The investigators seek to evaluate the effectiveness of Armeo®Spring Pediatric training, as compared to conventional treatment, in improving upper extremity function in children with Narakas I brachial plexus injury, aged 5-8 years, using the Mallet modified scale and passive range of movement, immediately post intervention and at 3 and 6 months´ follow up. The investigators will also monitor the appearance of adverse effects during and post intervention, with a follow up at 3 and 6 months.

Obstetric brachial plexus injury is caused by damage of the cervical nerve roots C5-T1 during delivery. It has traditionally been treated with occupational and physical therapy during the first few months, evaluating at 1, 3 and 6 months if primary surgery is required. The goal of primary surgery is to repair the damaged nerve roots and restore neural function. Despite surgery, a large percentage of children will remain with varying degrees of paralysis. Since Narakas I ("Erb's") paralysis is the most common, motor sequelae usually involve limited shoulder abduction, restricted shoulder external rotation and elbow flexion contracture. This sequelae requires ongoing physical and occupational therapy, especially during school age, to ensure adequate upper extremity function and participation.

Armeo Spring Pediatric is a robotic tool that enables upper extremity training using virtual reality. Virtual reality is usually well tolerated and highly motivating to school age children. Since it's a relatively new tool, its effectiveness in the treatment of obstetric brachial plexus injury has not been documented.

This study aims to evaluate the effectiveness of Armeo Spring Pediatric training as compared to conventional therapy (occupational and physical therapy), in improving the upper extremity function of children with Narakas I (C5-C6) obstetric brachial plexus injury.

It will study two parallel groups of children ages 5-8. Both groups will receive 45 minute sessions, 3 times a week, for a total of 5 weeks (15 sessions). One group will train upper extremity function using Armeo Spring Pediatric and the other group will receive occupational and physical therapy, as detailed in protocol. They will be reevaluated at 3 and 6 months.

The appearance of adverse events, such as pain, fatigue or muscle contracture, will be documented during intervention, post intervention, and at 3 and 6 months. In the presence of one such adverse event, the training session will be suspended and the patient evaluated by physiatrist or orthopedic surgeon, with treatment if necessary. If the symptoms resolve before the next session, the patient will complete training as planned. If the symptoms are not resolved by the next session, the patient will be removed from the clinical trial until recovery.

Inclusion Criteria:

• Ages between 5 and 8 years 11 months at beginning of intervention
• Obstetric brachial plexus injury classified as Narakas I
• Legal guardian signs informed consent form

Exclusion Criteria:

• Evident shoulder or elbow dislocation during physical or radiological examination
• Elbow flexion contracture of 40º or more
• Pain during shoulder or elbow manipulation