Gait dyspraxia as a clinical marker of cognitive decline in Down syndrome: A review of theory and proposed mechanisms

Blast Overpressures as a Military and Occupational Health Concern

PURPOSE

This tutorial reviews effects of environmental stressors like blast overpressures and other well-known acoustic contaminants (continuous, intermittent, and impulsive noise) on hearing, tinnitus, vestibular, and balance-related functions. Based on the overall outcome of these effects, detailed consideration is given to the health and well-being of individuals.

METHOD

Because hearing loss and tinnitus are consequential in affecting quality of life, novel neuromodulation paradigms are reviewed for their positive abatement and treatment-related effects. Examples of clinical data, research strategies, and methodological approaches focus on repetitive transcranial magnetic stimulation (rTMS) and electrical stimulation of the vagus nerve paired with tones (VNSt) for their unique contributions to this area.

RESULTS

Acoustic toxicants transmitted through the atmosphere are noteworthy for their propensity to induce hearing loss and tinnitus. Mounting evidence also indicates that high-level rapid onset changes in atmospheric sound pressure can significantly impact vestibular and balance function. Indeed, the risk of falling secondary to loss of, or damage to, sensory receptor cells in otolith organs (utricle and saccule) is a primary reason for this concern. As part of the complexities involved in VNSt treatment strategies, vocal dysfunction may also manifest. In addition, evaluation of temporospatial gait parameters is worthy of consideration based on their ability to detect and monitor incipient neurological disease, cognitive decline, and mortality.

CONCLUSION

Highlighting these respective areas underscores the need to enhance information exchange among scientists, clinicians, and caregivers on the benefits and complications of these outcomes.

Gait Abnormalities in Children with Phelan-McDermid Syndrome

Background: Phelan-McDermid syndrome is a genetic disorder caused by haploinsufficiency of the SHANK3 gene on chromosome 22q13.3 and is characterized by autism spectrum disorder, intellectual disability, speech and language abnormalities, hypotonia, and mild dysmorphic features. Early literature in Phelan-McDermid syndrome did not include gait abnormalities as part of the syndrome although recent prospective studies report that the prevalence of gait abnormalities ranges from 55% to 94%. We compared gait abnormalities in individuals with Phelan-McDermid syndrome, idiopathic autism spectrum disorder, and typically developing controls, and explored associations between gait abnormalities, autism spectrum disorder, and intellectual functioning. Method: The study cohort consists of 67 participants between the ages of 3 and 18 years, divided into 3 groups: Phelan-McDermid syndrome (n  =  46), idiopathic autism spectrum disorder (n  =  11), and typically developing controls (n  =  10). Gait was recorded using a video camera and scored across 26 gait features using a "Gait Clinical Observations scale" designed specifically for this study. Results: Gait abnormalities were significantly higher in the Phelan-McDermid syndrome group as compared to idiopathic autism spectrum disorder or typically developing controls. The number of gait abnormalities across groups was also significantly correlated with Intellectual Quotient/Developmental Quotient (IQ/DQ). In analysis of covariance including IQ/DQ, the effect of group was not significant, but the effect of IQ/DQ was significant. Conclusions: Overall differences in gait abnormalities were determined by the degree of intellectual disability, which was significantly higher in Phelan-McDermid syndrome.

Altered gait parameters in distracted walking: a bio-evolutionary and prognostic health perspective on passive listening and active responding during cell phone use

The underpinnings of bipedal gait are reviewed from an evolutionary biology and prognostic health perspective to better understand issues and concerns related to cell phone use during ambulation and under conditions of distraction and interference. We also consider gait-related health issues associated with the fear of or risk of falling and include prognostic dimensions associated with cognitive decline, dementia, and mortality. Data were acquired on 21 healthy young adults without hearing loss, vestibular, balance, otological or neurological dysfunction using a computerized walkway (GAITRite® Walkway System) combined with specialized software algorithms to extract gait parameters. Four experimental conditions and seven temporo-spatial gait parameters were studied: gait velocity, cadence, stride length, ambulatory time, single-support time, double-support time, and step count. Significant main effects were observed for ambulation time, velocity, stride velocity, and double-support time. The greatest impact of distraction and interference occurred during the texting condition, although other significant effects occurred when participants were verbally responding to queries and passively listening to a story. These experimental observations show that relatively simple distraction and interference tasks implemented through the auditory sensory modality can induce significant perturbations in gait while individuals were ambulating and using a cell phone. Herein, emphasis is placed on the use of quantifiable gait parameters in medical, psychological, and audiological examinations to serve as a foundation for identifying and potentially averting gait-related disturbances.

