Specific grasp characteristics of children with trisomy 21

Investigation of cardiopulmonary parameters, motor development and muscle strength in children with Down syndrome with and without congenital heart disease

BACKGROUND

Children with Down syndrome (DS) frequently have concomitant clinical problems. There are no studies in the literature evaluating gross motor development and handgrip strength in the presence of congenital heart disease (CHD), which is one of the most common comorbidities in population with DS. The aim of this study was to compare cardiopulmonary parameters, gross motor development and handgrip strength in children with DS with and without CHD.

METHODS

A total of 28 children with DS (14 with CHD and 14 without CHD) were evaluated. Demographic data and cardiopulmonary parameters were recorded. Gross motor development and handgrip strength were assessed.

RESULTS

Children with DS and CHD had lower GMFM-88 scores and right handgrip strength and higher Wang respiratory score than children with DS and no CHD (P < 0.05). GMFM-88 scores were moderately correlated with resting oxygen saturation (r = 0.46, P = 0.01) and right handgrip strength (r = 0.67, P < 0.001).

CONCLUSIONS

Peripheral muscle strength and oxygen saturation may be factors affecting gross motor development in children with DS. From this point of view, evaluating cardiopulmonary parameters, motor development and handgrip strength in children with DS and CHD is important to identify risks, provide early intervention and support development.

Determinants of hand function in children and adolescent with Down Syndrome-A scoping review

BACKGROUND

Down Syndrome (DS) is a genetic condition. Physical characteristics like short stature, hypotonia, small, and thick hands result in decreased grip and pinch strength and quality of fine motor tasks.

PURPOSE

The purpose of this review is to summarize the evidence of upper extremity physical characteristics and its influence on hand function in DS population.

STUDY DESIGN

A scoping review.

METHODOLOGY

A comprehensive electronic literature search was conducted through PubMed, CINAHL, Cochrane Library. The search was limited to articles written in English and published between 2010 to 2021. Additionally, books were referred for a better understanding of the hand function in DS. The Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews (PRISMA-ScR) was adopted to develop the protocol.

RESULTS

Following a detailed review of 28 articles meeting the inclusion criteria, fetuses with a diagnosis of DS are reported to have shortening of humerus on sonographic markers wherein 9% of fetuses had below 5th percentile shortening. Additionally, literature reports that during reaching there was increased trunk rotation (effect size = 0.88). DS population had 60% less grip strength, 33% less palmar pinch strength ,20% less key pinch strength and poor manual dexterity (CI = 4.5-5.5).

CONCLUSION

Findings of this review concludes that physical characteristics of the upper extremity have an influence on hand function performance in children and adolescents with DS.However, only arm length and hand span have been quantified and correlated with grip strength. Further work must focus on correlation of upper extremity anthropometry and overall hand function in children and adolscents with DS.

Visuomotor skill learning in young adults with Down syndrome

BACKGROUND

Individuals with Down syndrome (DS) have impaired general motor skills compared to typically developed (TD) individuals.

AIMS

To gain knowledge on how young adults with DS learn and retain new motor skills.

METHODS AND PROCEDURES

A DS-group (mean age = 23.9 ± 3 years, N = 11), and an age-matched TD-group (mean age 22.8 ± 1.8, N = 14) were recruited. The participants practiced a visuomotor accuracy tracking task (VATT) in seven blocks (10.6 min). Online and offline effects of practice were assessed based on tests of motor performance at baseline immediate and 7-day retention.

OUTCOMES AND RESULTS

The TD-group performed better than the DS-group on all blocks (all P < 0.001). Both groups improved VATT-performance online from baseline to immediate retention, (all P < 0.001) with no difference in online effect between groups. A significant between-group difference was observed in the offline effect (∆TD - ∆DS, P = 0.04), as the DS-group's performance at 7-day retention was equal to their performance at immediate retention (∆DS, P > 0.05), whereas an offline decrease in performance was found in the TD-group (∆TD, P < 0.001).

CONCLUSIONS AND IMPLICATIONS

Visuomotor pinch force accuracy is lower for adults with DS compared to TD. However, adults with DS display significant online improvements in performance with motor practice similar to changes observed for TD. Additionally, adults with DS demonstrate offline consolidation following motor learning leading to significant retention effects.

