Mechanical energy assessment of adult with Down syndrome during walking with obstacle avoidance.

The aim of this study is analyzing the differences between plane walking and stepping over an obstacle for two groups of healthy people and people with Down syndrome and then, evaluating the movement efficiency between the groups by comprising of their mechanical energy exchanges. 39 adults including two groups of 21 people with Down syndrome (age: 21.6 ± 7 years) and 18 healthy people (age: 25.1 ± 2.4 years) participated in this research. The test has been done in two conditions, first in plane walking and second in walking with an obstacle (10% of the subject's height). The gait data were acquired using quantitative movement analysis, composed of an optoelectronic system (Elite2002, BTS) with eight infrared cameras. Mechanical energy exchanges are computed by dedicated software and finally the data including spatiotemporal parameters, mechanical energy parameters and energy recovery of gait cycle are analyzed by statistical software to find significant differences. Regards to spatiotemporal parameters velocity and step length are lower in people with Down syndrome. Mechanical energy parameters particularly energy recovery does not change from healthy people to people with Down syndrome. However, there are some differences in inter-group through plane walking to obstacle avoidance and it means people with Down syndrome probably use their residual abilities in the most efficient way to achieve the main goal of an efficient energy recovery.

Gait analysis in anorexia and bulimia nervosa.

PURPOSE: Anorexia (AN) and Bulimia Nervosa (BN) are two common eating disorders, which appear to share some reduced motor capacities, such as a reduced balance. The presence and the extent of other motor disorders have not been investigated in a comprehensive way. The aim of this study was to quantify gait pattern in AN and BN individuals in order to ascertain possible differences from the normality range and provide novel data for developing some evidence-based rehabilitation strategies. METHODS: Nineteen AN patients (age 30.16+9.73) and 20 BN patients (age 26.8+8.41) were assessed with quantitative 3D computerized Gait Analysis. Results were compared with a group of healthy controls (CG; 30.7+5.6). RESULTS: AN and BN patients were characterized by different gait strategies compared to CG. Spatio-temporal parameters indicated shorter step length, with AN showing the shortest values. AN walked slower than BN and CG. As for kinematics, AN and BN showed a nonphysiologic pattern at pelvis and hip level on the sagittal and frontal plane, with BN yielding the most abnormal values. Both AN and BN patients were characterized by high ankle plantar flexion capacity at toe-off when compared to CG. As for ankle kinetics, both AN and BN showed physiologic patterns. Stiffness at hip level was close to CG in both pathologic groups; at the ankle level, stiffness was significantly decreased in both groups, with AN displaying lower values. CONCLUSIONS: Both AN and BN were characterized by an altered gait pattern compared to CG. Biomechanical differences were evident mainly at pelvis and hip level. Loss of lean mass may lead to musculoskeletal adaptation, ultimately causing alterations in the gait pattern.

An optoelectronic based approach for handwriting capture.

Clinical practice for the evaluation of motor and cognitive capabilities often relies upon writing and drawing tests. A non-invasive method to capture handwriting and analyze data is therefore needed. In this work a method to capture motion of a pen through a mo-cap optoelectronic system was developed, which could solve the limits of systems based on graphic tablets. Four IR passive markers were placed on a pen cap. Once a pen was equipped with the cap, track of tip was computed through a numeric algorithm using the 3D coordinates of markers provided by the optoelectronic system. Some tests were performed to estimate the error in track reconstruction and to compare the new protocol with previous reconstruction methods. The results showed a higher accuracy of the new method. The new protocol also overcomes the problems related to pen grasping and marker covering that affected other methods described in the literature and permits the evaluation of writing and drawing kinematics as well as postural behaviour related to them.

Feedback reliance during an arm-tapping task with obstacle avoidance in adults with Down syndrome.

