Explainable Automatic Evaluation of the Trail Making Test for Dementia Screening

The Trail Making Test (TMT) is a frequently used neuropsychological test for assessing cognitive performance. The subject connects a sequence of numbered nodes by using a pen on normal paper. We present an automatic cognitive assessment tool that analyzes samples of the TMT which we record using a digital pen. This enables us to analyze digital pen features that are difficult or impossible to evaluate manually. Our system automatically measures several pen features, including the completion time which is the main performance indicator used by clinicians to score the TMT in practice. In addition, our system provides a structured report of the analysis of the test, for example indicating missed or erroneously connected nodes, thereby offering more objective, transparent and explainable results to the clinician. We evaluate our system with 40 elderly subjects from a geriatrics daycare clinic of a large hospital.