Postural strategies in Prader-Willi and Down syndrome patients

Cyclogram-based evaluation of inter-limb gait symmetry in Prader-Willi Syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is characterized by a complex clinical condition, whose typical features lead to impaired motor and functional skills. To date, limited data is available as regards symmetry of gait in PWS.

RESEARCH QUESTION

The aim of this study was to characterize lower-limb asymmetry during gait in a group of Prader-Willi Syndrome (PWS) individuals by using the synchronized cyclograms and to compare it with those of two different control groups, a normal-weight group and an obese group.

METHODS

A total of 18 PWS, 30 normal weight (NW) and 28 obese individuals (OG) matched for age, sex and height were assessed via 3D gait analysis. Gait spatio-temporal parameters were computed together with angle-angle diagrams, characterized in terms of their geometric features (i.e. area, orientation, and trend symmetry index).

RESULTS

Individuals with PWS exhibit reduced speed, stride length and cadence and increased duration of both stance and double support phase than the other groups. OG was characterized by the same pattern when compared to NW. With respect to inter-limb symmetry, individuals with PWS exhibited significantly larger cyclogram areas at hip joint with respect to the other two groups (203.32 degrees2 vs. 130.73 degrees2 vs. 111.59 degrees2) and significantly higher orientation angle (4.17° vs. 2.11° vs. 1.22°) and Trend Symmetry (3.72 vs. 2.02 vs. 1.21) with respect to the other two groups at knee joint; no differences were found at ankle joint. Both individuals with PWS and those of OG exhibited reduced ROM at knee and ankle joints with respect with normal weight, but no statistically significant differences were observed between PWS and OG.

SIGNIFICANCE

The obtained results may provide novel and useful insights to understand better the impairments in motor control associated with this pathological state, supporting clinics in the identification of the best rehabilitation program for this rare pathological state, aimed to improve stability and motor control.

Analysis of the centre of pressure in bipedal stance among individuals with and without intellectual disabilities, individuals with Down syndrome and dancers with Down syndrome

BACKGROUND

Individuals with intellectual disabilities (IDs) often present deficiencies in motor, balance and postural control. On the other hand, the practice of physical activity and dance usually reduces these deficiencies. Therefore, in this study, we aimed to compare the control of the centre of pressure (COP) in people with Down syndrome (DS) or other causes of ID in relation to people without disabilities and to observe the influence of vision and the practice of dance.

METHODS

This cross-sectional study analyses the COP in a static standing position with open and closed eyes in four study groups. A total of 273 people were recruited (80 adults without ID, 46 adults with DS, 120 adults with other causes of ID and 27 dancers with DS).

RESULTS

A greater area of oscillation and path of the COP was observed in the participants with ID compared with the participants without ID, especially in the sway area of the COP. The oscillation speed of the COP was also higher. When analysing the displacement of the COP, anteroposterior and mediolateral components, there were also differences, except when comparing the group of dancers with DS with respect to the group without ID. The visual condition only influenced the group of participants without disabilities.

CONCLUSIONS

The results of our study show that there is a less efficient static postural control in people with ID, as greater displacements were observed in the COP of the participants with ID. The differences in some specific variables that analyse the displacement of the COP were smaller when comparing the group of dancers with DS and the individuals without ID.

The effectiveness of dance movement therapy for individuals with Down syndrome: a pilot randomised controlled trial

BACKGROUND

Individuals with Down syndrome (DS) exhibit deficits in static and dynamic balance abilities and maladaptive functions. This study aimed to determine the effectiveness of dance movement therapy (DMT) group intervention in individuals with DS.

METHODS

The 31 participating individuals with DS, aged 5-29 years, were randomly divided into intervention (n = 16) and control (n = 15) groups. Posturography was used for static balance measurement, timed up and go test for dynamic balance measurement and the Achenbach System of Empirically Based Assessment (ASEBA) questionnaire for adaptive function and behavioural problem measurement in participants before and after the DMT interventions. The intervention group underwent 60-min DMT intervention once a week for 10 times, while the control group had usual daily activities.

RESULTS

The results revealed a statistically significant difference and large effect sizes in dynamic balance [(f(1, 29) = 4.52, P = 0.04, η_p   ² = 0.14)] in the intervention group compared with the control group. There were no statistically significant differences in static balance and ASEBA scores between the groups.

CONCLUSIONS

This study found that the DMT interventions helped to improve the dynamic balance in individuals with DS.

Gait characteristics and effects of early treadmill intervention in infants and toddlers with down syndrome: a systematic review

PURPOSE

The aim of this study was to evaluate gait characteristics, and the effectiveness of treadmill interventions on gait in infants and toddlers with Down syndrome (DS).

