Side-to-side axial movements. Adding a new sign to the asymmetry of the clonic phase and asymmetric seizure termination in differentiating primary and secondarily generalised tonic-clonic seizures.

AIM: To study new semiological signs which help distinguish between primary and secondarily generalised tonic-clonic seizures (GTCS). METHODS: We retrospectively studied 86 GTCS, 13 primary and 73 secondary, in 58 patients who underwent video-EEG (vEEG) evaluation in our epilepsy monitoring unit. Eleven patients had generalised epilepsy and 47 focal epilepsy. Two expert epileptologists, blinded to diagnosis, examined the vEEGs independently for the presence of five semiological signs. RESULTS: Asymmetry of limb movements in clonic phase, side-to-side axial movements, and asymmetric seizure termination occurred more frequently (p<0.05) in secondary GTCS compared to primary GTCS. Combining asymmetry of limb movements in clonic phase and side-to-side axial movements provided the greatest value in differentiating secondary GTCS from primary GTCS. CONCLUSION: Careful examination of GTCS seizure semiology can help differentiate primary from secondary GTCS. The semiological sign of side-to-side axial movements, which has not previously been studied in this context, may add to existing literature of semiological signs and be of value for the evaluation of surgical patients in the epilepsy monitoring unit. In the out-patient setting, a clear history of these signs may help guide drug treatment choices.

Age-specific periictal electroclinical features of generalized tonic-clonic seizures and potential risk of sudden unexpected death in epilepsy (SUDEP).

Generalized tonic-clonic seizure (GTCS) is the commonest seizure type associated with sudden unexpected death in epilepsy (SUDEP). This study examined the semiological and electroencephalographic differences (EEG) in the GTCSs of adults as compared with those of children. The rationale lies on epidemiological observations that have noted a tenfold higher incidence of SUDEP in adults. We analyzed the video-EEG data of 105 GTCS events in 61 consecutive patients (12 children, 23 seizure events and 49 adults, 82 seizure events) recruited from the Epilepsy Monitoring Unit. Semiological, EEG, and 3-channel EKG features were studied. Periictal seizure phase durations were analyzed including tonic, clonic, total seizure, postictal EEG suppression (PGES), and recovery phases. Heart rate variability (HRV) measures including RMSSD (root mean square successive difference of RR intervals), SDNN (standard deviation of NN intervals), and SDSD (standard deviation of differences) were analyzed (including low frequency/high frequency power ratios) during preictal baseline and ictal and postictal phases. Generalized estimating equations (GEEs) were used to find associations between electroclinical features. Separate subgroup analyses were carried out on adult and pediatric age groups as well as medication groups (no antiepileptic medication cessation versus unchanged or reduced medication) during admission. Major differences were seen in adult and pediatric seizures with total seizure duration, tonic phase, PGES, and recovery phases being significantly shorter in children (p<0.01). Generalized estimating equation analysis, using tonic phase duration as the dependent variable, found age to correlate significantly (p<0.001), and this remained significant during subgroup analysis (adults and children) such that each 0.12-second increase in tonic phase duration correlated with a 1-second increase in PGES duration. Postictal EEG suppression durations were on average 28s shorter in children. With cessation of medication, total seizure duration was significantly increased by a mean value of 8s in children and 11s in adults (p<0.05). Tonic phase duration also significantly increased with medication cessation, and although PGES durations increased, this was not significant. Root mean square successive difference was negatively correlated with PGES duration (longer PGES durations were associated with decreased vagally mediated heart rate variability; p<0.05) but not with tonic phase duration. This study clearly points out identifiable electroclinical differences between adult and pediatric GTCSs that may be relevant in explaining lower SUDEP risk in children. The findings suggest that some prolonged seizure phases and prolonged PGES duration may be electroclinical markers of SUDEP risk and merit further study.

Carbamazepine and phenytoin induced Stevens-Johnson syndrome is associated with HLA-B*1502 allele in Thai population.

PURPOSE: Previous studies found a strong association between HLA-B*1502 and carbamazepine (CBZ)-induced Stevens-Johnson syndrome (SJS) in Han Chinese, but not in Caucasian populations. Even in Han Chinese, the HLA-B*1502 was not associated with CBZ-induced maculopapular eruptions (MPE). This study seeks to identify whether HLA-B*1502 is associated with CBZ- or phenytoin (PHT)-induced SJS or MPE in a Thai population. METHODS: Eighty-one Thai epileptic patients between 1994 and 2007 from the Chulalongkorn Comprehensive Epilepsy Program were recruited. Thirty-one subjects had antiepileptic drug (AED)-induced SJS or MPE (6 CBZ-SJS, 4 PHT-SJS, 9 CBZ-MPE, 12 PHT-MPE), and 50 were AED-tolerant controls. RESULTS: For the first time, a strong association between HLA-B*1502 and PHT-induced SJS was found (p = 0.005). A strong association was also found between the HLA-B*1502 and CBZ-induced SJS (p = 0.0005), making Thai the first non-Chinese population demonstrating such an association. Some patients, who were HLA-B*1502 and suffered from CBZ-induced SJS, could be tolerant to PHT and vice versa. This suggests that HLA-B*1502 may be a common attribute required for a Thai patient to develop SJS from these two AEDs; other different elements, however, are also needed for each AED. In addition, no association between HLA-B alleles and CBZ- or PHT-induced MPE was found. CONCLUSIONS: CBZ- and PHT-induced SJS, but not MPE, is associated with HLA-B*1502 allele in Thai population.

A newly identified locus for benign adult familial myoclonic epilepsy on chromosome 3q26.32-3q28.

Benign Adult Familial Myoclonic Epilepsy (BAFME) is an autosomal dominant disorder characterized by adult-onset cortical tremor or action myoclonus predominantly in the upper limbs, and generalized seizures. We investigated a Thai BAFME family. Clinical and electrophysiological studies revealed that 13 were affected with BAFME. There were a total of 24 individuals studied. Genetic analysis by genome-wide linkage study (GWLS) was performed using 400 microsatellite markers and excluded linkage of the previous BAFME loci, 8q23.3-q24.1, and 2p11.1-q12.2. GWLS showed that the disease-associated region in our Thai family was linked to a newly identified locus on chromosome 3q26.32-3q28. This locus represents the fourth chromosomal region for BAFME.