Quantitative magnetic resonance characterization of the effect of physical training on skeletal muscle of the Ts65Dn mice, a model of Down syndrome

Down syndrome (DS) is characterized by muscle hypotonia and low muscle strength associated with motor dysfunction. Elucidation of the determinants of muscle weakness in DS would be relevant for therapeutic approaches aimed at treating/mitigating a physical disability with a strong impact on the quality of life in persons with DS. The Ts65Dn mice is a recognized mouse model of DS, with trisomic mice presenting gross motor and muscle phenotypes. The aim of this work was to assess the effect of physical exercise, a well-known tool to improve skeletal muscle condition, in the hindlimbs of trisomic and euploid male mice using quantitative magnetic resonance imaging (MRI). Magnetic resonance spectroscopy (MRS) metabolomics and histological fiber typing were used to further characterize the post-exercise muscle. Quantitative MRI showed not significantly different amounts of skeletal muscle in proximal hindlimbs in trisomic and euploid mice both at baseline and after physical exercise (P>0.05). Similar results were obtained for hindlimbs subfascia adipose tissue, and subcutaneous adipose tissue (P>0.05). MRS showed lower amounts of exercise-related metabolites (valine, isoleucine, leucine) in euploid vs. trisomic mice after exercise (P≤0.05). The percentage of slow-twitch fibers was similar in the two genotypes (P>0.05). We conclude that in DS adapted physical exercise (one month of training) does not induce quantitative changes in skeletal muscle or fiber type composition therein; however, the metabolic response of skeletal muscle to exercise may be affected by trisomy. These findings prompt further research investigating the role of physical exercise as a cue to clarify the mechanisms of the muscular deficit found in DS.

Effect of Transcranial Direct Current Stimulation Combined With Xbox-Kinect Game Experience on Upper Limb Movement in Down Syndrome: A Case Report

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique used to enhance local synaptic efficacy and modulate the electrical activity of the cortex in neurological disorders. Researchers have sought to combine this type of stimulation with well-established therapeutic modalities, such as motor training involving Xbox Kinect games, which has demonstrated promising results. Thus, this study aimed to determine whether tDCS can enhance upper limb motor training in an eight-year-old child with Down Syndrome (DS) (cognitive age: five years, based on the Wechsler Intelligence Scale for Children). The evaluations consisted of three-dimensional analysis of upper limb kinematics during a reaching task performed before, after10 session, and one month after the intervention. The intervention protocol involved 1 20-min sessions of tDCS over the primary motor cortex at an intensity of 1 mA during Xbox Kinect game training involving an upper limb motor task. The analysis of the kinematic data revealed that in the pre-intervention evaluation, the dominant limb executed the task slowly and over a long path. These aspects improved at the post-intervention and follow-up evaluations, as demonstrated by the shorter total movement duration (3.05 vs. 1.58 vs. 1.52 s, respectively). Similar changes occurred with the non-dominant upper limb; a significant increase in movement velocity at the post-intervention and follow-up evaluations was observed (0.53 vs. 0.54 vs. 0.85 m/s, respectively). The present case report offers preliminary data from a protocol study, and the results confirm the notion that anodal tDCS combined with upper limb motor training leads to improvements in different kinematic variables.

Systematic Review of the Main Motor Scales for Clinical Assessment of Individuals with down Syndrome

Objective: The aim of the present review was to identify the motor scales currently used to assess individuals with Down Syndrome (DS).Method: PubMed, WOS and BVS databases were systematically searched to identify the most relevant published studies that used motor scales in the evaluation of individuals with DS.Results: Of the 99 studies that met the eligibility criteria in this process, 20 experimental and observational studies were found to fully meet the eligibility criteria.Conclusion: We identified several motor scales including the Alberta Infant Motor Scale (AIMS), Test of Infant Motor Performance (TIMP), BAYLEY, Peabody Gross Motor Scale (PGMS-PDMS-GM), Gross Motor Function Measure (GMFM), Movement Assessment Battery for Children (MABC) and Pediatric Evaluation of Disability Inventory (PEDI).

