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Approximately two-thirds of patients with epilepsy become seizure-free with the adequate antiepileptic drug therapy.It is generally believed that antiepileptic treatment might be gradually withdrawn until stopped after a minimum period of two years of seizure freedom,as well as making a careful evaluation of the risk/benefit ratio.In the antiepileptic drugs discontinuance literature,the most consistent risk factors predictive of relapse are remote symptomatic causes,abnormal electroencephalogram and special epilepsy syndrome.The impacts of abnormal electroencephalogram,especially interictal epileptiform discharges on the seizure relapse after antiepileptic drugs withdrawal are not completely clear for now.In this article the literature describing the predictive value of interictal epileptiform discharges in different withdrawal periods is reviewed.
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Objective To analyze the characteristics and some related influences of interictal epileptiform discharges (IEDs) for symptomatic temporal lobe epilepsy(TLE) and extratemporal lobe epilepsy(ETLE) patients in whom with focal lesion on structural imaging .Methods The electrophysiological and clinical data of 257 epilepsy patients were retrospectively analyzed , all of whom had a focal lesion revealed by structural imaging .Patients were divided into 2 groups according to the locaton of the lesion:TLE group and ETLE group , patients were also divided into 3 subgroups according to the relationship between the location of IEDs and the lesion :TLE-1/ETLE-1 subgroup with a norm interictal EEG; TLE-2/ETLE-2 subgroup with IEDs absolutely located in brain lobes in which lesion located;TLE-3/ETLE-3 subgroup with IEDs exceed or absolutely not located in the lobes in which lesion located . Results The proportion of TLE-1 was significantly lower than ETLE-1 ( P<0.01 ) , while the proportion of TLE-2 was significantly higher than ETLE-2(P<0.01).The proportion of the TLE-3 subgroup increased along with a longer duration, and the proportion of ETLE-3 subgroup decreased along with a lower seizure frequency , and also the older the age at onset .Conclusions The positive rate of IEDs and its positioning accuracy are significantly higher in symptomatic TLE than that in ETLE patients .The distribution of IEDs is more likely to be affected by epilepsy duration in TLE , while it is more easily to be affected by seizure frequency and age at onset in ETLE .
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Objective To investigate the effects of circadian rhythm on interictal epileptiform discharges in patients with localization-related epilepsy.Methods Patients diagnosed with epilepsy in Sanbo Brain Hospital from January 2011 to January 2012 participated in this study.All patients were subjected to comprehensive evaluation,which included prolonged video-electroencephalogram (EEG),magnetic resonance imaging.Intracranial electrodes,PET,SPECT were also adopted if necessary.Circadian rhythm was divided into four stages:REM,NREM Ⅰ-Ⅱ,NREM Ⅲ-Ⅳ,and waking.The amount and distribution of ⅡD were compared by ANOVA.Results Significant differences in the amount and distribution of ⅡD were found among NREM Ⅰ-Ⅱ,NREM Ⅲ-Ⅳ,REM,and waking.However,no differences in the amount and distribution of ⅡD were noted between NREM Ⅰ-Ⅱ and NREM Ⅲ-Ⅳ as well as between REM and waking.Conclusion The amount of ⅡD is higher in NREM than in REM and waking;thus,NREM is more sensitive to diagnose epilepsy.The distribution of ⅡD in REM and waking is more restricted than that in NREM.
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BACKGROUND: Interictal and ictal scalp EEG is the most often used and relied-on method of noninvasive presurgical evaluation in temporal lobe epilepsy. We attempted to compare unitemporal interictal epileptiform discharges (UIED) with bitemporal interictal epileptiform discharges (BIED) groups for lateralizing value and propagation patterns of ictal scalp EEGs. METHODS: We investigated ictal scalp EEGs in 48 patients who had undergone anterior temporal lobectomies. We divided them into UIED and BIED groups by cut-off value of 90% in the laterality of IED. RESULTS: We analyzed ictal EEG patterns in 201 seizures of 32 patients with UIED and 86 seizures of 16 patients with BIED. Ictal scalp EEG was correctly lateralized significantly more often in the UIED group compared with the BIED group; 93.5% versus 57.0% in seizures and 93.8% versus 62.5% in patients, respectively. Bilateral independent onset was seen more frequently in the BIED group whereas the maintenance of ictal discharges in the unilateral temporal or hemisphere occurred more frequently in the UIED group. Lateralization by a later significant pattern (LSP) presents additional value of correct lateralization rather than pattern at onset (PAO) only. CONCLUSIONS: Interpretation of ictal scalp EEGs must be considered more cautiously in patients with BIED because BIED may be correlated with bitemporal excitability.