Balance and Gait: Associations With Cognitive Impairment and Dementia in Individuals With Down Syndrome

BACKGROUND

Atypical aging in Down syndrome (DS) is associated with neuropathological characteristics consistent with Alzheimer disease. Gait abnormalities have been shown to be associated with an increased risk of dementia for the general population. The aim of this study was to determine whether gait disorders are associated with worse cognitive performance and dementia in adults with DS.

METHODS

We evaluated 66 individuals with DS (≥20 y of age), divided into 3 groups: stable cognition, prodromal dementia, and dementia (presumed Alzheimer disease). Each individual was evaluated with the Performance-Oriented Mobility Assessment (POMA), Timed Up and Go test, and Cambridge Examination for Mental Disorders of Older People with Down's Syndrome and Others with Intellectual Disabilities (CAMDEX-DS), in addition to a comprehensive clinical protocol to ascertain the occurrence of medical or psychiatric comorbidities.

RESULTS

The score on the POMA-Gait subscale score and body mass index were found to be independent predictors of prodromal dementia and dementia ( P <0.001 for both). With the exception of perception, all cognitive domains correlated with the POMA-Total score ( P <0.05).

CONCLUSION

A lower POMA-Gait score increases the chance of prodromal dementia and dementia in adults with DS. Unlike other research, in this study higher body mass index was also found to increase the chance of prodromal dementia and dementia. In those individuals, applying the POMA could facilitate the early diagnosis of dementia, help identify fall risks, and promote the adoption of geriatric interventions focused on improving functional mobility.

The test-retest reliability and limits of agreement of the balance evaluation systems test (BESTest) in young people with intellectual disability

Clinical tests for the assessment of postural balance in people with intellectual disability have been the most commonly used single or multi-item tests, but some tests have been developed, such as the BESTest. The purpose of the study was to evaluate the test-retest reliability and limits of agreement of the Balance Evaluation Systems Test (BESTest) in young people with intellectual disabilities. A descriptive cross-sectional study was conducted with 65 young people (ages 16-25 years) with intellectual disability. The participants completed the BESTest (27 items) twice. Intraclass correlation coefficients (ICC), 95% confidence intervals (CIs), and standard error of measurement (SEM) were calculated to determine the test-retest reliability of the BESTest. The BESTest overall scores' test-retest reliability was rated as excellent (≥ 0.75). Stability limits/verticality and reactive are fair to good (≥ 0.40- < 0.75). Biomechanical constraints, transitions and anticipatory movements, sensory orientation, and gait stability were excellent (≥ 0.75). Current evidence shows that young people with intellectual disabilities have impaired postural balance. However, there appears to be a lack of assessment tools that reliably evaluate the postural balance of this population. The results from this investigation show that BESTest provides "excellent reliability" (≥ 0.75) to assess postural balance in young people with intellectual disability.

Views of parents of children with Down syndrome on Alzheimer's disease vaccination

Individuals with Down syndrome (DS) experience increased risk of Alzheimer's disease (AD). Recent studies suggest that a vaccine against AD may be forthcoming. Parental buy-in is critical to the success of any intervention in this population, as adults with DS often rely on familial support. This study aims to characterize parents' perceptions of a hypothetical vaccine to prevent AD in individuals with DS. A mixed-methods, anonymous survey was distributed via social media. Participants were asked about their experiences with DS and reactions to proposed interventions. Open-ended responses were thematically analyzed using NVivo 12. Of 1,093 surveys initiated, 532 were completed. Of the parents sampled (N = 532), a small majority (54.3%), supported the proposed AD vaccine. All expressed the need for extensive pre-enrollment education and minimal risk. For many, limited research and long-term sequelae were concerns.

