.05). The only exception was aggregate modulus that was almost the same in both groups. Biomechanical properties of tibial plateau were not statistically different between the two groups.

Although the structural deterioration of articular cartilage in femoral condyle was less severe than tibial plateau within the first 9 weeks following complete ACLT, functional deterioration was significant only in femoral condyle. However, tibial plateau saved its biomechanical charachtristics despite significant degeneration. The biomechanical and histological alteration of the rabbit articular cartilage described in present study provides further evidence that this small animal model exhibits changes identical to secondary osteoarthritis.

Standing balance deficits are common in hemiplegic patients after stroke. One method to treat these deficits is to provide the patient with visual feedback while balance activities are performed. The purpose of this research was to investigate the effects of using visual biofeedback with conventional physical therapy on static postural stability following stroke.

This randomized clinical trial included 32 patients (11 females and 21 males) with hemiplegia secondary to stroke. These patients were randomly assigned in two groups; control and experimental groups. These groups were matched for age, weight and height. Patients were tested using Equitest (amplitude of postural sway) and two digital weight scales (symmetry) before, 6 sessions and 12 sessions after physical therapy intervention. The trained group received visual biofeedback from Biodex Balance System combined with conventional physical therapy whereas the control group performed conventional physical therapy without biofeedback.

Significant improvements in static stroke balance measurements were found in trained group. In trained group, symmetry of weight bearing was increased (P = 0.008) and postural sway was decreased (P = 0.03).

This study revealed that visual biofeedback training with conventional physical therapy improved proprioception and decreased hemineglect effects in stroke patients. Improved proprioception resulted in symmetry and decreased sway, subsequently increased static balance in stroke patients.

Postural instability has been identified as a potential precursor of falls in elderly subjects. Postural stability in quiet stance is commonly assessed with center of pressure (COP) measures. The purpose of this study was to determine testretest reliability and minimal detectable change (MDC) for the center of pressure (COP) measures in the elderly subjects.

Eighteen healthy elderly people over the age of 60 years participated in this study. For each subject the COP was recorded during quiet upright stance on different levels of postural difficulty (eyes open versus eyes closed, firm surface versus foam surface) and lean condition (forward and backward). All measurements were done on two sessions with 7 days interval. These indices: mean velocity, standard deviation of amplitude, standard deviation of velocity, phase plane parameter and area (95% confidence ellipse). Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were used to quantify testretest reliability. The MDC for each measure was calculated to quantify intervention effects.

In general, test-retest reliability of COP measures in the elder subjects was increased whenever postural difficulty of task increased in quiet standing. In standing conditions, mean velocity and phase plane parameter were the most sensitive and the most reliable measures. The lean range was the most sensitive and the most reliable measure, in the lean conditions.

Center of pressure measures in the quiet standing especially in difficult postural conditions demonstrated high sensitivity in the older subjects. These results may be useful in quantification and assessment of balance performance and treatment efficacy.

Computer simulation of a three dimensional model of the thumb and index finger was used to perform a sensitivity analysis of each joint position to individual muscle activation level. The results were used to study the effect of each muscle on hand posture and select specific muscles to get a desired posture of the hand to assist the implementation of FNS systems. The hand was treated as a multi-body system including rigid segments connected by joints. Each joint was subjected to a total moment including muscle active and joint passive components. The forward approach, in which the equilibrium equations are solved for joint positions as a function of muscle moments, was used. The results showed that at the base joint of the index finger, flexion effect of the extrinsic flexor muscles was about two times of that of the intrinsic muscles. It was also shown that each muscle of the extensor system is individually more effective than the extrinsic flexor muscles. At the more distal joints, intrinsic muscles acted as feeble extensors. At the base joint of the thumb, extensor muscles were much more powerful than the flexor and flexor effect of adductor muscles. Also, abductor muscles were much more effective than the adductors. It was revealed that flexor muscles of the more distal joints are as strong as the extensor muscles. The conclusions are that: the minimum required muscles for appropriate positioning of the hand and for grasp and applying force to objects are limited.