Seizure Disorders

A seizure is an abnormal, unregulated electrical discharge that occurs within the brain's cortical gray matter and transiently interrupts normal brain function. A seizure typically causes altered awareness, abnormal sensations, focal involuntary movements, or convulsions (widespread violent involuntary contraction of voluntary muscles).
About 2% of adults have a seizure at some time during their life. Two thirds of these people never have another one.

Definitions: Terminology can be confusing.
Epilepsy (also called epileptic seizure disorder) is a chronic brain disorder characterized by recurrent (= 2), unprovoked seizures (ie, not related to reversible stressors). Epilepsy is often idiopathic, but various brain disorders, such as malformations, strokes, and tumors, can cause symptomatic epilepsy.
Nonepileptic seizures are provoked by a temporary disorder or stressor (eg, metabolic disorders, CNS infections, cardiovascular disorders, drug toxicity or withdrawal). In children, fever can provoke a seizure
Symptomatic seizures are due to a known cause (eg, brain tumor, stroke). Symptomatic seizures are most common in neonates and the elderly.
Psychogenic seizures (pseudoseizures) are symptoms that simulate seizures in patients with psychiatric disorders but that do not involve an abnormal electrical discharge in the brain.

Etiology
Common causes of seizures : vary by age of onset:
•Before age 2: Developmental defects, birth injuries, and metabolic disorders
• Ages 2 to 14: Idiopathic seizure disorders
• Adults: Cerebral trauma, alcohol withdrawal, tumors, strokes, and unknown cause (in 50%)
• The elderly: Tumors and strokes
In reflex epilepsy, a rare disorder, seizures are triggered predictably by an external stimulus, such as repetitive sounds, flashing lights, video games, or even touching certain parts of the body.

Classification
Seizures are classified as generalized or partial.
Generalized: In generalized seizures, the aberrant electrical discharge diffusely involves the entire cortex of both hemispheres from the onset, and consciousness is usually lost. Generalized seizures result most often from metabolic disorders and sometimes from genetic disorders. Generalized seizures include the following:
• Infantile spasms
• Absence seizures
• Tonic-clonic seizures
• Atonic seizures
• Myoclonic seizures
Partial seizures: In partial seizures, the excess neuronal discharge occurs in one cerebral cortex, and most often results from structural abnormalities. Partial seizures may be
• Simple (no impairment of consciousness)
• Complex (reduced but not complete loss of consciousness)
Partial seizures may be followed by a generalized seizure (called secondary generalization), which causes loss of consciousness. Secondary generalization occurs when a partial seizure spreads and activates the entire cerebrum bilaterally. Activation may occur so rapidly that the initial partial seizure is not clinically apparent or is very brief.


Symptoms and Signs

Seizures may be preceded by an aura. Auras may consist of sensory, autonomic, or psychic sensations (eg, paresthesias, a rising epigastric sensation, abnormal smells, a sensation of fear, a déjà vu sensation).
Most seizures end spontaneously in 1 to 2 min. Generalized seizures are often followed by a postictal state, characterized by deep sleep, headache, confusion, and muscle soreness; this state lasts from minutes to hours. Sometimes the postictal state includes Todd's paralysis (a transient neurologic deficit, usually weakness, of the limb contralateral to the seizure focus).
Most patients appear neurologically normal between seizures, although high doses of the drugs used to treat seizure disorders, particularly anticonvulsants, can reduce alertness. Any progressive mental deterioration is usually related to the neurologic disorder that caused the seizures rather than to the seizures themselves. Rarely, seizures are unremitting.
Partial seizures: There are several types of partial seizures.
Simple partial seizures cause motor, sensory, or psychomotor symptoms without loss of consciousness. Specific symptoms reflect the affected area of the brain In jacksonian seizures, focal motor symptoms begin in one hand, then march up the arm. Other focal seizures affect the face first, then spread to an arm and sometimes a leg. Some partial motor seizures begin with an arm raising and the head turning toward the moving arm.
Epilepsia partialis continua, a rare disorder, causes focal motor seizures that usually involve the arm, hand, or one side of the face; seizures recur every few seconds or minutes for days to years at a time. In adults, the cause is usually a structural lesion (eg, stroke). In children, it is usually a focal cerebral cortical inflammatory process (eg, Rasmussen encephalitis), possibly caused by a chronic viral infection or autoimmune processes.


