Dual-task gait speed assessments with an electronic walkway and a stopwatch in older adults. A reliability study.

BACKGROUND/OBJECTIVES: Slow gait speed prospectively predicts elevated risk of adverse events such as falls, morbidity, and mortality. Additionally, gait speed under a cognitively demanding challenge (dual-task gait) predicts further cognitive decline and dementia incidence. This evidence has been mostly collected using electronic walkways; however, not all clinical set ups have an electronic walkway and comparability with simple manual dual-gait speed testing, like a stopwatch, has not yet been examined. Our main objective was to assess concurrent-validity and reliability of gait speed assessments during dual-tasking using a stopwatch and electronic walkway in older adults with mild and subjective cognitive impairment (MCI and SCI). DESIGN: Cross-sectional, reliability study. SETTING: Clinic based laboratory at an academic hospital in London, ON, Canada. PARTICIPANTS: 237 walk tests from 34 community-dwelling participants (mean age 71.84 SD 5.38; 21 female - 62%, 13 male - 38%) with SCI and MCI. were included from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) study. INTERVENTION: Each participant performed seven walk tests: three single gait walks at their normal pace, three dual-task walks (walking and counting backwards by one, by sevens, and naming animals), and one fast walk. MEASUREMENTS: Gait speed (cm/s) for each walk was measured simultaneously with an electronic walkway (Zeno Mat®) and a handheld stopwatch (Ultrak chronometer®). Dual-task cost (DTC) was calculated for the three individual dual-task walks as [((single gait speed - dual-task gait speed) / single gait speed) ∗ 100]. Level of agreement between the two measurement methods was analyzed using Pearson correlations, paired t-tests, and Bland-Altman plots. RESULTS: Gait speed was consistently lower when measured with the stopwatch than with the electronic walkway (mean speed difference: 10.6 cm/s ± 5.1, p < 0.001). Calculating DTC, however, yielded very similar results with both methods (mean DTC difference: 0.19 ± 1.18, p = 0.872). The higher the DTC, the closer the measurement between methods. CONCLUSION: Assessing and calculating DTC with a stopwatch is simple, accessible and reliable. Its validity and reliability were high in this clinical sample of community older adults with SCI and MCI.

Insight into dopamine-dependent planning deficits in Parkinson's disease: A sharing of cognitive & sensory resources.

Cognitive and sensorimotor processes are both needed for successful planning of footsteps during complex gait situations, but the interaction between these factors during motor planning, as well as their response to dopaminergic treatment is poorly understood in Parkinson's disease (PD). In the current study, we evaluated walking and gaze behaviors of individuals with PD while planning an approach toward an obstacle to be stepped over. The obstacle clearance task was completed both ON and OFF dopaminergic medication by individuals with Parkinson's disease (n=20) and compared to healthy age-matched control participants (n=19), as well as with and without an auditory digit monitoring dual task. In this novel protocol of synchronized gaze and gait data collection, each trial was split into an early and late phase prior to the obstacle, providing a unique opportunity to examine dopamine-dependent planning deficits in PD. Interestingly, only patients in the OFF medication state showed greater deceleration in the late phase (i.e., just before the obstacle) (F(1,37)=45.42, p<0.001), as well as an increase in step time variability (also in this late phase) with the additional demands of a dual task (F(2,74)=3.49, p=0.035). Only gait deceleration between approaching phases improved with dopaminergic treatment (F(1,18)=59.20; p<0.001). Although groups showed different walking behaviors, gaze behaviors were the same for all participants, in that they planned for the obstacle more so in the early phase (p<0.05), and fixations were reduced across participants with the presence of the dual task (p<0.001). Surprisingly, the gaze behavior of the PD OFF group showed no interactions with phase or condition suggesting that the deceleration and increased variability when approaching an obstacle is the result of a greater demand for online sensory feedback that cannot be compensated for with visual strategies. We conclude that dopamine influences planning by limiting sensorimotor processing capacity, especially in the presence of increased cognitive demand in PD.

Visual cues and gait improvement in Parkinson's disease: which piece of information is really important?

