The Functional Dexterity Test in Adult Populations: An Exploration of a Simplified Test Protocol and Parameters Guided by Statistical Outcomes

Abstract

The Functional Dexterity Test (FDT) is a standardized assessment used to quantify dexterity, in-hand manipulation, related to function. Recommendations to modify the scoring have been proposed to eliminate penalties, adapt the test protocol, and change the outcome parameter. A new psychometrically sound scoring system has been used in the pediatric population; however, research in the adult population requires exploration. The purpose of this study was to test if alterations in test administration, outcome recording, and outcome parameters show predictive validity for measured outcomes for age, ethnicity, and self-identified gender. The new method of administering the FDT eliminates penalties for improper performance and uses a score of speed derived from the timed score. It was theorized that eliminating assessment of reported errors in quality of movement in the quantitative scoring may improve the test validity. Clinical Measurement. The FDT was administered to 148 healthy adults aged between 18 and 78years. No penalties were included in the quantitative scoring. Age, self-identified gender, ethnicity, and self-reported hand dominance were recorded. Time to complete the test was measured in seconds per usual protocol. The result was recorded as time and calculated as speed. Linear regression was performed to predict FDT speed from age, hand dominance, and self-identified gender. The three predictors (age, hand dominance, and gender) associated with a linear decline in dexterity were significant (p ≤0.02). Dexterity showed a linear decline with age, and participants showed faster speeds with the dominant hand. Gender was a significant predictor of speed, with males having faster speeds by an average of 0.047 pegs per second (p=0.01). Scores using a simplified administration and speed as an outcome showed moderate predictive validity with age, gender, and the dominant hand used in this adult population. Future research exploring relationships with activities of daily living is needed.