Dissociation between motor and cognitive skills in patients with Duchenne muscular dystrophy

Gait and Sit-To-Stand Motor Compensation Strategies in Children and Adolescents With Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD), the most common form of muscular dystrophies, is characterized by progressive and generalized muscle weakness. The weakness of the trunk and other muscle groups leads these patients to perform motor compensation strategies to maintain their lower limb functionality for gait quality and for tasks such as getting up from a sitting position. In this cross-sectional observational study, we described and quantified trunk, gait, and sit-to-stand motor compensation strategies in different stages of this disease. Thirty-one ambulatory 5-18-year-old children and adolescents with a diagnosis of DMD, underwent cognitive assessment with the Mental Mini-Examination (MMSE) and motor assessment with the Vignos scale, Segmental Assessment of Trunk Control (SATCo-BR), Timed Up and Go test (TUG Test), and 10-m walk test. We found strong correlations between trunk and gait compensations, and identified motor compensation strategies characteristic of certain DMD classifications. Also, these lower limb and trunk compensations related to disease staging (Vignos) such that compensations were fewer for patients at relatively better disease staging.

Motor Compensation Strategies for Reduced Upper Limb Function Among Individuals With Duchenne Muscular Dystrophy

The purpose of this longitudinal study was to identify and verify the compensatory motor strategies for upper limb functioning of individuals with Duchenne Muscular Dystrophy (DMD). We evaluated 32 patients diagnosed with DMD (aged 6-19 years) for cognitive and motor functioning using the Mini Mental State Examination (MMSE), Vignos Scale Jebsen Taylor Test (JTT) and Functional Skill Scale (FSS) at baseline testing and over retest intervals of six and 12 months. We used the MMSE to screen participants for capacity to engage in the research, and we analyzed absolute and percentile changes in the frequency distribution of motor strategies participants used on each JTT subtest. We also used analysis of variance with repeated measures and Bonferroni post-hoc testing of multiple comparisons to identify disease progression through FSS scores. We observed an increased frequency of compensatory motor strategies over six months. We recommend the associated use of the JTT and FSS to assess patients with DMD, since we observed worsened movement quality over a time interval of six months even while essential motor competence was maintained.

RESPONSIVENESS OF UPPER LIMB SCALES AND TRUNK CONTROL FOR THE EVOLUTION OF PATIENTS WITH DUCHENNE MUSCULAR DYSTROPHY

Objective:

To verify the interval of responsiveness to the scales Segmental Assessment of Trunk Control (SATCo-BR), Performance of Upper Limbs (PUL), and Jebsen Taylor Test (JTT) in patients with Duchenne Muscular Dystrophy (DMD).

Methods:

We assessed patients with DMD aged 6 to 19 years old and with mini-mental (MMSE) score above 10 points. The assessments were performed individually, in a single session. The upper limb function was performed by PUL and JTT, and trunk control by SATCo-BR. Assessments were repeated six and 12 months after the initial assessment. The repeated-measures analysis of variance model and Bonferroni’s multiple comparison method were employed as post hoc analysis; when the ANOVA assumptions were not met, the Friedman test was applied.

Results:

The sample consisted of 28 patients evaluated in three moments (initial, and six and 12 months after the beginning). There was a time effect for the Upper Limb function performance in the total JTT, and for the subtests, except for subtests 1 and 6, which did not show a difference between the different moments. There was also a time effect for the score of total PUL, proximal PUL, intermediate PUL, and distal PUL. In the SATCo-BR, this effect was observed between the initial and 6 months, and between the initial and 12 months.

Conclusions:

The JTT, PUL, and SATCo-BR scales can detect changes over time, and they showed responsiveness to detect the evolution of the disease in the 6-month interval.

