The non-invasiveness of photoplethysmographic (PPG) acquisition systems, together with their cost-effectiveness and easiness of connection with IoT technologies, is opening up to the possibility of their widespread use. For this reason, the study of the reliability of PPG and pulse rate variability (PRV) signal quality has become of great scientific, technological, and commercial interest. In this field, sensor location has been demonstrated to play a crucial role. The goal of this study was to investigate PPG and PRV signal quality acquired from two body locations: finger and wrist. We simultaneously acquired the PPG and electrocardiographic (ECG) signals from sixteen healthy subjects (aged 28.5 ± 3.5, seven females) who followed an experimental protocol of affective stimulation through visual stimuli. Statistical tests demonstrated that PPG signals acquired from the wrist and the finger presented different signal quality indexes (kurtosis and Shannon entropy), with higher values for the wrist-PPG. Then we propose to apply the cross-mapping (CM) approach as a new method to quantify the PRV signal quality. We found that the performance achieved using the two sites was significantly different in all the experimental sessions (p < 0.01), and the PRV dynamics acquired from the finger were the most similar to heart rate variability (HRV) dynamics.

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Background: Social apathy, a reduction in initiative in proposing or engaging in social activities or interactions, is common in mild neurocognitive disorders (MND). Current apathy assessment relies on self-reports or clinical scales, but growing attention is devoted to defining more objective, measurable and non-invasive apathy proxies. Objective: In the present study we investigated the interest of recording action kinematics in a social reach-to-grasp task for the assessment of social apathy. Methods: Thirty participants took part in the study: 11 healthy controls (HC; 6 females, mean age = 68.3±10.5 years) and 19 subjects with MND (13 females, mean age = 75.7±6.3 years). Based on the Diagnostic Criteria for Apathy, MND subjects were classified as socially apathetic (A-MND, N = 9) versus non-apathetic (NA-MND, N = 10). SensRing, a ring-shaped wearable sensor, was placed on their index finger, and 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). Results: In the reach-to-grasp phase of the action, HC and NA-MND showed different acceleration and velocity profiles in the social versus individual condition. No differences were found for A-MND. Conclusion: Previous studies showed the interest of recording patients’ level of weekly motor activity for apathy assessment. Here we showed that a 10-min reach-to-grasp task may provide information to differentiate socially apathetic and non-apathetic subjects with MND, thus providing a tool easily usable in the clinical practice. Future studies with a bigger sample are needed to better characterize these findings.

Background The progressive ageing of the population is leading to an increasing number of people affected by cognitive decline, including disorders in executive functions (EFs), such as action planning. Current procedures to evaluate cognitive decline are based on neuropsychological tests, but novel methods and approaches start to be investigated. Reach-to-grasp (RG) protocols have shown that intentions can influence the EFs of action planning. In this work, we proposed a novel ring-shaped wearable inertial device, SensRing, to measure kinematic parameters during RG and after-grasp (AG) tasks with different end-goals. The aim is to evaluate whether SensRing can characterize the motor performances of people affected by Mild Neurocognitive Disorder (MND) with impairment in EFs. Methods Eight Individuals with dysexecutive MND, named d-MND, were compared to ten older healthy subjects (HC). They were asked to reach and grasp a can with three different intentions: to drink (DRINK), to place it on a target (PLACE), or to pass it to a partner (PASS). Twenty-one kinematic parameters were extracted from SensRing inertial data. Results Seven parameters resulted able to differentiate between HC and d-MND in the RG phase, and 8 features resulted significant in the AG phase. d-MND, indeed, had longer reaction times (in RG PLACE), slower peak velocities (in RG PLACE and PASS, in AG DRINK and PLACE), longer deceleration phases (in all RG and AG DRINK), and higher variability (in RG PLACE, in AG DRINK and PASS). Furthermore, d-MND showed no significant differences among conditions, suggesting that impairments in EFs influence their capabilities in modulating the action planning based on the end-goal. Conclusions Based on this explorative study, the system might have the potential for objectifying the clinical assessment of people affected by d-MND by administering an easy motor test. Although these preliminary results have to be investigated in-depth in a larger sample, the portability, wearability, accuracy, and ease-of use of the system make the SensRing potentially appliable for remote applications at home, including analysis of protocols for neuromotor rehabilitation in patients affected by MND.

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.