Sensory Stimulation Augments the Effects of Massed Practice Training in Individuals with Tetraplegia

Signature Grand, Davie, Florida, USA

Objective. To compare functional changes and cortical neuroplasticity associated with upper extremity use following massed practice training and somatosensory stimulation in persons with incomplete tetraplegia. Background. Impaired hand function severely limits the ability of individuals with tetraplegia to perform manual activities of daily living. Massed practice and somatosensory stimulation are two interventions that may be able to maximize transmission of information through the intact connections in the spinal cord. Methods. Twenty-four subjects with chronic incomplete tetraplegia were randomly assigned to one of four groups: massed practice combined with somatosensory stimulation (MP+SS), somatosensory stimulation alone (SS), massed practice alone (MP), and no intervention. Intervention sessions were 2-hours/session, 5-days/week for 3 weeks. Massed practice consisted of repetitive practice of upper extremity functional tasks. Somatosensory stimulation consisted of median nerve stimulation at sub-motor threshold. Outcome measures assessed changes in upper extremity function, pinch grip strength, sensory function, and changes in cortical excitation. Results. Following training, compared to the Control group all groups showed significant improvements in hand function. The MP+SS and SS groups demonstrated significant improvements in upper extremity function and pinch strength compared to the Control group. Only the MP+SS demonstrated a significant change in sensory scores compared to the Control group. The MP+SS and MP groups demonstrated greater change in threshold measures of cortical excitability. Conclusions. Individuals with incomplete tetraplegia obtain functional benefits from massed practice of task-oriented skills. Somatosensory stimulation appear to be a valuable adjunct to training programs designed to improve hand and upper extremity function in these individuals. Grants. This work was supported in part by the Miami Project to Cure Paralysis at the University of Miami Medical School and the Center of Excellence for Functional Recovery in Chronic SCI at the Miami VAMC.