Dynamic or not, here I come: Ambulatory assessment of psychomotor ability for clinical predictions

Neurological Soft Signs (NSS) are subtle neurological abnormalities prevalent in various psychopathologies. Mobile technologies offer a scalable and ecologically valid method for NSS assessment, potentially capturing momentary fluctuations influenced by affective states. This study aimed to examine whether momentary changes in negative affect influence NSS, as measured by mobile diadochokinetic (DDK) tasks, in both clinical and nonclinical populations.

A total of 25 patients meeting criteria for serious mental illness (SMI) and 65 nonpatients participated. Participants completed oral DDK tasks-alternating motion rate (AMR) and sequential motion rate (SMR)-using a mobile application over five days (patients) or three days (nonpatients). State negative affect and clinical symptoms were also assessed. Multilevel modeling evaluated the effects of state negative affect, clinical symptoms, and their interaction on DDK performance.

Psychomotor performance was reliably assessed in natural environments with minimal practice effects. Clinical symptoms alone did not predict DDK performance. Higher state negative affect was associated with poorer SMR performance in both patients and nonpatients. An interaction between clinical symptoms and state negative affect predicted AMR performance in patients significantly, and at a trend level in nonpatients.

The findings reveal that momentary negative affect significantly influences NSS, particularly on complex motor tasks (SMR), independent of underlying clinical symptoms. The interaction between negative affect and clinical symptoms impacts simpler motor tasks (AMR). This underscores the importance of considering emotional states in NSS assessment. Mobile DDK tasks can sensitively detect these fluctuations, highlighting their potential for real-time, scalable monitoring of NSS.