To investigate the diagnostic accuracy of the overlapping infinity loops, wire cube, clock drawing tests (CDT) and the combined score in the detection of mild cognitive impairment (MCI) and dementia.

The participants were 60 normal controls (NC), 35 patients with MCI, and 47 patients with dementia. For the overlapping infinity loops and wire cube tests, the participants were told to copy the figures from the examples. For the CDT, the participants were asked to draw a clock face with numbers on it with the hands at ten past five.

The results illustrate that infinity loops, cube, or CDT alone, or combined score, were not able to discriminate between NC and MCI groups. In dementia detection, the CDT had the highest diagnostic accuracy (sensitivity 76.6% and specificity 87.4%) followed by infinity loops (sensitivity 83.7% and specificity 78.9%) and cube (sensitivity 93.6% and specificity 46.3%). Additionally, when the three tests were combined, better diagnostic accuracy was demonstrated with a sensitivity of 87.2% and specificity 86.3%.

This study demonstrates that the three drawing tests are sensitive detectors of dementia but not MCI. The combination of these three drawing tests is a brief tool of good diagnostic accuracy for dementia screening.