Can the Jankovic-assessment be used as an alternative to electromyography? A cross-sectional study on facial dystonia patients treated with Botulinum toxin

Purpose: This study aims to quantitatively compare the Jankovic assessment (JA) with electromyography (EMG)-based measures for assessing changes in facial movements in patients with facial dystonia.Materials and methods: Thirteen patients (five males and eight females) affected with different forms of facial dystonia (hemifacial spasm and synkinesis) participated in this study. All patients were treated with Botulinum Toxin (BTX) and evaluated with the JA scale and EMG-based measures, including motor unit potentials (MUP) latency and presence of polyphasic potentials before and after BTX injection. Correlation between the JA scores and the EMG-based measures was calculated. Statistical analysis was performed with the Pearson test.Results: Correlation between the JA scores and the EMG-based measures was found to be statistically significant, both before and after treatment with BTX.Conclusion and relevance: JA scores significantly correlated with more objective EMG-based measures, suggesting that the JA scale can be used to assess facial movement changes, for example elicited by a treatment such as BTX injection. Thus, in facial dystonia patients, the JA scale may be used for evaluating treatment outcomes as a valid and low-cost alternative to EMG.