Elsevier

Clinical Neurophysiology

Volume 119, Issue 10, October 2008, Pages 2201-2204
Clinical Neurophysiology

K-complex-induced seizures in autosomal dominant nocturnal frontal lobe epilepsy

https://doi.org/10.1016/j.clinph.2008.07.212Get rights and content

Abstract

Objective

To examine in detail the relations between seizures and K-complexes in autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE).

Methods

Prolonged continuous video-EEG recording and analysis of 30 seizures in an 18-year-old woman suffering from ADNFLE with a CHRNA4 gene mutation.

Results

Twenty-seven of 30 recorded seizures started just after a K-complex. In nine cases a sound induced a K-complex that was immediately followed by the seizure. Most seizures preceded repetitive and brief ictal restarts.

Conclusions

Three new characteristics have been observed in this ADNFLE patient: a K-complex is almost invariably present at seizure onset; sounds trigger some seizures; ictal restarts occur often.

Significance

These new observations – the presence of K-complexes at seizure onset and occurrence of sound-triggered seizures – support the view that ADNFLE seizures may be initiated by K-complexes.

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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