zucconi.qxp 14/1/08 02:53 Page 62
Sleep
Nocturnal Frontal Lobe Epilepsy – An Update on Differential
Diagnosis with Non-rapid Eye Movement Parasomnia
a report by
Marco Zucconi
Sleep Disorders Centre, Department of Neurology, San Raffaele Institute, Milan
Nocturnal frontal lobe epilepsy (NFLE) is a distinct paroxysmal sleep-related slow-wave sleep (SWS). They typically occur during the maturational age
disorder covering a spectrum of presentations of presumed frontal lobe of life (childhood and adolescence), but may also persist in adulthood.
origin. NFLE starts in childhood and persists into young adulthood; is Notwithstanding the sleep EEG characteristics of these arousal disorders
characterised by repetitive attacks with predominantly motor component, as delta bursts or rhythmic delta activity preceding the episode, the
high frequency of attacks per night, inter-night repetition and stereotypy slow-wave activity during the episodes and the polygraphic modification
of the episodes; and displays uncommon electroencephalogram (EEG) ictal of heart rate, respiration and muscle tone, there is not, to date, a
and interictal paroxysms during sleep.
1–4
polysomnographic marker of these nocturnal phenomena.
5–7
NFLE is characterised by onset during infancy or childhood with NFLE should be differentiated from parasomnias, in particular from NREM
persistence in adulthood, family history of similar NFL seizures and parasomnias such as arousal disorders. The clinical/anamnestic features
nocturnal episodes simulating non-rapid eye movement (NREM) are quite similar; however, the older age of onset, the high frequency of
parasomnias (sleep terrors or sleepwalking), general absence of the episodes and their short duration, the partial preservation
morphological substrates based on clinical history and brain imaging, of consciousness and the tendency of the syndrome to persist in
motor dystonic–dyskinetic attacks emerging from NREM sleep, repetitive adulthood differentiate NFLE from arousal disorders. The motor pattern
and stereotypical features in the same patient and similar features among during sleep and the semiology of the attacks (stereotypy, dyskinetic and
different patients, normal ictal and interictal EEGs without clear-cut dystonic component, abrupt and sudden onset, dancing or jumping
epileptic paroxysms in more than 50% of the cases and general benefit features for the more complex seizures) may be helpful, although the
from some antiepileptic drugs (AEDs), but occasional resistance to AEDs definite boundaries between the two types of episodes are still not
in some severe forms. completely understood. Differentiating paroxysmal arousal (PA) from
confusional arousal (CA) is difficult because of the lack of paroxysmal EEG
The different types of NFLE seizures may cause severe sleep disruption discharges in PA, and requires videopolysomnography (video-PSG).
5,8
affecting both the macrostructure and microstructure of sleep and
resulting in poor sleep quality, daytime tiredness and sleepiness. The The features that differentiate REM parasomnias from NFLE include
movements may also be so severe that injuries resulting from striking later age of onset, motor episodes during the night enacting behaviour
hard objects can occur. One-third to half of patients also have occasional related to a dream, less stereotypical behaviour, polysomnographic
attacks during the day, not necessarily of the same type as those characteristics of REM without electromyogram (EMG) atonia and an
occurring at night-time, as well as secondary generalised tonic–clonic increase in EMG activity of the limbs.
6,9
Other motor phenomena during
seizures. Neurological examination is generally normal.
1–4
sleep or sleep transitions, such as rhythmic movement disorder, hypnic
myoclonus or physiological body movements, are easier to recognise.
Arousal Disorders Nocturnal panic attacks are characterised by sudden awakening with
NREM parasomnias (arousal disorders) include confusional arousals, sleep complex autonomic activities and an unpleasant sensation of fear or
terrors and sleepwalking. All are characterised by a motor component, imminent death, usually lasting longer than NFLE and, unlike in NFLE,
autonomic activation, emotional involvement, poor memory or not recurring. The presence of the same attacks during the day may
fragmented recalls of the episode, long duration (one to 20 minutes) and also help to differentiate the syndrome from NFLE.
3,4
occurrence on emergence from deep NREM sleep, typically in the first
third of the night with impairment in the ability to awake fully from Differential Diagnosis – Clinical and
Videopolysomnographic Findings
Marco Zucconi heads the Sleep Laboratory at the Sleep
Notwithstanding the spread of video-PSG and the wide diffusion of the
Disorders Centre, San Raffaele Institute, Milan. His research
concept of NFLE, the differential diagnosis between some types of
interests include sleep-related movement disorders, sleep
and epilepsy, parasomnias and sleep disorders in children. Dr
sleep-related seizures and paroxysmal non-epileptic motor events is still a
Zucconi is on the Editorial Board of Sleep Medicine and, since challenge, and no definite guidelines have been approved for this field.
2005, has been the President of the European Restless Legs
Recently, groups in Melbourne (Australia)
10
and Bologna (Italy)
6
tried to
Syndrome Study Group (EURLSSG). He is a member of the
American Academy of Sleep Medicine (AASM) and the
delineate some practical points to differentiate or correlate NFLE and
European Sleep Research Society (ESRS). He is author or
NREM parasomnias.
co-author of more than 120 peer-reviewed papers and book chapters on various topics related
to sleep medicine, epilepsy, neurophysiology and clinical neurology.
Given the time-consuming nature and the expense of executing a
E: zucconi.marco@hsr.it
video-PSG for episodes that are often too infrequent to catch during
62 © TOUCH BRIEFINGS 2007
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