Applications of Upper Limb Biomechanical Models in Spinal Cord Injury Patients

Abstract

Impaired upper limb function is one of the most common sequelae in central nervous system. In spinal cord injury (SCI) patients, upper limbs are affected in more than 50% of cases (Wyndaele and Wyndaele 2006). Upper limb strength is impaired to some extent in people who have suffered cervical SCI making it difficult for them to perform many activities of daily living (ADL) essential for their autonomy such as wheelchair manual propulsion, eating, drinking, and personal hygiene (Parker et al. 1986; Nakayama et al. 1994). In contrast with lower limbs, upper limbs have extensive functionally due to the mobility of numerous joints that can execute fine movements thanks to complex neuromuscular control. Lower limbs movements have been broadly analyzed in biomechanical studies specially regarding gait analysis. Gait analysis has evolved over the last decades as an important technique to assist in the clinical assessment of patients with mobility dysfunction. These techniques are useful for evaluation, treatment, and surgical planning; in addition, sequential assessments help to provide a functional outcome evaluation. Motion analysis offers an objective method for quantifying movement and is considered a gold standard for evaluating lower limb function during gait in different types of patients. Therapeutic and surgical interventions to improve upper limb function primarily focus on muscle balance and joint position to maximize hand function; however, the methods for characterizing specific upper limb motion deficits and measuring the functional outcome are varied and mostly subjective. Upper limb function has traditionally been evaluated by different scales that only assess the quality of upper limb movement based on observational analysis, e.g. Fugl-Meyer Assessment, Frenchay Arm Test, Motor Assessment Scale, Action Research Arm Test, Box and Block Test, Nine Hole Peg Test (Wade 1992; Finch 2002). These outcome measures are reliable and sensitive for measuring gross changes in functional performance but have less sensitivity to smaller specific changes. These tools provide information concerning the quality of movement and a quantifiable score of performance,