title: Repeatability of the Visual Manipulation Test.
abstract: BACKGROUND
  The Getman-Henderson-Marcus Visual Manipulation Test (VMT) is a commonly used test of visualization with an objective scoring procedure. However, its repeatability has not been studied.
  
  
  OBJECTIVE
  The purpose of this investigation was to assess the repeatability of the VMT in children in the second through fourth grades.
  
  
  METHODS
  The VMT was administered to the children (n = 193; mean age, 8.72 years) from a middle class elementary school near Columbus, Ohio. One class from each grade (n = 56) was retested by the same optometrist within 1 month. Repeatability analysis included plotting the difference vs. the mean of the scores obtained at the initial test and retest.
  
  
  RESULTS
  All the children were able to complete the test. Means and SD's were found to be 5.23+/-1.98 for second graders, 5.76+/-2.10 for third graders, and 6.95+/-2.30 for fourth graders. The mean difference between test and retest scores was close to zero. The 95% limits of agreement were found to be -4.5 to 5.2.
  
  
  CONCLUSIONS
  No consistent learning effect seemed to be present upon retest. However, analysis revealed poor repeatability for the VMT. Therefore, the VMT should not be used to monitor progress with therapy.
authors.affiliation: The Ohio State University College of Optometry, Columbus 43210, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Kulp
authors.forename: K
authors.initials: K
authors.lastname: Edwards
mesh_terms: D002648:Child; D006801:Humans; D015588:Observer Variation; D009820:Ohio; D015203:Reproducibility of Results; D013997:Time Factors; D014787:Vision Tests / Q000379:methods*; D014796:Visual Perception