MATERIALS AND METHODS

A comprehensive search was performed on six databases for evidence published up to November 2020 for articles related to infants and toddlers with DS. The Clinical Appraisal Skills Programme Checklist assessed the methodological quality. Strength of evidence were evaluated Sackett's level.

RESULTS

Nine articles analyzing instrumental gait met the inclusion criteria. Of these, 4 compared DS and typically developing (TD), and 5 included treadmill training interventions for DS. Kinematic analysis was applied in 8 studies and all articles presented evaluations at different times according to the walking experience. Analysis with EMG was used in only one of the intervention articles and in 3 of the 4 comparative articles.

CONCLUSIONS

Although similar improvements are seen in spatiotemporal parameters for toddlers with typical development and those with DS, the decrease in step width is not similar for DS. Early treadmill training can have a positively effect on the gait characteristics of DS infants. Further research should focus on the acquisition of gait characteristics, long-term evaluations, kinetics and EMG data, for these children.Implications For RehabilitationToddlers with DS walked significantly slower, shorter stride length and less stride frequency.Treadmill training before 1-year old had positive effects on gait characteristics in infants and toddlers with DS.High-intensity treadmill training may provide early walking (2 months earlier) than the low-intensity group, therefore clinicians can add treadmill training programs in rehabilitation protocols of infants and toddlers with DS.Limited evidence for the effects of treadmill training on the kinematic and kinetic parameters of walking in DS infants and toddlers.

Feasibility of wearable technology for 'real-world' gait analysis in children with Prader-Willi and Angelman syndromes

BACKGROUND

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are neurodevelopmental disorders in need of innovative 'real-world' outcome measures to evaluate treatment effects. Instrumented gait analysis (IGA) using wearable technology offers a potentially feasible solution to measure "real-world' neurological and motor dysfunction in these groups.

METHODS

Children (50% female; 6-16 years) diagnosed with PWS (n = 9) and AS (n = 5) completed 'real-world' IGA assessments using the Physilog®5 wearable. PWS participants completed a laboratory assessment and a 'real-world' long walk. The AS group completed 'real-world' caregiver-assisted assessments. Mean and variability results for stride time, cadence, stance percentage (%) and stride length were extracted and compared across three different data reduction protocols.

RESULTS

The wearables approach was found to be feasible, with all participants able to complete at least one assessment. This study also demonstrated significant agreement, using Lin's concordance correlation coefficient (CCC), between laboratory and 'real-world' assessments in the PWS group for mean stride length, mean stance % and stance % CV (n = 7, CCC: 0.782-0.847, P = 0.011-0.009).

CONCLUSION

'Real-world' gait analysis using the Physilog®5 wearable was feasible to efficiently assess neurological and motor dysfunction in children affected with PWS and AS.

Health Problems in Individuals With PWS Are Associated With Lower Quality of Life for Their Parents: A Snapshot in the Brazilian Population

Prader-Willi syndrome (PWS) is a complex genetic disorder requiring interdisciplinary team monitoring and intensive care by parents. So far there is little information on people with PWS in Brazil. Our aim was to describe health problems and treatments used by people with PWS in Brazil and their relationship to their parents' quality of life. Parents answered questionnaires about their child's medical and exercise history, behavior problems, sociodemographic characteristics, and their own quality of life. Results: The responses of the participants showed similar health problems as in other countries. Anxiety and tantrums were the behavioral problems most commonly cited by parents. Parents of people with PWS had lower scores in respect of quality of life than the Brazilian population. Behavioral problems in individuals with PWS were negatively associated with their parents' quality of life. Behavioral and medical conditions in the children were associated with reduced quality of life in the parents. We conclude that heath care should not only be directed toward those with PWS, but also their parents.

Altered Gesture Imitation and Brain Anatomy in Adult Prader-Willi Syndrome Patients

OBJECTIVE

To explore motor praxis in adults with Prader-Willi syndrome (PWS) in comparison with a control group of people with intellectual disability (ID) and to examine the relationship with brain structural measurements.

METHOD

Thirty adult participants with PWS and 132 with ID of nongenetic etiology (matched by age, sex, and ID level) were assessed using a comprehensive evaluation of the praxis function, which included pantomime of tool use, imitation of meaningful and meaningless gestures, motor sequencing, and constructional praxis.

RESULTS

Results support specific praxis difficulties in PWS, with worse performance in the imitation of motor actions and better performance in constructional praxis than ID peers. Compared with both control groups, PWS showed increased gray matter volume in sensorimotor and subcortical regions. However, we found no obvious association between these alterations and praxis performance. Instead, praxis scores correlated with regional volume measures in distributed apparently normal brain areas.