Optimal movement control reflects a combination of both feedback and feedforward processes. However, as motor control evolves, feedforward mechanisms become prevailing respect to feedback-based movements, and less reliance on sensory information leads to a decreased number of corrections in the trajectory. In subjects with Down syndrome (DS), the study of the wrist's trajectory during an arm-tapping task revealed feedback-based corrections designed to reduce the degree of discrepancy between the position of the limb and the target, leading to the assumption that performers with DS have problems with movement planning and feedforward control. The present study was aimed at expanding the evidence about motor control in DS by evaluating the influence of a perturbing factor (an obstacle) on motor control strategies during an arm-tapping task and to clarify if the presence of an obstacle elicited a higher reliance on feedback control in controls and in DS. Sixteen right-handed adults with DS and 21 right-handed, age-matched control subjects (N) were evaluated by means of quantitative motion analysis. The results suggest that the presence of an obstacle elicited changes in the motor strategies of both DS and N, with a destabilizing effect that led subjects to rely more on feedback control. DS showed some aspects of movement efficiency that were in accordance with N strategies, but the prevailing factor of optimization in these subjects remained safety. A focused rehabilitation could help DS subjects to develop more efficient motor strategies in the presence of motor uncertainty and perturbations.

Motor strategies and motor programs during an arm tapping task in adults with Down Syndrome.

Slow movements and atypical patterns of muscle activation are well-known features of Down Syndrome (DS). Some studies attribute these features to a deficit in voluntary motor commands and preprogramming of actions, that lead subjects with DS to be more reliant on feedback control. In the present study, we evaluated the movement strategies of 13 adult subjects with DS and of 22 age-matched controls (N) during an arm tapping task. By means of quantitative motion analysis, our aim was to describe movement differences in DS respect to typical population and provide a means of interpreting such differences in terms of the underlying different control processes. The results highlighted distinct motor strategies for the tapping task in the two groups, with DS relying more on the trunk motion and N relying on the elbow motion to accomplish the task. Furthermore, DS corrected their wrist trajectory more than N subjects, giving shape to multi-peaked velocity profiles. Longer duration of the trials and a higher index of curvature were found in DS. The results suggest that subjects with DS rely more on feedback control, whereas they have problems with movement planning and feed-forward control. The different strategy operated by subjects with DS leads to a different task performance.

Obstacle avoidance in Down syndrome.

INTRODUCTION: The ability to avoid obstacles requires to represent the properties of the obstacle, represent the location of the obstacle relative to the body and update these representations as the body moves. Individuals with Down syndrome (DS) often have trouble avoiding obstacles, leading to increased frequency of trips and falling. The aim of the present study was to deeply analyze obstacle avoidance strategies in normally developed young adults (N) and in young adults with DS, at different levels of obstacle heights, with particular attention to the strategies used for clearing the obstacle and to how the walking pattern was modified by obstacle perception. METHODS: 10 DS and 16 age-matched N walked along a walkway in three conditions: plain walking, walking with obstacle at ground level, walking with obstacle at 10% of the subject's height. Spatiotemporal parameters were analyzed. RESULTS: There was evidence for a different avoidance strategy in DS, and for a difficulty in regulating gait parameters when challenged with a complex situation as the presence of an obstacle. This may lead to an increased risk of fall. The results in addition suggested a lack in anticipatory movement adjustments in DS and provided further evidence of the presence of difficulties in perceptual-motor coupling in DS.

Quantitative evaluation of facial movement and morphology.

OBJECTIVES: The aim of our study was to quantitatively analyze facial motion kinematics by means of an optoelectronic system. In particular, we defined a set of easily recognizable reference points for markerization, and tested the applicability of our markerization method for an exhaustive characterization of the subjects' facial motion through the definition of some kinematic parameters. METHODS: Thirty healthy subjects (mean age, 24.6 +/- 1.0 years; 15 female and 15 male) participated in the study. A set of markers (diameter, 3 mm) was positioned on several reference points of the face, and some parameters were computed for the characterization of facial morphology and movement, such as ranges of motion, angles, times, and distances. RESULTS: The protocol was tested for inter-rater and intra-rater reliability by use of intraclass correlation, of which the results were good (between 0.4 and 0.75) to excellent (greater than 0.75). The parameters were useful for characterizing the resting position, mimicry, and speaking movements, and highlighted some distinctions between men and women in facial morphology. CONCLUSIONS: The protocol can be applied to a variety of facial movements, including speaking. Future works could address the use of the protocol in subjects with disorders and the integrated analysis of kinematic parameters and voice spectrography.