Defects in nerve conduction velocity and different muscle fibre-type specificity contribute to muscle weakness in Ts1Cje Down syndrome mouse model

BACKGROUND

Down syndrome (DS) is a genetic disorder caused by presence of extra copy of human chromosome 21. It is characterised by several clinical phenotypes. Motor dysfunction due to hypotonia is commonly seen in individuals with DS and its etiology is yet unknown. Ts1Cje, which has a partial trisomy (Mmu16) homologous to Hsa21, is well reported to exhibit various typical neuropathological features seen in individuals with DS. This study investigated the role of skeletal muscles and peripheral nerve defects in contributing to muscle weakness in Ts1Cje mice.

RESULTS

Assessment of the motor performance showed that, the forelimb grip strength was significantly (P<0.0001) greater in the WT mice compared to Ts1Cje mice regardless of gender. The average survival time of the WT mice during the hanging wire test was significantly (P<0.0001) greater compared to the Ts1Cje mice. Also, the WT mice performed significantly (P<0.05) better than the Ts1Cje mice in the latency to maintain a coordinated motor movement against the rotating rod. Adult Ts1Cje mice exhibited significantly (P<0.001) lower nerve conduction velocity compared with their aged matched WT mice. Further analysis showed a significantly (P<0.001) higher population of type I fibres in WT compared to Ts1Cje mice. Also, there was significantly (P<0.01) higher population of COX deficient fibres in Ts1Cje mice. Expression of Myf5 was significantly (P<0.05) reduced in triceps of Ts1Cje mice while MyoD expression was significantly (P<0.05) increased in quadriceps of Ts1Cje mice.

CONCLUSION

Ts1Cje mice exhibited weaker muscle strength. The lower population of the type I fibres and higher population of COX deficient fibres in Ts1Cje mice may contribute to the muscle weakness seen in this mouse model for DS.

Age- and speed-dependent modulation of gaits in DSCAM2J mutant mice

Gaits depend on the interplay between distributed spinal neural networks, termed central pattern generators, generating rhythmic and coordinated movements, primary afferents, and descending supraspinal inputs. Recent studies demonstrated that the mouse displays a rich repertoire of gaits. Changes in gaits occur in mutant mice lacking particular neurons or molecular signaling pathways implicated in the normal establishment of these neural networks. Given the role of the Down syndrome cell adherence molecule (DSCAM) to the formation and maintenance of spinal interneuronal circuits and sensorimotor integration, we have investigated its functional contribution to gaits over a wide range of locomotor speeds using freely walking mice. We show in this study that the DSCAM^2J mutation, while not precluding any gait, impairs the age- and speed-dependent modulation of gaits. It impairs the ability of mice to maintain their locomotion at high treadmill speeds. DSCAM^2J mutation induces the dominance of lateral walk over trot and the emergence of aberrant gaits for mice, such as pace and diagonal walk. Gaits were also more labile in DSCAM^2J mutant mice, i.e., less stable, less attractive, and less predictable than in their wild-type littermates. Our results suggest that the DSCAM mutation affects the behavioral repertoire of gaits in an age- and speed-dependent manner. NEW & NOTEWORTHY Gaits evolve throughout development, up to adulthood, and according to the genetic background. Using mutant mice lacking DSCAM (a cell adherence molecule associated with Down syndrome), we show that the DSCAM^2J mutation alters the repertoire of gaits according to the mouse's age and speed, and prevents fast gaits. Such an incapacity suggests a reorganization of spinal, propriospinal, and supraspinal neuronal circuits underlying locomotor control in DSCAM^2J mutant mice.

Differential Brain, Cognitive and Motor Profiles Associated with Partial Trisomy. Modeling Down Syndrome in Mice

We hypothesize that the trisomy 21 (Down syndrome) is the additive and interactive outcome of the triple copy of different regions of HSA21. Because of the small number of patients with partial trisomy 21, we addressed the question in the Mouse in which three chromosomal regions located on MMU10, MMU17 and MMU16 carries almost all the HSA21 homologs. Male mice from four segmental trisomic strains covering the D21S17-ETS2 (syntenic to MMU16) were examined with an exhaustive battery of cognitive tests, motor tasks and MRI and compared with TS65Dn that encompasses D21S17-ETS2. None of the four strains gather all the impairments (measured by the effect size) of TS65Dn strain. The 152F7 strain was close to TS65Dn for motor behavior and reference memory and the three other strains 230E8, 141G6 and 285E6 for working memory. Episodic memory was impaired only in strain 285E6. The hippocampus and cerebellum reduced sizes that were seen in all the strains indicate that trisomy 21 is not only a hippocampus syndrome but that it results from abnormal interactions between the two structures.