CONCLUSIONS

Our findings are consistent in showing significant impairment in gesture imitation abilities in PWS and, otherwise, further indicate that the visuospatial praxis domain is relatively preserved. Praxis disability in PWS was not associated with a specific, focal alteration of brain anatomy. Altered imitation gestures could, therefore, be a consequence of widespread brain dysfunction. However, the specific contribution of key brain structures (e.g., areas containing mirror neurons) should be more finely tested in future research.

Multi-segmental postural control patterns in down syndrome

BACKGROUND

Patients with Down Syndrome (DS) exhibit less efficient and unstable standing postural control. The specificities of somatosensorial deficits might result in a different utilization of resources and in distinct whole-body kinematic patterns, to date still unexplored. In this paper we aim at addressing multi-segmental coordination patterns in people with DS while maintaining standing balance under different visual conditions (open and closed eyes).

METHODS

This cross-sectional observational cohort study involved two groups of 23 patients with DS and 12 healthy controls. A 30-s standing balance test allowed to extract (i) the length of the trajectory of the center-of-pressure sway and 95% confidence ellipse area from Ground Reaction forces, and (ii) Principal Movement (PM) components from full-body motion kinematics; the latter were obtained exploiting a Principal Component Analysis-based approach, also embracing a motor-control perspective through the evaluation of the number of modifications applied by the neuromuscular controller on segments' acceleration.

FINDINGS

Trajectory length was significantly higher in patients; 95% ellipse confidence area did not differ between groups/condition. Postural movement components differed in people with DS from healthy controls not only in the "observable", behavioural phenotype (PM3 and PM8), but also in the amount of activation of the associated control (PM1 to PM8, over-activated in DS) in all spatial directions.

INTERPRETATION

Results reinforced the prevalence of a medio-lateral hip strategy (instead of an ankle strategy) in maintaining postural stability. Most important, they revealed a less frequent activation of postural patterns in all spatial directions.

Changes in symmetry during gait in adults with Prader-Willi syndrome

Most studies on locomotion of individuals with the Prader-Willi Syndrome (PWS) have been performed in a laboratory setting using quantitative motion analysis. Recently, wireless inertial sensors have been successfully employed for gait analysis in different pathological states with the advantages of reproducing a testing condition very close to those encountered in daily living. Using such devices, it is possible not only to characterize the conventional spatio-temporal parameters, but also extract information on further less conventional metrics, such as the harmonic ratio (HR), a measure of step-to-step symmetry based on trunk acceleration processing. In the present study, this technique was used to quantify gait parameters during level walking in 20 adults with PWS who were compared to 20 unaffected individuals. While no differences between the two groups were found in terms of spatio-temporal parameters, individuals with PWS exhibited significantly reduced values of HR in the antero-posterior and vertical directions. Such results, which indicate a poorer gait symmetry in PWS, suggest that upper body accelerations, as well as HR, provide novel information on gait in people with PWS that could not be extracted from spatio-temporal parameters only.

Correlational study of the center of pressure measures of postural steadiness on five different standing tasks in overweight adults

This study applied the posturography framework on five static standing tasks from the Berg Balance Scale (BBS). Thirteen participants were recruited and the trajectory data of the center of pressure (CoP) were collected. To analyze the postural performance, two approaches were taken: the scores from the BBS and statistical analysis. For the statistical analysis, Spearman's method was applied to determine the correlation of CoP parameters. The results revealed the correlations between CoP parameters in the anterior-posterior (AP) and medial-lateral (ML) directions, and on the statokinesgram (SK) plane for all tasks. To obtain the in-depth detail between normal weight and overweight groups, the differences in the postural control mechanism were defined by correlations of CoP parameters. The Mann-Whitney U test was conducted to define the difference in postural control in terms of difference in weight gain and standing task factors, while Cohen's d was used to investigate the influence of the difference in standing tasks and weight gain on postural control. The results showed that the correlations of CoP parameters could distinguish the balance impairment in the overweight condition from the normal postural control. Otherwise, the scores of BBS, the Mann-Whitney U test and Cohen's d did not separate this slightly compensatory movement during equilibrium. Therefore, the correlations of CoP parameters could provide more information to analyze the balance function in each individual, especially in terms of slight compensation.

Gait and postural control patterns and rehabilitation in Down syndrome: a systematic review

[Purpose] To describe (1) the current knowledge on gait and postural control in individuals with Down syndrome in terms of spatiotemporal, kinematics and kinetics, and (2) relevant rehabilitation strategies. [Methods] Randomized and non-randomized clinical trials published between January 1997 and October 2019 were selected by searching four scientific databases. We included studies on patients with Down syndrome involving gait analysis or postural control. A custom data-extraction and appraisal form was developed to collect the key features of each article. The PEDro Scale was used to evaluate the methodological quality of the studies. [Results] A total of 37 out of 146 cross-sectional and longitudinal studies were included in the review. The main abnormalities included: reduction of gait velocity and step length, poor static balance with increased anteroposterior and mediolateral oscillations and a larger step width. [Conclusion] A number of compensatory patterns during movement was observed, with a direct influence on improvements in stability and postural control throughout daily life. Intensive gait training at an early age appears to produce long-term improvements in this population. Future research should focus on the interaction between the motor and cognitive function, and on the functional effects due to the exposure to an enriched environment.

