Familial occurrence of benign myoclonus of early infancy

Transient benign paroxysmal movement disorders in infancy

This review summarizes the current empirical and clinical literature on benign paroxysmal movement disorders in infancy most relevant to practitioners. Paroxysmal benign movement disorders are a heterogeneous group of movement disorders characterized by their favourable outcome. We pay special attention to the recognition and management of these abnormal motor conditions strongly suggestive of epileptic disorders. They include: neonatal jitteriness; benign neonatal sleep myoclonus; benign paroxysmal tonic upgaze; paroxysmal tonic downgaze, benign paroxysmal torticollis and benign polymorphous movement disorder of infancy.

Benign convulsions in newborns and infants: occurrence, clinical course and prognosis

BACKGROUND

During early development severe epilepsies may appear, some with well established occurrence. Benign non-epileptic and epileptic paroxysmal syndromes with excellent prognosis occur in the same period. There are no exact data on their occurrence.

AIM

We have reviewed medical histories of children with benign non-epileptic or benign epileptic events: benign myoclonus of early infancy, benign neonatal sleep myoclonus, benign sleep myoclonus in infancy, benign partial epilepsy in infancy (BPEI) and benign infantile familial convulsions (BIFC) were established. The occurrence, clinical characteristics and prognosis of these syndromes were evaluated.

METHODS

Inclusion criteria were met in 31 children. Research included retrospective analysis of clinical characteristics, laboratory values, neuroimaging and neurophysiological assessments, followed by evaluation of psychosocial development with the use of the Strengths and Difficulties Questionnaire (SDQ), fulfilled by parents.

RESULTS

In our group the incidence of benign non-epileptic convulsions was 6.69 per 10 000 live births and the incidence of benign epileptic convulsions was 1.35 per 10 000. Male/female ratio in the group of children with non-epileptic events was 2.1:1. Among non-epileptic group 5 out of 23 children and among epileptic group 3 out of 8 children had minimal, mild or moderate abnormalities at neurological assessment at the time of the first clinical examination. Nonspecific changes in laboratory values were seen in 6 out of 23 in the non-epileptic and in 1 out of 8 children in the epileptic group. Neurophysiological assessments showed subtle changes in 4/23 in the non-epileptic and 6/8 in the epileptic group. Neuroimaging was not optimal in 5/23 with non-epileptic and 3/8 with epileptic events. Analysis of SDQ did not show significant deviations in psyhosocial development. Statistically significant deviation was observed only in relations with peers (p = 0.009).

CONCLUSIONS

Benign neonatal and infantile convulsions are more frequent than severe epilepsies of the same age period. Results show higher proportion of males with benign non-epileptic conditions. No deviations in further development was found. Laboratory values, neuroimaging and neurophysiological assessments were normal or nonspecifically changed.

The spectrum of nonepileptic events in children

Nonepileptic events (NEE) are common in children, and can be difficult to distinguish from epileptic events. Several strategies can assist in differentiation. The first is an age-based approach to the differential of commonly presenting EEs in neonates, infants, and adolescents. The next strategy is to identify key elements of the patient's history to narrow the possibilities, and third is a rational approach to ancillary testing. There are additional challenges to the diagnosis and evaluation of NEEs in patients with cognitive impairments or mental retardation (MR). Twenty to 25% of neurologically normal patients (34), and up to 60% of children with MR (35) referred for an evaluation of seizures, have NEE. In most instances, the clinical history leads to the diagnosis, and ancillary testing serves as confirmation. But in certain populations, neonates, children with concurrent epilepsy, children in whom pseudoseizures are suspected, and children with MR, early use of video-EEG telemetry is indicated to establish the diagnosis and avoid overtreatment with antiepileptic drugs (AEDs).

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.

Myoclonus and epilepsies

The possible associations of myoclonic phenomenae, progressive or non-progressive encephalopathies and epileptic features are reviewed, with special emphasis on pediatric age. This leads to recognize the following five groups of conditions: (1) Myoclonus without encephalopathy and without epilepsy; (2) Encephalopathies with non-epileptic myoclonus; (3) Progressive encephalopathies presenting myoclonus seizures of epileptic syndromes (Progressive myoclonus epilepsies); (4) Epileptic encephalopathies with myoclonic seizures; (5) Myoclonic epilepsies. Within the first group, which also includes physiologic myoclonus, a more thorough description of "Benign sleep myoclonus of newborn" and "Benign myoclonus of early infancy" is given. Characteristics of group 2 are "Kinsbourne Syndrome" and certain types of "Hyperekplexia" which pose interesting differential diagnosis with stimulus-sensitive epilepsies. In group 3, the concept of progressive encephalopathies is stressed. The fourth group refers to severe epilepsies, mainly on infancy and childhood, which lead to mental retardation irrespective of their aetiology. Group 5 comprises the true myoclonic epilepsies, differentiating syndromes recognized as idiopathic--such as "Benign myoclonic epilepsy of infancy" and "Juvenile myoclonic epilepsy"--from those which are cryptogenic and carry a more cautious prognosis--as "Cryptogenic myoclonic and myoclonoastatic epilepsies" and "Severe myoclonic epilepsy of infancy". Other epileptic syndromes not usually considered as myoclonic epilepsies, but presenting sometimes as myoclonic seizures, are finally referred.

Recent advances and some problems in the delineation of epileptic syndromes in children

The current International Classification of Epilepsies and Epileptic Syndromes has classified a number of age-related epileptic syndromes in children, but some of these entities have not been well delineated and many syndromes not included in the International Classification have been proposed. This article is intended to supplement some of the currently listed childhood epileptic syndromes, discuss certain problems with the classification system, and review some of the proposed pediatric syndromes.