The iTrail making test (iTMT): an evaluation of novel testing paradigms, hidden indices of measurement, and diagnostic accuracy in Parkinson’s disease

Introduction: The Trail Making Test (TMT) is an important test when assessing for cognitive difficulties in people with Parkinson’s Disease (PD). However, the pencil-and-paper format can be susceptible to administration and scoring errors and may disproportionately reflect motor impairments rather than cognitive performance. The current study sought to evaluate the reliability and diagnostic accuracy of two novel computerized versions of the TMT: iTMT-Tap and iTMT-Drag. Method: This study used a quasi-experimental diagnostic accuracy design, and included 34 healthy controls, 28 people with Parkinson’s disease with normal cognition (PD-NC), and 31 people with Parkinson’s disease mild cognitive impairment (PD-MCI). Participants were administered a short battery of cognitive tests, including three counterbalanced versions of the TMT (traditional TMT, iTMT-Tap & iTMT-Drag). Additionally, the iTMT-Tap and iTMT-Drag were readministered following a brief break. Results: Both the iTMT-Tap and iTMT-Drag demonstrated adequate convergent validity and retest reliability and achieved acceptable classification accuracy for identifying PD-MCI. The current study identified hidden indices of measurement which may minimize administration time or the confounding impact of motor functioning, and these indices achieved fair diagnostic accuracy also. Conclusion: The results of this research suggest that the iTMT-Tap and iTMT-Drag may be a valid substitute for the traditional TMT, and subject to further validation, could be a useful addition to clinical practice. Recommendations for future research and subsequent clinical deployment are discussed.