- Karnofsky >= 50% for patients > 10 years of age; Lansky play scale >= 50% for children =< 10 years of age; neurologic deficits in patients with CNS tumors must have been relatively stable for a minimum of 2 weeks prior to study entry; patients who are unable to walk because of paralysis, but who are up in a wheelchair will be considered ambulatory for the purpose of assessing the performance score