Diagnostic value of tremor analysis in identifying the early Parkinson's syndrome

Abstract

OBJECTIVE To investigate the diagnostic value of tremor analysis in early stages of Parkinson's syndrome, when the clinical symptoms of tremor onset are not unilaterally often able for a definite diagnosis to be made. METHODS We included 70 patients with unilateral tremor, under 45 years old and disease duration within 3 years enrolled in Peking University Third Hospital from January, 2014 to December 2015. We recorded clinical features, unified Parkinson's disease rating scale (UPDRS)-III, non-motor symptom (NMS) scores. Tremor analysis and transcranial sonography were performed for all the patients. Based on the results of tremor analysis, we arbitrarily divided the patients into 3 groups: (1) The patients with classical Parkinson's syndrome manifestations on one side (25 cases); (2) The patients with classical Parkinson's syndrome manifestations on both sides (15 cases); (3) The patients with no classical Parkinson's syndrome manifestations (30 cases). The patients were monitored every 6 months to 3 years, until the final diagnosis was made. RESULTS There was no significant difference in age, gender distribution, Hamilton depression scale (HAMD) scores and H-Y scores among the three groups (P>0.05). The average UPDRS-III motor scores of the three groups were significantly different (P=0.001), with 18.23, 18.79 and 14.67, respectively. The average scores of NMS were significantly different, with 15.81, 17.07 and 9.90, respectively (P<0.001). The positive rates of transcranial sonography (TCS) in the three groups were 48.0%, 60.0% and 26.67%, with no significant difference (P=0.702). After three years of follow-up, 35 patients (50%) met the diagnostic criteria of Parkinson's disease of International Parkinson and Movement Disorder Society (MDS) in 2015, 19 patients (27.1%) met the criteria of idiopathic tremor, and 7 patients (10%) met the criteria of Parkinson's plus syndrome. The sensitivity and specificity of tremor analysis for early diagnosis of Parkinson's disease were 82.8% and 68.6%, respectively. Compared with TCS, the sensitivity and specificity of TCS were 65.7% and 62.9%. There were consistency (Kappa=0.568) and significant difference (P=0.031) between the two methods. CONCLUSION Tremor analysis is sensitive and a superior way in identifying early Parkinson's syndrome patients with tremor dominant manifestation. The combination of non-motor symptoms and transcranial sonography are also needed at diagnosis.