Balance Control in Obese Subjects during Quiet Stance: A State-of-the Art

Obese individuals are characterized by a reduced balance which has a significant effect on a variety of daily and occupational tasks. The presence of excessive adipose tissue and weight gain could increase the risk of falls; for this reason, obese individuals are at greater risk of falls than normal weight subjects in the presence of postural stress and disturbances. The quality of balance control could be measured with different methods and generally in clinics its integrity is generally assessed using platform stabilometry. The aim of this narrative review is to present an overview on the state of art on balance control in obese individuals during quiet stance. A summary of knowledge about static postural control in obese individuals and its limitations is important clinically, as it could give indications and suggestions to improve and personalize the development of specific clinical programs.

Dual-task effects on postural sway during sit-to-stand movement in children with Down syndrome

BACKGROUND

Cognitive and postural tasks require common cognitive mechanisms, resulting in conflicts when both tasks are simultaneously performed. The presence of neuromotor dysfunctions, such as Down syndrome, may impair coordination processes required to perform dual-tasks. The objective of this study was to investigate the dual-task effects on postural sway during sit-to-stand movements in typical children and children with Down syndrome in a cross-sectional study.

METHODS

Twenty six typical children (10.2 ± 2.4 years) and 21 with Down syndrome (10.3 ± 2.3 years) performed sit-to-stand in the following conditions: (1) simple task; (2) dual-task bimanual activity (DT-Bim): sit-to-stand while carrying a tray using both hands; (3) dual-task unimanual dominant activity (DT-Uni-Dom): sit-to-stand while holding a plastic cup simulating water using the dominant hand; (4) dual-task unimanual non-dominant activity (DT-Uni-Nondom): sit-to-stand movement while holding a plastic cup simulating water. For data analysis, sit-to-stand was divided into three phases: preparation (phase 1), rising (phase 2), and stabilisation (phase 3). The following variables were calculated for each phase: anterior-posterior and medial-lateral amplitude of centre-of-pressure displacement, anterior-posterior and medial-lateral velocity of centre-of-pressure sway and area of centre-of-pressure sway.

RESULTS

Children with Down syndrome showed greater sway than typical children in all sit-to-stand phases. Typical children showed greater anterior-posterior amplitude in phase 2 of sit-to-stand during DT-Uni Nondom compared with DT-Uni Dom. Children with Down syndrome during simple task condition showed greater and faster values sway in phases 2 and 3 of sit-to-stand movement than in DT-Bim activity, DT-Uni Dom activity and DT-Uni Nondom activity. During the condition of DT-Bim activity, these children showed lower anterior-posterior velocity of sway in phase 2 than during DT-Uni Dom activity.

CONCLUSIONS

Children with Down syndrome showed greater postural sway during sit-to-stand than typical children. The addition of a concurrent motor task to sit-to-stand impacted postural sway in different intensities and in different ways across groups. Dual-tasks increased body sway in typical children in the DT-Uni Nondom condition compared with dominant one. In children with Down syndrome, dual-tasks decreased body sway, apparently resulting in a postural strategy of stiffness.

Men and women with Down syndrome exhibit different kinematic (but not spatio-temporal) gait patterns

BACKGROUND

Gait phenotypes are well documented in people with Down syndrome (pwDS), but sex-related differences are still unexplored. This study investigated the existence of possible differences in spatio-temporal and kinematic parameters of gait between men and women with DS using quantitative three-dimensional gait analysis.

METHODS

Gait patterns of 117 pwDS (53 F, 64 M) who underwent a computerised gait analysis from 2002 to 2017 were retrospectively analysed to obtain spatio-temporal gait parameters and kinematics in the sagittal plane at hip, knee and ankle joints, as well as foot progression.

RESULTS

Overall, when considered as a single group, the gait patterns found for pwDS confirmed the findings of previous studies. However, when analysed by sex, our data revealed that women with DS exhibit a larger hip flexion at late stance (42% to 54% of the gait cycle) and reduced knee flexion at the beginning of the swing phase (61% to 69% of the gait cycle). In contrast, men are characterised by larger foot extra-rotation angles through most of the stance phase (from 0% to 55% of the gait cycle) and at the end of the swing phase (92% to 99% of the gait cycle). No differences between men and women with DS were found concerning ankle dorsi- plantar-flexion or in all spatio-temporal parameters normalised by individuals' anthropometry, excluding cadence (higher in women).

