Electroencephalogram (EEG)

VideoEEG

The child is hospitalized for a period of 48 hours to 10 days to record the child’s usual seizures. EEG recording electrodes are glued to the scalp skin and connected to a brain electrical activity (EEG) recording system. The chamber is filmed 24 hours a day to analyze the behavioral changes associated with seizures and compare them to the EEG printout. Decreased antiepileptic treatment (drug withdrawal) may be necessary to facilitate seizure occurrence.

MRI

Cerebral magnetic resonance imaging allows us to visualize the morphological and functional abnormalities at the origin of epilepsy. This examination must be performed on a powerful machine (3 teslas) with sequences dedicated to an epilepsy protocol. The examination lasts between 20 and 40 minutes, and requires the immobility of the child.

Neuropsychological assessment

PETscan

SEEG

When the lesion is poorly limited in MRI or in case of discrepancy between the radiological data and the video EEG, the decision for intracranial brain mapping is taken in a multi-disciplinary meeting.

The operation is performed under general anesthesia in stereotactic conditions. EEG recording electrodes are inserted with infra millimetric precision with the help of a stereotaxis frame or a surgical robot. An MRI is performed immediately after implantation to check the correct positioning of the electrodes and the absence of complications (intracerebral hemorrhage).

After a night in the continuing care unit, the child goes back up to the recording room of the neurosurgery department, and the electrodes are connected to the recording system. The goal is to record the child’s usual seizures to determine their exact starting point. Electrical stimulation of the cortex is also carried out to map the functional areas of the brain (motor skills, language, vision…) and to try to trigger the seizures.

Lesionectomies and lobar resections

When the MRI finds a very limited focal anomaly compatible with the seizures recorded in video EEG, a focal resection is possible.

The main pathologies are developmental malformations of the cerebral cortex (focal cortical dysplasia), benign tumors associated with epilepsy (gangliogliomas, DNET dysembrioplasic tumors), vascular lesions (cavernomas, AVM). In case of temporal localization, it is sometimes necessary to perform an excision when it is pathological. Ablation of the tonsil nucleus and the hippocampus can cause transient mood and memory abnormalities that will be detected during the neuropsychological assessment and re-educated.

The surgical principle is to perform the removal of the lesion and the peri lesional cortex (gyrectomy). These interventions are performed with preoperative imaging guidance (neuronavigation), under an operating microscope, and according to the principles of microsurgery to respect the healthy brain.

The duration of hospitalization is 5 days, including 24-48 hours in continuous monitoring unit-resuscitation unit.

Patients are reviewed at 3 months postoperatively to perform an MRI and an EEG control, then at one year postoperatively to control the MRI, the EEG and perform a neuropsychological assessment during a day hospitalization.

Surgical success is obtained in more than 80% of the cases operated on, allowing the progressive reduction and then the discontinuation of antiepileptic treatments.

Hemispheric surgery

Certain pathologies cause epilepsy in one of the two cerebral hemispheres as a whole. These may be congenital (cortical developmental deformities, hemimegalencephalies, Sturge Weber syndrome), acquired (perinatal stroke) or inflammatory (Rasmussen’s encephalitis) abnormalities.

In most cases, preoperative neurological deficits already exist: hemiparesis, visual disorders, language acquisition delay, cognitive delay.

Epilepsy is primarily drug-resistant and the seizures evolve according to the child’s age: spasms, tonicoclonic seizures, contact breaks, continuous partial epilepsy.

The principle of the surgery is to disconnect the entire diseased hemisphere so that epileptic abnormalities can no longer be propagated. It is a major surgery, the consequences of which are always an aggravation of the preoperative neurological signs: motor deficit, visual field impairment, memory and language depending on the side operated on.

The children are hospitalized for about 15 days in neurosurgery, including 4 to 5 days in intensive care, then for several weeks in neurological rehabilitation.

The main complication is the occurrence in 10 to 20% of cases of hydrocephalus which will require drainage.

Surgical success is obtained in 80% of the cases operated on, with a disappearance of epileptic seizures. Rehabilitation allows the patient to recover or learn to walk, to speak and, eventually, to become autonomous.

Hypothalamic hamartomas

The localization of hyperexcitable ectopic neurons in the hypothalamus can lead to a characteristic clinical picture: gelastic seizures.

Vagus nerve stimulation

The antiepileptic effect is obtained by modulating brain activity through chronic intermittent electrical stimulation of the vagus nerve.

The intervention requires 2 nights of hospitalization and is not very painful. The main risk is infection, which requires the removal of the material and antibiotic therapy.

Approximately 50% of patients are defined as responders, with a reduction of at least 50% in the frequency of attacks, at least one year after the VNS procedure. Most patients and their families also report improved quality of life and wakefulness.

The procedure requires 2 nights of hospitalization. The electrode is placed in the neck on the vagus nerve and connected to the generator positioned behind the pectoral muscle. The 2 scars are closed by absorbable threads and biological glue, it is necessary to check them twice in a dressing consultation with the referring nurse the week following the surgery and to wear a custom-made compression jacket for 3 to 4 weeks. The intensity of stimulation is gradually increased during regular consultations with the pediatric neurologist until the effective current dose is reached.