Temporal Lobe Epilepsy Treatment & Management

There are many AEDs used for seizure control in temporal lobe epilepsy.

Neurostimulation is a treatment option if the patient is refractory and is not a good surgical resective candidate. Vagus nerve stimulation (VNS) was approved by the US Food and Drug Administration (FDA) in 1997 for the treatment of intractable partial epilepsy in patients aged 4 years and older. Responsive neurostimulation (RNS) is another option when the seizure focus is known and it could treat multifocal epilepsy. Deep brain stimulation (DBS) is awaiting FDA approval but has been available in other countries.

Temporal lobectomy is the definitive treatment for medically intractable temporal lobe epilepsy, as it has a high seizure-free rate. For patients who had mesial temporal lobe epilepsy and disabling seizures for no more than 2 consecutive years following adequate trials of 2 brand-name AEDs, Engel et al found that resective surgery plus AED treatment resulted in a lower probability of seizures for at least 2 years posttreatment, as well as improved health-related quality of life, than continued AED treatment alone. ^[5]  

About 47–60% of new-onset partial seizures are controlled effectively by the first drug. Studies in 1985 and 1992 by the US Department of Veterans Affairs (VA) have shown that the 3 major AEDs, phenytoin, carbamazepine, and valproate, are equally effective in controlling partial seizures, but carbamazepine was better tolerated. One VA study in the elderly compared carbamazepine, gabapentin, and lamotrigine and in this group lamotrigine had the best profile in terms of tolerability, and carbamazepine had the least.

The newer AEDs, such as gabapentin, topiramate, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, lacoasmide, and zonisamide, have similar efficacy than the older AEDs, but they stand out predominantly in having far less side effects in day-to-day use, as well as in long-term side effects. The newer drugs are easier to use in terms of having far fewer drug-drug interactions than do the older AEDs.

Vigabatrin and felbamate are reserved for intractable epilepsy patients due to the potential of serious adverse events.

A major advance in epilepsy treatment is the extended-release formulations, which allow for some AEDs to be used once a day for better adherence. Some of the AEDs with extended-release formulations also have better tolerability, improving quality of life for patients with epilepsy.

About 40% of patients continue to have seizures in spite of trials with 3 AEDs. Semah and colleagues showed that seizures are more likely to be refractory to AEDs in patients with hippocampal sclerosis. ^[6]

Go to Antiepileptic Drugs for complete information on this topic.

Vagus nerve stimulation (VNS) was approved by the FDA in 1997 for the treatment of intractable partial epilepsy and is now approved for patients aged 4 years or older. In VNS, a battery-operated stimulator device is implanted in the chest and an electrode is attached to the left vagus nerve in the neck.

VNS has been found to result in a mean reduction in seizure frequency of 25–28% at 3 months but with improvement to about 40% by year 1. The exact mechanism through which VNS exerts its antiepileptic effect is not known. A newer model of VNS monitors heart rate and provides responsive stimulation to heart rate increases that may be associated with seizures. Patients and caregivers can also deliver extra stimulation with a magnet.

Adverse effects of VNS treatment include hoarseness of voice, cough, local pain, paresthesias, dysphagia, and dyspnea when the device is on and almost none when the device is off, but the settings can be titrated so that side effects are minimized. VNS does not have the adverse effects associated with AEDs and is used adjunctively with AEDs.

Go to Vagus Nerve Stimulation for complete information on this topic.  

Responsive neurostimulation (RNS) is another stimulator device implanted into the skull with electrodes over or in the seizure focus. It monitors EEG activity and stimulates when seizures are detected. The RNS stimulation is not perceptible to the patient. 

Deep brain stimulation (DBS) has been in use for Parkinson disease and has been studied for epilepsy and is awaiting FDA approval.

Temporal lobectomy is the definitive treatment for medically intractable temporal lobe epilepsy. When seizures are not controlled by 2 different AED trials, the patient should be considered for a presurgical evaluation. These patients are not likely to achieve seizure control with medications alone (5-10% chance of becoming seizure free).

The presence of unilateral hippocampal sclerosis or mesial temporal sclerosis (MTS) and concordant EEG findings predict seizure-free outcome in patients considered for surgery.

Foldvary and colleagues showed that a higher monthly preoperative seizure frequency is associated with a less favorable surgical outcome. ^[7]

An extensive presurgical assessment for the feasibility of surgery is essential. This includes MRI, interictal and ictal EEG, neuropsychological testing, and the intracarotid amobarbital test called the Wada test.

Seizure-free state at 2 years postoperatively is predictive of long-term seizure-free outcome. In well-selected cases, 70-80% of patients with refractory temporal lobe epilepsy become seizure free after surgery.

Go to Epilepsy Surgery for complete information on this topic.

Selective amygdalohippocampectomy (SAH) is a more targeted mesial temporal resection that spares the temporal neocortex. Bandt et al examined seizure response rates, complications, and neuropsychological outcomes of trans-middle temporal gyrus SAH for medically intractable mesial temporal lobe epilepsy in 76 adult patients, 19 of whom underwent preoperative and postoperative neuropsychological evaluations. ^[8]

In this study, favorable seizure response rates were achieved in 92% of the patients, and rates of surgical morbidity were low. ^[8] Whereas a decline in verbal memory was observed in the left SAH group, improvements in memory were seen in the right SAH group.

The most common medicolegal issue arises from the fact that different states in the United States have different rules regarding the physician's responsibility to report a patient with diagnosed epilepsy.

For example, California, along with four other states, mandates that the physician is responsible for reporting a patient with new-onset seizure or epilepsy that may impair safe dririvng to the Department of Motor Vehicles (DMV).

The dietary therapy that can be tried for intractable epilepsy is the ketogenic diet or the Modified Atkins diet.