Spatiotemporal and kinematic aspects of obstacle avoidance in subjects with Down syndrome.

Obstacle avoidance studies have been extensively performed in normally developed subjects (N), but little work has been done on the characterization of this task in subjects with Down syndrome (DS). The aim of this study was to describe the management of walking with obstacle avoidance in adults with DS and in age-matched N subjects, considering both the lower and upper limbs. Ten subjects with DS and 16 N subjects were evaluated. The subjects walked along a walkway in two conditions: level, unobstructed walking and walking with an obstacle. The tasks were acquired using three-dimensional quantitative movement analysis. Spatiotemporal and kinematic parameters for the trunk, upper limbs and lower limbs were analyzed. The results demonstrated that the presence of a destabilizing element, the obstacle, enhanced different motor strategies in DS compared with N subjects, as shown by the parameters of the lower limbs, with a stabilization and safety strategy adopted at the upper limbs in DS.

A new approach for the quantitative evaluation of drawings in children with learning disabilities.

A new method for a quantitative and objective description of drawing and for the quantification of drawing ability in children with learning disabilities (LD) is hereby presented. Twenty-four normally developing children (N) (age 10.6 ± 0.5) and 18 children with learning disabilities (LD) (age 10.3 ± 2.4) took part to the study. The drawing tasks were chosen among those already used in clinical daily experience (Denver Developmental Screening Test). Some parameters were defined in order to quantitatively describe the features of the children's drawings, introducing new objective measurements beside the subjective standard clinical evaluation. The experimental set-up revealed to be valid for clinical application with LD children. The parameters highlighted the presence of differences in the drawing features of N and LD children. This paper suggests the applicability of this protocol to other fields of motor and cognitive valuation, as well as the possibility to study the upper limbs position and muscle activation during drawing.

Use of the Gait Deviation Index for the assessment of gastrocnemius fascia lengthening in children with Cerebral Palsy.

Gait analysis (GA) is widely used for clinical evaluations and it is recognized as a central element in the quantitative evaluation of gait, in the planning of treatments and in the pre vs. post intervention evaluations in children with Cerebral Palsy (CP). Otherwise, GA produces a large volume of data and there is the clinical need to provide also a quantitative measure of the patient's overall gait. Starting from this aim some global indexes were proposed by literature as a summary measure of the patient's gait, such as the Gait Deviation Index (GDI). While validity of the GDI is demonstrated for the evaluation of the functional limitation of CP patients, no studies have evaluated with the GDI the pre vs. post surgery gait condition in children with CP. The aim of our study was therefore to investigate the effectiveness of the GDI in the quantification of gait changes occurring after surgical intervention (gastrocnemius fascia lengthening for the correction of equinus foot deformity) in patients with CP. 19 children with CP were evaluated pre-operatively (PRE session) and about 1 year (POST: mean 13.1 ± 5.1 months) after gastrocnemius fascia lengthening using 3D GA. From GA data the GDI was computed. The results evidenced that the GDI value in the PRE session was 70.4 ± 14.8, showing a moderate global disturbance of the gait patterns of the patients. After the surgical treatment a significant improvement of the GDI mean value was found (82.9 + 7.4; p < 0.05; CG ≥ 100) with an improvement of 18% respect to the PRE session. A strong correlation (ρ = 0.83; p<0.05) existed between the GDI value in the PRE session and the percentage of improvement. Our results demonstrated that GDI seems to be an appropriate outcome measure for the evaluation of the effects of surgical treatment in CP.