Prior to treatment, after informed consent is obtained, each subject will be randomized into the ketamine or placebo (normal saline) infusion group. Both the patient and all other individuals involved in the study will be blinded as to the treatment except Guillermo Alexander PhD who will be responsible for the randomization and Margaret Rose RN who will be responsible for preparing the infusion solution. The patient will then receive a complete neurological examination and will be asked to complete a short form McGill and Quality of life questionnaires (Attachment 1).