Signal acquisition and analysis of ambulatory electromyographic recordings for the assessment of sleep bruxism: A scoping review

Background: Ambulatory electromyographic (EMG) devices are increasingly being used in sleep bruxism studies. EMG signal acquisition, analysis and scoring methods vary between studies. This may impact comparability of studies and the assessment of sleep bruxism in patients. Objectives: (a) To provide an overview of EMG signal acquisition and analysis methods of recordings from limited-channel ambulatory EMG devices for the assessment of sleep bruxism; and (b) to provide an overview of outcome measures used in sleep bruxism literature utilising such devices. Method: A scoping review of the literature was performed. Online databases PubMed and Semantics Scholar were searched for studies published in English until 7 October 2020. Data on five categories were extracted: recording hardware, recording logistics, signal acquisition, signal analysis and sleep bruxism outcomes. Results: Seventy-eight studies were included, published between 1977 and 2020. Recording hardware was generally well described. Reports of participant instructions in device handling and of dealing with failed recordings were often lacking. Basic elements of signal acquisition, for example amplifications factors, impedance and bandpass settings, and signal analysis, for example rectification, signal processing and additional filtering, were underreported. Extensive variability was found for thresholds used to characterise sleep bruxism events. Sleep bruxism outcomes varied, but typically represented frequency, duration and/or intensity of masticatory muscle activity (MMA). Conclusion: Adequate and standardised reporting of recording procedures is highly recommended. In future studies utilising ambulatory EMG devices, the focus may need to shift from the concept of scoring sleep bruxism events to that of scoring the whole spectrum of MMA

Φυσικές ιδιότητες προϊόντων εκβολής

In the present thesis, the effect of extrusion conditions on the physical properties of the extrusion products was investigated for mixtures of corn flour with flour of various legumes including chickpeas, kidney beans, white beans and lentils. The extrusion conditions investigated include a) the feed material characteristics including the moisture and composition (corn flour weight percentage in the corn- legume flour mixture) of the feed mixture, b) extrusion parameters such as temperature, screw rotation rate, feed rate and retention time. The physical properties of the extrusion products investigated include structural properties (bulk and true density, porosity, radial expansion), textural properties (compressive strength and strain, cutting force and maximum penetration), colour, and thermal properties (melting temperature and maximum heat flow during the differential calorimetric scanning tests). Simple mathematical models have been fitted to the experimental results. The aim was to develop models for the description and prediction of physical properties of extrusion products of corn or corn-legume mixtures, when feed characteristics and extrusion parameters are known. These models were applied to all the physical properties of the extrusion products which were investigated in this study.Στην παρούσα διατριβή εξετάστηκε η επίδραση των παραγόντων εκβολής στη μεταβολή των φυσικών ιδιοτήτων προϊόντων εκβολής μιγμάτων καλαμποκάλευρου με άλευρα οσπρίων, όπως ρεβιθιού, μεξικάνικου φασολιού, φασολιού και φακής. Στους παράγοντες εκβολής που μελετήθηκαν συμπεριλαμβάνονται: α) χαρακτηριστικά του υλικού τροφοδοσίας που περιλαμβάνουν την υγρασία του μίγματος τροφοδοσίας και το ποσοστό προσθήκης καλαμποκάλευρου στο μίγμα καλαμποκάλευρου - οσπρίων. β) Παράμετροι λειτουργίας του εκβολέα, όπως η θερμοκρασία εκβολής, η ταχύτητα περιστροφής κοχλιών, η παροχή και ο χρόνος παραμονής. Στις φυσικές ιδιότητες των προϊόντων εκβολής που εξετάστηκαν περιλαμβάνονται ιδιότητες δομής (πορώδες, λόγος διαστολής, φαινόμενη και πραγματική πυκνότητα), ιδιότητες υφής (τάση θραύσης και ανοιγμένη παραμόρφωση δοκιμών συμπίεσης, δύναμη κοπής και μέγιστη διείσδυση δοκιμών κοπής), οπτικές ιδιότητες (χρώμα) και θερμικές ιδιότητες (θερμοκρασία τήξης και ροή θερμότητας κατά τις δοκιμές διαφορικής θερμιδομετρίας σάρωσης). Στα πειραματικά αποτελέσματα προσαρμόστηκαν φαινομενολογικά πρότυπα πρόβλεψης των ιδιοτήτων των προϊόντων εκβολής με βάση τις συνθήκες εκβολής με στόχο την ανάπτυξη απλών προτύπων περιγραφής και πρόβλεψης των φυσικών ιδιοτήτων των τελικών προϊόντων εκβολής μιγμάτων καλαμποκάλευρου με ή χωρίς όσπρια όταν είναι γνωστά τα χαρακτηριστικά τροφοδοσίας και οι παράγοντες της διεργασίας εκβολής. Τα πρότυπα αυτά εφαρμόστηκαν για όλες τις φυσικές ιδιότητες των προϊόντων εκβολής που μελετήθηκαν

