Assessing Cognitive Test Performance Using Automatic Digital Pen Features Analysis

Abstract

Most cognitive assessments, for dementia screening for example, are conducted with a pen on normal paper. We record these tests with a digital pen as part of a new interactive cognitive assessment tool with automatic analysis of pen input. The clinician can, first, observe the sketching process in real-time on a mobile tablet, e.g., in telemedicine settings or to follow Covid-19 distancing regulations. Second, the results of an automatic test analysis are presented to the clinician in real-time, thereby reducing manual scoring effort and producing objective reports. The presented research describes the architecture of our cognitive assessment tool and examines how accurately different machine learning (ML) models can automatically score cognitive tests, without a semantic content analysis. Our system uses a set of more than 170 pen features, calculated directly from the raw digital pen signal. We evaluate our system with 40 subjects from a geriatrics daycare clinic. Using standard ML techniques our feature set outperforms previous approaches on the cognitive tests we consider, i.e., the Clock Drawing, the Rey-Osterrieth Complex Figure, and the Trail Making Test, by automatically scoring tests with up to 82% accuracy in a binary classification task.