Altered regularity and stability of multi-finger force production in individuals with mild cognitive impairment.

While previous studies have identified motor dysfunction in individuals with Mild Cognitive Impairment (MCI), the experimental tasks investigated to date have remained relatively limited. This study compared multi-finger force production in individuals with MCI and healthy controls (HC), employing a task designed to comprehensively reflect the complexities of neural integrity. Participants were instructed to match a target force using the net force of five fingers with real-time visual feedback, while individual finger forces were also measured. The analyses were conducted at two levels: net force level and individual finger force level. In addition, linear and non-linear approaches were utilized to examine spatial and temporal structures. At the net force level, the MCI group exhibited diminished accuracy (RMSE), increased fluctuation (CV), and lower adaptability (SampEn) in force patterns. Furthermore, the MCI group demonstrated significantly lower spatial (ΔVZ) and temporal stability (MLE) at individual finger level. These findings suggest that multi-finger tasks may reflect subclinical motor alterations associated with cognitive decline. Consequently, this research offers a valuable evidence-base for the potential development of non-invasive behavioral markers for MCI screening.