1,721,047 research outputs found
Auto e cross trasformate tempo - frequenza per l'analisi e la sintesi di brani di segnale EMG
No full textRelationships between SMES PSD and ACF main lobe width in localized muscle fatigue evaluation
No full text
A statistical method for the measurement of muscle activation intervals from surface myoelectric signal during gait
No full textThe aim of this work is to present an original double-threshold detector of muscle activation, specifically developed for gait analysis. This detector operates on the raw myoelectric signal and, hence, it does not require any envelope detection. Its performances are fixed by the values of three parameters, namely, false-alarm probability (P(fa)), detection probability, and time resolution. Double-threshold detectors are preferable to single-threshold ones because, for a fixed value of the P(fa), they yield higher detection probability; furthermore, they allow the user to select the couple false alarm-detection probability with a higher degree of freedom, thus, adapting the performances of the detector to the characteristics of the myoelectric signal of interest and of the experimental situation. In this paper, first we derive the detection algorithm and describe different strategies for selecting its parameters, then we present the performances of the proposed procedure evaluated by means of computer simulations, and finally we report an example of application to myoelectric signals recorded during gait. The characterization of the proposed double-threshold detector demonstrates that, in most practical situations, the bias of the estimates of the on-off transitions is smaller than 10 ms, the standard deviation may be kept lower than 15 ms, and the percentage of erroneous patterns is below 5%. These results show that this detection approach is satisfactory in research applications as well as in the clinical practice
A novel statistical approach for upper-limb movement segmentation using a single wrist-worn magneto-inertial measurement unit
No full textActivities of Daily Life (ADLs) are fundamental tasks that need to be carried out for maintaining a good quality of life. For patients with motor impairments, task-oriented therapy is a reasonable approach for recovering the ability to perform basic ADLs [1]. Magneto-Inertial Measurement Units (MIMUs) are commonly used for kinematic assessments in various pathological conditions [2]. The time needed to complete a motor task is a metric often used by physical therapists to assess motor impairments. To facilitate this evaluation, accurate algorithms that can distinguish between movement and rest states are needed. This contribution aims at introducing a segmentation method for the identification of upper-limb movements based on statistical considerations
Normative EMG activation patterns of school-age children during gait
No full textGait analysis is widely used in clinics to study walking abnormalities for surgery planning, definition of rehabilitation protocols, and objective evaluation of clinical outcomes. Surface electromyography allows the study of muscle activity non-invasively and the evaluation of the timing of muscle activation during movement. The aim of this study was to present a normative dataset of muscle activation patterns obtained from a large number of strides in a population of 100 healthy children aged 6-11 years. The activity of Tibialis Anterior, Lateral head of Gastrocnemius, Vastus Medialis, Rectus Femoris and Lateral Hamstrings on both lower limbs was analyzed during a 2.5-min walk at free speed. More than 120 consecutive strides were analyzed for each child, resulting in approximately 28,000 strides. Onset and offset instants were reported for each observed muscle. The analysis of a high number of strides for each participant allowed us to obtain the most recurrent patterns of activation during gait, demonstrating that a subject uses a specific muscle with different activation modalities even in the same walk. The knowledge of the various activation patterns and of their statistics will be of help in clinical gait analysis and will serve as reference in the design of future gait studie
Studio della tecnica di spinta su carrozzella sportiva mediante elettromiografia di superficie
No full textUsability of a multi-sensor array for the application of electro-phonocardiography in home care
No full textIn the latest years, the potentiality of a combined use of electrocardiography (ECG) and phonocardiography (PCG) for the assessment of the electromechanical coupling of the heart has gained interest within the scientific community. The availability of this technology in a home care context would enable the timely monitoring of patients where the electromechanical coupling is impaired, such as in heart failure. Nevertheless, the domiciliary use of electro-phonocardiography is at date prevented by the critical positioning of the electronic stethoscope, which cannot be reliably performed by inexperienced users. In this work, we propose a usability analysis of a multi-sensor array that we developed for this purpose. The multi-sensor array is a flexible pad embedding 3 electrodes and 48 microphones, distributed over the left hemithorax with a high spatial resolution. In our experimental protocol, we simulated a real home care scenario: volunteers with no technical nor clinical skills were enrolled in couples and alternatively performed the recordings on each other, simulating the roles of patient and caregiver. Results show that a Signal-to-Noise Ratio (SNR) higher that 13 dB was always achieved, even before any digital filtering. Moreover, the influence of the body structure of the patient, quantified in terms of Body Mass Index and thoracic circumference, on the quality of the signals was assessed. A moderate significant negative correlation was found, as expected, but in the overall the body structure did not prevent from obtaining reliable signals even in cases of severe overweight. We believe that the presented findings lay the foundations for the use of electro-phonocardiography in telemonitoring applications
- …
