Etiology And Electro-Clinical Characteristics Of Patients With Transient Loss Of Consciousness

Objective: To analyze the etiological constitution of patients with transient loss of consciousness(TLOC)who came to the video-EEG room of the Department of Neurology in our hospital,to summarize and to compare the clinical and EEG characteristics of the causes of TLOC,and to provide a reference for clinicians to diagnose and differentially diagnose the causes of TLOC.Methods: TLOC patients who came to the video-EEG room of the Department of Neurology in our hospital from June 2020 to August 2021 were studied,and the enrolled cases were screened according to the inclusion and exclusion criteria.The general data,clinical features of TLOC seizures,EEG findings,and relevant auxiliary examination results of these patients were recorded in detail.The etiology was preliminarily determined according to the diagnostic criteria and follow-up was continued for 6 months,combined with follow-up to further confirm or revise the diagnosis.The clinical and EEG characteristics of the three groups of patients with a final diagnosis of epilepsy,syncope,and PNES were summarized and compared.Results:1.The causes of 506 patients with TLOC were as follows: epilepsy in 280cases(55.34%),syncope in 95 cases(18.77%),PNES in 48 cases(9.49%),epileptic seizures in 41 cases(8.10%),unknown etiology in 23 cases(4.55%),rare etiology in 14cases(2.77%),and PNES in 5 cases(0.99%).2.The factors including age,Onset age,gender,course of disease,frequency of onset during follow-up,seizure form,degree of loss of consciousness,duration,complexion,eye-opening and closing state,muscle tension disorder,jaw clenching,sweating,motor symptoms,falls,postictal hazy state,predisposing factors,prodromal symptoms,awakening discomfort,comorbid anxiety,and depression were statistically significant among the three groups(P<0.05).Pairwise comparison:(1)Comparison of epilepsy and syncope: There was no significant difference in age,Onset age,gender,seizure form,degree of loss of consciousness,and presence or absence of predisposing factors between the two groups(P>0.05);but there was significant difference in other characteristics(P<0.05).(2)Comparison of epilepsy and PNES: There was no significant difference between the two groups in the presence or absence of sweating and motor symptoms,comorbid depression(P>0.05);but there was significant difference in other characteristics(P<0.05).(3)Comparison of syncope and PNES: There was no significant difference between the two groups in the course of disease,eye-closed state,hazy state after attack and symptoms after waking up(P>0.05),but there was significant difference in other characteristics(P<0.05).3.The EEG characteristics in the three groups:(1)Interictal EEG: 78.93% of the patients with epilepsy displayed abnormal EEG,and the most common abnormal manifestation was focal epileptiform discharges;5.26% of the patients with syncope displayed abnormal EEG,which showed increased slow waves;the EEG of all patients with PNES were normal.(2)Ictal EEG: 94.12% of epileptic patients showed abnormal power generation in the synchronized EEG;83.33% of syncopal patients showed a non-specific increase in fully slow waves in the synchronized EEG;and all PNES patients showed motion artifacts in the ictal synchronized EEG,with intermittent visible background rhythms.(3)40.16% of epileptic patients displayed Abnormal discharges increase significantly after falling asleep or displayed abnormal discharges only during sleep.Conclusions:1.Among the patients who came to our neurology video-EEG room with a chief complaint of transient loss of consciousness,patients with epilepsy were the most frequent,followed by patients with syncope and patients with psychogenic non-epileptic seizures.2.Carefully inquiry of the patient’s attack process or based to mobile phone video recording,comprehensive familiar with the medical history,verification of the clinical syndromes during transient loss of consciousness attacks,mainly including triggers and aura before attacks,position and duration during attacks,whether the loss of consciousness is complete,whether the symptoms are stereotyped,whether there are lip and tongue bites,urinary and fecal incontinence,and symptoms after attacks,are important for the etiological diagnosis and differentiation of transient loss of consciousness.3.VEEG monitoring is of great value in differentiating epilepsy,syncope,and psychogenic non-epileptic seizures.Interictal capture of epileptiform discharges increases the possibility of diagnosing epilepsy,and ictal synchronous electroencephalographic findings of epileptiform discharges can confirm the diagnosis of epilepsy.The detection rate of epileptiform discharges can be increased by including sleep periods during EEG monitoring.