There is evidence that cannabis has been used in numerous societies, as far back as 1800 BC, for the treatment of nocturnal convulsions, seizures, and epilepsy. The use of cannabis as a treatment for epilepsy continued up until the 20th century when the plant was made illegal in many countries. However, in recent years, cannabis derivatives have once again become the subject of epilepsy research.
The UK’s rescheduling of cannabis in 2018 was based considerably on evidence that cannabis-based medicines can reduce seizures in rare forms of epilepsy such as Dravet and Lennox-Gastaut syndromes. A number of studies have supported the use of cannabinoids in treatment-resistant epilepsy. A recent study has also aimed to understand how these compounds affect electroencephalography (EEG) in a child with Lennox-Gastaut Syndrome.
What is Lennox-Gastaut Syndrome?
Lennox-Gastaut syndrome is a rare form of treatment-resistant (intractable) epilepsy which starts during childhood. It is believed to affect between 1 and 5 in every 100 children with epilepsy. This form of epilepsy is also known as ‘epileptic and developmental encephalopathy’ as it causes abnormal EEG which is believed to be linked potential developmental delay and learning difficulties.
What is an Electroencephalography?
An electroencephalography (EEG) records the electrical activity of the brain. It uses electrodes to measure electrical activity in the brain. These recordings help us to understand how the brain signalling and responses. The activity of the brain changes when someone has a seizure, known as epileptiform brain activity. These changes can sometimes be seen on electroencephalography making them useful in understanding how treatments can affect epileptiform brain activity.
About the Patient and Previous Treatment
Researchers assessed the effects of Cannabidiol (CBD) in a child with Lennox-Gastaut syndrome using an EEG. The patient was a 9-year-old boy who presented with absence seizures. A year later, the child had their first generalised tonic-clonic seizure (GTCS). Following infrequent GTCS and daily absence seizures which were unsuccessfully managed with various treatments, Epidyolex – a purified form of CBD registered for medical use in the UK – was added to his treatment plan.
How Did CBD Affect Seizure Frequency?
CBD was titrated up to the target dose of 5mg/kg/day and administered alongside the maintenance of the previous dose of phenytoin mg/L. This combination was found to help control absence seizures; however, the patient began to have drop attacks at the age of 10.5. CBD dosage was then increased to 11mg/kg/day, while phenytoin was given at 9mg/kg/day. The patient became seizure free in May 2019.
What was the Effect on EEG Recordings?
Initial EEG readings presented “age-appropriate backgrounds and generalized 3 Hz spike and wave discharges”. This transitioned into EEG patterns associated with typical LGS after he began to experience GCTS (approximately a year after uncontrolled absence seizures).
This study found that CBD was able to improve EEG patterns, as well as control seizures in a patient with Lennox-Gastaut syndrome. The researchers also question whether early intervention with CBD treatment for LGS might influence these outcomes. While this study presents promising results demonstrating the positive effects of CBD on brain activity, the researchers stress that larger studies and analysis EEG in patients with unknown/genetic aetiology of LGS are needed.