Abstract
Aims: The Bicycle Drawing Test (BDT) is used in neuropsychological assessment to evaluate visuospatial and executive functions. Administration and scoring are short and simple.
The aim of this project was to examine psychometric properties of the BDT (reliability, validity) and the effect of demographic characteristics and to present results of healthy older adults. A secondary aim was to compare two different scoring systems.
Methods: We evaluated 111 drawings of cognitively healthy adults aged over 60 (age M = 74.4 years, SD = 7.8; education M = 13.5 years, SD = 3.6) and 57 drawings of patients with cognitive deficit (age M = 75.6 years, SD = 7.3; education M = 13.8 years, SD = 3.3). The group with cognitive deficit included patients with mild cognitive impairment, dementia due to Alzheimer's disease, and other dementias.
All subjects completed a detailed neuropsychological battery. Drawings were scored according to Lezak's and Greenberg's systems.
Results: We present values for inter-rater reliability, item-total correlation and internal consistency. Scores were not influenced by age or education but differed by gender.
Convergent and divergent validity analysis showed correlation with measures of visuospatial and executive functions and with global cognitive functioning, and lack of correlation with memory or language measures. We found satisfactory discriminative power of BDT for detection of dementia but not for MCI.
Conclusions: Psychometric properties of BDT substantiate its use in clinical practice for evaluation of visuospatial functions and global cognition level. Presented values for transformation of raw scores into standard scores allow clinicians to work with quantitative rating of results.