Dual-task during gait between elderly with mild cognitive impairment and Alzheimer: systematic review / Dupla tarefa durante a marcha entre idosos com comprometimento cognitivo leve e Alzheimer: revisão sistemática

Abstract Introduction: Studies report that mobility changes could be present in early stages of Alzheimer's disease (AD) or even in previous stages, such as mild cognitive impairment (MCI). The use of motor tests, involving dual task, could facilitate screening and differentiation between elderly with AD and MCI. Objective: to verify if gait tests associated with secondary tasks could differentiate elderly with AD and MCI. Methods: We conducted a systematic review in Pubmed, Web of Science, Medline and Scielo databases. Of the articles included, we collected information about year of the study, characteristics of the sample and the dual task test studied. Results: The databases were accessed during November 2014 and August 2015 and a total of 198 scientific papers was obtained. After reading first the summaries and then the full texts, five studies were inserted in the review. Elderly with AD presented a reduction of gait speed and stride length, using executive functions and countdown as secondary cognitive tasks. The type of MCI appears to influence the differentiation with AD. Conclusion: The review showed that some gait tests associated with a secondary task differentiate elderly with AD and MCI. It emphasizes the need of new studies involving this issue in order to obtain cut-off points and facilitate prevention, early diagnosis and observation of cognitive impairment's evolution in clinical practice of elderly.

Resumo Introdução: Estudos relatam que alterações da mobilidade podem estar presentes em fases iniciais da doença de Alzheimer (DA) ou mesmo em estágios prévios como o comprometimento cognitivo leve (CCL). O uso de testes motores, envolvendo dupla tarefa, pode facilitar o rastreio e a diferenciação entre idosos com CCL de DA. Objetivo: verificar se testes de marcha associada a tarefas secundárias conseguiriam diferenciar idosos com CCL de DA. Métodos: Para isso, realizou-se uma revisão bibliográfica sistemática nas bases de dados Pubmed, Web of Science, Medline e Scielo. Dos artigos incluídos, foram coletados informações quanto ao ano do estudo, dados da amostra avaliada e teste de dupla tarefa utilizada. Resultados: As bases de dados foram acessadas durante novembro de 2014 e agosto de 2015, sendo obtidos ao todo 198 textos científicos. Após a leitura primeiramente dos resumos, posteriormente dos textos completos, foram inseridos cinco artigos para a revisão. Dos artigos inseridos, observou-se redução da velocidade da marcha e comprimento do passo em idosos com DA, utilizando funções executivas e contagem recressiva como tarefas cognitivas secundárias. O tipo de CCL parece influenciar na diferenciação com DA. Conclusão: A revisão mostrou que há testes de marcha associada a uma tarefa que diferenciam idosos com CCL de DA. Enfatiza-se a realização de novos estudos envolvendo essa temática com o intuito de obter notas de corte e facilitar medidas de prevenção, diagnóstico precoce e observação da evolução da alteração cognitiva na prática clínica de idosos.

Can geometric indices of heart rate variability predict improvement in autonomic modulation after resistance training in chronic obstructive pulmonary disease?

Chronic obstructive pulmonary disease (COPD) is associated with autonomic dysfunctions that can be evaluated through heart rate variability (HRV). Resistance training promotes improvement in autonomic modulation; however, studies that evaluate this scenario using geometric indices, which include nonlinear evaluation, thus providing more accurate information for physiological interpretation of HRV, are unknown. This study aimed to investigate the influence of resistance training on autonomic modulation, using geometric indices of HRV, and peripheral muscle strength in individuals with COPD. Fourteen volunteers with COPD were submitted to resistance training consisting of 24 sessions lasting 60 min each, with a frequency of three times a week. The intensity was determined as 60% of one maximum repetition and was progressively increased until 80% for the upper and lower limbs. The HRV and dynamometry were performed at two moments, the beginning and the end of the experimental protocol. Significant increases were observed in the RRtri (4·81 ± 1·60 versus 6·55 ± 2·69, P = 0·033), TINN (65·36 ± 35·49 versus 101·07 ± 63·34, P = 0·028), SD1 (7·48 ± 3·17 versus 11·04 ± 6·45, P = 0·038) and SD2 (22·30 ± 8·56 versus 32·92 ± 18·78, P = 0·022) indices after the resistance training. Visual analysis of the Poincare plot demonstrated greater dispersion beat-to-beat and in the long-term interval between consecutive heart beats. Regarding muscle strength, there was a significant increase in the shoulder abduction and knee flexion. In conclusion, geometric indices of HRV can predict improvement in autonomic modulation after resistance training in individuals with COPD; improvement in peripheral muscle strength in patients with COPD was also observed.