Gross Motor Function Measure (GMFM-66 & GMFM-88) User's Manual, 2nd edition, by D. J. Russell, P. L. Rosenbaum, M. Wright, and L. M. Avery. Clinics in Developmental Medicine. London, England: Mac Keith Press; 2013, spiral-bound, 304 pages, ISBN: 978-1-908316-88-2, US $115.00.
The Gross Motor Function Measure (GMFM) is a widely used evaluative measure designed and validated to quantify change in gross motor function of children with cerebral palsy (CP). The second edition of the GMFM User's Manual is completely revised and includes the following new information: (1) updated psychometric properties of the original 88-item measure (GMFM-88) and the 66-item measure (GMFM-66), (2) the development and validation of 2 shorter alternatives of estimating GMFM-66 scores using the GMFM-66 item set approach (GMFM-66-IS) and the GMFM-66 basal-ceiling approach (GMFM-66-B&C), (3) a tutorial on the newly revised Gross Motor Ability Estimator–2 (GMAE-2) computerized data management and scoring program, (4) new case illustrations of the application and interpretation of the GMFM in clinical practice, and (5) research directions and future applications using the GMFM. The book contains a preface and acknowledgments for the first and second editions, 8 chapters, references, glossary of terms, 13 appendices, and an index.
Chapter 1: Overview of the Gross Motor Function Measure (GMFM) provides a clear, concise, 3-page summary of the GMFM in bullet form. It provides general information about the GMFM, recommendations regarding the use of the 4 GMFM approaches (GMFM-88, GMFM-66, GMFM-66-IS, and GMFM-66-B&C), and administration guidelines in terms of appropriate populations, time required, testing environment, equipment needed, examiner qualifications, and scoring.
Chapter 2: Conceptual Background provides general information on issues related to measuring gross motor function in children with CP. Topics include CP, measuring gross motor function, issues in measurement, purposes of measurement, characteristics of an evaluative measure, norm-referenced versus criterion-referenced tests, levels of measurement scale, Rasch analysis, and validation of an evaluative measure in terms of validity, responsiveness, and reliability.
Chapter 3: Development and Validation of the GMFM-88 describes the development and validation of the original 85- and 88-item versions of the GMFM. More recent evidence that supports the reliability, validity, and responsiveness for the GMFM-88 in children with CP is included. In addition, a short summary is included on the reliability, validity, and/or responsiveness of the GMFM-88 for children with various diagnoses, including traumatic brain injury, Down syndrome, acute lymphoblastic leukemia, spinal muscular atrophy, and osteogenesis imperfecta.
Chapter 4: Development and Validation of the GMFM-66 begins with a description of the limitations of the GMFM-88, which led to the development of the GMFM-66. It provides a concise yet thorough description of Rasch analysis, which was used to convert the GMFM-88 (an ordinal scale measure) to the GMFM-66 (an interval scale measure). The evidence for reliability, validity, and responsiveness of the GMFM-66 is described. Further information on item maps derived from Rasch analysis is provided in Appendices 1 and 2.
Chapter 5: GMFM-66: Two Short Forms of Administration describes the rationale, development, and validity of 2 shorter alternatives for testing and deriving the GMFM-66 scores: the GMFM-66-IS and GMFM-66 B&C. The GMFM-66 Item Set Score Sheet is available in Appendix 5. The GMFM-66 Basal & Ceiling Score Sheet is available in Appendix 6. The chapter concludes with a set of considerations that must be taken into account when determining whether to administer the GMFM-66 or an alternative short form (GMFM-66-IS, GMFM-66-B&C).
Chapter 6: Administration and Scoring Guidelines for the GMFM-88 and GMFM-66 is divided into 2 parts. Part 1 provides technical information on administration guidelines including the necessary equipment, appropriate testing environment, acceptable methods to engage a child during the assessment, and issues in interpreting specific aspects of a child's performance. Specific guidelines are also provided for testing children with Down syndrome and testing children with CP who are wearing orthotics and/or shoes or using a mobility aid. Part 2 describes each test item in detail. Appendix 8 includes GMFM-88 and GMFM-66 score sheets. Appendix 3 provides a tutorial on the newly revised GMAE-2 computerized scoring program used to score the GMFM-66 and its alternative short forms. Appendix 10 defines the standard error of measurement of the score computed by the GMAE-2.
Chapter 7: Interpretation and Uses of the GMFM-88 and GMFM-66 describes the appropriate uses of the GMFM-88, GMFM-66, GMFM-66-IS, and GMFM-66-B&C by referencing a case scenario to highlight the issues involved in the administration and interpretation of the 4 different approaches to assess gross motor function in children and adolescents with CP. Appendix 9 provides GMFM-66 and GMFM-88 tabulated centiles (cross-sectional and change scores) used to compare an individual child's score on the GMFM with scores from other children with CP at similar ages and Gross Motor Function Classification System (GMFCS) levels. Appendix 7 includes the GMFCS-E&R (expanded and revised). Appendix 13 includes a set of 5 reference curves that depict the average pattern of change in GMFM-66 scores from 2 to 12 years of age for each GMFCS level. Further examples of how to score and interpret the GMFM are included in Appendices 4, 11, and 12.
Chapter 8: Applications of the GMFM: What Have We Learned and Where Can We Go Next? describes current research directions and future applications using the GMFM. The chapter begins with a summary of previous research focused on identifying patterns of gross motor development of children and adolescents with CP including classifying the severity of CP using the GMFCS-E&R, creation of the GMFM-66 and its 2 alternative short forms, and tracking gross motor development prospectively using the GMFM tabulated centiles and reference curves. Ongoing research is then described, which focuses on the development of tools to assess change in quality of movement (Quality Function Measure) and assess the performance of higher-order tasks for children and adolescents with CP at GMFCS Level I (Challenge Module). The chapter concludes with future research directions to gain a more thorough understanding of the motor development trajectories of children with CP, for example, at the extremes of childhood and of children with different topographical classifications but similar ages and GMFCS levels.
Gross Motor Function Measure (GMFM-66 & GMFM-88) User's Manual, 2nd edition, provides updated information on the GMFM. Many items required to administer and score the GMFM are freely available at the Web site www.canchild.ca, including the GMFM scoring forms, GMFCS-E&R, GMAE-2 scoring software program, and motor growth curves. However, physical therapists and researchers who use the GMFM will find the User's Manual a valuable resource to administer and interpret the GMFM appropriately in clinical practice and research. The new case illustrations are particularly useful in selecting the most appropriate approach (GMFM-88, GMFM-66, GMFM-66-IS, and GMFM-66-B&C), administering the GMFM in a standardized manner, scoring the GMFM using the new GMAE-2, and interpreting the results using the GMFM tabulated centiles and reference curves.
Barbara Sargent, PT, PhD, PCS
University of Southern California, Los Angeles