**5. Epilepsy of infancy with migrating focal seizures (EIMFS)**

### **5.1 Overview**

EIMFS, previously called malignant migrating partial seizures of infancy, is a rare and severe condition describe in 1995 [63]. EIMFS is characterized by focal "migrating" or "random" seizures beginning within the first 6 months of life, severe global developmental delay, and acquired microcephaly. Epilepsy is highly pharmacoresistant. At onset brain MRI is typically normal, but later it may show delayed myelination, thin corpus callosum, and cerebral atrophy [64]. Patients with intractable seizures have a progressive deterioration with major axial and limb hypotonia, loss of visual contact, and loss of other motor and social skills. Pyramidal and/or extrapyramidal features with athetotic movements may appear; about 18% of the patients died [65].

De novo KCNT1 mutations have been reported in about 50% of patients with sporadic EIMFS [64–66].

### **5.2 Seizures: symptoms and semiology**

It is accepted that the natural history of the EIMFS goes through three distinct phases [63]. The first phase starts in the first 6 months of life and lasts a few weeks or months; patients have sporadic seizures with frequency every few weeks or months. Seizures used to be focal motor with quick generalization or associated with autonomic features like apnea, flushing, or cyanosis [63, 67]. The second phase, called "stormy phase," arises between 1 and 12 months; seizures become more frequent, occurring in clusters several times a day or being practically continuous for several days. Seizure consists of lateral deviation of the head and eyes, twitches of the eyelids, unilateral clonic or tonic jerks of one or both limbs, apnea, flushing and/or cyanosis of the face, chewing movements, and secondary tonicclonic seizures [68]. Additionally, clinical manifestations may be "subtle" or absent even with the long duration of seizures.

The age at onset of the third phase is variable, from the end of the first year to the fifth year of age. This phase is typically seizure-free, even if interposing illnesses can trigger recurrent seizures or SS. Some patients can evolve to a WS [63, 65].

Migrating focal seizures (MFS) are seizures which occur usually in clusters that last for a few days and are then followed by a few weeks or months of recovery. Within a cluster, seizures are very frequent and may even extend to SS. Clusters increase in frequency within the first 2 years of life.

**89**

*Epileptic Encephalopathies in Infants and Children DOI: http://dx.doi.org/10.5772/intechopen.85378*

EEG is usually normal during the first months apart from slowing for many hours after long-lasting seizures. As the disease progresses, background activities become gradually diffusely slower with decline of physiological features. Activity may show alternating asymmetries, with slow activity that change from one hemisphere to another [63]. In seizure-free periods, sleep and wakefulness are obviously differentiated; nevertheless sleep spindles are rare, asynchronous,

Interictal abnormalities are usually absent at onset; spikes rapidly grow in frequency and develop multifocal within a few months; multifocal spike-and-wave

Epileptic discharges (ED) sequentially involve different areas of the brain, such as describing a random migration, without a specific pattern. The ictal pattern is characterized by rhythmic monomorphic activity in the alpha-theta frequency range, although delta waves, spikes, and spike-waves can also be observed. It is common for epileptic activity to remain limited to one region for a period of time and then decrease in frequency until stop, with a tendency to progressively involve an adjacent area. ED is continued with slow postictal activity without prolonged voltage decrement [63, 68]. When epileptic seizures are frequent, ED changes from one region to another and from one hemisphere to another so that consecutive focal epileptic discharges overlap resulting in a continuous and changing multifocal ictal activity and a very complex epileptic status pattern [11].

Migrating partial seizures are usually refractory to pharmacologic treatment though some cases have responded to bromide (60–80 mg/kg/day), with a termination of the seizures for several months after almost 3 weeks of therapy [69]. Even so, one should be aware of a potential bromoderma tuberosum, which could be appearing with high doses of potassium bromide therapy [70]. Intravenous levetiracetam (60 mg/kg) rapidly interrupted migrating partial status in two children with a good tolerability and safety [71]. Other successful treatments include a combination of sodium bromide, stiripentol, and levetiracetam [72], rufinamide and acetazolamide

**6. Epilepsy with myoclonic-atonic seizures (EMAS) or Doose syndrome**

In 1970, Herman Doose reported seizures in 51 previously normal children between 1 and 5 years of age described as myoclonic and astatic, frequently combined with absences and GTCS and tonic seizures [75]. Doose suggested a genetic etiology [76] and later refined his criteria and emphasized that tonic seizures are rare [77].

[73, 74], and stiripentol associated with clonazepam.

activities do not show any specific pattern and are not activated in sleep.

**5.3 Electroencephalography**

*5.3.1 Background*

and asymmetric.

*5.3.3 Ictal EEG*

**5.4 Treatment**

**6.1 Overview**

*5.3.2 Interictal abnormalities*