Visual exproprioception refers to information of the body relative to the environment and may be the critical piece of sensory information that explains why gait improvements can be achieved with visual step cues in people with Parkinson's disease (PD). The primary aim of current study was to investigate the role of visual exproprioception in the positive effect of visual cues on gait in patients with PD. Nineteen individuals with PD and 15 healthy subjects participated in this study. Four conditions of self-paced gait were tested: normal walking, without exproprioception (exproprioceptive information of lower limbs removed), visual step length cues, and visual step length cues but without exproprioception. Gaze behavior, gait parameters and the accuracy and precision of foot placement on the visual cues were recorded. Individuals with PD improved step length in both cued conditions. Both groups fixated close to 46% on visual cues necessary to accomplish the next step (ongoing step), while 54% of fixations were focused on visual cues one or more steps ahead. Also, both groups increased absolute error and error variability of the foot placement around the visual cues without vision of their feet. These results suggest that exproprioceptive information is not critical to achieve step length and overall gait benefits with visual cues in PD, but is critical for the accuracy and precision of foot placement on targets. People with PD and healthy individuals use visual information from visual cues in both on-line and feedforward fashions. In conclusion, patients with PD likely focus attention on the discrete goal of each foot hitting a visual cue placed on the floor and then use the exteroceptive information (i.e. position of next foot placement location) to plan each step individually at a cortical level.

Evaluating the acute contributions of dopaminergic replacement to gait with obstacles in Parkinson's disease.

The influence of dopaminergic replacement (DR) on gait in people with Parkinson's disease (PD) is well documented. However, little is known about the acute effects of dopamine on more complex locomotor tasks that require visual guidance to avoid obstacles during gait. The authors investigated the influence of DR on locomotor behavior in a task where movement planning and control might be challenged by the height of the obstacle. The PD group included patients diagnosed with idiopathic PD (n = 12), as well as healthy controls (n = 12). Patients walked and stepped over obstacles of different heights before (OFF) and after (ON) levodopa intake. Spatial adjustments were not modulated by DR, but the step time to perform these anticipatory gait adjustments was longer only in PD-OFF (compared with healthy controls) when approaching the highest obstacle, but not PD-ON. During the crossing phase, trail limb toe clearance of PD patients was shorter than healthy controls only during the OFF state. ON-OFF comparisons were significantly different only for the time to reach the lead foot clearance over the highest obstacle. In summary, DR partially improved movement slowness but did not directly affect movement amplitude of lower limb regulation in this gait task.

Preditores espaço-temporais do andar para testes de capacidade funcional em pacientes com doença de Parkinson / Gait spatial and temporal predictors for functional capacity tests in Parkinson's disease patients

OBJETIVOS: Determinar quais parâmetros espaço-temporais são preditores do andar de indivíduos com doença de Parkinson idiopática para os testes de resistência aeróbia e agilidade, propostos pela bateria de testes da American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD). MATERIAIS E MÉTODOS: Foram selecionados seis homens e seis mulheres com comprometimento e estágio da doença em níveis leve e moderado, que realizaram os testes de agilidade e resistência aeróbia, conforme o protocolo da AAHPERD, e andaram 8m sobre uma passarela. Uma câmera digital registrou uma passada central. Marcadores foram fixados no quinto metatarso e na face lateral do calcâneo do membro inferior direito e no primeiro metatarso e na face medial do calcâneo do membro inferior esquerdo. As variáveis dependentes selecionadas foram: tempo nos testes de agilidade e resistência e as variáveis cinemáticas (comprimento da passada - CP, cadência - CAD, duração da passada - DP, duração da fase de duplo suporte - DDS, duração do suporte simples - SS, duração da fase de balanço - DB e velocidade da passada - VP). RESULTADOS: Para agilidade, o teste de Pearson apontou correlação estatisticamente significativa entre as variáveis CP (r=-0,70; p<0,05), CAD (r=-0,72; p<0,01), VP (r=-0,83; p<0,01), DP (r=0,71; p<0,01) e DDS (r=0,90; p<0,01). Para resistência, houve correlação com as variáveis CP (r=-0,67; p<0,05), CAD (r=-0,72; p<0,01), VP (r=-0,82; p<0,01), DP (r=0,71; p<0,01) e DDS (r=0,90; p<0,01). A análise de regressão múltipla revelou que a DDS foi a única variável preditora dos testes de agilidade (R²=0,82; p<0,01) e resistência (R²=0,81; p<0,01). CONCLUSÕES: Observou-se o uso potencial da DDS como parâmetro espaço-temporal do andar preditor do desempenho dos testes de resistência aeróbia e agilidade em pacientes com doença de Parkinson idiopática.