Funcionalidade de membro superior em pacientes deambuladores e não deambuladores com distrofia muscular de Duchenne

RESUMO Novos tratamentos propostos para os pacientes com distrofia muscular de Duchenne (DMD) têm sua eficácia avaliada por testes de membros inferiores. Contudo, os testes funcionais de membros superiores (MMSS) avaliam tanto deambuladores (D) como não deambuladores (ND). Assim, este estudo se propôs a comparar a funcionalidade de MMSS de pacientes D e ND com DMD e correlacionar o estadiamento da doença e a função de MMSS. Trata-se de um estudo transversal no qual os pacientes foram divididos em D e ND de acordo com a escala Vignos. Posteriormente, a funcionalidade dos MMSS foi avaliada pela escala performace of upper limb (PUL). Foi realizado o teste t independente, teste qui-quadrado, teste Mann-Whitney, regressão linear e teste de correlação de Spearman pelo programa SPSS, versão 22. A pesquisa foi composta de 51 pacientes, sendo 20 D e 31 ND. Houve diferença entre os grupos em relação à idade (p=0,001), ao índice de massa corporal (IMC) (p=0,016), à escolaridade (p=0,011), quanto ao escore na escala Vignos (p<0,001) e na função dos MMSS (p<0,001). Na análise de regressão linear observamos que o paciente ser D ou ND influencia na função dos MMSS em 18 pontos na escala PUL. Houve forte correlação entre o estadiamento da doença e a função de MMSS (r2=−0,769, p<0,001). A condição funcional dos MMSS depende se o paciente é D ou ND, sendo pior nos ND. Concluiu-se que a função de MMSS tem forte correlação com o estadiamento da doença.

Reliability, validity and description of timed performance of the Jebsen-Taylor Test in patients with muscular dystrophies

BACKGROUND

The Jebsen-Taylor Test evaluates upper limb function by measuring timed performance on everyday activities. The test is used to assess and monitor the progression of patients with Parkinson disease, cerebral palsy, stroke and brain injury.

OBJECTIVES

To analyze the reliability, internal consistency and validity of the Jebsen-Taylor Test in people with Muscular Dystrophy and to describe and classify upper limb timed performance of people with Muscular Dystrophy.

METHODS

Fifty patients with Muscular Dystrophy were assessed. Non-dominant and dominant upper limb performances on the Jebsen-Taylor Test were filmed. Two raters evaluated timed performance for inter-rater reliability analysis. Test-retest reliability was investigated by using intraclass correlation coefficients. Internal consistency was assessed using the Cronbach alpha. Construct validity was conducted by comparing the Jebsen-Taylor Test with the Performance of Upper Limb.

RESULTS

The internal consistency of Jebsen-Taylor Test was good (Cronbach's α=0.98). A very high inter-rater reliability (0.903-0.999), except for writing with an Intraclass correlation coefficient of 0.772-1.000. Strong correlations between the Jebsen-Taylor Test and the Performance of Upper Limb Module were found (rho=-0.712).

CONCLUSION

The Jebsen-Taylor Test is a reliable and valid measure of timed performance for people with Muscular Dystrophy.

Patients with Duchenne and Becker muscular dystrophies are not more asymmetrical than healthy controls on timed performance of upper limb tasks

This study aimed to investigate possible asymmetries and relationships between performance of dominant and non-dominant upper limbs (UL) in patients with Duchenne and Becker muscular dystrophies (DMD/BMD), to compare UL performance of patients and healthy subjects and to investigate the relationship between timed performance of UL and age, motor function and muscle strength in DMD/BMD patients. Sixteen patients with DMD and 3 with BMD were evaluated with Jebsen-Taylor Test (timed performance), Vignos scale and Dimension 3 of Motor Function Measure (motor function), and Medical Research Council scale (muscle strength) on a single session. ANOVA showed no asymmetry between dominant and non-dominant UL, except in the writing subtest, in patients and in healthy controls. There were relationships between dominant and non-dominant UL performances. Correlations between timed performance, motor function and muscle strength were found, but age was not correlated with these variables. These findings may reduce the assessment time, prevent fatigue and provide more accurate clinical reasoning involving UL in DMD/BMD treatment.