Robotic-assisted Locomotor Training on Mobility and Cardiopulmonary Function in Patients Suffering From Spinal Cord Injury

A validated mobility independence assessment tool for spinal cord injury (SCI) population (Burns, Delparte, Patrick, Marino, & Ditunno, 2011). Subjects will be asked to walk on a 10-meter straight line and score will be given based on the use of walking aids, orthoses, manual assistance and distance covered.

A validated assessment tool for SCI patients (Catz et al., 2007) to measure performance in different aspects, including self-care ability, respiratory and sphincter management and mobility.. For self-care and respiratory & sphincter domain, scoring will be given based on patient's subjective report while the mobility performance will be tested by the assessors.

The sum of muscle power of the 5 key muscles of lower limb. Manual muscle testing will be adopted in testing the muscle power and the grading will be based on the Medical Research Council scale for muscle strength.

Hip and knee flexors and extensors will be tested. Subjects will be asked to relax during lying supine and assessor will passively move the limbs in fast speed. Scoring will be given based on the occurrence and quality of resistance.

Strength will be assessed by L-force function which is installed in Lokomat system. subjects will be asked to perform isometric muscle contraction of hips and knees, the sensors in orthoses will measure the force exerted on it and record the result.

Walking speed, heel-heel base of support, bilateral legs stance duration and bilateral symmetry will be assessed by gait analysis system (GAITRite System, CIR Systems, Inc., US) . Subjects will be asked to walk on a pressure-detectable walkway, which is connected to a computer system. Assistance as well as orthoses will be provided based on subject's own choice. Two meters of acceleration distance will be provided before the subject walk onto the walkway while another two meters of deceleration distance will be provided so as to ensure that subjects walk with their fastest comfortable speed on the whole track of walkway. Bilateral symmetry will be assessed by the stride length ratio as well as stance phase duration ratio of the weak limb to strong limb, where the strong limb is defined as the one with higher score in lower extremity motor score.

For cardiopulmonary functioning, the subject will be asked to perform upper limb ergometry (Endorphin's 300 e2 resistance system, Endorphin Corporation, US) with a gas analysis system (Fitmate pro, COSMED, Italy). Subjects will wear a mask connecting to the gas analysis system and they will be asked to perform the upper limb ergometry with the following protocol: 1 minute of rest following with 1 minute of warm-up using the least resistance, then the resistance will be increased by 1 level per 1 minute time. The test will be stopped when the heart rate reaches 85% of maximal heart rate, or the subject cannot further tolerate the test. Maximal oxygen consumption will be recorded for further analysis.

Stiffness will be assessed by L-stiff function, which subjects will be asked to keep relaxing on the system while the Lokomat system performs passive limbs movement at different speed. The torque during movement will be detected by the sensors in the orthoses and recorded the result.

Spirometry will be used to assess the respiratory function of subjects. Subjects will be asked to perform a forced and prolonged expiration via mouth piece which connecting to a spirometer (Pony FX, COSMED, Italy) followed with a forced inspiration. A soft clip will be applied to subject's nose to minimize air leak from nose during test. Peak expiratory flow (PEF), forced expiratory flow rate in first second (FEV1) and forced vital capacity (FVC) will be assessed. 3 trials will be performed with 1 minute rest interval to prevent hyperventilation and the average value of the 3 trials will be recorded for analysis.