Construct validity of the Knox Cube Test as a neuropsychological measure

The Knox Cube Test is used in conjunction with some neuropsychological test batteries as a measure of visual attention and memory, but no data are available regarding the validity of this measure in a neuropsychological context. The present investigation examined the construct validity of the Knox Cube Test as a measure of attention span, and also as a neuropsychological instrument. Two independent samples were administered a battery of tests including the Knox Cube Test. The test was found to be strongly related to most of the measures, and in both samples the highest correlations were found with digit span backwards, Trail Making Test and Speech Perception Test. Factor analysis in the two samples revealed that the highest loadings for the Knox Cube Test were observed on a factor interpreted as measuring attention and concentration. These findings were discussed in regard to the validity of the Knox Cube Test, and its potential use in clinical neuropsychological examination.