Ulrik Röijezon

Proprioception in musculoskeletal rehabilitation. Part 1: Basic science and principles of assessment and clinical interventions

INTRODUCTION Impaired proprioception has been reported as a feature in a number of musculoskeletal disorders of various body parts, from the cervical spine to the ankle. Proprioception deficits can occur as a result of traumatic damage, e.g., to ligaments and muscles, but can also occur in association with painful disorders of a gradual-onset nature. Muscle fatigue can also adversely affect proprioception and this has implications for both symptomatic and asymptomatic individuals. Due to the importance of proprioception for sensorimotor control, specific methods for assessment and training of proprioception have been developed for both the spine and the extremities. PURPOSE The aim of this first part of a two part series on proprioception in musculoskeletal rehabilitation is to present a theory based overview of the role of proprioception in sensorimotor control, assessment, causes and findings of altered proprioception in musculoskeletal disorders and general principles of interventions targeting proprioception. IMPLICATIONS An understanding of the basic science of proprioception, consequences of disturbances and theories behind assessment and interventions is vital for the clinical management of musculoskeletal disorders. Part one of this series supplies a theoretical base for part two which is more practically and clinically orientated, covering specific examples of methods for clinical assessment and interventions to improve proprioception in the spine and the extremities.

Proprioception in musculoskeletal rehabilitation. Part 2: Clinical assessment and intervention

INTRODUCTION Proprioception can be impaired in gradual-onset musculoskeletal pain disorders and following trauma. Understanding of the role of proprioception in sensorimotor dysfunction and methods for assessment and interventions is of vital importance in musculoskeletal rehabilitation. In Part 1 of this two-part Masterclass we presented a theory-based overview of the role of proprioception in sensorimotor control, causes and findings of altered proprioception in musculoskeletal conditions, and general principles of assessment and interventions. PURPOSE The aim of this second part is to present specific methods for clinical assessment and interventions to improve proprioception in the spine and extremities. IMPLICATIONS Clinical assessment of proprioception can be performed using goniometers, inclinometers, laser-pointers, and pressure sensors. Manual therapy, taping, and bracing can immediately enhance proprioception and should be used to prepare for exercise interventions. Various types of exercise (active joint repositioning, force sense, co-ordination, muscle performance, balance/unstable surface, plyometric, and vibration training) should be employed for long-term enhancement of proprioception.

Elbow joint angle estimation by using integrated surface electromyography

Electromyography (EMG) signals represent the electrical activation of skeletal muscles and contain valuable information about muscular activity. Estimation of the joint movements by using surface EMG signals has great importance as a bio-inspired approach for the control of robotic limbs and prosthetics. However interpreting surface EMG measurements is challenging due to the nonlinearity and user dependency of the muscle dynamics. Hence it requires complex computational methods to map the EMG signals and corresponding limb motions. To solve this challenge we here propose to use an integrated EMG signal to identify the EMG-joint angle relation instead of using common EMG processing techniques. Then we estimate the joint angles for elbow flexion-extension movement by using an auto-regressive integrated moving average with exogenous input (ARIMAX) model, which takes integrated EMG measurements as input. The experiments showed that the suggested approach results in a 21.85% average increase in the estimation performance of the elbow joint angle compared to the standard EMG processing and identification.

Decline in sensorimotor systems explains reduced falls self-efficacy

Physical performance including balance tasks is one of the main factors explaining the variance in falls self-efficacy in older adults. Balance performance is often measured by use of gross assessment scales, which assess the result of integration of all systems involved in postural control. We aimed to investigate which measurements of postural control correlate to falls self-efficacy scores as measured by the FES-I instrument, and which sensory and motor systems best explain them. A cross sectional study was designed, in which 45 older adults performed quiet stance and limits of stability trials during which their center of pressure (CoP) excursion was recorded. Falls self-efficacy was measured using the Falls Efficacy Scale - International. Eyesight, vestibular function, proprioception, reaction time and strength were also measured. Hierarchical orthogonal projection of latent structures was used to model FES-I with the CoP trials and then with the sensory and muscle function data. Fes-I could be explained to 39%, with the eyes open trials and the limits of stability trials loading the heaviest. The base model could be explained to 40% using the sensory and muscle function data, with lower limb strength, leg proprioception, neck proprioception, reaction time and eyesight loading the heaviest.

A laser dot tracking method for the assessment of sensorimotor function of the hand

Assessment of sensorimotor function is crucial during the rehabilitation process of various physical disorders, including impairments of the hand. While moment performance can be accurately assessed in movement science laboratories involving highly specialized personnel and facilities there is a lack of feasible objective methods for the general clinic. This paper describes a novel approach to sensorimotor assessment using an intuitive test and a specifically tailored image processing pipeline for the quantification of the test. More specifically the test relies on the patient being instructed on following a zig-zag pattern using a handled laser pointer. The movement of the pointer is tracked using image processing algorithm capable of automating the whole procedure. The method has potential for feasible objective clinical assessment of the hand and other body parts.

Electromyography based joint angle estimation and control of a robotic leg

Musculoskeletal modeling based on Electromyography (EMG) has many applications in physiotherapy and biologically-inspired robotics. In this article, a novel methodology for the modeling of the dynamics of an antagonistic muscle pair that actuates the human ankle joint movements will be established. As it will be presented, the musculoskeletal model is based on a multi input single output (MISO) auto-regressive integrated moving average with exogenous input (ARIMAX) model, which takes the integrated EMG measurements as input and estimates the corresponding joint angles. Based on this methodology, a Pneumatic Artificial Muscle (PAM) robotic leg setup that mimics the flexion/extension movement of human ankle joint is controlled to replicate the human movement. The experimental results demonstrate the performance of EMG-based joint angle estimation and control of the robotic leg with the proposed model.