Benign neonatal sleep myoclonus.

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.     

Benign neonatal sleep myoclonus mimicking status epilepticus

Benign neonatal sleep myoclonus is a self-limited movement disorder characterized by neonatal-onset myoclonic jerks only during sleep, abrupt and consistent cessation with arousal, and absence of concomitant electrographic changes suggestive of seizures. It has a good outcome and was included in the differential diagnosis of neonatal seizures. A presumed transient serotonin imbalance and genetic factors may play a role in the pathogenesis of this disorder. We report a case of benign neonatal sleep myoclonus mimicking status epilepticus in an infant with a family history of nocturnal myoclonus, tic disorder, and sleep disturbance. We suggest that this benign entity should be included in the differential diagnosis of status epilepticus during the newborn period.     

A case of benign neonatal sleep myoclonus

We report on a male infant with benign neonatal sleep myoclonus (BNSM). At 12 days of age, he began to have frequent myoclonic jerks in the lower and/or upper extremities during sleep. Myoclonic jerks appeared bilaterally/synchronously and persisted for several minutes to 10 minutes. Both interictal and ictal EEG findings were normal. During follow-up, the patient did not take any medication, and his myoclonic jerks gradually decreased. They completely disappeared at 50 days of age. The patient's development was normal. BNSM is a benign disorder and myoclonic jerks generally disappear without medication. Early diagnosis is important to avoid unnecessary treatment. EEG-EMG recording is useful for diagnosis.     

Benign myoclonus of early infancy: a case report

The author reports a male infant with benign myoclonus of early infancy (BMEI). Series of spasms were first seen at the age of 6 months, then occurred from once to three times a day while he was awake, but never during sleep. The first examination at the age of 8 months revealed a normally developed infant with no neurological abnormality. Both interictal- and ictal-electroencephalograms (EEG) were normal. During three months of follow-up observation with no medication, the spasms completely disappeared. He was subsequently observed up to 2 years and 0 month of age and showed normal psychomotor development, normal EEG with no epileptic discharges, and absence of any types of seizures. The spasms associated with BMEI have been considered to be a non-epileptic phenomenon. They are benign and disappear spontaneously without any complication. Therefore, it is important to differentiate BMEI from various epileptic syndromes, especially West syndrome, to avoid unnecessary administration of antiepileptic drugs.     

Palatal myoclonus in postinfectious opsoclonus myoclonus syndrome : a case report.

An adult male presenting with acute onset opsoclonus, myoclonus and cerebellar ataxia is being reported. Patient had myoclonus involving limbs and palate. There are only a few reported cases associated with palatal myoclonus. Patient showed gradual spontaneous recovery. Possibility of underlying malignancy was excluded by detailed investigations.     

Propriospinal myoclonus: report of a case

Propriospinal myoclonus is an unusual movement disorder. Here we reported a patient with electrophysiological data. The 32-year-old man had spontaneous, intermittent and brief jerks over the trunk, hip and lower limbs muscles for 4 years. The jerks were not sensitive to external stimuli and usually exacerbated whenever the patient felt relaxed, particularly preceding the onset of sleep. Electromyographic (EMG) recordings showed a long duration in each EMG burst (over 200 milliseconds) with a slow propagating pattern initiating from the rectus abdominis muscles. There was no time-locked cortical potential before the spontaneous jerks; however, we found movement-related cortical potential, while the patient was requested to mimic the jerks voluntarily. These results provided evidence to demonstrate that the jerks were not cortical origin and supported the diagnosis of propriospinal myoclonus. A comprehensive clinical evaluation including distinctive electrophysiological findings is important for the diagnosis.     

Danon disease: a novel Lamp-2 gene mutation in a family with four affected members

This is a report of a family with four members affected with Danon disease and variable clinical presentations, including cardiomyopathy, skeletal muscle pathology, and hepatopathy. Analysis by electron microscopy of the quadriceps muscle from the proband and his brother showed abnormal mitochondria, and immunohistochemistry revealed no expression of LAMP-2 protein. This defect is due to a yet undescribed mutation located at the second nucleotide in the intron 8 of the Lamp-2 gene (c.1093+2 T>A) that generated exon 8 skipping confirmed at RNA level in the proband.     

