Signs and symptoms of pediatric brain tumors and diagnostic value of preoperative EEG

In pediatric patients, brain tumors have been estimated to be the cause for seizures in only 0.2-0.3 % of cases, whereas seizures occurred in about 13 % of pediatric brain tumor patients at presentation. This survey was conducted to analyze EEG findings in pediatric tumor patients over the past 14 years to evaluate the diagnostic value of preoperative EEG for diagnosis of brain tumors. Surface EEG was obtained in awake patients using the international 10- to 20-electrode placement in all pediatric patients with intracranial neoplasms between 2000 and 2013 at the University Hospital of Leipzig except for those who needed emergency operative treatment. One hundred forty-two pediatric patients with 80 infratentorial and 62 supratentorial tumors (WHO grades I-II: 91 patients; WHO grades III-IV: 46 patients). Symptomatic hydrocephalus was found in 37. Sensitivity and specificity of ophthalmologic examination for predicting hydrocephalus was 0.39 and 0.72. Preoperative EEG has been conducted in 116 patients, showing normal activity in 54 patients (47 %). Out of 62 pathologic EEGs, 40 indicated correctly to the site of the lesion, 15 were pathologic despite of infratentorial location of the tumor. Nineteen patients had a history of seizures of which six had normal EEGs. Sensitivity for and specificity of EEG examination for symptomatic epilepsy was 0.68 and 0.7. Conclusion Preoperative routine EEG provides no additional value in the diagnostic algorithm of pediatric train tumors. The low specificity and sensitivity of EEG (even in patients with clinical seizures as primary symptom of a brain tumor) underline that EEG does not contribute to diagnosis and a normal EEG might even delay correct diagnosis.