Tatsuto Suzuki

Linking wheelchair kinetics to glenohumeral joint demand during everyday accessibility activities

The aim of the study was to investigate if push-rim kinetics could be used as markers of glenohumeral joint demand during manual wheelchair accessibility activities; demonstrating a method of biomechanical analysis that could be used away from the laboratory. Propulsion forces, trunk and upper limb kinematics and surface electromyography were recorded during four propulsion tasks (level, 2.5% cross slope, 6.5% incline and 12% incline). Kinetic and kinematic data were applied to an OpenSim musculoskeletal model of the trunk and upper limb, to enable calculation of glenohumeral joint contact force. Results demonstrated a positive correlation between propulsion forces and glenohumeral joint contact forces. Both propulsion forces and joint contact forces increased as the task became more challenging. Participants demonstrated increases in trunk flexion angle as the requirement for force application increased, significantly so in the 12% incline. There were significant increases in both resultant glenohumeral joint contact forces and peak and mean normalized muscle activity levels during the incline tasks. This study demonstrated the high demand placed on the glenohumeral joint during accessibility tasks, especially as the gradient of incline increases. A lightweight instrumented wheelchair wheel has potential to guide the user to minimize upper limb demand during daily activity.

A clinical trial of a prototype of wireless surface fes rehabilitation system in foot drop correction

The purpose of this study is to develop a wireless FES rehabilitation system to assist effective improvement of the lower limbs. In this report, a prototype system combined with foot drop correction and gait evaluation using wireless surface electrical stimulator and the wireless inertial sensors was developed and tested with a right hemiplegic subject. For gait evaluation, lower limb joint angles and segment angles were estimated by the Kalman filter from the data measured with wireless inertial sensors. Electrical stimulation was applied to the common peroneal nerve or the tibialis anterior muscle by detecting stimulus timing automatically from the data of wireless inertial sensor attached on the shank of the hemiplegic side. The maximum joint angle of ankle dorsiflexion of the paralyzed side at the swing phase was increased approximately to the value of the healthy side by applying the electrical stimulation. The developed system was performed well in foot drop correction and the measured data of the inertial sensors showed the characteristics and difference of paralyzed side with and without electrical stimulation using the segment angles and joint angles.

Assisting control for attendant propelled wheelchair based on force velocity relationship

There is a need to develop an assisting device which can be adapted to the individual capabilities of elderly attendants, which would allow them to maintain a level of fitness when pushing a wheelchair, while minimising the risk of injury to them. Furthermore there is a need to reduce the overall energy consumption of the device in keeping with the current trends of reducing carbon emissions. The control system for attendants pushing wheelchairs that reduces the energy needed by the assisting device is an increasing trend of optimisation of assistive technology devices to individual capabilities to ensure less energy expenditure of the attendant. The control parameters for existing assisting systems for attendant wheelchair propulsion are difficult to optimise for individual capabilities. We focus on the individual propelling performance, and propose an assisting control method based on the force velocity relationship of the individual. Our proposed assisting controller generates an assisting force when the attendants propelling force exceeds an assisting boundary defined by the force velocity relationship. In this paper, we tested the performance of the assisting controller based on force velocity (FV) relationship using simulation. The simulation used an attendant wheelchair model with parameters determined from experiments. From the simulated results of the assisting force trajectories, the FV assisting system worked as we defined. The FV assisting system used less energy consumption than the existing proportional assisting systems. Also the FV assisting system would have a limit of maximum attendant propelling power, so the distribution between the attendant force and the assisting force can be easily adjusted to the individuals force velocity relationship. Our proposed FV assisting system would be useful as it would allow an optimised system based on individual capabilities to be created for rehabilitation/training systems, which would allow optimum energy consumption when propelling a wheelchair.

Identifying key experience-related differences in over-ground manual wheelchair propulsion biomechanics

Objectives The purpose of this study was to investigate technique differences between expert and novice manual wheelchair users during over-ground wheelchair propulsion. Method Seven experts (spinal cord injury level between T5 and L1) and six novices (non-wheelchair users) pushed a manual wheelchair over level ground, a 2.5% cross slope and up a 6.5% incline (7.2 m length) and 12% incline (1.5 m length). Push rim kinetics, trunk and shoulder kinematics and muscle activity level were measured. Results During the level and cross slope tasks, the experts completed the tasks with fewer pushes by applying a similar push rim moment over a greater push arc, demonstrating lower muscle activity. During the incline tasks, the experts required fewer pushes and maintained a greater average velocity, generating greater power by applying a similar push rim moment over a greater push arc with greater angular velocity, demonstrating greater trunk flexion and higher shoulder muscle activity. Conclusions This study identifies experience-related differences during over-ground manual wheelchair propulsion. These differences are particularly evident during incline propulsion, with the experts generating significantly greater power to maintain a higher velocity.

Navigational cue effects in Alzheimer's disease and posterior cortical atrophy

Deficits in spatial navigation are characteristic and disabling features of typical Alzheimers disease (tAD) and posterior cortical atrophy (PCA). Visual cues have been proposed to mitigate such deficits; however, there is currently little empirical evidence for their use.