Developmental Coordination Disorder and Most Prevalent Comorbidities: A Narrative Review

This narrative review describes, in detail, the relationships between Developmental Coordination Disorder (DCD) and most prevalent associated comorbidities in their complexity, heterogeneity and multifactoriality. The research has been conducted on the main scientific databases, excluding single case papers. Blurred borders between the different nosographic entities have been described and advances in this field have been highlighted. In this multifaceted framework a specific profiling for co-occurring DCD, ADHD and ASD signs and symptoms is proposed, confirming the need for a multidisciplinary approach to define new diagnostic paradigms in early childhood.

DYRK1a Inhibitor Mediated Rescue of Drosophila Models of Alzheimer’s Disease-Down Syndrome Phenotypes

Alzheimer’s disease (AD) is the most common neurodegenerative disease which is becoming increasingly prevalent due to ageing populations resulting in huge social, economic, and health costs to the community. Despite the pathological processing of genes such as Amyloid Precursor Protein (APP) into Amyloid-β and Microtubule Associated Protein Tau (MAPT) gene, into hyperphosphorylated Tau tangles being known for decades, there remains no treatments to halt disease progression. One population with increased risk of AD are people with Down syndrome (DS), who have a 90% lifetime incidence of AD, due to trisomy of human chromosome 21 (HSA21) resulting in three copies of APP and other AD-associated genes, such as DYRK1A (Dual specificity tyrosine-phosphorylation-regulated kinase 1A) overexpression. This suggests that blocking DYRK1A might have therapeutic potential. However, it is still not clear to what extent DYRK1A overexpression by itself leads to AD-like phenotypes and how these compare to Tau and Amyloid-β mediated pathology. Likewise, it is still not known how effective a DYRK1A antagonist may be at preventing or improving any Tau, Amyloid-β and DYRK1a mediated phenotype. To address these outstanding questions, we characterised Drosophila models with targeted overexpression of human Tau, human Amyloid-β or the fly orthologue of DYRK1A, called minibrain (mnb). We found targeted overexpression of these AD-associated genes caused degeneration of photoreceptor neurons, shortened lifespan, as well as causing loss of locomotor performance, sleep, and memory. Treatment with the experimental DYRK1A inhibitor PST-001 decreased pathological phosphorylation of human Tau [at serine (S) 262]. PST-001 reduced degeneration caused by human Tau, Amyloid-β or mnb lengthening lifespan as well as improving locomotion, sleep and memory loss caused by expression of these AD and DS genes. This demonstrated PST-001 effectiveness as a potential new therapeutic targeting AD and DS pathology.

Rodent Modeling of Alzheimer's Disease in Down Syndrome: In vivo and ex vivo Approaches

There are an estimated 6 million people with Down syndrome (DS) worldwide. In developed countries, the vast majority of these individuals will develop Alzheimer's disease neuropathology characterized by the accumulation of amyloid-β (Aβ) plaques and tau neurofibrillary tangles within the brain, which leads to the early onset of dementia (AD-DS) and reduced life-expectancy. The mean age of onset of clinical dementia is ~55 years and by the age of 80, approaching 100% of individuals with DS will have a dementia diagnosis. DS is caused by trisomy of chromosome 21 (Hsa21) thus an additional copy of a gene(s) on the chromosome must cause the development of AD neuropathology and dementia. Indeed, triplication of the gene APP which encodes the amyloid precursor protein is sufficient and necessary for early onset AD (EOAD), both in people who have and do not have DS. However, triplication of other genes on Hsa21 leads to profound differences in neurodevelopment resulting in intellectual disability, elevated incidence of epilepsy and perturbations to the immune system. This different biology may impact on how AD neuropathology and dementia develops in people who have DS. Indeed, genes on Hsa21 other than APP when in three-copies can modulate AD-pathogenesis in mouse preclinical models. Understanding this biology better is critical to inform drug selection for AD prevention and therapy trials for people who have DS. Here we will review rodent preclinical models of AD-DS and how these can be used for both in vivo and ex vivo (cultured cells and organotypic slice cultures) studies to understand the mechanisms that contribute to the early development of AD in people who have DS and test the utility of treatments to prevent or delay the development of disease.