OBJECTIVE: To determine which spatial and temporal parameters are predictors of the gait pattern of individuals with idiopathic Parkinson's disease, for the aerobic endurance and agility tests included in the battery of tests of the AAHPERD protocol. METHODS: Six men and six women with mild and moderate impairment and disease stage were selected. They performed agility and aerobic endurance test in accordance with the AAHPERD protocol, and walked 8 m on a walkway. A digital video camera recorded one central stride. Markers were attached to the fifth metatarsal and lateral face of the calcaneus of the right leg and to the first metatarsal and medial face of the calcaneus of the left leg. The dependent variables selected were the time taken in the agility and endurance tests and the kinematic variables: stride length (SL), cadence (CAD), stride time (ST), double support time (DS), single support time (SS), swing time (SW) and stride velocity (SV). RESULTS: For agility, Pearson's test showed statistically significant correlations with SL (r=-0.70; p<0.05), CAD (r=-0.72; p<0.01), SV (r=-0.83; p<0.01), ST (r=0.71; p<0.01) and DS (r=0.90; p<0.01). For endurance, there were correlations with SL (r=-0.67; p<0.05), CAD (r=-0.72; p<0.01), SV (r=-0.82; p<0.01), ST (r=0.71; p<0.01), and DS (r=0.90; p<0.01). Multiple regression analysis revealed that DS was the only variable that predicted performance in both the agility (R²=0.82; p<0.01) and the endurance (R²=0.81; p<0.01) tests. CONCLUSIONS: It was observed that DS measure has a potential use as a kinematic parameter of gait that predicts the performance in agility and aerobic endurance tests in patients with idiopathic Parkinson's disease.

Parâmetros cinemáticos da marcha com obstáculos em idosos com Doença de Parkinson, com e sem efeito da levodopa: um estudo piloto / Kinematic parameters for gait with obstacles among elderly patients with Parkinson's disease, with and without levodopa: a pilot study

CONTEXTO: Os efeitos da levodopa na marcha de pacientes com Doença de Parkinson (DP) em terrenos desobstruídos são conhecidos, mas pouco se conhece sobre seus efeitos na marcha com obstáculos. OBJETIVO: Este estudo objetivou descrever, por meio de ferramenta cinemática, o comportamento locomotor de pacientes com DP e verificar as estratégias locomotoras, sem e sob o efeito da levodopa, durante a ultrapassagem de obstáculos de diferentes alturas. MÉTODO: Cinco pacientes com DP (Hoehn e Yahr= 2±0; idade= 68,4±5,7 anos) percorreram, andando, 10m e ultrapassaram um de dois obstáculos (alto= metade da altura do joelho e baixo= altura do tornozelo) posicionado no meio da passarela em duas sessões (em jejum e no pico de ação do medicamento). As seguintes variáveis foram coletadas e analisadas: distância horizontal pé-obstáculo (DHPO), distância vertical pé-obstáculo (DVPO); distância horizontal obstáculo-pé (DHOP) e velocidades médias, horizontais e verticais, nas fases de abordagem e aterrissagem (respectivamente, VHAO,VVAO; VHDO,VVDO). RESULTADOS: A ANOVA, por tentativa, revelou efeito principal de obstáculo para DVPO (F1,49=15,33; p< 0,001), para VVAO (F1,49= 82,184; p< 0,001), para VHDO (F1,49= 15,33; p< 0,001) e para VVDO (F1,49= 31,30; p< 0,001); e efeito principal de medicamento para DVPO (F1,49= 6,66; p< 0,013) e para VVAO (F1,49= 10,174; p< 0,002). CONCLUSÕES: Pacientes foram mais perturbados pelo obstáculo alto. Os sintomas da DP (bradicinesia e hipocinesia) foram diminuídos com o medicamento, evidenciando aumento geral da velocidade da perna de abordagem e da margem de segurança sobre os obstáculos. Pacientes com DP, independente da condição de medicamento, apresentaram um comportamento que garantiu segurança e estabilidade na marcha.