Title: Dual Task Performance and Prioritization in Parkinson’s Disease and Healthy Elderly Individuals
Description: Background. The Clinch Token Transfer Test (C3t) is a seated assessment combining a bimanual coin transfer and manipulation task with a secondary cognitive task under three levels of complexity. Aims. The six aims of this study were to determine if: 1 & 2) the C3t was a reliable and valid measure of manual dexterity and dual task ability in PwPD; 3 & 6) C3t performance or movement component parameters differed between healthy controls and PwPD and were sensitive to disease severity; 4) baseline assessments were predictors of C3t performance, and 5) DT prioritization differed between the C3t and Timed Up & Go tests. Methods. Thirty-nine participants were selected and placed into three groups: 1) mild PD (Hoehn & Yahr (H&Y)=I) (n=13); 2) mod PD (H&Y=II or III) (n=13); 3) healthy controls (HC) who were age, gender and education matched to mild PD (n=13). During session 1 participants completed a battery of cognitive and motor assessments including the C3t and TUG. PwPD returned for a second C3t assessment.

Results. The C3t demonstrated good test re-test reliability for baseline and complex but poor reliability for DT conditions; construct validity as a manual dexterity measure was established with the 9-Hole Peg Test. Significant C3t performance differences were seen between: 1) mod PD and HC on all task conditions; and 3) between mild and mod PD on baseline and complex conditions. Regression analysis indicated hand dexterity and Stroop tests were performance predictors on the less complex C3t tasks. Task prioritization patterns differed between the C3t and TUG dual task conditions. On the C3t, PwPD and HC demonstrated a prioritization pattern of mutual interference while demonstrating varied patterns of cost/benefit on the DT TUG. Movement component analysis revealed time differences in four components between mod PD and HC. Conclusions. The C3t is a reliable and valid manual-dexterity assessment in PwPD. All C3t task scores differentiated between PwPD and HC. Baseline and complex scores were sensitive to disease severity, differentiating between mild PD and mod PD.

The C3t DT condition was not found to be reliable requiring further development and additional evaluation prior to implementation.