Complex partial seizures are often preceded by an aura. During the seizure, patients may stare. Consciousness is impaired, but patients have some awareness of the environment (eg, they purposefully withdraw from noxious stimuli). The following may also occur:
• Oral automatisms (involuntary chewing or lip smacking)
• Limb automatisms (eg, automatic purposeless movements of the hands)
• Utterance of unintelligible sounds without understanding what they say
• Resistance to assistance
• Tonic or dystonic posturing of the extremity contralateral to the seizure focus
• Head and eye deviation, usually in a direction contralateral to the seizure focus
• Bicycling or pedaling movements of the legs if the seizure emanates from the medial frontal or orbitofrontal head regions
Motor symptoms subside after 1 to 2 min, but confusion and disorientation may continue for another 1 or 2 min. Postictal amnesia is common. Patients may lash out if restrained during the seizure or while recovering consciousness if the seizure generalizes. However, unprovoked aggressive behavior is unusual.
Left temporal lobe seizures may cause verbal memory abnormalities; right temporal lobe seizures may cause visual spatial memory abnormalities.
Generalized seizures: Consciousness is usually lost, and motor function is abnormal from the onset.
Infantile spasms are characterized by sudden flexion and adduction of the arms and forward flexion of the trunk. Seizures last a few seconds and recur many times a day. They occur only in the first 5 yr of life, then are replaced by other types of seizures. Developmental defects are usually present.
Typical absence seizures (formerly called petit mal seizures consist of 10- to 30-sec loss of consciousness with eyelid fluttering; axial muscle tone may or may not be lost. Patients do not fall or convulse; they abruptly stop activity, then just as abruptly resume it, with no postictal symptoms or knowledge that a seizure has occurred. Absence seizures are genetic and occur predominantly in children. Without treatment, such seizures are likely to occur many times a day. Seizures often occur when patients are sitting quietly, can be precipitated by hyperventilation, and rarely occur during exercise. Neurologic and cognitive examination results are usually normal.
Atypical absence seizures usually occur as part of the Lennox-Gastaut syndrome, a severe form of epilepsy that begins before age 4 yr. They differ from typical absence seizures as follows:
• They last longer.
• Jerking or automatic movements are more pronounced.
• Loss of awareness is less complete.
Many patients have a history of damage to the nervous system, developmental delay, abnormal neurologic examination results, and other types of seizures. Atypical absence seizures usually continue into adulthood.
Atonic seizures occur most often in children, usually as part of Lennox-Gastaut syndrome. Atonic seizures are characterized by brief, complete loss of muscle tone and consciousness. Children fall or pitch to the ground, risking trauma, particularly head injury.
Tonic seizures occur most often during sleep. Tonic seizures occur most often in childhood. The cause is usually the Lennox-Gastaut syndrome. Tonic (sustained) contraction of axial muscles may begin abruptly or gradually, then spread to the proximal muscles of the limbs. Tonic seizures usually last 10 to 15 sec. In longer tonic seizures, a few, rapid clonic jerks may occur as the tonic phase ends.
Tonic-clonic seizures may be primarily or secondarily generalized. Primarily generalized seizures typically begin with an outcry; they continue with loss of consciousness and falling, followed by tonic contraction, then clonic (rapidly alternating contraction and relaxation) motion of muscles of the extremities, trunk, and head. Urinary and fecal incontinence, tongue biting, and frothing at the mouth sometimes occur. Seizures usually last 1 to 2 min. There is no aura. Secondarily generalized tonic-clonic seizures begin with a simple partial or complex partial seizure.
Myoclonic seizures are brief, lightning-like jerks of a limb, several limbs, or the trunk. They may be repetitive, leading to a tonic-clonic seizure. The jerks may be bilateral or unilateral. Unlike other seizures with bilateral motor movements, consciousness is not lost unless the myoclonic seizures progress into a generalized tonic-clonic seizure.
Juvenile myoclonic epilepsy is an epilepsy syndrome characterized by myoclonic, tonic-clonic and absence seizures. It typically appears during adolescence. Seizures begin with a few bilateral, synchronous myoclonic jerks, followed in 90% by generalized tonic-clonic seizures. They often occur when patients awaken in the morning, especially after sleep deprivation or alcohol use. Absence seizures may occur in 1/3 of patients.
Febrile seizures occur, by definition, with fever and in the absence of intracranial infection; they are considered a type of provoked seizure. They affect about 4% of children aged 3 mo to 5 yr . Benign febrile seizures are brief, solitary, and generalized tonic-clonic in appearance. Complicated febrile seizures are focal, last > 15 min, or recur = 2 times in <> 5 to 10 min
• = 2 seizures between which patients do not fully regain consciousness
The previous definition of > 30-min duration was revised to encourage more prompt identification and treatment. Untreated generalized seizures lasting > 60 min may result in permanent brain damage; longer-lasting seizures may be fatal. Heart rate and temperature increase. Generalized convulsive status epilepticus has many causes, including rapid withdrawal of anticonvulsants and head trauma.
Complex partial status epilepticus and absence status epilepticus often manifest as prolonged episodes of mental status changes. EEG may be required for diagnosis.

