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At a glance

A disorder characterized by the triad of infantile spasms, an interictal EEG pattern termed hypsarrhythmia, and mental retardation. Most affected patients develop cerebral palsy, facial malformations, and skeletal deformities. The characteristic of the disease resides in the description of the spasms, which is described as violent jackknife or “salaam” movements where the whole body bends in half. The onset is during infancy. It is also observed in childhood where it is called “epileptic spasms” rather than infantile spasms.


Generalized Flexion Epilepsy; Infantile Epileptic Encephalopathy; Epileptic Spasms; Infantile Myoclonic Encephalopathy; Jackknife Convulsion; Massive Myoclonia; Salaam Spasms; Infantile Spasms.


This medical condition was first described in 1841 as “infantile spasms” by William J. West (1794-1848). In 1850, Dr West wrote a letter to the Lancet to inquire about any information concerning the disease of his son, James. James had developed a form of epilepsy that is now known as infantile spasms. His description was “bobbing of the head, complete heaving of the head forward towards his knees, and then immediately relaxing …… these bowings and relaxing would be repeated alternately at intervals of a few seconds, 20 or more times at each attack, which attack would not continue more than 2 or 3 minutes.” Dr West was a successful small-town surgeon-apothecary in Tonbridge, England, who took a major role in the local movement for medical reform. In 1837 he published the first series of ovariotomies in England. Around 110 years later, the West Syndrome was reported as a triad of “infantile spasm, physical and mental disorder and characteristic EEG findings.” One year later, the characteristic EEG finding was named “hypsarrhythmia.” Eventually, in 1958, Sorel and Dusaucy-Bauloye reported that infantile spasm disappeared with adrenocorticotropic hormone (ACTH).


The incidence is established at approximately 1 per 3,200 to 3,500 live births in the general population. It is estimated at 3.1 per 10,000 live births in the United States. West Syndrome accounts for approximately 30% of all cases of epilepsy affecting infants. Females are affected more than males at a proportion of 1.3:1.

Genetic inheritance

There is no genetic basis for the disease, although a positive family history for epilepsy is present in a minority of these patients. However, in a significant number of cases, ☞Tuberous Sclerosis can be found and should therefore be ruled out. Basically any type of brain damage has the potential to result in infantile spasms.

Clinical aspects

Infantile spasms begin in the first year of life, most often around 4 to 7 months of age. Close neurologic examination of the child reveals abnormal mental function with cognitive deficits that are consistent with developmental delay or regression. However, there are no pathognomonic signs for West Syndrome. The symptoms ...

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