Walking execution is not affected by divided attention in patients with multiple sclerosis with no disability, but there is a motor planning impairment

Abstract

ARTICLE 521Walking execution is not affected by divided attention in patients with multiple sclerosis with no disability, but there is a motor planning impairment A execução da marcha não é afetada pela atenção dividida em pacientes com esclerose múltipla sem incapacidade, mas existe um comprometimento do planejamento motor ABSTRACT Purpose: We analysed the cognitive influence on walking in multiple sclerosis (MS) patients, in the absence of clinical disability. Method: A case-control study was conducted with 12 MS patients with no disability and 12 matched healthy controls. Subjects were referred for completion a timed walk test of 10 m and a 3D-kinematic analysis. Participants were instructed to walk at a comfortable speed in a dual-task (arithmetic task) condition, and motor planning was measured by mental chronometry. Results: Scores of walking speed and cadence showed no statistically significant differences between the groups in the three conditions. The dual-task condition showed an increase in the double support duration in both groups. Motor imagery analysis showed statistically significant differences between real and imagined walking in patients. Conclusion: MS patients with no disability did not show any influence of divided attention on walking execution. However, motor planning was overestimated as compared with real walking.Key words: mild cognitive impairment, multiple sclerosis, walking. RESUMOO objetivo do estudo foi analisar a influência cognitiva na caminhada de pacientes com esclerose múltipla (EM) sem incapacidade clínica. Foi conduzido um estudo caso-controle com 12 pacientes com EM sem incapacidade com 12 pessoas saudáveis como controles pareados. Os sujeitos fizeram um teste de caminhada de 10 metros , acompanhado de análise cinemática 3D, e foram orientados a caminhar em velocidade confortável, realizando dupla-tarefa (tarefa aritmética), e o planejamento motor foi medido pela cronometria mental. Os valores de velocidade da caminhada e da cadência não evidenciaram diferenças estatisticamente significativas entre os grupos nas três condições. A condição de dupla-tarefa demonstrou um aumento na duração do duplo apoio em ambos os grupos. A imagética motora evidenciou diferenças estatisticamente significativas entre a caminhada real e a imaginada nos pacientes com EM. Pacientes com EM sem incapacidade não apresentaram influência da atenção dividida na execução da caminhada. Entretanto, o planejamento motor esteve superestimado.Palavras-Chave: comprometimento cognitivo leve, esclerose múltipla, caminhada.

Comparing Three Dual-Task Methods and the Relationship to Physical and Cognitive Impairment in People with Multiple Sclerosis and Controls

“…When collapsing the MS groups, we report a paradoxical phenomenon in which stride width is either narrowed or unaltered during DT in MS subjects and widened in control subjects which suggests a maladaptive balance response in MS subjects. Our findings concur with those of Nogueira et al who reported that, in people with MS, step width (calculated in a similar way to stride width) decreases by about 1 cm during a dual task whereas it increases the same amount in controls [ 24 ]. Several authors have shown that stride/step width is not altered during DTC in MS; however previous studies have tested less severely affected subjects [ 12 , 16 ].…”

“…We also sought to determine which gait parameter would be uniquely altered in MS subjects. Although other studies have focused on DTC of gait velocity [ 6 , 10 – 12 , 14 – 17 , 22 , 24 ], we found that velocity, stride length, and cadence were reduced in a similar manner among MS subjects and controls. Furthermore, the DTC of these variables were not altered by level of disability (EDSS score ≥ or <3) suggesting that DTC of velocity, stride length, and cadence are likely “blunt” tools to detect change as a result of intervention or the course of the disease.…”

“…Our findings conflict with those of Motl et al who showed that DS was not significantly altered by DT in a sample of 82 people with RRMS [ 11 ]. Nogueira and colleagues also reported that DS increased during DT in both MS subjects and controls [ 24 ]. The discrepancies may be related to the fact that we tested subjects with greater variability in walking disability.…”

Nonsignificant Associations Between Measures of Inhibitory Control and Walking While Thinking in Persons With Multiple Sclerosis

“…The MS sample demonstrated a mean DTC of walking (ie, 17.8%) that was similar to the magnitude of DTCs of selfselected gait velocity in other samples of persons across the MS disability spectrum. 8,12,18 The lack of a statistically significant difference in DTC of walking between persons with MS and controls is consistent with other studies 7,10,33 involving CMI in persons with MS, and it is currently unclear whether DTC of walking is greater in MS than controls, despite persons with MS having worse walking ability. We replicate the lack of a definitive association between CPS and DTC of walking in persons with MS, consistent with previous research in persons with a broad range of MS disability.…”

“…Such comparisons could provide important information relative to the generalizability of potential rehabilitative interventions for reducing DTC of walking in MS. Those studies 12,13 examined DTC of walking at a self-selected walking speed, rather than fastest walking speed (ie, T25FW), which might underestimate realworld CMI. 10 The current study examined CPS and inhibitory control measures as potential neuropsychological correlates of DTC of walking in 28 persons with MS and 28 matched controls without MS. We hypothesized that persons with MS and matched controls would have similar DTCs of walking despite persons with MS having worse walking ability based on previous research, 9,17,18 and that inhibitory control, but not CPS, would be associated with DTC of walking in persons with MS and matched controls.…”