Abstract Sleep-related paroxysmal disorders in infancyand childhood have recently been reviewed and classifiedby the American Sleep Disorders Association. Although insome patients diagnosis is easy to achieve, at times avideo/EEG recording of the episodes is required becauseof the similarity to epileptic seizures. These disordersoften represent a challenge for paediatricians as an accu-rate diagnosis is required. We report a review of the litera-ture and a characterisation of our series of patients.Paroxysmal events during sleep are frequently misdiag-nosed as psychogenic fits, epileptic seizures or physiolog-ic events with evident disadvantages for children and fam-ilies. The widespread use of neurophysiological tech-niques and better knowledge of the semeiology of epilep-tic seizures have led us to correctly define these events,which have sometimes been erroneously treated in thepast.

Key words Childhood parasomnias Childhood epilepsy Sleep terrors Pavor nocturnus Frontal lobe seizures

Introduction

Epileptic seizures and parasomnias represent the twomajor groups of sleep-related paroxysmal disorders inchildhood. Usually epileptic seizures can be easily identi-fied by random occurrence, stereotyped behaviour, briefduration and, when present, motor stiffness and clonicrhythmic movements. Movement disorders and paroxys-mal behaviour belonging to parasomnias are at times moredifficult to recognise.

Parasomnias have been defined as a group of clinicaldisorders associated with undesirable physical phenomenathat occur predominantly during sleep [1]. They representpartial activation of the central nervous system producingskeletal muscle activity. Some are associated with violentmotor and autonomic activity, whereas others have mini-mal muscle disturbance. Some parasomnias, such as night-mares and hypnic jerks, are so common that most individ-uals have experienced them.

A great number of parasomnias are more common inchildhood than in adult people: Laberge et al. [2] found,among 1353 subjects aged between 3 and 13 years, that78% experienced at least one episode of parasomnias.

The International Classification of Sleep Disorders [1]divides parasomnias into four categories, which aredefined by the phase of the sleep in which they occur:arousal disorders, sleep-wake transition disorders, para-somnias usually associated with REM sleep and otherparasomnias which could occur either in the REM orNREM sleep.

In clinical practice, paediatricians are, not infrequently,asked to diagnose such nocturnal paroxysmal events,which could be misdiagnosed as epileptic seizures, psy-chogenic seizures or physiologic events.

The need to classify them implicates that they have tobe recorded by a Video-EEG and polysomnographic tech-nique [3], either if they are suspected to be epileptic or tobe parasomnias. On the other hand hyperkinetic seizures in

Neurol Sci (2005) 26:s205s209DOI 10.1007/s10072-005-0488-4

L. Fusco N. Specchio

Non-epileptic paroxysmal manifestations during sleep in infancyand childhood

L. Fusco () N. SpecchioDivision of NeurologyBambin Ges Childrens HospitalScientific InstitutePiazza S. Onofrio 4, I-00165 Rome, Italye-mail: fusco@opbg.net

children can be difficult to recognise because of the simi-larity of the clinical manifestations with non-epilepticevents such as parasomnias and pseudoseizures: also insuch cases Video-EEG appears as the most effective pro-cedure for the correct diagnosis of this type of seizure [4].

We describe a series of patients referred to us becauseof the presence of paroxysmal non-epileptic events occur-ring during sleep.

Benign neonatal sleep myoclonus

Benign neonatal sleep myoclonus (BNSM) is a phenome-non characterised by the occurrence of repetitivemyoclonic jerks during NREM sleep in the early life ofhealthy newborns [5]. It is recognised as a non-epilepticparoxysmal event and video-polygraphic recording of ictalphenomena helps the diagnosis [6]. BNSM is included inthe fourth category of the International Classification ofSleep Disorders [1] defined as other parasomnias, inwhich disorders entirely benign such as BNSM are associ-ated to other dramatic events such as unexplained noctur-nal death, REM-related sinus arrest and homicidal som-nambulism [7].

