The Clinical Analysis And Trigeminal Somatosensory Evoked Potentials Research In Patients With Meige Syndrome

Background:Meige syndrome is a segmental dystonia. In the early stage of the disease only the minority of patients have spasm symptoms, and majority of them performed with non-spasm symptoms, such as dry eye, photophobia, difficult in eyelid open and dry mouth. Patients are first treated in ophthalmology, dental and psychiatric clinic constantly. Even most of the neurologists cannot recognize the disease in the early stage, which result in a high misdiagnosis rate. At present the pathogenesis of Meige syndrome is not clear. The diagnosis of the disase is mainly depended on the clinical feature. Functional imaging can show abnormal metabolism of areas within the brain, but it is a complicated technology and difficult to apply to clinical experience. Electrophysiology is a non-invasive, simple and feasible detection technology, which can carried out easily in clinical. Some scholars have applicated EMG and blink reflex to study muscle electric characteristics and the brainstem function. Trigeminal somatosensory evoked potentials is a technology which stimulating the trigeminal nerve endings through the electrical impulses, and recording the cortical potentials in corresponding cortex. The detection can respond the conduction function of trigeminal lemniscus, and to some extent represent the central conduction and activity of orofacial somatosensory and motor pathway. Currently TSEP is used only in clinical diagnosis and intraoperative monitoring of the trigeminal neuralgia. Both at home and abroad, there is no TSEP applicated in the research of Meige syndrome.Objectives:1. To analyze the clinical features of Meige syndrome. To improve the clinical doctors'understanding of the disease to decrease the misdiagnosis rate.2. Analyze the TSEP characteristics of Meige syndrome to explore the objective diagnosis index and the possible pathogenesis of Meige syndrome. Methods:1. 50 Meige syndrome patients patients were selected to analysis the general data, early manifestation, diagnosis, and detailed history using retrospectively method.2. Trigeminal somatosensory evoked potentials research(1) TSEP was investigated in 25 patients affected Meige syndrome and 19 controls. The interpeak latency of N13-P19, P19-N30 and the interpeak amplitude of N13-P19, P19-N30 ware compared between the two groups.(2) The 25 patients was divided into two groups by the course of disease, which defined group1(patients within 30 months) and group 2(patients out of 30 month). Define the controls as group 3. Analyze the index mentioned above among three groups.Results:1.Clinical analysis(1) The study includes 50 patients, among which 45 patients(90%) demonstrate non-spasm symptoms in the early stage, including dry eye(n=26,52%), difficult in eyelids open(n=10,20%),blink frequency increase(n=9,18%),eye fatigue(n=8,16%),eyelid beating(n=8,16%), photophobia(4 cases, 8%), dry mouth (4 cases, 8%), eye pain (3 cases, 6%), nasal discomfort (3 cases, 6%), facial discomfort (3 cases, 6%), and neck constricted (3 patients 6%).That the median duration of spasm symptoms progresses to BS and/or OMD is demonstrated as following: eyelid beating 18 months, dry mouth 18 months , blink frequency increase 12 months, difficult in eyelids open 12 months, eye dry 11 months, facial discomfort 10 months, eye fatigue 9 months, neck constricted 7 months, photophobia 6 months, eye pain 6 months, and nasal discomfort 1 month.(2) There only 5 patients were correct diagnosed in the early stage of Meige syndrome, and 45 patients were not correct recognized. The recognized rate is 90%. The faulty diagnose include: dry eye (n=21, 42%), conjunctivitis/keratitis (n=20, 40%), myasthenia gravis (n=7, 14%), neurosis (n=6,12%), and rhinitis (n=1, 2%).2. Trigeminal somatosensory evoked potentials research(1) Compared with controls, patients with Meige syndrome present a higher interpeak amplitude of P19-N30, which has a significant differences in statistics(P<0.05).(2) The group1 and group2 have a significant higher interpeak amplitude of P19-N30 than group3(P<0.05), but group1 and group2 have no significant differences in statistics(P>0.05). Group 2 have a significant prolonged interpeak latency of N13-P19 compared with group1 and group3 (P<0.05), but group 1 and group3 do not have differences in statistics(P>0.05).Conclusions:1. There are several reasons for the low diagnose rate of Meige syndrome: patients demonstrate diversity clinical manifestations, majority of them performed with non-spasm symptoms in the early stage, and the lack of effective auxiliary examination means for diagnosis.2. Patients with Meige syndrome through TSEP demonstrate a highly P19-N30 interpeak amplitude and a prolonged N13-P19 interpeak latency as the course of the disease extended.3. Through TSEP revealed that patient with Meige syndrome appears significantly enhanced the excitability of sensorymotor cortex, thalamus, and basal ganglia.