Patients who fit the Aicardi Alternating Hemiplegia of Childhood clinical criteria of any age. The Aicardi Criteria are six (Heinzen et al 2015). (1) Paroxysmal hemiplegia episodes. (2) Bilateral hemiplegia or quadriplegia episodes. (3) Other paroxysmal manifestations, such as abnormal eye movements, nystagmus, strabismus, ataxia, dystonia, choreoathetosis, tonic spells, or autonomic disturbances. (4) Evidence of permanent neurological dysfunction, which can manifest as cognitive impairment, developmental delay, and/or persistent motor deficits such as spastic diplegia/quadriplegia, hypotonia, ataxia, choreoathetosis, or dystonia. (5) Sleep relieves symptoms, although attacks may resume soon after awakening. (6) First signs of dysfunction occur prior to the age of 18 months.

Patients having some but not all the above criteria and have the mutation in ATP1A3 gene can be included.

Review of past medical history; review of paroxysmal events; identification of presence of seizures & epilepsy & epilepsy classification; characterization of the non-paroxysmal features; degree of paroxysmal, non-paroxysmal disability indices; Vineland II adaptive behavior scales scoring; behavioral evaluation; presence of a genetic mutation; pharmacological treatments already used; AHC paroxysmal events assessement during the time of study; patient calendar for the follow up of events, for the follow up of epileptic seizures; whether, or not, there was occurrence of a serious or potentially life-threatening event (status epilepticus, apnea requiring intervention, or death) during time of study; growth and somatic complaints; further information concerning family history & comorbidities; past instrumental & biochemical investigations (ECG, cardiac ultrasound results if done as part of patient's follow-up); electroencephalogram; polysomnography; urine samples of melatonin ; pupillometry

The aim is to study the modification of the final index compared to the initial index of non-paroxysmal disability in order to evaluate the parameters that influence its evolution.

The non-paroxysmal disability index is calculated from different variables : ability to walk independently, presence of a behavioral disorder, presence and degree of communication disorders, abnormality of global motor skills, abnormality of fine motor skills, movements disorders, intellectual deficiency. The study also aims to evaluate the sleep architecture in AHC