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Robots based on simplified or abstracted biomechanical concepts can be a useful tool for investigating how and why animals move the way they do. In this paper we present an extremely simple quadruped robot, which is able to walk with no form of software or controller. Instead, individual leg movements are triggered directly by switches on each leg which detect leg loading and unloading. As the robot progresses, pitching and rolling movements of its body result in a gait emerging with a consistent leg movement order, despite variations in stride and stance time. This gait has similarities to the gaits used by walking primates and grazing livestock, and is close to the gait which was recently theorised to derive from animal body geometry. As well as presenting the design and construction of the robot, we present experimental measurements of the robot’s gait kinematics and ground reaction forces determined using high speed video and a pressure mat, and compare these to gait parameters of animals taken from literature. Our results support the theory that body geometry is a key determinant of animal gait at low speeds, and also demonstrate that steady state locomotion can be achieved with little to no active control.

Background: Identifying quantitative gait markers of preclinical dementia may lead to new insights into early disease stages, improve diagnostic assessments and identify new preventive strategies. Objective: To examine the relationship of quantitative gait parameters to decline in specific cognitive domains as well as the risk of developing dementia in older adults. Methods: We conducted a prospective cohort study nested within a community based ageing study. Of the 427 subjects aged 70 years and older with quantitative gait assessments, 399 were dementia-free at baseline. Results: Over 5 years of follow-up (median 2 years), 33 subjects developed dementia. Factor analysis was used to reduce eight baseline quantitative gait parameters to three independent factors representing pace, rhythm and variability. In linear models, a 1 point increase on the rhythm factor was associated with further memory decline (by 107%), whereas the pace factor was associated with decline on executive function measured by the digit symbol substitution (by 29%) and letter fluency (by 92%) tests. In Cox models adjusted for age, sex and education, a 1 point increase on baseline rhythm (hazard ratio (HR) 1.48; 95% CI 1.03 to 2.14) and variability factor scores (HR 1.37; 95% CI 1.05 to 1.78) was associated with increased risk of dementia. The pace factor predicted the risk of developing vascular dementia (HR 1.60; 95% CI 1.06 to 2.41). Conclusion: Our findings indicate that quantitative gait measures predict future risk of cognitive decline and dementia in initially non-demented older adults.

Postural instability (PI) is a common and serious problem in Parkinson's disease (PD). Dopaminergic medication is of negligible use and a positive effect of deep brain stimulation on this issue has not been reported.To develop a method of repetitive training of compensatory steps to enhance protective postural responses by using training strategies based on recent neurophysiological research.Fourteen patients with PD took part in a multiple baseline design study and were trained for 14 days in an ambulant setting consisting of two daily sessions.After training, the length of compensatory steps increased and the step initiation shortened. In a gait analysis, the cadence and the step length increased, gait velocity improved, and the period of double support shortened. The "mobility" subscore of a quality of life questionnaire (PDQ-39) also improved. All these changes were significant (p0.05). These effects were stable for two months without additional training.The repetitive training of compensatory steps is an effective approach in the treatment of PI and should be applied if PI is evident clinically or in a patient's history.

Background: A direct quantitative measurement of locomotor activity in an individual’s own environment over an extended period may help in evaluating the impact of impairments in neurological disorders. Objective: To investigate the reliability and validity of activity monitoring in neurological patients and healthy subjects. Methods: Initial reliability studies were completed on 10 healthy subjects and 10 mobility restricted neurological patients. Validity was investigated using 7 days of ambulatory monitoring with the Step Watch™ step activity monitor, laboratory based measures of gait and the Rivermead Mobility Index (RMI) in 10 patients with multiple sclerosis, 10 with Parkinson’s disease, and 10 with a primary muscle disorder. Additionally, 30 healthy subjects participated in the study. Two clinical illustrations of ambulatory monitoring are provided. Results: The mean (range) right step count of 7 days of monitoring in both healthy and neurological patients proved a reliable measure of activity (intra-class correlations 0.89 and 0.86 respectively). The 7 day mean (range) right step count was 5951 (2886?9955) in healthy subjects, 3818 (1611?5391) in patients with Parkinson’s disease, 3003 (716?5302) in those with muscular disorders, and 2985 (689–5340) in those with multiple sclerosis. A moderate correlation was noted between 7 day mean step count and gait speed (r?=?0.45, p?=?0.01) in the grouped neurological patients but not the RMI (rs?=?0.3, p?=?0.11). Conclusion: Ambulatory monitoring provides a reliable and valid measure of activity levels. Neurological patients, living independently, demonstrate lower activity levels than healthy matched controls. Ambulatory monitoring as an outcome measure has potential for improving the evaluation of ambulation and providing insight into participation.

