Assessment of mental chronometry (MC) in healthy subjects

Objective: This study examined the temporal congruency between real and imagined movements and explored intermanual transfer effects in healthy subjects. Methods: Seventy-six right-handed healthy subjects were allocated to three age groups and tested with a modified version of the Box and Block Test (BBT). We focussed on two aspects. First, the BBT was evaluated with respect to its ability to assess MC. Second, we were interested whether performance of motor imagery (MI) and real execution with one hand would modify performance with the other hand. To explore MC, we measured motor execution (ME) time as the time needed to perform the BBT, and MC time as the time difference between ME and the time needed for imagination of task execution. The BBT was performed with both hands consecutively to study transfer effects from one hand to the other and then repeated with the first hand for practice effects. Results: The age group with the oldest subjects exhibited a slower BBT performance and a less precise MC than the other 2 age groups. Irrespective of the age, MC abilities could be transferred to the other hand, whereas ME only improved when repeating the task with the same hand. Conclusions: The BBT was able to demonstrate an age-related decline of dexterity and MC. Intermanual transfer of MI abilities occurred even after a single run.