Clinical study of ambulatory electroencephalography in reduction of prophylactic antiepileptic drugs after craniotomy

Abstract

Objective To retrospectively analyze the characteristics of ambulatory electroencephalogram (AEEG) in postcraniotomy patients, with epileptic seizures and without seizures after reduction of preventive antiepileptic drugs, and qualitatively and quantitatively investigate the relationship between AEEG waveforms and seizures, in order to explore the guiding value of AEEG for the reduction of prophylactic antiepileptic drugs. Methods A total of 166 postcraniotomy patients with epileptic seizures after discontinuation of prophylactic antiepileptic drugs admitted in our department from 2010 to 2017 were recruited and subjected to seizure group in this study. Another 166 postcraniotomy patients without seizure who have the similar proportions in age, gender, etiology, location with the seizure group in our department during the same period served as non-epileptic seizure group. The 2 groups of patients were followed up for 1 to 8 years. Referring to the classification of Hughes J R, we divided them into following types: R type (rare), R-M type (rare-moderate), M type (moderate), M-L type (moderate-large), L type (large), NS type (non-sharp spike), RS type (rare sharp spike), MS type (moderate sharp spike), and LS type (large sharp spike). The waves were also assigned into S type (scattered), F type (focal), and P type (paroxysmal) according to the appearance of slow waves. The differences of AEEG waveforms were compared between the 2 groups before the discontinuation of prophylactic antiepileptic drugs. The seizure group was further divided into a controlled subgroup and a non-controlled subgroup according to whether the epilepsy be controlled after taking the drugs again. The number of spike-wave between the 2 subgroups was compared. Results ① Significant differences presented in AEEG type composition ratio between the patients in the seizure group and non-epilepsy seizure group (P 1). ②After taking the drugs again, the number of patients in the control group were gradually decreased from RS-type to LS-type, and the numbers in the uncontrolled group were gradually increased. Conclusion The high-risk waveforms for postcraniotomy seizures after discontinuation of anti-epileptic drugs are slow waves of M, M-L, L and P types and spike waves of MS and LS types. AEEG is of certain guiding value in the prevention and treatment of antiepileptic drugs in patients undergoing neurosurgical craniotomy.

Keywords

• craniocerebral operations
• ambulatory electroencephalogram
• epilepsy