Associations between sleep bruxism and (peri-)implant complications: lessons learned from a clinical study

Objective: To report and discuss the lessons learned from the conduct of a clinical study on the associations between sleep bruxism and (peri-)implant complications, the protocol of which has been pre-published. Materials and methods: A single-center, double-blind, prospective cohort study with a 2 year follow-up was performed in the Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. Eleven adult participants were included, where an inclusion of 98 was planned. Sleep bruxism was assessed by multiple single-channel electromyographic (EMG) recordings. Main outcomes were biological and technical complications. Results of the study are presented alongside with comments on encountered difficulties. Results: Insufficient participant recruitment and failed EMG recordings were encountered. The small sample size did not allow answering the study’s main aim, and was mainly attributed to the study’s protocol complexity. EMG recording failures were attributed to insufficient quality of the EMG signal and detachments of the electrode. Discussion: The lessons learned from the conduct of this study can be used to design successful future clinical studies. Conclusions: Adequate participant recruitment, effective EMG recordings, and a careful selection of predictor variables are important ingredients for the successful conduct of a longitudinal clinical study on the association between sleep bruxism and (peri-)implant complications

Clinical jaw-muscle symptoms in a group of probable sleep bruxers

Objectives: To investigate, in a sample of probable sleep bruxers with and without temporomandibular disorder (TMD) pain, the presence and relationships between clinical jaw-muscle symptoms, and test their associations with jaw-muscle electromyographic (EMG) activity during sleep. Methods: Pain, unpleasantness, tiredness, tension, soreness, and stiffness were scored on a 0–10 numerical rating scale (NRS) in 50 probable sleep bruxers. The sample was subdivided into two groups, i.e., with and without TMD pain. Multiple-night, single-channel EMG recordings were performed. Descriptive data, correlations between the six symptoms, and correlations between symptoms and EMG measures, i.e. EMG events/recording, EMG events/hour, and night-to-night variability in EMG events, were calculated. Results: In the total sample, 90% of the participants reported at least one symptom. Tiredness and tension were the most prevalent symptoms (both 78%), and pain the least (30%). In the TMD pain group, pain remained the least reported symptom (57%). Intensity of symptoms was low to moderate, with tension presenting the highest median in the total sample (NRS 4), the TMD pain group (NRS 5), and non-TMD group (NRS 3). Significant correlations between all symptoms were found in the total sample, but not in the two subgroups. No significant associations between EMG measures and muscle symptoms emerged. Conclusion: Jaw-muscle symptoms other than pain were highly prevalent in a sample of probable sleep bruxers. There were no associations between these symptoms and EMG measures of jaw-muscle activity during sleep. These findings challenge the concept of simple relationships between jaw-muscle activity during sleep and clinical muscle symptoms

Patient‐based experiences with the use of an ambulatory electromyographic device for the assessment of masticatory muscle activity during sleep

Background: It is important to know how easy or difficult it is to use an ambulatory electromyographic (EMG) device for sleep bruxism assessment, and how this might affect its future utilisation. Objective: To explore the experience of individuals using an EMG device that pairs with a smartphone app, in order to detect factors that could facilitate and/or hamper its utilisation in future scientific research. Methods: Fifteen adults were recruited in the Orofacial Pain and Dysfunction Clinic of the Academic Centre for Dentistry Amsterdam (ACTA). Overnight recordings were performed in the home setting during one week. Time investment, feelings and thoughts, encountered difficulties and reasons for not using the device were assessed in a diary through open-ended questions and 5-point Likert scales. Content analysis of textual data was performed, and descriptives of quantitative data were calculated. Results: Time investment was low (mean 10.2 minutes in the clinic, and 1.9 minutes per recording at home). Quantitative data showed an overall good experience (median of 4). Qualitative diary data showed that the desire to gain insight into one's masticatory muscle activity formed the main motivation to use the device. Device detachment and difficulty in using the app were the most prominent negative experiences. Conclusion: The EMG device was well accepted for multiple overnight recordings. Curiosity for gaining insight into muscle activity was the most important factor that facilitated its use, and the app addressed this need. Device detachment and difficulties in using the app were the main factors that hampered its use