Cognitive, Motor and Oculomotor Contributions to the Trail Making Test in Progressive Supranuclear Palsy.

BACKGROUND

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by motor, oculomotor and cognitive impairments. Yet disentangling cognitive deficits from motor and oculomotor dysfunction remains a diagnostic and methodological challenge.

OBJECTIVES

This study aims to evaluate how cognitive, motor, and oculomotor impairments contribute to performance in the Trail Making Test (TMT) in PSP patients.

METHODS

Eighty-one patients with PSP-Richardson's syndrome underwent the Toronto Cognitive Assessment, the Movement Disorder Society Unified Parkinson's Disease Rating Scale-part III and the PSP rating scale. Structural equation modeling was used to examine associations between TMT performance, cognitive function, and motor/oculomotor measures derived from these assessments.

RESULTS

TMT performance was mainly driven by cognitive factors, particularly executive function, with no significant influence from motor or oculomotor deficits.

CONCLUSIONS

These findings suggest that the TMT is a valuable tool for assessing cognitive impairment in PSP, reflecting fronto-striatal (associative loop) dysfunction rather than motor or oculomotor impairments.