title: The development of a scale of the Guttman type for the assessment of mobility disability in multiple sclerosis.
abstract: OBJECTIVE
  To develop a valid and reliable scale of the Guttman type for the assessment of mobility disability in multiple sclerosis (MS).
  
  
  METHODS
  Sixty-eight subjects with a definite diagnosis of MS participated. They were living in the community and attending as outpatients at a MS unit at a District General Hospital. Thirty had the primary progressive pattern of disease, and 38 had the relapsing-remitting pattern.
  
  
  METHODS
  Formal assessments used for neurological disability were inspected, and 14 test items of gross motor function were extracted and ordered according to criteria. These were that tests required trunk control and did not require isolated movement at a single limb or body segment, that actions progressed from lying, to sitting, to standing and walking tasks, proceeding from broader to narrower bases of support. All subjects carried out all test items which were scored as 'pass' or 'fail'.
  
  
  METHODS
  Data were tested for internal consistency, reliability, inter-item correlation, reproducibility and scalability. On the basis of the results, the items were reordered in rank, and reduced to 11 tests. The 11-item scale was reanalysed.
  
  
  RESULTS
  Results showed that the scale had an internal consistency of 0.88 (alpha coefficient) and a coefficient of reproducibility (CR) of 0.95 and above for both MS subject groups. The coefficient of scalability (CS) for items was 0.78 for primary progressive subjects and 0.74 for the relapsing-remitting group. Reliability ranged from moderate (kappa = 0.49) for one item, to perfect for six items.
  
  
  CONCLUSIONS
  The scale was demonstrated to be a hierarchical scale of the Guttman type exhibiting homogeneity and good reliability. The high CR indicated that scores may be summed, and the very acceptable levels of CS indicated that the cumulative scores are meaningful within the defined concept of hierarchy used in this study.
authors.affiliation: Centre for Research in Rehabilitation, Department of Health Studies, Brunel University, Isleworth, Middlesex, UK. Lorraine.desouza@brunel.ac.uk
authors.forename: L H
authors.initials: LH
authors.lastname: De Souza
mesh_terms: D001696:Biomechanical Phenomena; D004185:Disability Evaluation; D006304:Health Status; D006801:Humans; D009068:Movement / Q000502:physiology; D020528:Multiple Sclerosis, Chronic Progressive / Q000175:diagnosis / Q000503:physiopathology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis / Q000503:physiopathology*; D009460:Neurologic Examination; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D016138:Walking / Q000502:physiology