We report a 30-year-old man with an extensive cerebral contusion. He presented with severe left upper and lower limb paralysis and mild right lower limb palsy. He was diagnosed with severe sleep apnea syndrome and was treated with nighttime nCPAP (nasal Continuous Positive Airway Pressure). Four years after the injury, he was able to walk with Lofstrand crutches. However, he gradually began to have difficulty standing, walking and driving his wheelchair because his spasticity developed markedly. He received ITB (intrathecal baclofen) therapy and noted a reduction in spasticity. He was once again able to drive his wheelchair and to walk with support. In addition, his respiratory function didn't show any deterioration. Spasticity is a common complication after cerebral or spinal cord injury, for which treatment has been difficult. ITB therapy can dramatically reduce spasticity, but has been demonstrated that it may also depress respiratory function in patients with respiratory insufficiency. This case suggests that ITB therapy may reduce spasticity without affecting respiratory function even in patients with a respiratory disorder.