| Objective To explore the applied value of electromyography tremor analysis in differential diagnosis of PD(Parkinson’s disease,PD)and ET(Essential tremor,ET).To evaluate the sensitivity and the specificity of tremor analysis in clinical diagnosis of Parkinson’s disease and to found the valuable tremor analysis indicators for identifying tremor diseases.Methods A total of 46 PD patients were recruited from the patients visiting the department of neurology of Qilu hospital of Shandong university(Qingdao)between January 2019 and March 2021.Patients who were eligible to participate in the cohort were mean age 60.9 ± 11.4 years,range 38 to 82 years.The average course of disease was 6.1± 3.4 years,range 3 to 19 years.A total of 55 ET patients were recruited from the same hospital and at the same time.Patients who were eligible to participate in the cohort were range 20 and 77 years of age.Their course of disease was 3 to 15 years.The average age was 59.6± 14.8 years old and the average course of disease was 5.8±3.2 years.Electromyography tremor analyses were undertaken for all the patients.Nicolet EDX was used to measure and record the patient’s tremor signals and software TRAS system was used to analysis tremor data.Tremor dominant frequency,tremor amplitude,spectrum and muscle contraction model were carefully analysed and the changes were followed-up.The sensitivity and the specificity of tremor analysis were determined by ROC curve.Results There were no significant differences in mean age,sex distribution and course of disease in PD group versus ET group.Onste of PD was given priority to hemi-limbs which was observed in 71.7%PD patients.Static tremor was observed in 84.8%of the PD cohort,which there was significant difference in patients with PD compared with ET patients(P<0.05).The predominat frequency of tremor in PD group were 4.98±1.13 Hz and 5.38± 1.46 Hz in rest and postural positions respectively.The predominat frequency of tremor in ET group were 6.32± 1.85 Hz and 6.34± 1.14 Hz in rest and postural positions respectively.There were statistically significant differences between the PD group and the ET group both in rest and postural positions(P<0.05).But there were no significant differences between rest and postural position in patients with PD or patients with ET(P>0.05).ROC curve showed that cutoff value of tremor frequency were 5.10 and 5.65 in rest positions and postural positions respectively.The sensitivity and the specificity of tremor frequency in rest positions were 0.667and 0.862 respectively,which the area of under curve was 0.781(95%Cl 0.663～0.889).The sensitivity and the specificity of tremor frequency in postural positions were 0.773 and 0.714 respectively,which the area of under curve was 0.744(95%CI 0.586?0.901).Vibration amplitudes between PD group and ET group there were no significant differences both in the stationary state and postural positions(P>0.05).Muscle contraction model of PD group was given priority to alternation,while ET group was given priority to synchronicity.Statistic difference could be found in two groups.As the illness progress,PD group alternate tremor tend to be synchronized.In PD group synchronization tremor has increased significantly but no significant change in tremor amplitude,both in the stationary state and postural positions.Conclusions Electromyography tremor analysis can differentiate PD and ET with sensitive and specific.Tremor frequency and muscle contraction model were valuable judgment indicators for identifying tremor diseases. |
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