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.

Effect of triceps surae and quadriceps muscle fatigue on the mechanics of landing in stepping down in ongoing gait.

The aim of this study was to evaluate the effects of muscle fatigue of triceps surae and quadriceps muscles in stepping down in ongoing gait. We expected that the subjects would compensate for muscle fatigue to prevent potential loss of balance in stepping down. A total of 10 young participants walked over a walkway at a self-selected velocity to step down a height difference of 10-cm halfway. Five trials were performed before and after a muscle fatigue protocol. Participants performed two fatigue protocols: one for ankle muscle fatigue and another for knee muscle fatigue. Kinematics of and ground reaction forces on the leading leg were recorded. Fatigue did not cause a change in the frequency of heel or toe landing. Our results indicate that in stepping down fatigue effects are compensated by redistributing work to unfatigued muscle groups and by gait changes aimed at enhancing balance control, which was however only partially successful.

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.

Ginkgo biloba extract in an animal model of Parkinson's disease: a systematic review.

Although the exact cause of neuronal loss in Parkinson's disease is not known, evidence points to oxidative stress and the production of reactive oxygen species as the main events that occur in the substantia nigra pars compacta of the brain of parkinsonians. EGb761 is an extract of the leaves from the Ginkgo biloba tree that has been reported as an antioxidant and neuroprotective agent. The objective of this work was to perform a systematic review of the studies that analysed the effect of Ginkgo biloba extract on Parkinson's disease or Parkinsonism. This research was conducted using the following databases: Medline, PsycInfo, Cinahl, Sigle, Lilacs, Scielo, Cochrane Library, and Embase. Initially, we selected 32 articles. After a more detailed analysis, only 10 articles remained. One of the hypotheses for the positive effect of EGb761 on Parkinson's disease is the reduction or inhibition of monoamine-oxidase activity. This enzyme metabolises dopamine, inducing the formation of free radicals, which in turn damage nigrostriatal neurons. Another hypothesis is that the neuroprotective effect of EGb761 against 6-hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and MPP+ toxins. As there are few studies on the effect of EGb761 on humans, this review could contribute new data to further the discussion of this issue.

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.

Risco de quedas em idosos com doença de Parkinson e demência de Alzheimer: um estudo transversal / Risk of falls among elderly people with Parkinson's disease and Alzheimer's dementia: a cross-sectional study

OBJETIVO: Comparar o risco de quedas entre idosos com doença de Parkinson (DP), demência de Alzheimer (DA) e saudáveis (controle). Além disso, pretendeu-se analisar as relações do risco de quedas com declínio cognitivo e com nível de atividade física. MÉTODO: vinte idosos, sendo sete com DP (69,57 ± 2,40 anos), seis com DA (77,5 ± 2,32 anos) e sete saudáveis (74,71 ± 2,58 anos), foram avaliados por meio dos seguintes instrumentos: Escala de Equilíbrio Funcional de Berg (EEFB), Timed Up and Go test (TUG), Mini-Exame do Estado Mental (MEEM) e Questionário Baecke Modificado para Idosos (QBMI). RESULTADOS: O teste de Kruskal-Wallis apontou diferença significativa entre os grupos, tanto em relação à EEFB (KW=9,67, p<0,01), quanto em relação ao TUG (KW=9,14, p<0,01, para tempo despendido, e KW=10,04, p<0,01, para número de passos). A "análise aos pares" do teste post-hoc de Bonferroni apontou comprometimento maior do equilíbrio no grupo DA, no qual também foram observados menores valores no MEEM. O grupo DP foi caracterizado por apresentar um maior nível de atividade física. A análise de correlação de Spearman apontou correlação baixa entre MEEM e EEFB (r s=0,59); entre MEEM e TUG (r s=-0,62 e r s=-0,52); entre QBMI e EEFB (r s=0,54); e entre QBMI e TUG (r s=-0,39 e r s=-0,42). CONCLUSÕES: As baixas correlações observadas devem ser analisadas com cautela, pois tais variáveis sofrem influência de múltiplos fatores. No grupo DA, o declínio cognitivo pode estar relacionado ao maior risco de quedas e, no grupo DP, a atividade física pode ter auxiliado a manter um risco de quedas próximo ao grupo controle.

OBJECTIVE: To compare the risk of falls among elderly people with Parkinson's disease (PD) and Alzheimer's dementia (AD) and among healthy peers (controls). In addition, the aim was to analyze relationships between risk of falls and cognitive decay and between risk of falls and physical activity. METHOD: Twenty subjects were assessed: seven with PD (69.57 ± 2.40 years), six with AD (77.5 ± 2.32 years) and seven healthy peers (74.71 ± 2.58 years). The following instruments were used: Berg Balance Scale (BBS), Timed Up and Go test (TUG), Mini-Mental State Examination (MMSE) and Modified Baecke Questionnaire for Older Adults (MBQOA). RESULTS: The Kruskal-Wallis (KW) test indicated significant differences between the groups, relating to BBS (KW = 9.67, p<0.01) and TUG (KW = 9.14, p<0.01, for time expended, and KW = 10.04, p<0.01, for number of steps). Bonferroni post-hoc pairs analysis showed that balance was highly compromised in the AD group, such that lower MMSE values were observed. The PD group was characterized by presenting higher levels of physical activity. Spearman's test produced low correlations between MMSE and BBS (r s=0.59); MMSE and TUG (r s=-0.52 and r s=-0.62); MBQOA and BBS (r s=0.54); and MBQOA and TUG (r s=-0.39 and r s=-0.42). CONCLUSION: These low correlations must be analyzed carefully, because these variables are influenced by multiple factors. In the AD group, the cognitive decay can be positively associated with greater risk of falls. In the PD group, physical activity may have assisted in maintaining the risk of falls at similar levels to the control group.

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.