Contributions to Neurosurgery
      Dr Rasmussen contributed to important aspects of neurosurgery. In addition to the surgery of the pituitary gland and treatment of pain, he carried out experimental studies on cerebrovascular problems and reported on tumors of the brain and spinal cord. He substantiated the application of the carotid-amytal test introduced by Juhn Wada so that it could be used safely, not only for testing cerebral lateralization of speech function, but modified as well for assessment of memory and EEG localization of epileptogenic areas. In these studies he worked closely with Herbert Jasper, Peter Gloor, Brenda Milner and a continuing roster of young neurosurgical fellows. But his main interest centered on the surgical treatment of epilepsy and on the meticulous documentation of the long-term surgical results. Rasmussen consolidated and extended the pioneer work of Wilder Penfield and by his assiduous focus on follow-up studies established the evidence-based role of surgery in the amelioration and frequently the cure of focal seizures. In his 25 years (1955-1980) at the Neuro, Rasmussen probably performed more operations for epilepsy than any other surgeon of his time and became the foremost authority in this field. The MNI surgical records, an unmatched world series of some 3000 cases, continue to serve as the standard of reference for other neurosurgical centers where the systematic surgical treatment of epilepsy became eventually adopted.

Rasmussen's Syndrome
      In 1958, with Jerzy Olszewski and Donald Lloyd-Smith, Theodore Rasmussen published the clinical and pathological features of three patients with chronic encephalitis associated with epilepsy. This newly defined entity, later referred to as Rasmussen's syndrome, provoked much discussion and research in regard to etiology and possible treatment. The role of the surgical treatment in selective examples of this syndrome was established and often involved major interventions such as hemispherectomy. This later led to the recognition of postoperative hemosiderosis and hydrocephalus, a sometimes fatal complication. Rasmussen pioneered the modification of the surgical technique to a "functional disconnection" leaving in situ most of the abnormal brain tissue, a maneuver that greatly reduced this hazard.

     Achievements
      In 1972, after retiring from his administrative positions at the Neuro and McGill, he continued actively in his surgical practice and follow-up analyses of seizure surgery. During his career he published 175 papers and served effectively as a teacher and role model to many young neurosurgeons and neuroscientists. He represented the Neuro at national and international meetings, being widely sought after as a visiting professor and lecturer. As one of the outstanding leaders in neurosurgery, he was president of many societies, including the Association of Neurosurgeons of Quebec, the Canadian