K-complex-induced seizures in autosomal dominant nocturnal frontal lobe epilepsy
Introduction
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) was first described in 1994 (Scheffer et al., 1994). Mutations associated with this hereditary epilepsy involve subunits of the neuronal nicotinic acetylcholine receptor (nAChR) (Steinlein et al., 1995). For many years nocturnal frontal lobe epilepsy (NFLE) seizures were not clearly differentiated from sleep disorders (Tinuper et al., 1990) and the relation between seizures and sleep is still not clear. EEG transients, rhythms or microstructural components of sleep have been suspected to facilitate or trigger NFLE seizures – the cyclic alternating pattern phase A (CAP-A) sequences (Terzano et al., 1991) in epilepsies with nocturnal partial motor seizures, a slow wave resembling a K-complex (KC) in NFLE (Tinuper et al., 1990), an atypical KC (Oldani et al., 1996) or spindles (Picard et al., 2006) in ADNFLE. Since these reports have not been documented in detail, we carried out a comprehensive video-EEG study of an ADNFLE case with a new mutation in which seizure onsets often coincided with KCs and were sometimes triggered by sound stimuli.
Section snippets
Patient and methods
An 18-year-old woman was monitored continuously over 8 days in our video-EEG unit for diagnosis. She had suffered from nocturnal seizures since the age of three: frequent nocturnal generalized clonic seizures initially, replaced later by seizures consisting of brief, stereotyped episodes, sometimes starting with an ascending heat sensation. The patient often remembered her ictal manifestations: right arm stretching, slow arm movements, mouth opening, chewing and breathing difficulties. Seizures
Results
Continuous video-EEG monitoring revealed clustered seizures consisting of 7–13 episodes per night which occurred on three nights. Nine of 30 recorded seizures were triggered by sudden noises such as door opening or shouting. Seizures started abruptly during sleep with an axial extension, then forced mouth opening, apnoea, dystonic posturing of the right then left arm followed by athetotic movements of right then both arms and ended with a snoring sound (see Supplementary Video). Some movements
Discussion
This analysis of 30 seizures from a genetically confirmed ADNFLE case shows that K-complexes were associated with the onset of 90% of seizures. Thirty per cent of these seizures were associated with a sudden sound, pointing to a likely causal relation. For these noise triggered seizures, the sound provoked the K-complex (Halász, 1993) and the seizure, and linked together these two latter events in such a way that the KC occurred just at the beginning of the seizure. Thanks to these noise
Acknowledgements
The authors wish to thank Dr. Richard Miles for corrections and comments on the manuscript. J.E. was supported by grant from the “Société Française de Neurologie”. We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. The authors report no conflicts of interest.
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