A systematic recurrent theme analysis of the reported limitations of facial electromyography

BACKGROUND: Advances in digital technology hold promise in expanding the clinical and consumer applications of facial electromyography (EMG) through thedevelopment of wireless pervasive systems capable of operating in a nonclinical environment. This systematic review aims to appraise the most commonly reported limitations of the technology in clinical research and practice. METHODS: A systematic search for clinical facial EMG literature was performed using MEDLINE, EMBASE, PsychINFO and CINAHL. No language limits were applied. Search results were screened using defined criteria by two authors with disagreements resolved by a third. Practical limitations in the technology, as reported by the authors, were recorded and characterised using recurrent theme analysis. RESULTS: A total of 4,983 records were identified. Of those, 1,061 articles met eligibility criteria and were subsequently reviewed. In the medical domain, the most common area of application was in psychosocial studies (28% of medical studies); in the surgical domain monitoring of facial nerve integrity was the most common application of facial electromyography (27% of surgical studies). Collectively, the three most commonly reported limitations were motion artefact (13.7%), inter-subject variability in response and anatomy (13.1%), and muscle crosstalk (12.0%). CONCLUSIONS: This is the first study to evaluate the limitations of facial EMG using a systematic analysis of author reports. Highlighting technology limitations in this non-biased manner raises awareness to users key issues and reliably informs the development of future systems.