95 Handedness as a Consideration for Computerized Neuromotor Performance Testing
Authors: Kohnen Sarah L. , Saganis Xanthia , Kondraske George , Goreczny Anthony J. , Nussbaum Paul 
Published: December 2023

Objective:The COVID-19 pandemic created barriers to healthcare that necessitated changes in services to meet needs of individuals. With these changes, technological advances in computerized cognitive testing became critical. As researchers and clinicians accelerated adaptation of computerized testing formats, considerations for development and interpretation of such tools have proved imperative. One such computerized tool, RC21X, utilizes performance measurement software comprising 15 modules to evaluate an individual’s processing speed, memory, executive functions, and neuromotor coordination. Although initial data has revealed strong psychometric properties (Saganis et al., 2020), a need to explore various attributes of this web-based tool has emerged. The current study examined impact of dominant handedness on an RC21X neuromotor task.Participants and Methods:The sample consisted of 602 participants: 553 (91.86%) were right-hand dominant and 49 (8.14%) were left-hand dominant. Of participants who identified their sex, 81.2% were male, 18.3% were female; 0.5% chose not to identify. Age ranged from 7-95 years (M = 41.21, SD = 18.81). This study focused on the RC21X Eye-Hand Coordination subtest. Using a Fitts’ Law paradigm, the module provided instruction for participants to alternately press the “A” and “L” keys on a keyboard as quickly and accurately as possible using only one upper extremity (UE) at a time (tested separately for right then left UE). We computed a one-way between groups multivariate analysis of variance (MANOVA) to investigate handedness differences on task performance. Dependent variables were individuals’ performances on right- and left-UE tasks; the independent variable was dominant handedness. We conducted preliminary assumption testing with no serious violations noted. We also separated the sample by dominant handedness to compare right versus left-hand performance using paired samples t-tests within each group. There were no significant differences between the two groups on either age or sex.Results:There was a statistically significant difference between right-hand dominant and left-hand dominant participants on the dependent variables, F (2, 599) = 8.84, p < .001, Wilks’ Lambda = .971. Mean scores indicated that right-hand dominant participants (M = 52.87, SD = 20.42) outperformed their left-hand dominant counterparts (M = 46.30, SD = 12.79) when using their right UE, though both groups performed similarly when using their left UE (right-hand dominant M = 48.55, SD = 17.81; left-hand dominant M = 49.70, SD = 14.13). These findings were present despite expected results from paired samples t-tests that revealed individuals performed best with their dominant hand.Conclusions:Results revealed that handedness is necessary to consider in design and utilization of computerized neuropsychological tests. The large proportion of right-hand dominant individuals may have affected our results; however, our sample is representative of handedness distribution in the general population. Although our paired samples t-tests support validity of RC21X, continued investigation of computerized performance measurement tools is necessary. Future research must explore the possibility of an ordering effect (i.e., right-handed participants starting with their dominant UE, but left-handed participants starting with their nondominant UE) or due to construction of everyday items (e.g., computer keyboards) primarily for right-hand dominant people.