Benign neonatal sleep myoclonus.
ABSTRACT Benign neonatal sleep myoclonus is a non-epileptic disorder. This phenomenon of the first weeks of life is characterized by erratic myoclonic jerks occurring only during sleep and with no electroencephalographic changes. It is not associated with perinatal complications, disappears spontaneously within two to four months, and it does not compromise future development. We illustrate with a video this relatively frequent condition, which is often misdiagnosed as epileptic in nature, and discuss the clinical characteristics and differential diagnosis.
- [Show abstract] [Hide abstract]
ABSTRACT: Benign neonatal sleep myoclonus is a non-epileptic movement disorder that may mimic neonatal seizures. The aim of this study was to clarify the clinical manifestations and outcomes in Japanese infants with benign neonatal sleep myoclonus. We reviewed the clinical manifestations and outcomes in 15 consecutive patients with benign neonatal sleep myoclonus (males: 10), including three paired familial cases, referred to our center between 1996 and 2011. The diagnosis of benign neonatal sleep myoclonus was based on a neonatal onset, characteristic myoclonic jerks that occurred during sleep, and normal electroencephalogram findings. All were healthy full-term neonates at birth. The age at onset ranged from 1 to 18days (median: 7days). Prior to referral to our center (3-8weeks), two infants had been placed on antiepileptic drugs, without effects. During the clinical course, the myoclonic jerks resolved by 6months in 14 of the 15 patients. On follow-up (final evaluation, mean: 38months), all but one patient (speech delay) showed normal development. None developed epilepsy. Of note, migraine occurred after 5years of age in three children, including one who developed cyclic vomiting syndrome, evolving to migraine. Another boy developed cyclic vomiting syndrome, a precursor of migraine, before 1year, and was being followed. A high incidence of migraine was observed in five (42%) of 12 parents whose detailed family history was available. Our study suggests that benign neonatal sleep myoclonus is related to migraine. With the high rate of familial cases, further genetic study, including migraine-related gene analysis, is necessary to determine the underlying mechanism responsible for benign neonatal sleep myoclonus.Brain & development 04/2014; · 1.74 Impact Factor
Clinical commentary with video sequences
Benign neonatal sleep
Catherine Marx1, Marcelo Rodrigues Masruha2, Eliana Garzon1,
Luiz Celso Pereira Vilanova2
1Epilepsy Treatment and Research Unit
2Division of Child Neurology, Department of Neurology and Neurosurgery,
Federal University of São Paulo, São Paulo, Brazil
Received August 14, 2007; Accepted March 14, 2008
ABSTRACT – Benign neonatal sleep myoclonus is a non-epileptic disorder. This
occurring only during sleep and with no electroencephalographic changes. It is
not associated with perinatal complications, disappears spontaneously within
two to four months, and it does not compromise future development. We
illustrate with a video this relatively frequent condition, which is often misdi-
agnosed as epileptic in nature, and discuss the clinical characteristics and
differential diagnosis. [Published with video sequences].
Key words: myoclonus, benign neonatal sleep myoclonus, non-epileptic events,
A 27-day-old, male newborn was
transferred to our hospital because of
a myoclonic “epileptic status”. He
was born at a primary care hospital by
normal delivery, following an un-
3.84 kg and with a normal cephalic
measurement (35 cm). There was no
family history of epilepsy or any other
neurological impairment. In the first
days of life, he started to present mul-
a frequency of one to three per sec-
ond, affecting all limbs, especially the
upper extremities, occurring in clus-
ters and only during sleep. He was
transferred to the intensive care unit
(ICU) and treated as status epilepticus.
There were no changes in skin color,
eye deviation, face movements, heart
the events. The pediatricians consid-
ered it to be an epileptic disorder and
treatment with phenobarbital. He
remained sleepy with the jerks wors-
ening. At that time, the infant received
intravenous phenytoin, with no im-
provement of the abnormal move-
ments. After 27 days being treated for
epilepsy without improvement, he
was transferred to our hospital, a
tertiary care unit with neurological
On admission to our hospital his vital
signs, general physical and neurologi-
cal examinations were normal. Nor-
mal values were obtained for the fol-
lowing parameters: blood glucose,
complete blood count (CBC), serum
electrolytes, LDH, CK, total and par-
tial fat analysis, hepatic and renal
The patient underwent 24-hour video-
EEG monitoring using colloidon-fixed
electrodes in the neonatal arrange-
oculogram, ECG and electromyogram
from right upper and left lower limbs
and head, including all sleep stages
and wakefulness (figures 1 and 2).