Grip and pinch strength in children with Down syndrome

Introduction

Children with Down syndrome present with joint laxity, hypotonia and shortened hands resulting in reduced grip and pinch strength. Limited information on grip and pinch strength in children with Down syndrome motivated this study.

Methods

A convenience sample of 30 children with Down syndrome (9–16 years) from special schools and 30 age- and gender-matched healthy school children was studied. Grip and pinch strength were measured according to ASHT standard procedure using JAMAR® dynamometer and B&L pinch gauge. Anthropometric data of upper limb and subject characteristics were recorded.

Results

Children with Down syndrome had significantly lower values for grip, palmar and key pinch strength (p < 0.001) (6.3 kg, 1.91 kg, 2.75 kg) compared to healthy children (15.9 kg, 2.86 kg, 3.52 kg), respectively. A positive moderate correlation was observed between right hand grip strength and body height (r = 0.67), bodyweight (r = 0.69), total arm length (r = 0.68), upper arm length (r = 0.68), forearm length (r = 0.63), hand length (r = 0.68) and hand breadth (r = 0.66) in children with Down syndrome.

Conclusions

Children with Down syndrome presented with 60% less grip strength, 33% less palmar pinch strength and 22% less key pinch strength when compared to children without Down syndrome. Positive moderate correlation was observed between grip strength, body height, body weight and upper limb anthropometric variables in children with Down syndrome.

Bimanual coordination in typical and atypical infants: movement initiation, object touching and grasping

The development of bimanual actions reflects perceptual, motor and cognitive processes, as well as the functional connectivity between brain hemispheres. We investigated the development of uni- and bimanual actions in typically-developing (TD) infants and infants with Down syndrome (DS) while they reached for objects with varying sizes. Eight TD infants and seven infants with DS (ages 4-8 months) were tested at several stages of reaching experience. Movement strategies at movement initiation, object touching and grasping were recorded. With reaching experience, typical infants increased ability to anticipate reaching strategies, and independent use of the hands according to task demands. Strategies used by infants with DS were mostly compensatory rather than anticipatory, and showed a weaker tendency for interlimb coupling at early ages. These differences may underlie functional limitations, and should be subject to early intervention.

Development of motor planning for dexterity tasks in trisomy 21

We examined the macroscopic aspects of motor planning in two manual dexterity tasks, comparing children, adolescents, and young adults with trisomy 21 (T21) with typically developing controls from a developmental perspective. We analyzed the order in which objects were picked up from a table during two manual tasks of the Movement Assessment Battery for Children (M-ABC). Participants with T21 were always slower than controls. Task completion times depended on the strategy used by participants to gather up the pegs or coins. A structured strategy, in which the participants picked the items up moving methodically along each row/column, contributed to rapid task completion by younger children and participants with T21. This study highlights the ability of children with T21 to select and maintain an efficient strategy that takes account of their motor difficulties. Developmental trajectories help to explain T21 functioning in these dexterity tasks.

Força de preensão e destreza manual na criança com Síndrome de Down

Crianças com Síndrome de Down (SD) apresentam atraso na aquisição das habilidades motoras em relação às crianças com desenvolvimento normal, podendo interferir em atividades como a força de preensão e a destreza manual. A avaliação destas atividades pode fornecer indicadores de desempenho nas atividades diárias. O objetivo deste estudo foi analisar a correlação entre força de preensão e destreza manual em crianças com SD e crianças saudáveis com idade entre 7 e 9 anos. Participaram 26 crianças com SD, de ambos os sexos, que constituíram o Grupo SD, e 30 crianças saudáveis, compondo o Grupo Controle (GC). A avaliação da força de preensão foi realizada com o dinamômetro Jamar, e a da destreza manual pelo Teste Caixa e Blocos. O Grupo SD apresentou desempenho inferior tanto na força de preensão quanto na destreza manual, quando comparado ao GC; não houve correlação significativa entre a força de preensão e a destreza manual no Grupo SD; no GC esta correlação existiu; não houve diferença de desempenho entre os sexos para os itens avaliados; o desempenho nos testes de força de preensão e destreza manual no GC mostrou uma evolução com o decorrer da idade; no Grupo SD esta evolução não ocorreu. Conclui-se que foram encontradas diferenças no desempenho dos dois grupos, indicando características peculiares para a SD. Estes dados merecem maior investigação, uma vez que podem contribuir para a identificação de objetivos a serem considerados nos programas de estimulação.