Because myoclonic manifestations in a newborn areusually warning symptoms and may indicate brain damageor progressive encephalopathy, the recognition of thisbenign form of myoclonus will avoid unnecessary diag-nostic tests and possibly harmful treatment. In a previouspaper [6] we reported about 12 newborns with BNSM whowere referred to us for investigations of convulsion andsince then many children been diagnosed with BNSM.Usually the neonates are born after normal pregnancy anddelivery and none has a family history of convulsions,

s206 L. Fusco, N. Specchio: Non-epileptic paroxysmal manifestations during sleep

epilepsy or sleep disturbances. The age at onset ofmyoclonic jerks during sleep ranges from 1 to 15 days.The main feature of the myoclonus is that the jerks endwith awakening. All neonates are neurologically normal.Video-polygraphic EEG recording shows that myoclonusoccurs only during NREM sleep and is characterised bysynchronous jerks at a frequency of four to five per second(Fig. 1). Bouts recur irregularly in series lasting 2030min. If the infant is woken or the sleep phase is changed,myoclonus stops. The distribution of myoclonus is usual-ly generalised, although the arms are involved more thanthe legs. At times the jerking spreads progressively toother muscle groups. At times myoclonus is segmentary,involving only one limb or one side of the body. Facialmyoclonias are rare. Myoclonus is rhythmic and some-times so intense and frequent as to provoke shakingthroughout the body. EEG is always normal, as is psy-chomotor development of the infants during the follow-up.

Repetitive sleep starts

Sleep starts, also known as hypnagogic or hypnic jerks,are bilateral, brief body jerks that coincide with sleeponset. Usually they occur during the transition from wake-fulness to sleep and may be considered a physiologicalaccompaniment of falling asleep. They are included in thecategory of sleep-wake transition parasomnias by theInternational Classification of Sleep Disorders [1]. Attimes sleep starts may be excessive, and configure a truesleep disorder, characterised by frequent awakenings andsleep onset difficulty. Excessive sleep starts have beenreported in patients with Parkinsonism [8] and in childrenwith migraine [9]. Excessive sleep starts occurring in

Fig. 1 Neonate aged 17 days. Duringquiet sleep repetitive myoclonic jerkshave been recorded without epilepti-form EEG counterpart (modifiedfrom [6])

Repetitive jerks Quiet sleep

clusters at the onset of sleep have already been reported byus [10] in neurologically impaired children. We observedand described the repetitive occurrence of sleep starts inepileptic children with spastic-dystonic diplegia and cog-nitive deficits. Usually the children who present withrepetitive sleep starts have tetraparesis, from light to verysevere, both with pyramidal or extrapyramidal features.Often they previously had a diagnosis of epilepsy in thefirst year of life, sometimes West Syndrome or more oftenfocal motor epilepsy. The onset of repetitive sleep starts isin the second year of life. The parents came to the physi-cian because of the appearance of multiple spasms dur-ing the initial phase of sleep, which have usually beenbelieved to be a new type of epileptic seizure. Video/EEGrecordings of the events during sleep show the presence ofclusters of massive myoclonic/tonic contractions, resem-bling sleep starts, in the transition phase between wakeful-ness and sleep stage I, with the EEG counterpart beingunremarkable. The clusters last from a few to 15 minutes.The duration of each muscle contraction is from 500 ms to5 s, depending on the rapidity of the contraction, whichcan be more or less tonic. No epileptiform pattern isobserved corresponding to the jerks and often an arousalresponse can follow the jerks (Fig. 2). The interictal EEGis abnormal in most of the children, usually with poorlyorganised background activity with a lack of regional dif-ferentiation, and the possibility of multiple spike activity,as they have static encephalopathy and epilepsy. Althoughphysiological sleep starts are usually a non-periodic event,in these cases the clinical and EEG characteristics of everysingle event permits their definitive classification as sleepstarts. Indeed, muscle contraction is massive, involvingmore trunk than limbs, and onset is sudden and usuallyspontaneous, but can be induced by acoustic and tactilestimulation. Clinical characteristics are similar to a startle,although duration exceeds that usually accepted for physi-

Fig. 2 EEG polygraphic recording of fourspontaneous sleep starts during drowsiness.The EEG counterpart is a diffuse movementartefact

ological sleep starts. Even in normal subjects sleep startscan occur in a brief cluster, due to the physiological oscil-lation between sleep and wakefulness during the period offalling asleep. In neurologically impaired subjects, thisoscillation can be enhanced by the lack of physiologicalinhibition of the pyramidal tract, due to the pyramidallesion. Parents suggested that the phenomenon can be lim-ited by the prone position, and this position is now recom-mended to parents, more than drug therapy. The proneposition can limit movement itself, thus limiting arousaldue to movement and improving the quality of fallingasleep. If drugs are necessary, in cases of severe sleep dis-turbance and daily drowsiness, benzodiazepine appears tobe the drug of choice.

