Summary and agreement statement of the 1st International Symposium on Concussion in Sport, Vienna 2001.

*International Ice Hockey Federation, Zurich, Switzerland; †Neurosurgery Service & Sports Medicine Service, Emerson Hospital, Concord, Massachusetts, and National Center for Catastrophic Sports Injury Research, Chapel Hill, North Carolina, U.S.A.; ‡FIFA Medical Research and Assessment Center (F-MARC), and Schulthess Clinic, Zurich, Switzerland; §FIFA Medical Research and Assessment Center (F-MARC), Tenningen, Germany; ¶Division of Neurosurgery, McGill University Health Centre (MUHC), McGill University and McGill Sport Medicine Centre, Montreal, Canada; Chicago Neurological Institute, Northwestern University Medical School, Chicago, Illinois; **Sports Medicine Concussion Program, University of Pittsburgh, and National Hockey League Neuropsychology Program, Pittsburgh, Pennsylvania, U.S.A.; ††Brain Research Institute and Center for Sports Medicine Research and Education, University of Melbourne, Melbourne, Australia; ‡‡University of Calgary Sport Medicine Center, and National Hockey League, Calgary, Alberta, Canada; and §§International Olympic Committee Medical Commission, Lausanne, Switzerland