Identifying dementia in Down syndrome with the Severe Impairment Battery, Brief Praxis Test and Dementia Scale for People with Learning Disabilities

BACKGROUND

Individuals with Down syndrome (DS) are at high risk for dementia, specifically Alzheimer's disease. However, many measures regularly used for the detection of dementia in the general population are not suitable for individuals with DS due in part to floor effects. Some measures, including the Severe Impairment Battery (SIB), Brief Praxis Test (BPT) and Dementia Scale for People with Learning Disabilities (DLD), have been used in clinical trials and other research with this population. Validity research is limited, particularly regarding the use of such tools for detection of prodromal dementia in the DS population. The current project presents baseline cross-sectional SIB, BPT and DLD performance in order to characterise their predictive utility in discriminating normal cognition, possible dementia and probable dementia in adult DS.

METHOD

Baseline SIB, BPT and DLD performances from 100 individuals (no dementia = 68, possible dementia = 16 & probable dementia = 16) were examined from a longitudinal cohort of aging individuals with DS. Receiver operating characteristic curves investigated the accuracy of these measures in relation to consensus dementia diagnoses, diagnoses which demonstrated high percent agreement with the examining neurologist's independent diagnostic impression.

RESULTS

The SIB and BPT exhibited fair discrimination ability for differentiating no/possible versus probable dementia [area under the curve (AUC) = 0.61 and 0.66, respectively]. The DLD exhibited good discrimination ability for differentiating no versus possible/probable dementia (AUC = 0.75) and further demonstrated better performance of the DLD Cognitive subscale compared with the DLD Social subscale (AUC = 0.77 and 0.67, respectively).

CONCLUSIONS

Results suggest that the SIB, BPT and DLD are able to reasonably discriminate consensus dementia diagnoses in individuals with DS, supporting their continued use in the clinical assessment of dementia in DS. The general performance of these measures suggests that further work in the area of test development is needed to improve on the AUCs for dementia status discrimination in this unique population. At present, however, the current findings suggest that the DLD may be the best option for reliable identification of prodromal dementia in this population, reinforcing the importance of including informant behaviour ratings in assessment of cognition for adults with DS.

The Clinical and Neuropathological Features of Sporadic (Late-Onset) and Genetic Forms of Alzheimer's Disease

The purpose of this review is to compare and highlight the clinical and pathological aspects of genetic versus acquired Alzheimer's disease: Down syndrome-associated Alzheimer's disease in (DSAD) and Autosomal Dominant Alzheimer's disease (ADAD) are compared with the late-onset form of the disease (LOAD). DSAD and ADAD present in a younger population and are more likely to manifest with non-amnestic (such as dysexecutive function features) in the prodromal phase or neurological features (such as seizures and paralysis) especially in ADAD. The very large variety of mutations associated with ADAD explains the wider range of phenotypes. In the LOAD, age-associated comorbidities explain many of the phenotypic differences.

The unmet clinical needs of children with developmental coordination disorder

BACKGROUND

The aim of this study was to understand the challenges experienced by families obtaining a diagnosis and therapy for developmental coordination disorder (DCD).

METHODS

Parents of 435 children aged 4-18 years with persistent motor difficulties consistent with a diagnosis of DCD completed an online survey. Diagnostic timeline and diagnostic label/s received were examined, along with therapies accessed.

RESULTS

There was inconsistent diagnostic terminology (nine separate terms) with more children diagnosed with dyspraxia (64.7%) than DCD (48.8%). Even though most parents (87.0%) reported that receiving a diagnosis was helpful, children did not receive a diagnosis until years after seeking help (mean 2.8 ± 2.3 years). Many children were diagnosed with at least one co-occurring neurodevelopmental, language or learning disorder (70.0%). Almost all families had accessed therapy for their child's movement difficulties (93.9%), but more than half did not have access to funding to support therapy costs (57.8%) and reported that the costs caused financial strain (52.6%). Two out of every three families reported that they did not feel the current level of therapy was sufficient.

CONCLUSIONS

This critical advocacy research highlights inconsistent and incorrect terminology and the challenges families experience in obtaining a diagnosis and adequate access to therapy for their child's movement difficulties.

IMPACT

This is the first comprehensive study to examine the challenges families experience gaining a diagnosis and therapy for their child with DCD. Families regularly experienced prolonged diagnosis; 45% waited between 2 and 4 years. There is no clear diagnostic pathway, with children more likely to be diagnosed with dyspraxia than the correct clinical diagnosis of DCD. More extensive implementation of the diagnostic guidelines into clinical practice is needed.