Segmental spinal myoclonus and syringomyelia: A case report

We report the case of a 75-year-old woman who developed involuntary jerks of the abdominal musculature. They occurred spontaneously or triggered by a forced inspiration or attempts to rise from the supine position. Electromyography (EMG) recorded abnormal bursts of muscle activity in the abdominal, thoracic paraspinal, and intercostal muscles up to the 3rd intercostal space. The bursts were bilateral, arrythmic and synchronous in all muscles. Magnetic resonance imaging (MRI) of the spine revealed a syringomyelic cavity between the T3 and T10 levels. The topological correlation between the EMG muscle activities and the MRI findings was consistent with spinal myoclonus arising from the thoracic spinal cord. The synchronous bursts in muscles depending from few adjacent spinal segments suggested the diagnosis of segmental spinal myoclonus (SSM). There are few reports of SSM related to syringomyelia in the literature.     

Benign myoclonus of early infancy: an imitator of West's syndrome

Benign myoclonus of early infancy is a rare condition characterized by nonepileptic spasms that may resemble the epileptic spasms seen in West's syndrome. The spells in benign myoclonus of early infancy begin before age 1 year and are self-limited. The electroencephalogram (EEG) is invariably normal, and neurologic development is not affected. West's syndrome is characterized by infantile spasms that appear before 1 year of age, an abnormal EEG with hypsarrhythmia, and a poor prognosis. We describe six infants who presented for evaluation of clusters of head, trunk or extremity spasms, eye blinking, brief jerking of upper extremities or trunk, and head nodding episodes. In most, a presumptive diagnosis of West's syndrome was made prior to the referral. One infant had been placed on valproate. Routine EEG recordings or prolonged video EEG monitoring were normal both during and between episodes. After the negative evaluations, the diagnosis of benign myoclonus of early infancy was made in each infant. Subsequently, no infant was treated with anticonvulsants. Follow-up revealed complete resolution of the episodes in all children within 2 weeks to 8 months of onset. All had normal neurologic development. Based on our cases and review of the literature, the prognosis for this disorder is excellent. Care should be taken to recognize this rare entity and avoid unnecessary and potentially harmful antiepileptic therapy.     

Excessive fragmentary myoclonus in NREM sleep: a report of 38 cases

We report 38 consecutive patients referred to a sleep disorder clinic who on diagnostic polysomnography showed excessive amounts of brief fragmentary myoclonus throughout all stages of NREM sleep. Almost all patients were male despite a reasonably equal sex distribution of referral. The phenomenon was found associated with sleep-related respiratory problems, periodic movements in sleep (PMS), narcolepsy, intermittent hypersomnia and (rarely) insomnia. It also occurred associated with excessive daytime sleepiness (EDS) as an isolated polysomnographic finding apart from some degree of sleep fragmentation.     

Benign familial neonatal convulsions: A family with a rare disorder

The authors report a family from Punjab (India) with 10 members having benign familial neonatal convulsions (also known as benign familial neonatal seizures) in two generations. This disorder is quite rare. The clinical presentation of index case along with the findings of computed tomography of the brain and electroencephalograph is described. Important features of all the family members along with a brief review of the literature are also given.     

Fatal neonatal nemaline myopathy: a case report.

A fatal neonatal nemaline myopathy in a Japanese girl was described. The patient was hypotonic at birth and failed to establish effective respiration. Rod-like structures were observed within a variety of skeletal muscles, particularly in the diaphragm. This is the first case of fatal neonatal nemaline myopathy in which many satellite cells were observed.     

Segmental action and stimulus-sensitive myoclonus with acute onset. A case report

A 23-year old man developed action and stimulus-sensitive myoclonus involving neck and proximal arm muscles. The finding of abnormally long and tortuous vertebral and carotid arteries and the abrupt onset of symptomatology suggest a possible hemodynamic mechanism. The electrophysiological characters and the sensitivity to serotonin precursors are consistent with the definition of “reticular reflex myoclonus”.

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Sommario Viene riportato il caso di un paziente affetto da mioclono d'azione e stimolo-sensibile che interessava la muscolatura del collo e i muscoli prossimali degli arti. Il riscontro di una anomala lunghezza e tortuosità delle arterie vertebrale e carotide e l'esordio acuto della sintomatologia suggeriscono che la patogenesi possa essere riferita ad un meccanismo emodinamico. Le caratteristiche elettrofisiologiche e la sensibilità ai precursori della serotonina sono in accordo con la definizione di “mioclono reticolare riflesso”.

     

Segmental action and stimulus-sensitive myoclonus with acute onset. A case report

A 23-year old man developed action and stimulus-sensitive myoclonus involving neck and proximal arm muscles. The finding of abnormally long and tortuous vertebral and carotid arteries and the abrupt onset of symptomatology suggest a possible hemodynamic mechanism. The electrophysiological characters and the sensitivity to serotonin precursors are consistent with the definition of “reticular reflex myoclonus”.