Diagnosis
Evaluation must determine whether the event was a seizure vs another cause of obtundation, a pseudoseizure, or syncope), then identify possible causes or precipitants. Patients with new-onset seizures are evaluated in an emergency department; they can sometimes be discharged after thorough evaluation. Those with a known seizure disorder may be evaluated in a physician's office.
History: Patients should be asked about unusual sensations, suggesting an aura and thus a seizure, and about typical seizure manifestations. However, other conditions, such as suddenly decreased brain circulation (eg, due to ventricular arrhythmia) can have similar manifestations, including loss of consciousness and some myoclonic jerks.
History should include information about the first and any subsequent seizures (eg, duration, frequency, sequential evolution, longest and shortest interval between seizures, aura, postictal state, precipitating factors). All patients should be asked about risk factors for seizures:
• Prior head trauma or CNS infection
• Known neurologic disorders
• Drug use or withdrawal, particularly of recreational drugs
• Alcohol withdrawal
• Nonadherence to anticonvulsants
• Family history of seizures or neurologic disorders
Patients should also be asked about rare triggers (eg, repetitive sounds, flashing lights, video games, touching certain parts of the body) and about sleep deprivation, which can lower the seizure threshold.

Physical examination: A bitten tongue, incontinence (eg, urine or feces in clothing), or, in patients who have lost consciousness, prolonged confusion suggest seizure.
In pseudoseizures, generalized muscular activity and lack of response to verbal stimuli may at first glance suggest generalized tonic-clonic seizures. However, pseudoseizures can usually be distinguished from true seizures by clinical characteristics:
• Pseudoseizures often last longer (several minutes or more).
• Postictal confusion tends to be absent.
• Typical tonic phase activity, followed by clonic phase, usually does not occur.
• The progression of muscular activity does not correspond to true seizure patterns (eg, jerks moving from one side to the other and back (nonphysiologic progression), exaggerated pelvic thrusting).
• Intensity may wax and wane.
• Vital signs, including temperature, usually remain normal.
• Patients often actively resist passive eye opening.
Physical examination rarely indicates the cause when seizures are idiopathic but may provide clues when seizures are symptomatic


Testing: Testing is done routinely, but normal results do not necessarily exclude a seizure disorder. Thus, the diagnosis may ultimately be clinical. Testing depends on the status of seizures and results of the neurologic examination.
If patients have a known seizure disorder and examination results are normal or unchanged, little testing is required except for blood anticonvulsant levels, unless patients have symptoms or signs of a treatable disorder such as trauma, infection, or a metabolic disorder. If seizures are new-onset or if examination results are abnormal for the first time, neuroimaging is required.
Head CT is usually done immediately to exclude a mass or hemorrhage. Some experts say that CT can be deferred and possibly avoided in children with typical febrile seizures whose neurologic status rapidly returns to normal.
Follow-up MRI is recommended when CT is negative. It provides better resolution of brain tumors and abscesses and can detect cortical dysplasias, cerebral venous thrombosis, and herpes encephalitis. An epilepsy-protocol MRI of the head uses high-resolution coronal T1 and T2 sequences, which can detect hippocampal atrophy or sclerosis. MRI can detect some common causes of seizures, such as malformations of cortical development in young children and mesial temporal sclerosis, traumatic gliosis, and small tumors in adults.
EEG is critical in the diagnosis of epileptic seizures, particularly of complex partial or absence status epilepticus, when EEG may be the most definitive indication of a seizure. EEG may detect epileptiform abnormalities (spikes, sharp waves, spike and slow-wave complexes, polyspike and slow-wave complexes). Epileptiform abnormalities may be bilateral and generalized in patients with generalized seizures and may be localized in patients with partial seizures. EEG findings may include the following:
• Epileptiform abnormalities in temporal lobe foci between seizures (interictal) in complex partial seizures originating in the temporal lobe
• Interictal symmetric bursts of 4- to 7-Hz epileptiform activity in primarily generalized tonic-clonic seizures
• Focal epileptiform discharges in secondarily generalized seizures
• Spikes and slow-wave discharges at a rate of 3/sec in typical absence seizures
• Slow spike and wave discharges usually at a rate of <>Prognosis
With treatment, seizures are eliminated in 1/3 of patients with epileptic seizures, and frequency of seizures is reduced by > 50% in another 1/3. About 60% of patients whose seizures are well-controlled by drugs can eventually stop the drugs and remain seizure-free.
Sudden unexplained death in epilepsy (SUDEP) is a rare complication of unknown cause.