CONCLUSIONS

The findings of the present study highlight the need to investigate gait dysfunctions in pwDS by taking their sex into consideration. Such an approach may be useful not only in gaining a better understanding of the pathophysiology of gait disturbances associated with DS but also in supporting a better orientation of rehabilitative treatments.

Using computational support in motor ability analysis of individuals with Down syndrome: Literature review

BACKGROUND

The lack of motor ability is one of the main Down syndrome (DS) effects. However, there are several types of motor disorders that can be attenuated or corrected if they are early identified and properly analyzed.

OBJECTIVES

The aim of our study is to support the local Physical Activity research group, which works with about 25 DS children, by means of computational resources for motor analysis. To that end, we first needed to identify the main computational approaches that support the motor analysis of DS individuals, if they are already connected to intervention programs, and potential opportunities to extend the current state of the art.

METHOD

We carried out a systematic review that identified 28 papers from the current literature. These papers were then analyzed to answer the research questions defined in our study.

RESULTS

Our main findings were: (1) the temporal distribution of papers shows this area is new and it is starting to create a body of knowledge that in fact supports motor treatments of DS individuals; (2) there is a diversity of studies that consider different research directions such as comparisons of motor features of DS with non-DS individuals, characterization of DS motor features, and approaches for intervention programs to improve DS motor abilities; (3) there are several types of sensing hardware that enables the development of studies from different perspectives; (4) spatial monitoring is performed but only in laboratory conditions; (5); mathematical tools are largely used while strategies based on artificial intelligence for automated analysis are ignored; and (6) proposals for DS post-intervention monitoring are not found in the literature.

CONCLUSION

DS motor analysis is still a new research area and it is not mature yet. Thus, the use of computational resources is very pragmatic and focused only on mathematical tools that support the numerical analysis of the acquired data. The main proposals for motor analysis are performed in laboratory, so that there are several opportunities to create computational resources to obtain real-time data on the move. The integration of this data with intervention strategies is also a potential area for future researches.

Coupling between visual information and body sway in adults with Down syndrome

BACKGROUND

Prior studies suggest that infants with Down syndrome (DS) need more experience to acquire a similar relationship between visual information and body sway than infants without DS. However, it is unclear how adults with DS deal with visual information to control posture.

AIM

To examine the coupling between visual information and body sway in adults with DS.

METHODS

Twenty adults with DS (25.8±4.0years) and twenty age- and sex-matched controls (25.6±4.0years) stood upright inside a "moving room" in two experimental conditions: continuous (room oscillated continuously at 0.1, 0.2, and 0.5Hz) and discrete (room moved forward or backward for a brief moment). Tridimensional body sway and moving room displacement data were registered.

RESULTS

Individuals with DS coupled their body sway to the imposed visual stimulus, but showed higher position variability at frequencies other than the frequency of room movement (0.48cm) and lower coherence (0.80) than controls (0.40cm and 0.90, respectively).

CONCLUSIONS

Adults with DS were able to couple to the visual cue, but with differences in terms of the scaling of postural responses to spatial parameters of the visual stimulus.

The effects of low arched feet on foot rotation during gait in children with Down syndrome

BACKGROUND

In children with Down syndrome (DS) hypotonia and ligament laxity are characteristic features which cause a number of orthopaedic issues, such as flat foot. The aim of this study was to determine if children with flat foot are characterised by an accentuated external foot rotation during walking.

METHOD

Fifty-five children with DS and 15 typically developing children recruited as control group were assessed using three-dimensional gait analysis, using an optoelectronic system, force platforms and video recording. Parameters related to foot rotation were identified and calculated and the participants' foot morphology was assessed using the arch index.

RESULTS

Data obtained in this study showed that while DS children without flat foot displayed the foot position on the transverse plane globally close to controls during the whole gait cycle, the DS children with flat foot were characterised by higher extra-rotation of the foot in comparison with those without flat foot and controls.

CONCLUSIONS

Our results suggest that the presence of flatfoot lead the children with DS to extra-rotate their feet more than the children without flat foot. From a clinical point of view, these results could enhance the rehabilitative programmes in DS.

Postural stability in young adults with Down syndrome in challenging conditions

To evaluate postural control and performance in subjects with Down syndrome (SwDS), we measured postural sway (COP) in quiet stance in four 20-second tests: with eyes open or closed and on hard or foam surface. Ten SwDS and eleven healthy subjects participated, aged 29.8 (4.8) and 28.4 (3.9), respectively. The time-series recorded with the sampling rate of 100 Hz were used to evaluate postural performance (COP amplitude and mean velocity) and strategies (COP frequency, fractal dimension and entropy). There were no intergroup differences in the amplitude except the stance on foam pad with eyes open when SwDS had larger sway. The COP velocity and frequency were larger in SwDS than controls in all trials on foam pad. During stances on the foam pad SwDS increased fractal dimension showing higher complexity of their equilibrium system, while controls decreased sample entropy exhibiting more conscious control of posture in comparison to the stances on hard support surface. This indicated that each group used entirely different adjustments of postural strategies to the somatosensory challenge. It is proposed that the inferior postural control of SwDS results mainly from insufficient experience in dealing with unpredictable postural stimuli and deficit in motor learning.