Department of Neurology and
Botucatu Street, 720,
Federal University of São Paulo,
Epileptic Disord 2008; 10 (2): 177-80
Epileptic Disord Vol. 10, No. 2, June 2008
Continuous, twenty-four hour-registered traces demon-
strated brief erratic myoclonic jerks, during sleep and
sleepiness, affecting the head and upper limbs, involving
mainly flexor muscle groups. Occasionally, some jerks of
the low left limb were observed (see video sequence).
Bouts of myoclonic jerks lasted, at most, 50 seconds.
These jerks were mostly of high amplitude. The move-
ments stopped abruptly when the patient was aroused by
touch or repositioning, and tended to recur a few minutes
later. There were only muscular artifacts during the event,
no paroxysmal discharges and no disturbances at the
electrical baseline were observed. The heart rate did not
Figure 1. Neonatal electroencephalographic (EEG) montage, electrocardiogram (ECG) and electromyogram of right upper and left lower limbs
alteration of EEG.
Figure 2. Another brief subtle myoclonic jerk occurs during sleepiness, this time of the lower limbs (not represented in the picture) showing no
other alteration of the parameters monitored-EEG, ECG and EMG of upper limbs.
C. Marx, et al.
Epileptic Disord Vol. 10, No. 2, June 2008
change much from baseline during the myoclonic jerks.
Blood pressure was not taken. The jerks never occurred
when the infant was awake.
later. The neurological examination was normal and there
was normal development. The episodes of myoclonic
jerks resolved spontaneously over the third month of life.
Benign neonatal sleep myoclonus (BNSM) should be con-
sidered a sleep disorder and the use of the term “seizure”
in its description should be avoided (Daoust-Roy and
Seshia 1992). It was first described in 1982 by Coulter and
Allen. They reported three infants who presented with
repetitive, bilateral, myoclonic jerks, involving mainly the
forearms and hands. Neurological examination and elec-
troencephalograms (EEG) were normal and remained nor-
mal during follow-up (Coulter and Allen 1982).
BNSM occurs in neurologically healthy neonates, with
onset in the first month of life, more commonly in the first
two weeks, usually disappearing before six months of age
and requires no treatment (Richelme et al. 1990). The
myoclonic jerks may be focal, multifocal or generalized,
occurring in clusters with a frequency of one to 15 per
second, and they do not stop with restraint, mimicking
neonatal seizures. However, several features of BNSM
help in its recognition: it only occurs during non-REM
sleep or quiet sleep (mainly in stages III and IV), and tends
to resolve during REM sleep, stopping abruptly and con-
sistently when the child is aroused and electrographic
seizures do not occur during events (Goraya et al. 2001).
The episodes can be exacerbated or provoked by admin-
istration of benzodiazepines (Daoust-Roy and Seshia
1992). There are no sequelae, and psychomotor and cog-
nitive development is normal. The syndrome is usually
sporadic; only a few familial cases have been reported in
the literature (Cohen et al. 2007, Paro-Panjan and Neu-
The differential diagnoses for neonatal sleep myoclonus
include benign familial and non-familial neonatal sei-
zures, benign myoclonus of early infancy, essential myo-
clonus and myoclonic seizures (Daoust-Roy and Seshia
1992, Coulter and Allen 1982, Richelme et al. 1990,
Goraya et al. 2001). In healthy, newborns the main differ-
ential diagnosis primarily concerns benign familial and
non-familial neonatal seizures. BNSM usually manifests
on the second or third postnatal day. Seizures occur 10 to
20 times a day and have a characteristic electroclinical
presentation, which consists of EEG flattening accompa-
nied by apnoea and tonic motor activity followed by
by clonic activity. It is a self-limiting disorder usually
resolving after one to six months of age, however 10% of
infants exhibit subsequent non-febrile seizures and may
require long-term anticonvulsant therapy. Normal neuro-
logical development is expected (Volpe 2001).
Benign myoclonus of early infancy, first described by
Fejerman and Lombroso, is a paroxysmal phenomenon of
the first two years of life, which occurs in neurologically
healthy infants during wakefulness, and is usually trig-
gered by excitement or frustration (Lombroso and Fejer-
man 1977). It is characterized by a group of spasms that
usually appears during meals, the intensity and severity of
which increase after weeks or months and tending to
resolve within three months. Occasional episodes may
occur later. MRI and EEG studies are normal and no
treatment is necessary (Pachatz et al. 1999).
Essential myoclonus is a sporadic or hereditary disorder
with a benign course, exaggerated by muscle activation
and suppressed by consumption of alcohol. Age-at-onset
ranges from two months to 16 years, with involuntary
movements of the face, neck, or extremities and with no
known etiology. It has been linked to a mutation on
chromosome 7 (Cohen et al. 2007).
Under most circumstances neonatal seizures occur in a
setting of perinatal insult such as asphyxia and metabolic
or infectious processes. The relationship of the attacks
of the infant, and the normality of the EEG are important
clues to a diagnosis of BNSM.