Treatment
• Elimination of the cause if possible
• Avoidance of or precautions during situations when loss of consciousness could be life threatening
• Drugs to control seizures
• Surgery if = 2 drugs do not control seizures
Optimal treatment is to eliminate the causes whenever possible. If the cause cannot be corrected or identified, anticonvulsants are often required, particularly after a 2nd seizure; usefulness of anticonvulsants after a single seizure is controversial, and risks and benefits should be discussed with the patient. Because the risk of a subsequent seizure is low, drugs may be withheld until a 2nd seizure occurs, particularly in children. In children, certain anticonvulsants cause important behavior and learning problems.
During a generalized tonic-clonic seizure, injury should be prevented by loosening clothing around the neck and placing a pillow under the head. Attempting to protect the tongue is futile and likely to damage the patient's teeth or the rescuer's fingers. Patients should be rolled onto their left side to prevent aspiration. These measures should be taught to the patient's family members and co-workers.
Because partial seizures can become generalized, patients are at risk of losing consciousness and thus should be advised to take certain precautions. Until seizures are controlled, patients should refrain from activities in which loss of consciousness could be life threatening (eg, driving, swimming, climbing, operating power tools, bathing in a bathtub). After seizures are completely controlled (typically for > 6 mo), many such activities can be resumed if appropriate safeguards (eg, lifeguards) are used, and patients should be encouraged to lead a normal life, including exercise and social activities. In a few states, physicians must report patients with seizures to the Department of Motor Vehicles. However, most states allow automobile driving after patients have been seizure-free for 6 mo to 1 yr.
Patients should be advised to avoid cocaine and some other illicit drugs (eg, phencyclidine Some Trade Names
No US trade name

, amphetamines), which can trigger seizures, and to avoid alcohol. Some drugs (eg, haloperidol Some Trade Names
HALDOL

, phenothiazines) may lower seizure threshold and should be avoided if possible.
Family members must be taught a commonsense approach toward the patient. Overprotection should be replaced with sympathetic support that lessens negative feelings (eg, of inferiority or self-consciousness); invalidism should be prevented. Institutional care is rarely advisable and should be reserved for severely cognitively impaired patients and for patients with seizures so frequent and violent despite drug treatment that they cannot be cared for elsewhere.
Acute seizures and status epilepticus: Most seizures remit spontaneously in several minutes or less and do not require emergency drug treatment. Status epilepticus and most seizures lasting > 5 min require drugs to terminate the seizures, with monitoring of respiratory status. Endotracheal intubation is necessary if there is any indication of airway compromise. IV access should be quickly obtained, and lorazepam Some Trade Names
ATIVAN

0.05 to 0.1 mg/kg IV is given at a rate of 2 mg/min. Larger doses are sometimes required. However, if seizures continue after about 8 mg is given, fosphenytoin Some Trade Names
CEREBYX

15 to 20 PE ( phenytoin Some Trade Names
DILANTIN

equivalents)/kg IV is given at a rate of 100 to 150 PE/min; phenytoin Some Trade Names
DILANTIN

15 to 20 mg/kg IV at a rate of 50 mg/min is a 2nd choice. Additional seizures require an additional 5 to 10 PE/kg of fosphenytoin Some Trade Names
CEREBYX

or 5 to 10 mg/kg of phenytoin Some Trade Names
DILANTIN

. If IV access cannot be obtained, options include IM fosphenytoin Some Trade Names
CEREBYX

and sublingual or rectal benzodiazepines.
Seizures that persist after use of lorazepam Some Trade Names
ATIVAN

and phenytoin Some Trade Names
DILANTIN

define refractory status epilepticus. Recommendations for a 3rd anticonvulsant vary and include phenobarbital Some Trade Names
LUMINAL

