The treatment of epilepsy depends on its origin (focal or generalised) and its cause (lesion, genetic, etc.).
Treatment must be comprehensive, aiming on the one hand to make the seizures disappear, or at least to attenuate them, and on the other hand to eliminate or correct their causes, as well as to identify and treat the consequences of the disease on the patient’s life, such as learning difficulties or depression.
Anti-epileptic therapies
1) Anti-epileptic drugs act by different mechanisms, in an attempt to prevent the recurrence of seizures:
- by stabilising the membrane of neurons by regulating the opening and closing of ion channels, particularly those permeable to sodium, thus preventing the excessive propagation of neuronal discharges.
- by blocking excessive stimulation of receptors that excite neurons (such as glutamate receptors)
- by activating receptors that inhibit neurons (such as GABA receptors)
- modulating the release of synaptic vesicles.
These treatments are chosen by the neurologist on the basis of the type of seizure (some drugs may be ineffective for absences or myoclonus) and, above all, the patient’s condition (each treatment has its own side effects, so the choice will depend on the patient’s age, sex and associated illnesses).
In 30% of patients, anti-epileptic drugs are ineffective. It is therefore necessary to continue to identify new anti-seizure mechanisms, and therefore to develop new drugs. The epilepsy team at the Salpêtrière hospital, in coordination with the Clinical Investigation Centre at the Institut du Cerveau, headed by Dr Céline Louapre and Prof Jean-Christophe Corvol, enables new anti-epileptic drugs to be assessed at an early stage, as part of therapeutic trials. This enables certain patients to benefit from new drugs before they are marketed.
2) Epilepsy surgery
In the case of drug-resistant focal epilepsy, removal of the area of the brain causing the seizures may be considered.
In order to target the area of the brain responsible for the seizures, the epileptogenic focus, the clinicians and researchers at the Brain Institute use a variety of technologies, as part of a technical platform that is unique in the Ile-de-France region. The pre-surgical assessment involves :
- Electroencephalography (EEG), surface and sometimes intracerebral. These continuous recordings are made 24 hours a day, 7 days a week, for 2 to 3 weeks, in the Epilepsy Unit, in order to record several seizures.
- Positron emission tomography (PET), carried out in the Nuclear Medicine Department, is used to identify areas of the brain that do not take up glucose well, and are therefore involved in the epileptogenic focus.
- SPECT during an epileptic seizure is an examination that enables the brain region activated by a seizure to be visualised: this examination identifies the increase in local cerebral blood flow, linked to the increased energy requirements of the neurons recruited by the seizure.
- Functional Magnetic Resonance Imaging (fMRI), carried out in the Neuroradiology Department, is used to assess whether the area of the brain identified as the source of the seizures can be operated on. If this area is still functional, i.e. it is activated during certain exercises, then the operation can be rejected.
When the brain region at the origin of the epilepsy is very precisely determined at the end of this complex assessment, neurosurgical intervention is proposed: resection of the epileptogenic focus, in the Neurosurgery Department, by Dr Bertrand Mathon, results in a complete cure for 50 to 80% of patients.
Other neurosurgical approaches, such as vagus nerve stimulation, may be proposed. The principle is to perform chronic neuromodulation of the brain in order to reduce the frequency and severity of seizures.
New techniques are currently being evaluated, including laser treatment of the epileptogenic region when this is inaccessible to conventional surgery.