Development of a cognitive function assessment tool based on psychomotor function tests in patients with schizophrenia

Background: Cognitive dysfunction has a significant impact on social functioning, such as employment, in patients with schizophrenia. However, existing cognitive assessments are time-consuming, impose a significant burden on patients, and require specialized training for evaluators, making them impractical for routine clinical use. Therefore, the present study investigated whether a simple and novel assessment tool, called Psychomotor Function Tests (PFT), correlates with existing Neuropsychological Tests (NT) and assessments with the Life Assessment Scale for the Mentally Ill (LASMI), which evaluates social functioning, including employment. Methods: Cognitive function was examined in 24 patients with schizophrenia using NT (the Japanese Adult Reading Test, Trail Making Test (TMT), and word fluency test) and tablet-based PFT, while social functioning was evaluated using LASMI. Twenty-four healthy controls (HCs) underwent the same cognitive assessments. Results: Psychomotor function, as evaluated by the choice reaction time, compensatory tracking test, and rapid visual information processing, was significantly worse in patients with schizophrenia than in HCs (p < 0.001). Furthermore, the composite score of PFT correlated with the time required for TMT (r = −0.707, −0.637) and LASMI subscales related to work, endurance & stability, self-recognition, required skills, and retention skills (r = −0.640, −0.689, −0.634, −0.420, −0.548). Conclusion: PFT correlated with existing NT, which are widely used in cognitive function assessments. Cognitive function examined by PFT was closely associated with social functioning. These results suggest the potential of PFT for evaluating cognitive function in routine clinical settings for patients with schizophrenia.