Effectiveness of Multiple EEGs in Supporting the Diagnosis of Epilepsy: An Operational Curve

Abstract

Interictal epileptiform activity (IIEA) on EEG may be useful in the diagnosis and characterization of epilepsy. A single scalp EEG may fail to detect this abnormality, which is then discovered on repeat recordings. Since many people with epilepsy have persistently normal EEGs, a practical question arises concerning the yield of multiple EEGs. To determine the probability of finding IIEA with serial EEGs (the operational curve), we reviewed data from 1,201 EEGs on 429 adult patients, most with definite epilepsy presenting in adulthood. The diagnosis was made either clinically or with the support of the EEG. In 50% of our patients with IIEA, the abnormality is present on the first record, in 84% by the third EEG, and in 92% by the fourth. There is relatively little yield to serial EEGs beyond this point.

Sensitivity and Specificity of Electroencephalography (EEG) Among Patients Referred to an Electrophysiology Lab in Bangladesh

“…Granieri et al 49 , Olafsson et al 51 and Tekle-Haimanot et al 53 found a higher proportion of HTCS like our study. Studies on adult epilepsies showed that the chance of detecting interictal epileptiform discharges (IEDs) from the first EEG varies between 29% and 55% [54][55][56] . A Repeat EEG may ultimately demonstrated the IEDs in 80%-90% of the patients 54,56 .…”

“…Studies on adult epilepsies showed that the chance of detecting interictal epileptiform discharges (IEDs) from the first EEG varies between 29% and 55% [54][55][56] . A Repeat EEG may ultimately demonstrated the IEDs in 80%-90% of the patients 54,56 . We had a similar yield of abnormal report in EEG.…”

“…But, the frequency of reported EEG abnormalities in patients with seizures varies widely between studies. The sensitivities of EEG range from 29 to 69% [26][27][28][29] .…”

Interpretação da diretriz da Associação Nacional de Medicina do Trabalho (ANAMT) “Epilepsia e Trabalho: Rastreamento” utilizando a razão de verossimilhança

“…Assim, no exame único, encontrase sensibilidade de 52,7% 13 e, em quatro exames sequenciais, vai a 87,6% 14 . Já a especificidade varia entre 78,0 e 98,0% 15 , dependendo do examinador.…”

International Issues: Neurology mission in the Ecuadorian Amazon rainforest

“…The rate of abnormal EEG findings in the epilepsy patients was 65% (epileptiform discharges and focal slowing), which seems to be higher than what we typically find in developed countries. 4 Our higher rate of abnormal EEGs may be explained by referral bias, lack of neurologists in the area, and, more importantly, because epilepsy and EEG abnormalities are more prevalent in the developing world. 5 In Tena, carbamazepine is most frequently used (Ͼ45%), followed by valproic acid (35%), and then phenytoin (10%).…”