Psychometric Properties of the Digital Trail Making Test and Symbol Digit Modalities Test among People with Post-COVID-19 Conditions and Healthy Controls: Implications for Pilot Screening and Flight Safety

Introduction : Post-acute COVID-19 neurocognitive impairments in attention and executive function threaten flight safety, making early detection in pilots essential for timely interventions and adjustments in work duties. The digital versions of the Trail Making Part A and B (TMT-A/B) and the Symbol Digit Coding version of the Symbol Digit Modalities Test (SDMT) are potential screening tools. However, their effectiveness in identifying post-COVID-19 cognitive deficits requires further investigation. This study, therefore, aimed to evaluate the psychometric properties of these tests in individuals with post-COVID-19 conditions versus healthy controls. Methods : This study included 48 individuals living with post-COVID-19 conditions and 23 healthy controls, aged 18–65 years. Statistical analyses, such as the Shapiro-Wilk test, Mann-Whitney U test, Spearman’s rank correlation, multiple regression, and the area under the receiver operating characteristic curve (AUC), were performed. Results : Mann-Whitney U tests revealed significant differences between cases and controls on all tests (p<0.001). TMT-B and SDMT had a large effect size, r=-0.59 and r=0.53, respectively, and TMT-A had a medium effect size (r=-0.45). TMT-B showed the highest discriminative power (AUC=0.85, p<0.001), followed by SDMT (AUC=0.81, p<0.001), and TMT-A (AUC=0.76, p=0.01), which is crucial to detect subtle but safety significant post-COVID-19 neurocognitive impairments. Conclusions : The digital version of TMT-B therefore provides a way of selecting likely impaired pilots for further comprehensive neuropsychological evaluation, alongside other medical and operational checks. Furthermore, it is a quick, suitable, and reasonably practicable test for neurocognitive assessment in routine pilot aeromedical examinations. A large-scale study is warranted to establish an aircrew-specific normative dataset.