Rhythmic movement disorders

Rhythmic movement disorders are classified as a sleep-wake transition disorder in the International Classificationof Sleep Disorders [1] and comprise head banging, headrolling and body rocking.

All of these are rhythmic movements occurring onfalling asleep, and their maximum peak of expression isduring early development in normal children, althoughthey are usually seen more frequently in patients affectedby mental retardation [11]. This phenomenon usuallybegins during the first year of life with an average age of 9months and ends spontaneously by 4 years of age [12, 13].

Head banging and body rocking usually involve largegroups of muscles, usually the head, the neck and the trunk[14]. The head is sometimes forcedly and repetitively bangedinto the pillow. The movements typically occur just prior tosleep onset, but continue into light sleep, and can recur dur-ing the whole night, always into light sleep. Movements are

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stereotyped and repetitive and last from several minutes tohours, then end spontaneously and sleep is restored.Irritability and daytime somnolence may occur. Children areusually non-responsive during the attack and do not recallthe events on awakening. The video/EEG monitoring showsthat, just before the onset of movements, the child awakes.Then, during the episode, the EEG shows active wakefulnessintermingled with muscle and movement artefacts (Fig. 3).

Arousal disorders

The arousal disorders include sleep-related paroxysmalphenomena such as sleepwalking, sleep terrors and confu-sional arousals [1]. They have been considered as arousaldisorders based on the hypothesis that during the events,

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an incomplete arousal occurs, due to an immature or dis-turbed arousal mechanism [15]. Sleep terrors are charac-terised by a confusional partial arousal, sudden screams, attimes in series, followed by incomprehensive language andbehavioural manifestations of intense fear; usually occur-ring at the end of the first slow-wave phase of NREMsleep. The episode lasts several minutes, not unusuallymore than ten. The child appears to not recognise his par-ents, and at times is afraid of them. Successive episodes inthe same night are not common and usually the intervalbetween the events is of months. The video/EEG recordingof one episode of sleep terror show on the EEG the persis-tence of delta slow activity at the onset of the event (Fig.4a) and throughout (Fig. 4b), suggesting a persistentasleep brain in an awakened body.

Sleep terrors, but also confusional arousal and sleep-walking, may be confused with epileptic seizures, especial-

L. Fusco, N. Specchio: Non-epileptic paroxysmal manifestations during sleep

Fig. 3 Child aged 5 years. Just before theonset of movements, the child awakes.Then, during the episode, the EEG showsactive wakefulness intermingled with mus-cle and movement artefacts

Fig. 4 EEG recording of one episode of sleep terror in a 4-year-old child. The EEG shows the persistence of delta slow activity at theonset of the event (a) and throughout (b)

a b

ly with focal seizures involving the frontal lobes. Frontallobe epilepsy, both sporadic and familial forms, is charac-terised by mainly nocturnal seizures, with a bilateral hyper-kinetic motor component. Seizures are at times so confusedthat they can be misinterpreted as parasomnia phenomena.The differential diagnosis is made on the basis of an accu-rate anamnesis, as epilepsy is characterised by stereotypedseizures, more than one seizure per night and recurrencenightly. At times epileptic children may have had non-epileptic phenomena in early childhood, such as sleep ter-ror or confusional arousal. Definite criteria in differentialdiagnosis between parasomnias and epileptic seizures havebeen widely reported in the last few years [16].

Conclusions

Paroxysmal phenomena during sleep in childhood are acommon occurrence and usually depend on sleep distur-bance, such as parasomnias. Otherwise, epileptic seizures,especially with frontal lobe onset, have their maximumexpression during sleep, often with behavioural ictal ma-nifestation, which could be confused with parasomnias.Carefully collected anamnestic data and, in selected cases,the video/EEG recording of the event, can be useful in dif-ferential diagnosis.

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