Normal Pressure Hydrocephalus in Down Syndrome: The Report of Two Cases

Down syndrome (DS) is the most common cause of intellectual disability in infants and has a well-known relationship with the Alzheimer's disease. The association between DS and the other pathologies of senescence, such as normal pressure hydrocephalus (NPH), has been poorly investigated. This series included two DS patients with NPH. In both cases, NPH symptoms were initially misdiagnosed as DS associated senescence. Patients were treated with ventricular-peritoneal shunt, showing a sustained improvement (1 and 4 years of follow-up). To our knowledge, this is the first description of the occurrence of NPH in adult patients with DS and surgical outcomes.

Reliability and Validity of the Six Spot Step Test in People with Intellectual Disability

Clinical tests for the evaluation of balance in people with intellectual disability that have been most commonly used depend on the subjective evaluation of the evaluator, easily reach the ceiling effect and are poorly sensitive to small changes; but new tests have been developed, such as the Six Spot Step Test. The aim of this study was to determine the validity and within-day and day-to-day test–retest reliability of the Six Spot Step Test in people with intellectual disability. A descriptive cross-sectional study was conducted with 18 people with intellectual disability. The participants conducted the Six Spot Step Test three times and a set of five clinical tests for the balance assessment. The relative reliability was excellent (Intraclass Correlation Coefficient (ICC) = 0.86 − 0.97), and the absolute reliability ranged between 4.7% and 7.3% for coefficient variation and between 0.6 and 1.2 for the standard error of measurement. Linear regression models showed that that test can explain the results of the Timed Up & Go, Four Square Step Test and the Berg Balance Scale. The Six Spot Step Test proved to be as valid and reliable for the evaluation of dynamic balance in people with intellectual disability as the most frequently used tests for the clinical evaluation of postural control.

The Influence of Hearing Impairment on Mental Age in Down Syndrome: Preliminary Results

The increased life expectancy for patients with Down Syndrome (DS) has elicited the need to improve their quality of life by enhancing functional outcomes and identifying the factors that contribute to their long-term cognitive decline. Although the majority of individuals with DS have issues with hearing impairment (HI) since early childhood, to our knowledge no study has investigated whether HI represents a potential modulator of cognitive decline over time. The present explorative cohort study, albeit very preliminary due to the limited cohort (17 children), highlights the significant relation of a significant HI not only with receptive language abilities, but also with mental age in young patients with DS. Additional studies are required to confirm the link between HI and mental age and to assess the impact of audiological treatment on the enhancement of functional outcomes and of cognitive decline in individuals with DS.

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.

Down Syndrome: Gait Pattern Alterations in Posture Space Kinematics

Gait characteristics in Down syndrome (DS) are documented in terms of discrete kinematic variables. However, such features are strictly interrelated and reflect neurological and developmental delays. A phenotypical, quantitative assessment of how multi-joint walking patterns are activated and controlled during gait would enhance the understanding of locomotor mechanisms in such patients. We adopted an analysis framework based on principal component analysis: the gait kinematics of 221 patients aged 6-45 were expressed in terms of a reduced set of one-dimensional movement components. Their time course during the gait cycle was described by score vectors, here called principal positions; its second time derivative, called principal acceleration, characterized the activity of the neuromuscular controller on each component. Outcomes were compared to an age-matched group of 49 healthy individuals. After controlling for the effect of walking speed, we observed that the main alterations in gait patterns emerged in the fourth component which is mostly devoted to stability management (group differences, p < 0.001). Rather, the main sagittal-plane locomotor patterns showed only subtle differences from the control group. Using statistical parametrical mapping, we found when (step-to-step transitions) and how (interrelated joints motion) the fourth movement deviated from normal: in particular, an excessive hip adduction and trunk inclination during the transition between single and double support phases. These findings match the neurological and sensorimotor trait of DS and suggest the promotion of targeted rehabilitative interventions. Furthermore, this paper opens to the adoption of principal positions and principal accelerations to investigate the neuromuscular control of movement patterns during locomotion.