The etiology of BNSM is uncertain. Some authors have
suggested that it is a maturation disorder of the
brainstem/reticular activating system, an area of the brain
known to be linked with both myoclonic movements and
the control of normal sleep. Other authors have suggested
that a transient disorder of the serotoninergic system might
play a role in the pathogenesis of this disorder (Resnick
et al. 1986). Siblings have been seen with BNSM, suggest-
ing a genetic link, but this also remains speculative
(Noone et al. 1995).
Other authors have reported cases of BNSM, but few have
been documented polygraphically. The progressive in-
crease in the phenomenon up to the third week of life
could depend of the increase in quiet sleep with respect to
active sleep normal at this age (Di Capua et al. 1993). The
antiepileptic drug treatment employed probably contrib-
uted to increase the frequency of myoclonic jerks. The
infant was treated for status epilepticus with an AED
causing sedation and an increase in quiet sleep time.
The prevalence is unknown; the condition is under-
recognized (Ramelli et al. 2005) Maneuvers such as rock-
ing in a head-to-toe direction and repetitive sound stimuli
have been described as activating procedures for myo-
clonic jerks in BNSM (Alfonso et al. 1995, Paro-Panjan
BNSM as an epileptic event in this case were troublesome,
leading to lengthened hospitalisation, unnecessary expen-
sive, complementary investigations, parental anxiety, and
pointless administration of AED that exacerbated the clini-
Epileptic Disord Vol. 10, No. 2, June 2008
Benign neonatal sleep myoclonus
BNSM is expressed as myoclonic jerks occurring only
during sleep, soon after birth, interrupted on arousal or
rally remitting in a few months. Recognition as an innocu-
ous and non-epileptic entity is important so that needless
treatment, unnecessary investigations and undue hospital-
ization can be avoided, and parental anxiety minimized
(Lombroso and Fejerman 1977, Coulter and Allen 1982,
Seshia 1992, Di Camua et al. 1993, Noone et al. 1995,
Ramelli et al. 2005, Pachatz et al. 1999, Goraya et al.
2001, Volpe 2001, Cohen et al. 2007). M
Acknowledgments. This study was sponsored by Fundação de
Amparo à Pesquisa do Estado de São Paulo (FAPESP).
Alfonso I, Papazian O, Jeffries HE. A simple maneuver to pro-
voke benign neonatal sleep myoclonus. Pediatrics 1995; 96:
Cohen R, Shuper A, Strussberg R. Familial benign neonatal sleep
myoclonus. Pediatr Neurol 2007; 36: 334-7.
Coulter DL, Allen RJ. Benign neonatal sleep myoclonus. Arch
Neurol 1982; 39: 191-2.
Daoust-Roy J, Seshia SS. Benign neonatal sleep myoclonus - a
differential diagnosis of neonatal seizures. Am J Dis Child 1992;
Di Capua M, Fusco L, Ricci S, et al. Benign neonatal sleep myo-
clonus: clinical features and video-polygraphic recordings. Mov
Disord 1993; 8: 191-4.
Goraya JS, Poddar B, Parmar VR. Benign neonatal sleep myoclo-
nus. Indian Pediatr 2001; 38: 81-3.
Lombroso CT, Fejerman N. Benign myoclonus of early infancy.
Ann Neurol 1977; 1: 138-48.
Noone PG, King M, Loftus BG. Benign neonatal sleep myoclo-
nus. Ir Med J 1995; 88: 172.
Pachatz C, Fusco L, Vigevano F. Benign myoclonus of early in-
fancy. Epileptic Disord 1999; 1: 57-61.
Paro-Panjan D, Neubauer D. Benign neonatal sleep myoclonus:
experience from the study of 38 infants. Eur J Paediatr Neurol
2008; 12: 14-8.
Ramelli GP, Sozzo AB, Vella S, et al. Benign neonatal sleep myo-
clonus: an under-recognized, non-epileptic condition. Acta Pae-
diatr 2005; 94: 962-3.
Resnick TJ, Moshé SL, Perotta L, et al. Benign neonatal sleep
myoclonus - relationship to sleep states. Arch Neurol 1986; 43:
Richelme C, Delpont E, Deswart M, et al. A propos d’un cas de
myoclonies du sommeil profond du nouveau-né. Pediatrie 1990;
Volpe JJ. Neonatal seizures. In: Volpe JJ, ed. Neurology of the
newborn. 4thed. Philadelphia: Saunders, 2001: 178-214.
Legend for video sequence
Brief erratic myoclonic jerks occurring in upper and
lower limbs simultaneously or not, during sleepiness
and quiet sleep in a term newborn baby involving
mainly flexor group muscles, ceasing when aroused.
C. Marx, et al.
Epileptic Disord Vol. 10, No. 2, June 2008