Objectives: The aim was to measure changes in walking patterns and self rated fatigue in people with multiple sclerosis (MS) compared with age matched control subjects, from the morning to the afternoon within a single day. Methods: Fourteen patients with MS and the same number of matched control subjects performed four 10 m gait trials at their preferred walking speed at 10 00 am and then again at 3 00 pm on the same day. Gait speed, stride length, cadence, and the percentage of the gait cycle spent in double limb support were measured using a foot switch stride analyzer. Patients with MS also self rated their fatigue levels in the morning and afternoon using an 11 point scale. Results: Compared with control subjects, patients walked very slowly, with reduced stride length and around twice as much variability in gait performance. Although self rated fatigue significantly increased from the morning to the afternoon, walking patterns remained consistent in both groups over the course of the day. Conclusions: These findings imply that mechanisms controlling locomotion are separate from those regulating perceived fatigue. Objective measures of performance, rather than self report, should be used to monitor change in patients with multiple sclerosis.

Inspired by the morphology characteristics of the earthworms and the excellent deformability of origami structures, this research creates a novel earthworm-like locomotion robot through exploiting the origami techniques. In this innovation, appropriate actuation mechanisms are incorporated with origami ball structures into the earthworm-like robot 'body', and the earthworm's locomotion mechanism is mimicked to develop a gait generator as the robot 'centralized controller'. The origami ball, which is a periodic repetition of waterbomb units, could output significant bidirectional (axial and radial) deformations in an antagonistic way similar to the earthworm's body segment. Such bidirectional deformability can be strategically programmed by designing the number of constituent units. Experiments also indicate that the origami ball possesses two outstanding mechanical properties that are beneficial to robot development: one is the structural multistability in the axil direction that could contribute to the robot control implementation; and the other is the structural compliance in the radial direction that would increase the robot robustness and applicability. To validate the origami-based innovation, this research designs and constructs three robot segments based on different axial actuators: DC-motor, shape-memory-alloy springs, and pneumatic balloon. Performance evaluations reveal their merits and limitations, and to prove the concept, the DC-motor actuation is selected for building a six-segment robot prototype. Learning from earthworms' fundamental locomotion mechanism-retrograde peristalsis wave, seven gaits are automatically generated; controlled by which, the robot could achieve effective locomotion with qualitatively different modes and a wide range of average speeds. The outcomes of this research could lead to the development of origami locomotion robots with low fabrication costs, high customizability, light weight, good scalability, and excellent re-configurability.

Contains fulltext : 52526.pdf (Publisher’s version ) (Closed access) OBJECTIVES: Gait and mobility problems are difficult to treat in people with Parkinson's disease. The Rehabilitation in Parkinson's Disease: Strategies for Cueing (RESCUE) trial investigated the effects of a home physiotherapy programme based on rhythmical cueing on gait and gait-related activity. METHODS: A single-blind randomised crossover trial was set up, including 153 patients with Parkinson's disease aged between 41 and 80 years and in Hoehn and Yahr stage II-IV. Subjects allocated to early intervention (n = 76) received a 3-week home cueing programme using a prototype cueing device, followed by 3 weeks without training. Patients allocated to late intervention (n = 77) underwent the same intervention and control period in reverse order. After the initial 6 weeks, both groups had a 6-week follow-up without training. Posture and gait scores (PG scores) measured at 3, 6 and 12 weeks by blinded testers were the primary outcome measure. Secondary outcomes included specific measures on gait, freezing and balance, functional activities, quality of life and carer strain. RESULTS: Small but significant improvements were found after intervention of 4.2% on the PG scores (p = 0.005). Severity of freezing was reduced by 5.5% in freezers only (p = 0.007). Gait speed (p = 0.005), step length (p

Objectives: Clinicians often base the implementation of therapies on the presence of postural instability in subjects with Parkinson’s disease (PD). These decisions are frequently based on the pull test from the Unified Parkinson’s Disease Rating Scale (UPDRS). We sought to determine whether combining the pull test, the one-leg stance test, the functional reach test, and UPDRS items 27–29 (arise from chair, posture, and gait) predicts balance confidence and falling better than any test alone. Methods: The study included 67 subjects with PD. Subjects performed the one-leg stance test, the functional reach test, and the UPDRS motor exam. Subjects also responded to the Activities-specific Balance Confidence (ABC) scale and reported how many times they fell during the previous year. Regression models determined the combination of tests that optimally predicted mean ABC scores or categorised fall frequency. Results: When all tests were included in a stepwise linear regression, only gait (UPDRS item 29), the pull test (UPDRS item 30), and the one-leg stance test, in combination, represented significant predictor variables for mean ABC scores ( r 2 = 0.51). A multinomial logistic regression model including the one-leg stance test and gait represented the model with the fewest significant predictor variables that correctly identified the most subjects as fallers or non-fallers (85% of subjects were correctly identified). Conclusions: Multiple balance tests (including the one-leg stance test, and the gait and pull test items of the UPDRS) that assess different types of postural stress provide an optimal assessment of postural stability in subjects with PD.

