A Proposal for Case Definitions and Outcome Measures in Studies of Infantile Spasms and West Syndrome: Consensus Statement of the West Delphi Group


  • Andrew L. Lux,

    1. Bath Unit for Research in Paediatrics, Royal United Hospital, Bath, and School for Health, University of Bath, Bath, United Kingdom for The West Delphi Group
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  • John P. Osborne

    1. Bath Unit for Research in Paediatrics, Royal United Hospital, Bath, and School for Health, University of Bath, Bath, United Kingdom for The West Delphi Group
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  • The West Delphi Group

  • Andrew L. Lux and John P. Osborne, Bath Unit for Research in Paediatrics, Bath, England, and School for Health, University of Bath, Bath, U.K.; Giuliano Avanzini and Tiziana Granata, Istituto Neurologico “C. Besta,” Milan, Italy; Tallie Z. Baram, University of California at Irvine, Irvine, CA, U.S.A.; Roberto Caraballo, Hospital Nacional de Pediatria “Juan P. Garrahan,” Buenos Aires, Argentina; Kevin Farrell, University of British Columbia, Vancouver, British Columbia, Canada; Ellie Hancock, Great Ormond Street Hospital, London, U.K.; Masatoshi Ito, Shiga Medical Center for Children, Moriyama, Japan; Jun Kohyama, Tokyo Medical and Dental University, Tokyo, Japan; Roshan Koul, Sultan Qaboosh Hospital, Alkhad, Oman; Wei-Ling Lee, National Neuroscience Institute, Singapore; Jianxiang Liao, Shenzhen Children's Hospital, Shenzhen, China; Marissa B. Lukban and Aida R. Mendoza-Salonga, University of the Philippines College of Medicine, Manila, Philippines; Anthony G. Marson, University of Liverpool, Liverpool, U.K.; Brian Neville, Institute of Child Health, London, U.K.; Harry O. Nomayo, Klinikum Weiden Kinderklinik, Weiden, Germany; Hirokazu Oguni. Tokyo Women's Medical University, Tokyo, Japan; Shunsuke Ohtahara, Okayama University Medical School, Okayama, Japan; Hian-Tat Ong, National University Hospital, Singapore; Desiderio Pozo Lauzan, William Soler Children's Hospital, Havana, Cuba; Dietz Rating, University of Heidelberg, Heidelberg, Germany; Bernhard Schmitt, University Children's Hospital, Zurich, Switzerland; Malinee A. Thambyayah, Hospital Selayang, Kuala Lumpur, Malaysia; Federico Vigevano, Ospedale Pediatrico Bambinu Gesu, Rome, Italy; Anannit Visudtibhan, Mahidol University, Bangkok, Thailand; William Whitehouse, University of Nottingham, Nottingham, U.K.; Virginia Wong, The University of Hong Kong, Hong Kong SAR, China; Hideo Yamanouchi Dokkyo University School of Medicine, Tochigi, Japan; Chainllie Young, Washington University School of Medicine, St. Louis, Mo, U.S.A.; and Zhongshou Zhou, China-Japan Friendship Hospital, Beijing, China.

Address correspondence and reprint requests to Dr. J.P. Osborne at Bath Unit for Research in Paediatrics, Royal United Hospital, Combe Park, Bath, BA1 3NG, U.K. E-mail: mpsjpo@bath.ac.uk


Summary: Purpose: To reach a broad consensus on case definitions, outcomes, and outcome measures that will ease future study design and facilitate comparison of data from different studies of infantile spasms and West syndrome.

Methods: Persons who had recently presented or published first-author original research in this field were invited to participate in an e-mail Delphi process and to invite other investigators or clinicians who they thought might participate.

Results: The process consisted of six rounds, anonymous except to the facilitator. In total, responses were received from 46 participants. The final statement was approved by 31 participants from 15 countries. It concluded that the primary clinical outcome, cessation of spasms, should denote absence of witnessed spasms from within 14 days of commencement of treatment, and for ≥28 consecutive days from the last witnessed spasm. Primary electroclinical outcome denotes cessation of spasms with resolution of hypsarrhythmia. West syndrome should be a defined subset of the syndrome of infantile spasms. An infantile spasms single-spasm variant should be recognized. Ways are suggested of handling subtle spasms in the context of clinical studies. It proposes a standard for reporting modifying and atypical features of hypsarrhythmia, a minimal set of baseline characteristics and outcomes that should be reported in trials of infantile spasms, and suggests a standard definition of relapse. Consensus was not reached on a definition of hypsarrhythmia.

Conclusions: We reached a clear consensus on many aspects of study design for the investigation of infantile spasms, although incomplete consensus was found on how to define EEG criteria.