Relationship between flat foot condition and gait pattern alterations in children with Down syndrome

BACKGROUND

In patients with Down syndrome (DS) one of the most common abnormalities is flat foot which can interfere significantly with normal daily activities, such as gait. The aim of this study was to quantitatively assess the relationship between the flat foot and the gait alterations in DS children.

METHOD

Twenty-nine patients with DS and 15 non-affected subjects were assessed using 3D Gait Analysis, using an optoelectronic system, force platforms and video recording. The degree of flat foot was assessed using the arch index and kinematic and kinetic parameters were identified and calculated from 3D Gait Analysis for each study participant.

RESULTS

Data showed that ankle plantarflexion moment and ankle power during terminal stance were significant to differentiate the patients with and without flat feet: their peak values were significantly lower for the patients with flat foot. In addition, the research for correlation demonstrated that the higher the arch index value, the lower the peak of ankle moment and of the generated ankle power during terminal stance and the minimum of absorbed ankle power.

CONCLUSIONS

Children with flat foot displayed a less functional gait pattern in terms of ankle kinetics than children without flat foot, suggesting that the presence of flat foot may lead to a weaker efficient walking. Then, the increasing flat foot tended to result in lower push-off ability, leading to a less functional walking.

Quantitative 3D evaluation of step ascent and descent in individuals with Down syndrome--analysis of a daily challenging task

BACKGROUND

Step ascent and descent can perturb stability increasing the incidence of falls, especially in older individuals with functional limitations and intellectual disabilities, such as those with Down syndrome (DS). The aim of this study was to investigate the biomechanics and motor coordination of step ascent and descent in adults with DS and compare them with a group of healthy individuals, considering movement kinematics and kinetics.

METHOD

Fourteen adults with DS and 12 similarly aged adults without DS who were free of known motor problems were quantitatively assessed during ascending and descending a step using an optoelectronic system (BTS SMART-D), force platforms and video recording. Kinematic and kinetic parameters were identified and calculated for each study participant and comparisons were made between the DS and a control group (CG).

RESULTS

Despite similar age ranges, subjects in the DS group performed the step ascent and descent movements slower, with longer duration and with a more accentuated range of motion of the trunk and of the ankle joint than those in the CG. Additionally, the double stance phase on the step was substantially longer in the DS group when represented as a percentage of the entire stepping sequence (ascent, double stance on the step and descent). In terms of kinetics, ground force platform data revealed that the DS subjects showed higher instability in the medio-lateral direction during double support phase than similarly aged CG subjects and cannot be attributed to age-associated changes in stability.

CONCLUSIONS

These findings help to elucidate the complex biomechanical strategy of people with DS during a step ascent and descent movement task and may have a major role in the multidimensional evaluation and tailored management for them.

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.

The fractal dimension approach in posture: a comparison between Down and Prader-Willi syndrome patients

The suitability of new dynamic system analysis was investigated to compare postural control in Prader-Willi syndrome (PWS) and Down syndrome (DS) patients. Time-domain, frequency-domain parameters and fractal dimension (FD) of centre of pressure (CoP) were computed in maintaining normal standing on a force platform in 20 DS and 13 PWS patients, compared to 26 obese (obese control group, OCG) and 20 healthy individuals (healthy control group, HCG). DS and PWS showed greater displacements along both directions and longer sway path (SP) parameter than HCG and OCG, with statistical differences between PWS and DS for anteroposterior displacement and SP. DS used higher frequency strategy when compared to PWS, OCG and HCG. Both DS and PWS were characterised by greater values of FD than OCG and HCG, with higher values in DS. The analyses in frequency domain and of the dynamic nature of CoP suggest that DS patients are characterised by a more complex and irregular signal than PWS patients.

Posture control after 5 months body balance training in Down syndrom children and youth

Aim of the study: The aim of this study was to verify whether the 5-month training exercises using specific balance exercises of the authorial program improves body balance control in children with Down syndrome (DS).

Materials and methods: The purpose of this study was the verification if the 5-months posture control exercises training by original program relays to posture control in Down syndrome (DS) children and youth. The subjects were 8 DS persons: 4 males and 4 females, aged 13-24. Two 20-seconds consecutive trails of natural bipedal standing position on 2 force platforms AccuSway (AMTI), one under each foot, were performed during research. On the basis of COP (centre of pressure) time series the following indices were computed: range, variability, velocity and area of COP shifts. There were 2 sessions of the research: one just before and the second just after 5-month lasting specific posture control training based on the original exercise program.

