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Monitoring spatio-temporal parameters of gait, such as Stride Length, Gait Time and Gait Speed, through inertial measurement units is a research topic of great interest in clinics. Despite the high interest in the field, the development of a high accuracy wearable solution for spatio-temporal parameters assessment in a clinical scenario, suitable for both normal and pathological gait, is still an open challenge. In this study we proposed a novel solution to estimate spatio-temporal parameters through Inertial Measurement Units and an optimized strap-down approach for drift reduction. For the accuracy evaluation three healthy subjects were enrolled. Each subject was equipped with two inertial sensors placed on feet. Subjects were asked to repeat seven walking trials, through the calibration volume of an optoelectronic system, used as a reference. As a clinical application, we used the solution to assess fatigue effects on healthy and pathological subjects considering the 6-Minute Walking Test. Results showed high accuracy in the estimation of spatio-temporal parameters for each subject. The mean relative error of the Stride Length estimation among subjects was 1.1±0.7% and 0.8±0.5% for the left and right side. The clinical application was conducted on a cohort of ten patients with Systemic Sclerosis and ten age-matched healthy adults. Statistical differences were observed between populations in the Stride Length and in the Gait Speed. Moreover, all subjects experienced fatigue effect reporting lower values of spatio-temporal parameters in the last minute, compared to the first one. The excellent results in the accuracy evaluation encourage application of this methodology in normal and in pathological gait monitoring where a low error in the estimation of spatial gait parameters is required.

Monitoring physiological parameters under stress conditions – i.e., heart rate, breath frequency or heart rate variability - through non-invasive and comfortable wearable devices was a research topic of great interest in many medical fields. In the last decade, several wearable devices and methods have been developed for stress monitoring, showing suitable performance in estimating the stress indicator. In spite of the interest in the field, the development of wearable solutions suitable for child neuropsychiatry applications was still an open challenge. In this study, we evaluate the cardiac activity in children - with and without neurodevelopmental disorders - through a novel wearable solution in order to compare the stress response in different structured activities and games. Each subject was equipped with a 3-lead electrocardiograph device and a piezoelectric respiratory sensor embedded into a thoracic belt. Subjects were asked to carry out five different activities previously chosen from a subset of specific behavioral tests (three different free-games and two structured activities). All experimental sessions were video-recorded. Results highlighted how wearable devices could help in estimating stress indicators for long-tests (over twenty-five minutes). The clinical application was conducted on a cohort of 32 children so divided: 13 with Specific Language Disorder, 15 with Autism Spectrum Disorder, and 4 control children without neurodevelopmental disorders. Statistical differences were observed between populations in the heart rate. Moreover, all subjects experienced stress effects evidenced by variation of heart rate and standard deviation, which are supported by the video analysis.