Developing non‐invasive, objective assessment tools for social apathy in neurocognitive disorders: The role of action kinematics

Background Apathy, a reduction in goal‐directed activities in the domains of behavior, cognition, emotion and social interaction, is one of the most common behavioral symptoms in Neurocognitive Disorders (NCD) [1]. Current apathy assessment strongly relies on self‐reports or clinical scales, which are subjective and dependent on the information provided by patients and caregivers. For this reason, growing attention is devoted to defining more objective, measurable and non‐invasive apathy proxies. In the present study we investigated the interest of recording action kinematics in a short reach and grasp protocol [2] for the assessment of apathy social component, characterized by a reduction of the willingness to interact with others. Methods 19 subjects with Mild NCD (6M, age=75,7±6,3y, MMSE=26,0±3,0) were recruited at the Nice Memory Center. Based on the Apathy Motivation Index (social motivation subscale [3] ), subjects were classified as socially apathetic (N=9) vs non‐apathetic (N=10). SensRing, a novel ring‐shaped wearable sensor [4] , was placed on their dominant hand’s index finger. Subjects were asked to reach and grasp a can to place it into a cup (individual condition) and pass it to a partner (social condition). Several parameters were extracted, including movement velocity, acceleration, jerk (representing the smoothness of the movement) and execution time. Results Non‐apathetic participants showed a significantly lower peak velocity (p=0,009) and a lower jerk (p=0,038) in the social vs individual condition when moving the can to the final position, suggesting a more careful approach in placing the object in the partner’s hand vs a cup. Non‐apathetic participants showed no significant differences between conditions in any of the extracted parameters. Conclusion Previous studies showed the interest of recording patients’ level of weekly motor activity for apathy assessment. Here, for the first time, we showed that a 5‐minutes reach and grasp protocol may be able to show differences between socially apathetic and non‐apathetic subjects with Mild NCD, thus providing a tool easily usable in the clinical practice. Future studies with a bigger sample are needed to better characterize these findings. [1] Manera et al., 2019, doi.org/10.1002/gps.5125. [2] Becchio et al., 2008, doi.org/10.1016/j.concog.2007.03.003. [3] Ang et al., 2017, doi:10.1371/journal.pone.0169938. [4] Rovini et al., 2020, EMBC‐2020.