Treatments
There are many oral medications available for the management of epileptic seizures. They were previously called anticonvulsants however this term is misleading because most seizures are not convulsions. The modern term is antiepileptic drugs (AEDs). In TLE, the most commonly used older AEDs are phenytoin, carbamazepine, primidone, valproate and phenobarbital. Newer drugs, such as gabapentin, topiramate, levetiracetam, lamotrigine, pregabalin, tiagabine, lacosamide, and zonisamide promise similar effectiveness, possibly with fewer side-effects. Felbamate and vigabatrin are newer AEDs, but can have serious adverse effects so they are not considered first-line AEDs. Nearly all AEDs function by decreasing the excitation of neurons (e.g., by blocking fast or slow sodium channels or modulating calcium channels) or by enhancing the inhibition of neurons (e.g., by potentiating the effects of inhibitory neurotransmitters like GABA). Unfortunately, many patients with medial temporal lobe epilepsy (up to one-third) will not experience adequate seizure control with medication.
For patients with medial TLE whose seizures remain uncontrolled after trials of several AEDs (intractable), resective surgery should be considered. Epilepsy surgery has been performed since the 1860s and physicians and surgeons had observed for decades that it was highly effective in producing seizure freedom. However, it was not until 2001 that a scientifically sound study was performed on the effectiveness of temporal lobectomy. This study proved that after the failure of several AEDs to control seizures in TLE temporal lobe surgery is far more effective in producing seizure freedom than is additional medication trials. The unanswered question that remains is how many medications a person must fail before considering surgery. A United States sponsored research study called ERSET was begun to answer the question of whether surgery can successfully be performed early in the course of TLE. The primary outcome variable was freedom from disabling seizures during year 2 of follow-up. The study ended earlier than anticipated with a total enrollment of 38 patients. Of these, 23 were enrolled in the anti-epileptic drug (AED) treatment arm, whereas 15 received both AED treatment and surgery for TLE. The results showed that none of the patients who only received AED achieved the study endpoint; that is, none were free of disabling seizures during year 2 of follow-up. In contrast, 11 of the 15 who both received AED and surgery for TLE were free of disabling seizures (odds ratio = ∞; 95% CI, 11.8 to ∞; P < .001).
In preparation for these surgeries, patients are monitored by various methods to determine the focus of their seizures (that is, the region of the brain where seizures tend to arise before spreading). This can be done with video-EEG monitoring, intracranial EEG (where electrodes are placed beneath the skull, either within or resting just outside the brain), or SPECT imaging. MRI studies may additionally be used to seek evidence of hippocampal sclerosis. Once the epileptic focus has been determined, it can be excised, which usually involves removing part of the hippocampus and often the amygdala. To avoid removing areas of the brain responsible for speech (so-called "eloquent" areas), the surgical team will conduct a Wada test pre-operatively, wherein amobarbital is injected in the left or right carotid artery to temporarily quiet one half of the brain. If the patient performs poorly on neuropsychological testing during the intracarotid amobarbital (Wada) test, the surgical team may advise the patient against surgery or may offer a more limited operation.
If a person is not an optimal candidate for epilepsy surgery, then AEDs not previously tried, the vagus nerve stimulator, or AEDs in clinical research trials might be alternative treatments.For children, the ketogenic diet may also be tried.Other possible future therapies such as brain cortex responsive neural stimulators, deep brain stimulation, and stereotactic radiosurgery (such as gamma knife) are undergoing research studies for treatment of TLE and other forms of epilepsy.
Read more about this topic: Temporal Lobe Epilepsy