Fractionation

The ability to move individual fingers independently of one another, a key measure of fine motor control assessed in stroke rehabilitation. After a stroke, patients often lose fractionation, meaning that attempting to move one finger causes involuntary coupled movement in adjacent fingers. Fractionation is quantified by comparing the range of motion of the target finger to the unintended movement of other fingers — higher fractionation scores indicate greater independence of finger movement. Restoring fractionation is essential for functional hand use in activities of daily living such as typing, buttoning clothing, and manipulating small objects.