CLINICAL REVIEWMovement disorders in sleep: Guidelines for differentiating epileptic from non-epileptic motor phenomena arising from sleep
Section snippets
The influence of sleep on epileptic activity
The influence of sleep stages on paroxysmal activity and seizures is well known. Epileptic interictal discharges may be influenced by the state of arousal and seizures, particularly in some epileptic conditions, may be precipitated by sleep or occur primarily according to a recognizable circadian rhythm.1 Drowsiness and NREM sleep EEG activity facilitate the propagation and synchronization of epileptiform discharges. In the presence of a diminished, but still preserved, muscular tone, these
The wide spectrum of nocturnal frontal lobe epilepsies
NFLE is a peculiar form of partial epilepsy in which seizures, characterized by bizarre motor behaviour or sustained dystonic posture, appear almost exclusively during sleep. The clinical spectrum of NFLS comprises distinct paroxysmal sleep-related attacks of variable duration and complexity.6, 7, 8, 9, 10, 11, 12, 13, 14 In a large series studied by video-polysomnographic recording,6 we described four main semeiological patterns: minor motor events, the so called paroxysmal arousals (PAs),15
The difficulties of differential diagnosis
Distinguishing nocturnal seizures originating from the frontal lobe from paroxysmal non-epileptic sleep disorders is often difficult and sometimes impossible on clinical grounds alone, even for experienced epileptologists and sleep physicians.16, 17, 28, 29, 30, 32, 34
There are three orders of problems in differentiating epileptic seizures from non-epileptic sleep-related events on the basis of clinical history:
First, the behavioural patterns encountered in NREM arousal parasomnias, REM
Clinical and polygraphic features of non-epileptic paroxysmal events during sleep
According to the International Classification of Sleep Disorders (ICSD-II) (Table 1), the non-epileptic paroxysmal motor events during sleep include different categories such as (1) parasomnias, (2) sleep-related movement disorders, and (3) isolated symptoms, apparently normal variants and unresolved issues. We will treat only the motor phenomena which in our experience tend to pose differential diagnostic difficulties with epileptic seizures.
- (1)
Parasomnias
- (a)
NREM parasomnias
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Confusional arousals
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Sleep
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- (a)
Open problems
Video-polysomnography may be indicated to assist in the diagnosis of PAs or other sleep disruption thought to be seizure related or in a presumed parasomnia,64 but accepted criteria for the diagnosis of nocturnal frontal lobe seizures are lacking and even ictal scalp EEG recordings could fail to disclose paroxysmal abnormalities. The difficulties in distinguishing nocturnal epileptic seizures from parasomnias reflect just one aspect of the intriguing issue of the physiopathological
Final considerations
In recent decades, motor phenomena during sleep have been the topic of intensive studies, mainly since the introduction of video-polysomnographic recording techniques. Many conditions have been described and others are under investigation. The differentiation between physiological and pathological events during sleep is part of neurologists’ daily work either as epileptologists or sleep experts. However, much work has yet to be done in this field. Given the absence of standardized clinical or
Acknowledgements
We thank our EEG and sleep laboratory technicians and Elena Zoni and Massimo Armaroli for help in manuscript editing.
References (74)
- et al.
The wide clinical spectrum of nocturnal frontal lobe epilepsy
Sleep Med Rev
(2000) - et al.
From nocturnal paroxysmal dystonia to nocturnal frontal lobe epilepsy
Clin Neurophysiol
(2000) - et al.
Autosomal dominant frontal epilepsy misdiagnosed as sleep disorder
Lancet
(1994) - et al.
NREM parasomnias: arousal disorders and differentiation from nocturnal frontal lobe epilepsy
Clin Neurophysiol
(2000) - et al.
Genetic aspects and genetic epidemiology of parasomnias
Sleep Med Rev
(2003) - et al.
Polysomnographic study of sleeplessness and oneiricisms in the alcohol withdrawal syndrome
Sleep Med
(2002) - et al.
Sleep disorders in multiple system atrophy: a correlative video-polysomnographic study
Sleep Med
(2004) - et al.
Bruxism and orofacial movements during sleep
Dent Clin North Am
(2001) - et al.
Excessive fragmentary myoclonus in NREM sleep: a report of 38 cases
Electroenceph Clin Neurophysiol
(1985) - et al.
Excessive fragmentary hypnic myoclonus: clinical and neurophysiologic findings
Sleep Med
(2002)
Increased sensitivity of the neuronal nicotinic receptor alpha 2 subunit causes familial epilepsy with nocturnal wandering and ictal fear
Am J Hum Genet
Paroxysmal periodic motor attacks during sleep: clinical and polygraphic features
Electroencephalogr Clin Neurophysiol
CAP, epilepsy and motor events during sleep: the unifying role of arousal
Sleep Med Rev
Chronobiology
Effect of sleep and sleep stage on epileptic and nonepileptic seizures
Epilepsia
The grand mal epilepsies and the sleeping-waking cycle
Epilepsia
Epilepsy with impulsive petit mal (juvenile myoclonic epilepsy)
Acta Neurol Scand
The seizures of benign childhood epilepsy with rolandic paroxysmal discharges
Epilepsia
Nocturnal frontal lobe epilepsy. A clinical and polygraphic overview of 100 consecutive cases
Brain
Nocturnal paroxysmal dystonia with short-lasting attacks: three cases with evidence for an epileptic frontal lobe origin of seizures
Epilepsia
Seizures during sleep
Nocturnal frontal lobe epilepsy
The concept of paroxysmal nocturnal dystonia
Ictal video-EEG features in children with nocturnal frontal lobe seizures
Hyperkinetic manifestations in nocturnal frontal lobe epilepsy. Semeiological features and physiopathological hypothesis
Neurol Sci
Paroxysmal arousals during sleep
Neurology
Nocturnal paroxysmal dystonia
Epilepsy Res Suppl
Epileptic nocturnal wanderings
Sleep
Mesial frontal epilepsy
Epilepsia
Complex partial seizures of frontal lobe origin
Ann Neurol
Sleep-related hyperkinetic seizures of temporal lobe origin
Neurology
Nocturnal frontal lobe epilepsy: intracerebral recordings of paroxysmal motor attacks with increasing complexity
Sleep
Intracerebral recordings of minor motor events, paroxysmal arousals and major seizures in nocturnal frontal lobe epilepsy
Neurol Sci
Nocturnal paroxysmal dystonia and nocturnal wandering
Neurology
Split-screen synchronized display. A useful video-EEG technique for studying paroxysmal phenomena
Epileptic Disord
Hypnogenic paroxysmal dystonia: epileptic seizures or a new syndrome?
Sleep
Hypnogenic paroxysmal dystonia: epilepsy or sleep disorder? A case report
Clin Electroencephalogr
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- *
The most important references are denoted by an asterisk.