Chronological age versus developmental age in evaluating patients' performances on motion perception tests

In neuropsychological assessments, a patient’s raw score is frequently compared to a large general population normative sample. It is common to use the chronological age as entry of norm tables to assess a patient’s current cognitive function. In individual patients with a developmental delay or cognitive impairment, this may result in misinterpretation of performance. The aim of this study was to test the impact of chronological and developmental age parameters on motion perception outcomes and to construct and evaluate normal motion perception limits for clinical practice. In the present study, the developmental age and four aspects of motion perception (biological motion, global motion, motion speed, motion-defined form) were assessed in 49 children with indications of brain damage and in 60 controls. Based on current results, we present the preliminary normal limits and we suggest the use the developmental age as entry of norm tables.