Results: The results revealed decreasing of the COP velocity of right lower limb and the COP range in anterior-posterior direction of both lower limbs after the training, comparing to the values from the first research session.

Conclusions: It is concluded that the specific posture control training by the presenting of the original exercises program influenced the posture control improving it and the program can be used in therapy of DS children and youth.

Functional assessments of the knee joint biomechanics by using pendulum test in adults with Down syndrome

In this study, we assessed kinematics and viscoelastic features of knee joint in adults with Down syndrome (DS) by means of the Wartenberg pendulum test. This test allows the measuring of the kinematics of the knee joint during passive pendular motion of leg under the influence of gravity. In addition, by a combination of kinematic and anthropometric data, pendulum test provides estimates of joint viscoelastic properties by computing damping and stiffness coefficients. To monitor the occurrences of muscle activation, the surface electromyogram (EMG) of muscle rectus femoris was recorded. The experimental protocol was performed in a group of 10 adults with DS compared with 10 control adults without DS. Joint motion amplitude, velocity, and acceleration of the leg during the first knee flexion significantly decreased in persons with DS with respect to those without DS. This behavior was associated with the activation of rectus femoris in subjects with DS that resulted in increasing of joint resistance shortly after the onset of the first leg flexion. The EMG bursts mostly occurred between 50 and 150 ms from the leg flexion onset. During the remaining cycles of pendular motion, persons with DS exhibited passive leg oscillations with low tonic EMG activity and reduced damping coefficient compared with control subjects. These results suggest that adults with DS might perform preprogrammed contractions to increase joint resistance and compensate for inherent joint instability occurring for quick and unpredictable perturbations. The reduction of damping coefficients observed during passive oscillations could be a predictor of muscle hypotonia.

Relationships between task-oriented postural control and motor ability in children and adolescents with Down syndrome

Individuals with Down syndrome (DS) have been characterized by greater postural sway in quiet stance and insufficient motor ability. However, there is a lack of studies to explore the properties of dynamic postural sway, especially under conditions of task-oriented movement. The purpose of this study was to investigate the relationships between task-oriented postural control and motor ability in children and adolescents with DS. The participants were 23 children and adolescents with DS (DS group, M±SD age, 14.4±2.8 years) and 18 age- and gender-matched peers (M±SD age, 13.8±3.6 years). A force plate was used to collect postural data represented by center of pressure (COP) parameters. Postural measurements were conducted for both groups in quiet standing with eyes open and with eyes closed, and also while throwing a ball at erect standing. Assessments of motor ability were only applied to the DS group by using two dimensions of the original version of Gross Motor Function Measure and 4 subtests of the Bruininks Oseretsky Test of Motor Proficiency, second edition. The results showed that while the participants with DS showed greater displacement and higher velocity of COP sways at quiet standing, they exhibited smaller COP displacement in anterior/posterior direction during throwing the ball. Three areas of motor ability, including standing motor skills, walk/run/jump motor skills and muscle strength, were found to make a significant contribution to the displacement and velocity of postural sway during the voluntary movement. It is suggested that future research should focus on investigating the definite underlying mechanism of postural sway during movement and the influence of increasing motor ability on the reactive postural sway in this population.

Foot-ground interaction during upright standing in children with Down syndrome

This study aimed to quantitatively characterize the main foot-ground contact parameters during static upright standing and to assess foot evolution with increasing age in young individuals affected by Down syndrome (DS). To this end, 99 children with DS of mean age 9.7 (1.7) were tested using a pressure sensitive mat, and the raw data were processed to extract information about overall and rearfoot, midfoot and forefoot contact area, Arch Index (AI) and average contact pressure. The values obtained were then compared with those calculated from a sample of age- and gender-matched participants (control group, CG). Children with DS exhibited larger midfoot and reduced forefoot contact areas with respect to CG participants (+53% and -35% respectively, p<0.001), increased AI values (DS 0.31, CG 0.20, p<0.001) and increased average contact pressures in the midfoot and forefoot. The overall foot development for the two groups followed a similar trend, although in individuals with DS a curve that relates increases in midfoot contact area with age is characterized by a steeper gradient, and the forefoot contact area appeared systematically smaller regardless of age. The large prevalence of the flatfoot type in children with DS (which is known to be originated by hypotonia and ligamentous laxity) associated with the presence of higher average contact pressure in midfoot and forefoot justify the need for careful podiatric surveillance throughout childhood to reduce balance and gait impairment which are likely to affect untreated subjects when they reach adulthood.

