Visuo-constructional functions in patients with mild cognitive impairment, Alzheimer's disease, and Parkinson's disease.

Background: Several recently proposed criteria for assessing cognitive disorder require measuring the cognitive domain of visuo-constructional function. The aims of the present study were to develop a new test (Vienna Visuo-constructional Test-VVT) measuring visuo-constructional functions and to determine the reliability and validity of the VVT in patients with mild cognitive impairment (MCI), Parkinson's disease (PD), and Alzheimer's disease (AD). We further examined age and sex effects and the psychometric quality of the VVT.