The stops walking while talking test; a dual task for motoric neurorehabilitation—further complexities of the test? In their study, Hyndman and Ashburn administered the stops walking while talking test (SWWT) to predict the occurrence of falls (see p 994, this issue) .1 Optimising multi-task cognitive and motor performance and targeting individuals who may benefit from therapeutic interventions to improve gait and reduce falls after stroke are important goals of neurorehabilitation. Dual task paradigms, such as walking while talking, can …

To investigate the relations between premorbid and current mental ability, mood, and white matter signal abnormalities detected by T2 weighted brain magnetic resonance imaging (MRI) and impairment of balance and mobility in older adults.97 subjects from the Aberdeen 1921 birth cohort underwent brain MRI, evaluation of balance, and measurement of gait speed. White matter hyperintensities detected on T2 weighted MRI scans were rated by three independent raters on three variables: white matter lesions; periventricular lesions; and brain stem lesions.Decreased gait speed was correlated with impaired visual acuity (p = 0.020), shorter stature (p = 0.008), a lower childhood IQ (p = 0.030), a lower current Raven's progressive matrices score (Raven score) (p0.001), a higher hospital anxiety and depression scale (HADS) score (p = 0.004), and an increased grade of brain stem lesions on MRI. Inability to balance was correlated with Raven score (p = 0.042), brain stem lesions (p = 0.003), white matter lesions (p = 0.003), and periventricular lesions (p = 0.038). Binary logistic regression identified brain stem lesions (odds ratio (OR) 0.22; 95% confidence interval 0.09 to 0.54) and HADS depression score (OR 0.75; 0.58 to 0.97) as the only significant associations with balance. Structural equation modelling detected an association between two latent traits representing white matter disease and an integrating function, respectively.In this cohort, white matter lesions, periventricular lesions, and brain stem lesions were associated with impaired balance. Current mental ability was strongly related to gait speed. There appears to be a concordance between motor skills and intellect in old age, which is degraded by white matter disease.

Objective: To quantify postural sway in subjects with Parkinson's disease and elderly controls, and determine the effects of Parkinson's disease, deep brain stimulation, levodopa, and their interactions on postural control during quiet stance. Methods: Centre of foot pressure (CoP) displacement under each foot was measured during three 60 s trials of quiet stance with eyes open in 11 controls and six patients with Parkinson's disease. Subjects with Parkinson's disease were tested in four treatment conditions: off both deep brain stimulation and levodopa (off condition); on deep brain stimulation; on levodopa; and on both deep brain stimulation and levodopa. The variables extracted from CoP included: root mean square distance (rms), mean velocity, 95% power frequency (f95%), area of the 95% confidence ellipse (ellipse area), direction of its major axis (mdir), and postural asymmetry between the feet. Results: rms and area of postural sway were larger than normal in subjects with Parkinson's disease in the off condition, increased further with levodopa, and significantly decreased with deep brain stimulation. Mean velocity and f95% were also larger than normal but were restored to normal by all treatments, especially by deep brain stimulation. The combined effect of deep brain stimulation and levodopa resulted in a postural sway that was an average of the effect of each treatment individually. Levodopa increased sway more in the mediolateral than in the anterior-posterior direction. Subjects with Parkinson's disease had asymmetrical mean velocity and f95% between the feet, and this asymmetry increased with levodopa but decreased with deep brain stimulation. The f95% of the CoP correlated with tremor, posture, and gait subcomponents of the unified Parkinson's disease rating scale. Conclusions: Subjects with Parkinson's disease have abnormal postural sway in stance. Treatment with levodopa increases postural sway abnormalities, whereas treatment with deep brain stimulation improves postural sway. Quantitative evaluation of static posturography may be a useful adjunct to clinical measures in patients with Parkinson's disease.

Walking track analysis is an investigative technique that allows a researcher to assess objectively the functional capacity of the limb in the rat sciatic nerve model. This study has shown that paint and paper is a better method for imaging the rat foot plantar surface than other methods described in the literature. The block printing paint has the distinct advantage of keeping radial diffusion error to a minimum. Paint more correctly images the important anatomical landmarks of the rat plantar surface. There is better traction (less slippage) rendering the prints easier to interpret. The authors conclude that the paint and paper is a superior method to the other methods currently available.