The value of electroencephalography in differential diagnosis of altered mental status in emergency departments.

OBJECTIVE To evaluate the value of electroencephalography in patients with altered mental status in emergency departments. METHODS Demographical characteristics, types and aetiologies of seizures, and clinical outcomes of the patients were recorded. Patients were divided into 4 groups according to the complaints of admission: findings and symptoms of seizure; stroke and symptoms of stroke-related seizures; syncope; and metabolic abnormalities and other causes of altered mental status. The electroencephalography findings were classified into 3 groups: epileptiform discharges; paroxysmal electroencephalography abnormalities; and background slowing. Electroencephalography abnormalities in each subgroup were evaluated. SPSS 21 was used for statistical analysis. RESULTS Of the total 190 patients in the study, 117 (61.6%) had pathological electroencephalography findings. The main reason for electroencephalography in the emergency department was the presence of seizure findings and symptoms in 98 (51.6%) patients. The ratio of electroencephalography abnormality was higher in patients who were admitted with complaints of metabolic abnormality-related consciousness disturbances (p < 0.001). A total of 124 (65.3%) patients had neuroimagings. Electroencephalography abnormalities were found to be significantly higher in patients with neuroimagings compared to those without neuroimagings (p < 0.003). CONCLUSION Despite advanced neuroimaging techniques, electroencephalography is still an important tool in the differential diagnosis of altered mental status such as epileptic seizures, metabolic abnormalities, pseudo-seizures and syncope.