Dementia in Down syndrome: unique insights for Alzheimer disease research

Virtually all adults with Down syndrome (DS) show the neuropathological changes of Alzheimer disease (AD) by the age of 40 years. This association is partially due to overexpression of amyloid precursor protein, encoded by APP, as a result of the location of this gene on chromosome 21. Amyloid-β accumulates in the brain across the lifespan of people with DS, which provides a unique opportunity to understand the temporal progression of AD and the epigenetic factors that contribute to the age of dementia onset. This age dependency in the development of AD in DS can inform research into the presentation of AD in the general population, in whom a longitudinal perspective of the disease is not often available. Comparison of the risk profiles, biomarker profiles and genetic profiles of adults with DS with those of individuals with AD in the general population can help to determine common and distinct pathways as well as mechanisms underlying increased risk of dementia. This Review evaluates the similarities and differences between the pathological cascades and genetics underpinning DS and AD with the aim of providing a platform for common exploration of these disorders.

Neuronal overexpression of Alzheimer's disease and Down's syndrome associated DYRK1A/minibrain gene alters motor decline, neurodegeneration and synaptic plasticity in Drosophila

Down syndrome (DS) is characterised by abnormal cognitive and motor development, and later in life by progressive Alzheimer's disease (AD)-like dementia, neuropathology, declining motor function and shorter life expectancy. It is caused by trisomy of chromosome 21 (Hsa21), but how individual Hsa21 genes contribute to various aspects of the disorder is incompletely understood. Previous work has demonstrated a role for triplication of the Hsa21 gene DYRK1A in cognitive and motor deficits, as well as in altered neurogenesis and neurofibrillary degeneration in the DS brain, but its contribution to other DS phenotypes is unclear. Here we demonstrate that overexpression of minibrain (mnb), the Drosophila ortholog of DYRK1A, in the Drosophila nervous system accelerated age-dependent decline in motor performance and shortened lifespan. Overexpression of mnb in the eye was neurotoxic and overexpression in ellipsoid body neurons in the brain caused age-dependent neurodegeneration. At the larval neuromuscular junction, an established model for mammalian central glutamatergic synapses, neuronal mnb overexpression enhanced spontaneous vesicular transmitter release. It also slowed recovery from short-term depression of evoked transmitter release induced by high-frequency nerve stimulation and increased the number of boutons in one of the two glutamatergic motor neurons innervating the muscle. These results provide further insight into the roles of DYRK1A triplication in abnormal aging and synaptic dysfunction in DS.

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Overexpression of minibrain (DYRK1A) causes Down's relevant phenotypes including:

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Age-dependent degeneration of brain neurons

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Accelerated age-dependent decline in motor performance and shorted lifespan

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Modified presynaptic structure and enhanced spontaneous transmitter release

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Slowed recovery from short-term depression of synaptic transmission

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.

Aging With Down Syndrome: The Dual Diagnosis: Alzheimer's Disease and Down Syndrome

BACKGROUND

People with Down syndrome (DS) enjoy a longer life expectancy now than they ever have before and are therefore at greater risk of developing conditions associated with aging, including dementia.

OBJECTIVES

To explore the phenomenon of dementia in DS.

METHODS

Medline and Google Scholar searches were conducted for relevant articles, chapters, and books published until 2017. Search terms included Alzheimer's disease, cognitive impairment, dementia, DS, and trisomy 21. Publications found through this indexed search were reviewed for further references.

RESULTS AND CONCLUSIONS

Virtually, all subject aged 35 to 40 show key neuropathologic changes characteristic of Alzheimer's disease, but only a part of them show clinical signs of dementia, usually around the age of 50 years. Early signs of dementia in people with DS may be different from those experienced by the general population. Failure to recognize this can delay diagnosis and subsequent interventions.

Examination of participation and performance of dancing movement in individuals with Down syndrome

Purpose: Many observations and anecdotes have suggested that individuals with Down syndrome (DS) love music, specifically moving to music. The purpose of this study, with the assumption that the music makes people with DS dance showing more movement than general public's, is to observe the change in movement patterns of people with DS while they dance. Methods: The present study videotaped 10 individuals with DS and 10 mental age-matched (MA) participants dancing in response to five different types of music (e.g. rock fast, rock slow, classical, jazz, pop). Results: Our preliminary results suggest that individuals with DS had significantly more body sway than MA participants. In addition, individuals with DS were more active to the music than MA participants. However, no motor timing deficit was evident. Conclusions: This suggests that individuals with DS actively maintain their posture position in the challenging condition. Furthermore, they clearly enjoyed listening to the music and dancing. Based on our results, we suggest that more research need to be conducted examining the effects of dancing program on postural control, and timing in this population.