The effect of growth hormone treatment or physical training on motor performance in Prader-Willi syndrome: a systematic review

Although motor problems in Prader-Willi syndrome (PWS) are prominent in infants, and continue into childhood and adulthood, there is little insight into the factors important for clinical management. The literature was reviewed to: (1) provide an overview of the characteristics and prevalence of motor problems and (2) evaluate the effects of growth hormone (GH) treatment and physical training on motor performance. A systematic search revealed 34 papers: 13 on motor performance; 12 on GH treatment; and nine on physical training. In infants, motor development is 30-57% of the normal reference values, and children and adults also have significant problems in skill acquisition, muscle force, cardiovascular fitness, and activity level. GH treatment positively influenced motor performance in infants, children, and adults, although not all studies demonstrated an effect. All studies on physical training demonstrated beneficial effects in PWS patients. We suggest a combination of GH treatment and physical training to be started as soon as possible, especially in infants, to improve motor development as this will positively influence general development.

The effect of physical training on static balance in young people with intellectual disability

Intellectual disability affects all spheres of people's lives who suffer from it. It lowers the level of intellectual functioning, often stigmatizes, characteristically changing features, and decreases motor performance. Unfortunately, modern medicine cannot cure intellectual disability; however, there is a chance to improve the quality of life of people with mental retardation by means of physical exercises and by enhancing coordination, the quality of gait and efficiency in performing everyday activities. This paper deals with observations of static balance in 40 young females and males with mild Down syndrome, out of which 20 were subjected to a three-month sensorimotor training programme. The participants performed exercises with rehabilitation balls and air pillows twice a week, and the remaining persons constituted a control group. The balance platform test conducted at the beginning of the experiment revealed that the level of static one-legged balance was similar in both groups. A significant difference was noted in the length of the path of the general centre of gravity (COG) and the time frame in which the vertical projection of COG remained within the 13 mm radius circle, between the result of the test conducted under visual control and with the eyes closed, both in the group of the participants performing exercises and the ones who did not do them. After the training sessions the results of both tests improved in the group of the persons subjected to the training programme, however differences between the groups were not statistically significant, apart from the comparison of the time of keeping COG within the 13 mm radius circle at the beginning and at the end of the experiment by the participants who were physically active. Our results lead to a conclusion that exercises with the use of unstable surfaces improve deep sensibility in people with mild mental retardation.

Muscle-bone characteristics in children with Prader-Willi syndrome

BACKGROUND

A decrease in muscle mass, low motor performance, and normal lumbar spine bone mineral density (BMD) have been reported in children with Prader-Willi syndrome (PWS). However, these data are limited by the fact that PWS children (who have short stature) were compared to age-matched healthy or obese individuals of normal height.

OBJECTIVE

The goal of the present study was to compare bone and muscle characteristics in PWS children to sex- and age- or height-matched healthy subjects.

MATERIALS AND METHODS

The study population included 17 PWS children (ages 6.2 to 17.5 yr; nine girls) who were not treated with GH. The axial skeleton was analyzed at the lumbar spine using dual-energy x-ray absorptiometry, and the appendicular skeleton (radius and tibia) was evaluated using peripheral quantitative computed tomography. Muscle parameters (mass, size, and functional parameters) were measured by dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and jumping mechanography, respectively.

RESULTS

Compared to height-matched controls, PWS patients had normal axial and appendicular BMD, as well as normal muscle size. Compared to age- or height-matched controls of normal weight, PWS patients had lower maximal muscle force and power relative to body mass during jumping. PWS patients had similar absolute maximal muscle force but lower absolute maximal power compared to age- or height-matched controls. Relationships between bone mass and muscle size and force were similar in PWS patients and in healthy subjects.

CONCLUSION

Relative to their height, PWS patients not treated with GH had normal axial and appendicular BMD, muscle size, and muscle-bone relationships.

The effect of vision on postural strategies in Prader-Willi patients

The aim of this study was to quantify the role of visual contribution in patients with Prader-Willi syndrome (PWS) on balance maintenance using a force platform. We enrolled 14 individuals with PWS free from conditions associated with impaired balance, 44 obese (OG) and 20 healthy controls (CG). Postural sway was measured for 60s while standing on a force platform (Kistler, CH; acquisition frequency: 500 Hz) integrated with a video system. Patients maintained an upright standing position with Open Eyes (OE) and then with Closed Eyes (CE). The ratio between the value of the parameter under OE and CE conditions was measured. Under OE condition PWS and OG were characterized by higher postural instability than CG, with the PWS group showing poorer balance capacity than OG. The Romberg ratio showed that while OG and CG had lower balance without vision, PWS maintained the same performance changing from OE to CE. The integration of different sensory inputs appears similar in OG and CG with higher postural stability under OE than CE. Balance in PWS is not influenced by the elimination of visual input.