A-110: Examining Error Rates on Tests of Executive Function in Parkinson’s Disease and Essential Tremor

Abstract

Objective: Executive dysfunction is common in persons with Parkinson’s disease (pwPD) and essential tremor (pwET), often assessed using task completion time (e.g., Trail Making Test). Far fewer studies have examined error rate or type in these populations. We compared both speed and accuracy on executive function measures in pwPD and pwET. Method/Data Selection: 80 pwPD (Mage=70.0, SD=6.9), 15 pwET (Mage=70.9, SD=6.5), and 40 cognitively unimpaired older adults (CU; Mage=65.8, SD=8.3), 97.8% White completed the TMT and D-KEFS Color-Word Interference Test (CWIT) as part of comprehensive clinical neuropsychological evaluation. Group differences in completion times, total errors, and CWIT error types were examined using parametric and non-parametric tests. Results/Data Synthesis: Controlling for age, pwPD and pwET took longer to complete both TMT Parts A (p<.001) and B (p=.003), CWIT color naming (p=.01), word reading (p=.028), inhibition (p=.002). More TMT-B errors were made by pwPD than CU (p = .002), though no other group effects or TMT group differences emerged. On CWIT Inhibition, pwPD made more total errors than pwET (p=.025), but no other group effects emerged. However, pwPD made more self-corrected errors than pwET (p=.031) and CU (p =.036). There were no main or interaction effects involving sex on any variable. Conclusions: Despite slow completion time across measures in both pwPD and pwET, and similar error rates on TMT-B in these two groups, only pwPD showed elevated error rate (self-corrected but not uncorrected) on CWIT inhibition. Thus, examining error rates/types can reveal different profiles of executive dysfunction in PD and ET, though this may depend on the measure employed.