A Contrast Study On The Features Between Scalp EEG And Intracranial EEG In Initial Temporal Lobe Seizures

Purpose:To submit the orientational EEG marks for increasing the orientational accuracy of epilepsy through a contrast study on the features between scalp EEG and intracranial EEG in initial temporal lobe seizures. Methods:Twenty intractable temporal lobe epilepsy (TLE) patients fulfilled the inclusion criteria( male:13,female:7) The average age of the patients was 24 (range 19-48 years). The average course of the disease was11.2 years (range 2-29years),The patients still had seizures from 10 times a month to 5 times a day ,partial patients had more than one type of seizures, though the regular antiepileptic drugs were taken .CT and MRI showed positive in 13 patients. Scalp-EEG was taken by routine methods including opening/closing eyes. flash stimulation. over air exchange and sphenoid bone electrodes with the standard of 3 times caught during monitoring time in one day or more .Sleeping deprivation or drugs-induced onset was taken if necessary. Intracranial video- EEG was taken for patients if accurate orientations could't got by no-invasive methods. The electrodes were put under and/or deeper scleromeninx through drilling cranial bone or bone flap craniotomy. The Intracranial video- EEG was analyzed by the relevant software for contrast studying and the accuracy for orientation of seizure focus between scalp -EEG and intracranial - EEG recording in initial temporal lobe seizures. Results:Abnormal discharge of all 20 patients was recorded in primary onset. Scalp-EEG presented the following types: ① low-amplitude with rapid -rhythm. ② θ -waveoidrhythm. ③θ -wave rhythm--rapid-rhythm, ④rapid -wave-- θ -waveoid rhythm. ⑤ α oid-sharp-wave rhythm. Intracranial-EEG recorded as 4 types of onset: ①low-amplitude with rapid-rhythm. ②sharp-wave rhythm, ③ acanthoid-wave rhythm, ④ slow-wave rhythm. There were 9 patients whose intracranial-EEG presented as low-amplitu –de with rapid-rhythm.scalp-EEG with low-amplitude with rapid-rhythm. 3 θ-wave rhythm--rapid-rhythm. 1 θ-wave rhythm1.1 rapid-wave--θ-wave rhythm. Intracranial-EEG presented as sharp-wave rhythm with 6 patients: 5 scalp-EEG with θ-wave rhythm. 1 α-sharp-wave rhythm. Intracranial– EEG presented as acanthoid-wave rhythm with 3 patients:2 scalp-EEG with θ-wave rhythm--rapid-rhythm.1 low-amplitude with rapid-rhythm. Intracranial-EEG presented as θ-wave rhythm with 2 patients: 1 with θ–wave rhythm--rapid-rhythm.1 with θ-wave rhythm. Scalp-EEG presen- ted bilateral abnormal discharge with 7 patients and one side origin with 7 patients.Intracranial-EEG of 5 of 7 Patients whose scalp-EEG presented bilateral abnormal discharge presented one side discharge.Intracranial electrodes all discharged in one side when patients with scalp electrodes discharged in one side. Conclusion:Intracranial-EEG significantly increased the orientational accuracy of seizure focus .Our data showed that the positive rate in scalp-EEG and intracranial-EEG were respective 50% and 100%. 1. Scalp-EEG with low-amplitude with rapid-rhythm and temporal lobe acanthoid-wave indicated the good effect on orientation but the slow- rapid rhythm by beginning with slow-wave(θ-wave )had no ideal effect on orientation.The best orientational effects with intracranial EEG were presented by low-amplitude with rapid-rhythm,acanthoid-wave rhythm and sharp-wave rhythm . 2. The same representation that 80% of patients of scalp-EEG with low-amplitude with rapid-rhythm showed with intracranial EEG indicated that there was a better unifying between scalp-EEG and intracranial EEG. 80% of patients of scalp-EEG with temporal lobe acanthoid-wave were monitored to be sharp-wave by intracranial EEG. This indicated the clear orientational value of scalp-EEG presented temporal lobe acanthoid –wave.sharp-wave and acanthoid slow-wave in the beginning of the seizure. When the structure of brain was in companyed with lesions most of the EEG showed the slow-wave rhythm. The EEG of lesions was in accordance with seizure focus with 61% ratio.