Infants with Down syndrome and their interactions with objects: development of exploratory actions after reaching onset

During infant development, objects and their functions are learned by means of active exploration. Factors that may influence exploration include reaching and grasping ability, object properties and the presence of developmental disorders. We assessed the development of exploratory actions in 16 typically-developing (TD) infants and 9 infants with Down syndrome (DS) after reaching onset. Infants with DS reached for and explored objects less frequently than TD infants, especially small objects. Over time, the amount of reaches increased in both groups, with no changes in the amount of exploration in the DS group. Pre-grasping actions were different across objects, but less efficient in generating action-relevant information in the DS group. These infants also performed fewer behaviors requiring complex motor skills. The results suggest that perceptual-motor abilities determine different exploratory behaviors in TD and DS infants. The reduced amount and complexity of exploratory actions may impact developmental outcome in DS.

Desempenho motor fino e funcionalidade em crianças com síndrome de Down

O objetivo do estudo foi comparar crianças com síndrome de Down (SD) e crianças típicas quanto ao desempenho motor fino, avaliado pela Bayley Scales of Infant and Toddler Development - Third Edition (BSITD-III), e o desempenho em autocuidado segundo o Inventário Pediátrico de Avaliação de Incapacidade (PEDI); e investigar associação entre ambos os domínios. Participaram 12 crianças típicas e 12 crianças com SD, avaliadas na idade de 2 anos. As crianças com SD apresentaram desempenho motor fino e funcionalidade inferior às crianças típicas, possivelmente por dificuldades em desempenhar tarefas que exijam destreza e coordenação manual, como as que compõem a BSITD-III. Apesar disso, sua pontuação em autocuidado foi adequada para a faixa etária, possivelmente porque as habilidades funcionais exigidas nesse período, como retirar calçados/vestimenta, impõem menor demanda motora fina do que tarefas da BSITD-III. Esse fato pode ter contribuído para o bom desempenho funcional das crianças com SD, e para a ausência de associação entre os domínios. Fatores como os cuidados oferecidos à criança pelos cuidadores, bem como ambientes estimuladores provavelmente também contribuíram para os resultados.

Neurological phenotypes for Down syndrome across the life span

This chapter reviews the neurological phenotype of Down syndrome (DS) in early development, childhood, and aging. Neuroanatomic abnormalities in DS are manifested as aberrations in gross brain structure as well as characteristic microdysgenetic changes. As the result of these morphological abnormalities, brain circuitry is impaired. While an intellectual disability is ubiquitous in DS, there is a wide range of variation in cognitive performance and a growing understanding between aberrant brain circuitry and the cognitive phenotype. Hypotonia is most marked at birth, affecting gait and ligamentous laxity. Seizures are bimodal in presentation with infantile spasms common in infancy and generalized seizures associated with cognitive decline observed in later years. While all individuals have the characteristic neuropathology of Alzheimer's disease (AD) by age 40 years, the prevalence of dementia is not universal. The tendency to develop AD is related, in part, to several genes on chromosome 21 that are overexpressed in DS. Intraneuronal accumulation of β-amyloid appears to trigger a cascade of neurodegeneration resulting in the neuropathological and clinical manifestations of dementia. Functional brain imaging has elucidated the temporal sequence of amyloid deposition and glucose metabolic rate in the development of dementia in DS. Mitochondrial abnormalities contribute to oxidative stress which is part of AD pathogenesis in DS as well as AD in the general population. A variety of medical comorbidities threaten cognitive performance including sleep apnea, abnormalities in thyroid metabolism, and behavioral disturbances. Mouse models for DS are providing a platform for the formulation of clinical trials with intervention targeted to synaptic plasticity, brain biochemistry, and morphological brain alterations.