Infantile spasms (IS) are seizures associated with a severe infantile epileptic encephalopathy. Both cessation of spasms and electrographic response are necessary for the best neurodevelopmental outcomes. Adrenocorticotrophic hormone (ACTH), or prednisolone, or vigabatrin are considered the first-line treatment individually. However, ACTH expense and availability are the barriers in developing countries including Thailand. Vigabatrin, therefore, is the first recommended by Epilepsy Society of Thailand due to ACTH unavailability. Recently, combined steroid treatments (either ACTH or high dose prednisolone) with vigabatrin are superior in cessation of spasms compared to steroid treatment alone. Thus, this study is aimed to compare the efficacy of vigabatrin with high dose prednisolone combination therapy and vigabatrin alone.

Infantile spasms are recognized as epileptic encephalopathy which include the hypsarrhythmia or variants electroencephalographic (EEG) features and psychomotor regression. Various underlying conditions are associated with the infantile spasm included cerebral malformation, hypoxic ischemic encephalopathy, genetic disorders (Down syndrome), tuberous sclerosis complex (TSC), etc. Although vigabatrin has the evidence to use as the first line treatment for infantile spasm related with TSC. Adrenocorticotrophic hormone (ACTH), or high dose prednisolone, or vigabatrin are the first line treatment of IS in non-TSC.

The effectiveness of ACTH versus high dose prednisolone question have not yet definitely answered. Furthermore, ACTH expense and availability are the barriers in developing countries including Thailand. Vigabatrin, therefore, is the first option of therapy recommended by Epilepsy Society of Thailand due to ACTH unavailability. Recently, combined steroid treatments (either ACTH or high dose prednisolone) with vigabatrin are superior in cessation of spasms compared to steroid treatment alone. Questions about the clinical cessation of IS and electrographic remission by combination treatment with vigabatrin and high dose prednisolone compare to vigabatrin alone have not fully elucidated. Thus, this study is aimed to compare the efficacy of vigabatrin with high dose prednisolone combination therapy and vigabatrin alone.

Inclusion Criteria:

• Age at 2-14 months at date of enrollment
• Clinical diagnosis of infantile spasm assessed by pediatric neurologist and hypsarrhythmic pattern or variants interpreted by pediatric epileptologist
• Thai nationality

Exclusion Criteria:

• Previous treatment (within the last 28 days) with vigabatrin or corticosteroid
• Previous diagnosis of epileptic encephalopathy e.g. early infantile epileptic encephalopathy and early myoclonic epileptic encephalopathy
• Has a clinical suspicious or diagnosis of tuberous sclerosis complex characterized by one of these; known affected parent, previously diagnosed cardiac rhabdomyoma, hypomelanotic macules, forehead fibrous plaque, shagreen patch, retinal phakoma, or known polycystic kidneys
• A contraindication to vigabatrin or corticosteroid such as recent varicella or herpes zoster infection, gastrointestinal hemorrhage etc.
• Thai language ability of the parents or guardians is that they may not understand what is being requested of them.
• Predictable lack of availability of follow up

There is not a plan to make IPD available for the confidentiality.

Each patient will visit the clinic at Day 8, 14, 43, and 3 months by outcome assessor who is blinded for treatment to determine seizure frequency and adverse events. Those patients will be seen and under taking care of primary neurologists and pharmacists who are not blinded to treatment at the same visit as a standard clinical practice and check with compliance and adjust vigabatrin or prednisolone following each treatment allocated (if needed). Family or caregivers will not be blinded to treatment. EEG will be scored using BASED scores at Day 0 (before treatment), 14, and 43 to assess the resolution of hypsarrhythmia.