Kurtosis, a new variable with possible diagnostic value in analysis of jaw muscle surface EMG

Background There is a need for methods to compare differences of voltage levels and distribution anomalies in the study of skeletal muscle function. Calculating the kurtosis values has been found to be of value. Aim The aim was to record and analyse voltage and kurtosis levels of SEMG recorded bilaterally in the masseter and anterior temporalis areas during rest and clenching and to compare the kurtosis levels between controls and patients with TMJ disc dysfunction. Material and methods Twenty-three healthy subjects and 21 patients with TMJ disc dysfunction were taken part in this study. Recordings were made with the BioPAK EMG System. Gain was adjusted to record the data within the range of +/- 2000 mu V. SEMG was recorded in four facial areas, the right masseter, left masseter, right anterior temporalis, and left anterior temporalis areas. Kurtosis levels of SEMG, at clenching with maximal force, and mandibular rest, were compared between the control and patient groups. Results The kurtosis levels of clenches were significantly higher in patients in all four areas with sensitivity, 38.1% to 61.9%, and specificity, 82.6% to 100.0%. No differences were found in kurtosis levels during mandibular rest. Conclusion The results support that kurtosis values of SEMG recorded during clenching have a potential diagnostic interest.

Automated summary

The study aimed to compare voltage and kurtosis levels of SEMG between controls and patients with TMJ disc dysfunction. Results showed significantly higher kurtosis levels in patients during clenching, with no differences during mandibular rest.