[The Impact of Visual Perceptual Abilities on the Performance on the Wechsler Nonverbal Scale of Ability (WNV)].

BACKGROUND: The use of psychometric tests in with children and adolescents is especially important in psychological diagnostics. Nonverbal intelligence tests are very often used to diagnose psychological abnormalities and generate developmental prognosis independent of the child´s verbal abilities.

METHODS: The correlation of the German version of the Developmental Test of Visual Perception - Adolescents and Adults (DTVP-A) with the Wechsler Nonverbal Scala of Abilities (WNV) was calculated based on the results of 172 children, adolescents and young adults aged 9-21 years. Furthermore, it was examined if individuals with poor visual perceptual abilities scored lower on the WNV than healthy subjects.

RESULTS: The correlations of the results scored on DTVP-A and WNV ranged from moderate to strong. The group with poor visual perceptual abilities scored significantly lower on the WNV than the control group.

CONCLUSIONS: Nonverbal intelligence tests like the WNV are not reliable for estimating the intelligence of individuals with low visual perceptual abilities. Therefore, the intelligence of these subjects should be tested with a test that also contains verbal subtests. If poor visual perceptual abilities are suspected, then they should be tested. The DTVP-A seems to be the right instrument for achieving this goal.