Electromyogram Study On Masticatory And Neck Muscles In Temporomandibular Disorders Patients

Objectives:The study contracts the bilateral masseter and sternocleidomastoid muscle surface electromyography of normal people with temporomandbular disorder patients, to provide the basis for diagnosis and treatment of temporomandibular disorders with cervical spine disorders. Method:Firstly, We applied the biological signal sample system to sample the masseter and sternocleidomastoid electromyo graphic activity signals in the jaw movement and neck movements of 19 healthy adults and 15 patients with temporomandibualr disorders. Then, we analyzed the peek-peek value, mean square deviation, media frequency and mean power frequency of signals by the time domain analysis and joint time-frequency analysis. In Maximum bite movement, we defined the larger side of EMG parameters as dominant side (DS), and the smaller side as non-dominant side (NDS). In chew movement, we re-group the larger ratio of parameters of non-working side and working side as dominant group (DG), and the smaller one as non-dominant group (NDS). Parameters in the same group were compared by paired t test, while between two groups by independent-sample t test. Results:(1) In maximum bite movement, there was no significant difference of NDSP/DSP between control group and patients group (p>0.05), while we found significant difference of NDSm/DSm (p<0.05). In chew movement, the result shows prominent difference of DGP, NDGP, DGm, NDGm and NDGm/DGm between control group and patients group (p<0.05), but no notable difference of NDGP/NDGP (p>0.05); (2) The masseter and sterocleidomastoid correlated in the movement of mandibular and neck, which decreased in patients group; (3) Short time Forier transform analysis demonstrates that in the largest open-closed bite and the maximum bite movement, the mean power frequency (MPF) of ipsiateral masseter and setrocleidomastoid were marked different between the control group and patient group (p<0.05). and the media frequency (MF) of ipsiateral setrocleidomastoid was significant different between the control group and patient group too(p<0.05); (4) In Ville Wigner distribution analysis, there were abnormal signals seen in patients group. Conclusion:(1) the EMG peak-peak values and mean square deviation indicate that the temporomandibular patients have uncoordinated bilateral chew function; (2) the muscular chain of stomatognathic system has influence in temporomandibular disorders directly, moreover, the abnormal muscle electrical activity of masseter muscle and sterolceidomastoid in patients with temporomandibular disorders may lead to cervical spine disorder; (3) mean power frequency (MPF) can be used as a auxiliary index for clinical diagnosis of temporomandibular disorders because of its high specificity; (4) Ville Wigner distribution analysis of EMG shows a good recognition of muscle movement pattern, this analysis method of EMG has yet to be further study.