DIRECTIONAL LIGHTING-BASED INTERVENTIONS TO SUPPORT REAL-WORLD NAVIGATION FOR INDIVIDUALS WITH DEMENTIA-RELATED VISUAL IMPAIRMENT

extended this work to estimate step length, step time walking speed and stride length since early indications of functional loss include change in gait characteristics. Methods: Up to 128 sensors produce a voltage due to a person walking on the carpet. We obtained the walking data from both the smart carpet and the GAITRite [3] mat simultaneously by overlaying the smart carpet over the GAITRite mat. Subjects walked across the carpet and mat for 9 trials each. The data acquisition system of the smart carpet recorded the location of the active sensors, and used to extract the gait parameters. Volunteers performed 9 walks. Data frames read from the data acquisition system provided step counts, walking distance and time. Results: We achieved excellent agreement for walking speed, stride length and stride time between the two systems. The mean percentage error difference for walking speed is 1.43% (SD, 4.4%), stride length is -4.32% and stride time is -5.73%. We compared our work to the work done using a Kinect and web cameras system with excellent agreement. Conclusions: As we showed previously we can detect falls with high accuracy and display this data in real-time. We can now estimate important gait parameter that can lead to an assessment of fall risk. References [1] Alzheimer’s Disease Facts and Figures, 2015. [2] Neelgund R.,“Floor sensor development using signal scavenging for personnel detection system”, University of Missouri, Columbia 2010. Masters thesis for MS Degree. [3] K. E. Webster, J. E. Wittwer, Julian F. Feller, “Validity of GAITRite Walkway System for the Measurement of Averaged and Individual Step Parameters of Gait”, Gait and Posture 22, pp 317-321, 2005.

PRINCIPAL COMPONENT ANALYSIS OF DIFFERENCES IN EYE MOVEMENTS AND LOCOMOTION BETWEEN POSTERIOR CORTICAL ATROPHY AND TYPICAL ALZHEIMER’S DISEASE PATIENTS

and the Euclidian distance from the origin (0, 0, 0) to the score coordinates (ADL, Cognitive function, BPSD) were calculated for evaluations. The Euclidian distances are highly correlated with the scores of MMSE, NPI-D, DAD, CDR sum of box (CDR SOB) and Global CDR of which the correlation coefficients are 0.736, -0.600, 0.717, -0.830 and -0.826, respectively. The specificities and sensitivities to discriminate the severities of AD may be reasonable enough to use practically. For example, the sensitivity and the specificity of probable MCI versus other severities were 0.928 and 0,684, respectively. If the baseline severity was CDR0/0.5, CDR1 or CDR2, the changes of the three dimensional distance between the baseline and 12 weeks were statistically significant. Conclusions: The novel dementia assessment scale can be measured in 10 minutes on average by raters without a special training and qualifications. It can diagnose the severity of AD with high sensitivity and the specificity and detect the changes of the scores by 12 weeks. This scale may be relevant for clinical practice. This research was funded by Daiichi Sankyo Co., Ltd. (Tokyo, Japan). ClinicalTrials.gov Identifier: NCT02667665.

VISUAL SEARCH ABILITIES OF POSTERIOR CORTICAL ATROPHY AND TYPICAL ALZHEIMER’S DISEASE PATIENTS IN REAL-WORLD SETTINGS

Figure 3. A captured scene and a fixation (red circle) from a video of a Ayako Suzuki, Keir Yong, Ian McCarthy, Tatsuto Suzuki, Dilek Ocal, Nikolaos N. Papadosifos, Derrick Boampong, Nick Tyler, Sebastian J. Crutch, University College London, Engineering Sciences, London, United Kingdom; Dementia Research Centre, Institute of Neurology, University College London, London, United Kingdom; University College London, Institute of Neurology, London, United Kingdom. Contact e-mail: a.suzuki@ucl.ac.uk

EFFECTS OF GROUND LIGHTING UNIFORMITY AND CLUTTER ON NAVIGATIONAL ABILITY IN POSTERIOR CORTICAL ATROPHY AND TYPICAL ALZHEIMER’S DISEASE

0.36-0.87) and ARBs (HR 0.60, 95% CI 0.37-0.98) were independently associated with a decreased risk of dementia. The association of CCBs with dementia was most apparent in participants without a history of cardiovascular disease (HR 0.38, 95% CI 0.18-0.81) and with uncontrolled hypertension (HR 0.26, 95% CI 0.11-0.61). Systolic blood pressure was not significantly lower in participants using CCBs or ARBs. Conclusions:Both use of CCBs and ARBs are independently associated with a decreased risk of dementia in older people. der clutter (right) and consistent (A) vs inconsistent (B) lighting.

A basic study on temporal parameter estimation of wheelchair propulsion based on measurement of upper limb movements using inertial sensors

Wheelchairs are the most widely used assistive device to aid activities of daily living (ADL) for disabled people. However, manual pushing of a wheelchair frequently leads to overuse of upper extremities causing shoulder pain and carpal tunnel syndrome. The purpose of this study was to test a novel method of estimating temporal parameters of wheelchair propulsion using inertial sensors. In this paper, normalized coordinate values of the vector defined on the upper arm were calculated from an inertial sensor attached on the upper arm. The number of strokes and push cycle timings including duration of propulsion and recovery phases were estimated for steady state wheelchair propulsion. This estimation was completed using a novel vector-based approach and a previously published resultant acceleration method; both were compared to timings measured using the SmartWheel. Measurements were performed on level and sloped surfaces with 10 able bodied subjects. The vector-based method improved estimation of the number of strokes when compared to the resultant acceleration method. However, the push cycle was estimated with better accuracy by the resultant acceleration method. Therefore, a combination of the vector-based and the resultant acceleration methods is proposed to ensure more accurate estimation of temporal parameters. The results suggest inertial sensors can be used to measure wheelchair activity accurately and reliably.