Randomized crossover trial consisting of two test visits separated by a washout period of 3 to 5 weeks. Subjects are randomized into two equal groups. Group 1 receives the digital pen (DCTclock-pen) version of the test at the first visit, with the tablet version (DCTclock-tablet) given at the second visit; Group 2 receives DCTclock-tablet at the first visit, followed by DCTclock-pen at the second visit. At Visit 1 (day 0), eligibility is assessed and a version of the DCTclock test is administered based on the group allocation. A battery of Linus Platform tests and reference standard tests are also administered. At visit 2 (day 21-35), eligibility is assessed and the alternate version of the DCTclock test is administered based on the group allocation. A battery of Linus Platform tests is also administered, together with reference standard tests. Equivalence of DCTclock-pen and DCTclock-tablet will be tested. Linus Platform test data will also be collected to develop novel measures of cognitive and motor function and assess their accuracy in detecting impairment, construct validity, and test-retest reliability.
