Transcutaneous Spinal Stimulation: Safety and Feasibility for Upper Limb Function in Children With Spinal Cord Injury

Transcutaneous Spinal Stimulation: Safety and Feasibility for Upper Limb Function in Children With Spinal Cord Injury

Transcutaneous Spinal Stimulation Promoting Recovery of Hand and Arm Function After Pediatric-onset Spinal Cord Injury

Children who suffer a spinal cord injury in the neck region have difficulty using their hands due to paralysis and/or weakness of their arms and hand muscles. The purpose of this project is to test the safety, comfort, and practicality of a new therapy that stimulates the spinal cord to facilitate activation of arm and hand muscles while practicing grasping, pinching, and reaching movements. The long-term goal is to provide better therapies that will improve the ability of children with SCI to more successfully play and accomplish everyday tasks using their arms and hands, similar to before their injury.

Adults with cervical spinal cord injury (SCI) rank gaining arm and hand function as the highest priority for improving their quality of life. Children with SCI, similarly experience paralysis of hand and arm muscles that limits their engagement in play and exploration typical for child development . Furthermore, pediatric-onset SCI disrupts the acquisition of motor skills involved in activities of daily living such as feeding, dressing and grooming increasing the child's dependence on a parent/caregiver. Current interventions teach persons with SCI to use a brace or splint to compensate for paralysis or weakness of hand muscles. Others are invasive requiring nerve or tendon transplantation and/or electrode implantation for functional electrical stimulation. Transcutaneous electrical spinal cord stimulation (TcStim) is a non-invasive painless technique that augments the intrinsic capacity of the spinal cord below the level of injury to generate patterned motor output. In adults with chronic SCI, TcStim acutely (immediately) augments trunk control and improves upper extremity function when combined with task-specific training. In children with cerebral palsy, TcStim in combination with locomotor training improves walking ability. Thus, the long-term objectives are 1) to investigate the therapeutic potential of TcStim for improving arm/hand function and 2) provide high quality scientific evidence to guide the clinical use of neurotherapeutic interventions promoting recovery in children with SCI. As children with SCI represent a vulnerable population, we first must establish the safety and feasibility of any potential novel therapeutic approach. Therefore, the specific aims of this proposal are to 1) determine proof-of-principle, safety and feasibility of TcStim for acute increase of hand/arm function in children with SCI and 2) determine the safety and feasibility of TcStim in combination with activity-based upper extremity training (AB-UET) across 40 sessions in children with SCI. For this pilot study 8-10 participants, ages 5-18 years with chronic, acquired SCI who have completed ≥ 40 sessions of activity-based upper extremity training (AB-UET) with neuromuscular stimulation will be recruited. For Aim 1, TcStim parameters will be optimized for arm/hand function. Arm/hand function will be assessed using the three tasks: overhead reach, forward reach and grasp and in-hand manipulation for no-TcStim and TcStim conditions measuring kinematics, electromyography of arm and hand muscles. For Aim 2 (safety and feasibility), two participants will undergo 40 sessions of AB-UET in combination with TcStim. To assess long-term safety and feasibility, participant compliance and any difficulties (i.e. risks, discomfort) will be documented and risk-likelihood/risk-benefit established. The long-term goal is to provide better therapies that will improve the ability of children with SCI to use their arms and hands with more success to grasp, reach and use their hands for everyday play and daily tasks.

Safety and feasibility outcome measures are collected during application of transcutaneous spinal stimulation while upper extremity function is assessed at 3 time points (acute) and/or in combination with activity-based upper extremity training (40 sessions, 1.5 hours/day, 5 days/week); stimulation will be applied intermittently for no more than 10 minutes at a time. Upper extremity training is based on usual care activities to challenge use of the hands and arms, e.g. reaching, grasping, manipulating objects.

Safety and feasibility will be monitored during transcutaneous spinal stimulation in children with spinal cord injury

Skin color, particularly change in skin color to pink indicating irritation in the location of the stimulating electrode placement will be assessed prior to stimulation experiments and immediately after; incidence of pink- or redness or irritation and time (minutes-days) to dissipation will be recorded.

Faces Pain Scale - Revised is a self-report measure of pain intensity developed for children (C.L. Hicks et al. Pain 93 (2001). It will be used to score the sensation of pain on 0 (min - no pain)-to-10 (max - worst pain ever) metric. The scale depicts 6 facial expressions: first - face with a neutral expression corresponds to pain score of 0, next facial expression is scored as 2, etc. The faces scale will be presented to the participant (ages 3-8) prior to the experiment for baseline measurement, during stimulation and following the experiment.

To assess pain in the participants ages 8 and above, Visual Analog Scale (self-reported measure) will be presented with 0 corresponding to no pain and 10 corresponding to the "worst pain ever"; the scale will be presented at baseline measurement, during stimulation and following the experiment.

continuous beat-by-beat blood pressure (mmHg) recordings will be made using Finapres finger cuff system for 5 minutes prior to and 5 minutes immediately following stimulation while the child is sitting; Brachial arm blood pressure will be periodically measured during stimulation (mmHg). systolic and diastolic blood pressure values will be compared with the established norms for typically developing children (age and height matched);

Number of participants requesting (or number of request per participant within experimental sessions) to stop stimulation due to pain, fatigue or any other reason (documented)

heart rate (beats per minute) will be continuously monitored and recorded using 3-lead electrocardiogram.

Inclusion Criteria: history of chronic, acquired SCI, (>1 year since injury); SCI involves cervical and/or high thoracic (T1) levels moderate to severe upper extremity deficit as assessed by the Pediatric Neuromuscular Recovery Upper Extremity Scale (scores less than 4A out of a 12 point range from 1A-4C on upper extremity tasks, e.g. including inability to fully reach overhead, grasp, or pinch without compensation) discharged from in-patient rehabilitation Exclusion Criteria: botox use within past 3 months; current baclofen use unhealed upper extremity fracture any other medical complication limiting participation in the assessments and/or activity- based upper extremity training; congenital SCI total ventilator dependence