, propofol Some Trade Names
DIPRIVAN

, midazolam Some Trade Names
No US trade name

, and valproate Some Trade Names
DEPAKENE

. Phenobarbital Some Trade Names
LUMINAL

15 to 20 mg/kg IV at 100 mg/min (3 mg/kg/min in children) is given; continued seizures require another 5 to 10 mg/kg. A loading dose of valproate Some Trade Names
DEPAKENE

10 to 15 mg/kg IV is an alternative. At this point, if status epilepticus has not abated, intubation and general anesthesia are necessary. The optimal anesthetic to use is controversial, but many physicians use propofol Some Trade Names
DIPRIVAN

15 to 20 mg/kg at 100 mg/min or pentobarbital Some Trade Names
NEMBUTAL

5 to 8 mg/kg (loading dose) followed by infusion of 2 to 4 mg/kg/h until EEG manifestations of seizure activity have been suppressed. Inhalational anesthetics are rarely used. After initial treatment, the cause of status epilepticus must be identified and treated.
Posttraumatic seizures: Drugs are given to prevent seizures if head injury causes significant structural injury (eg, large contusions or hematomas, brain laceration, depressed skull fracture) or a Glasgow Coma Scale (GCS) score of <> 1 wk after head injury, long-term treatment with drugs is required.
Principles of long-term treatment: No single drug controls all types of seizures, and different patients require different drugs. Some patients require multiple drugs. (See also the practice guideline for thetreatment of refractory epilepsy from the American Academy of Neurology and the American Epilepsy Society.) Some general principles apply:
• A single drug, usually the first or 2nd one tried, controls epileptic seizures in about 60% of patients.
• If seizures are difficult to control from the outset (in 30 to 40% of patients), = 2 drugs may eventually be required.
• If seizures are intractable (refractory to an adequate trial of = 2 drugs), patients should be referred to an epilepsy center to determine whether they are candidates for surgery.
Some drugs (eg, phenytoin Some Trade Names
DILANTIN

, valproate Some Trade Names
DEPAKENE

), given IV or orally, reach the targeted therapeutic range very rapidly. Others (eg, lamotrigine Some Trade Names
LAMICTAL

, topiramate Some Trade Names
TOPAMAX

) must be started at a relatively low dose and gradually increased over several weeks to the standard therapeutic dose, based on the patient's lean body mass. Dose should be tailored to the patient's tolerance of the drug. Some patients have symptoms of drug toxicity when blood drug levels are low; others tolerate high levels without symptoms. If seizures continue, the daily dose is increased by small increments. The appropriate dose of any drug is the lowest dose that stops all seizures and has the fewest adverse effects, regardless of blood drug level. Blood drug levels are only guidelines. Once drug response is known, following the clinical course is more useful than measuring blood levels.
If toxicity develops before seizures are controlled, the dose is reduced to the pretoxicity dose. Then, another drug is added at a low dose, which is gradually increased until seizures are controlled. Patients should be closely monitored because the 2 drugs can interact, interfering with either drug's rate of metabolic degradation. The initial, ineffective drug is then slowly tapered and eventually withdrawn completely. Use of multiple drugs should be avoided if possible because incidence of adverse effects, poor adherence, and drug interactions increases significantly. Adding a 2nd drug helps about 10% of patients, but incidence of adverse effects more than doubles. The blood level of anticonvulsants is altered by many other drugs, and vice versa. Physicians should be aware of all potential drug-drug interactions before prescribing a new drug.
Once seizures are controlled, the drug should be continued without interruption until patients have been seizure-free for at least 2 yr. At that time, stopping the drug may be considered. Most of these drugs can be tapered by 10% q 2 wk. Relapse is more likely in patients who have had any of the following:
• A seizure disorder since childhood
• Need for > 1 drug to be seizure-free
• Previous seizures while taking an anticonvulsant
• Partial or myoclonic seizures
• Underlying static encephalopathy
• Abnormal EEG results within the last year
Of patients who relapse, about 60% do so within 1 yr, and 80% within 2 yr. Patients who have a relapse when they are not taking anticonvulsants should be treated indefinitely.
Drug choice for long-term treatment: The drugs preferred vary according to type of seizure For more detailed drug-specific information,
For partial seizures and generalized tonic-clonic seizures, the newer anticonvulsants (eg, clonazepam Some Trade Names
KLONOPIN

, felbamate Some Trade Names
FELBATOL

, lamotrigine Some Trade Names
LAMICTAL

, levetiracetam Some Trade Names
KEPPRA

, oxcarbazepine Some Trade Names
TRILEPTAL

, pregabalin, tiagabine Some Trade Names
GABITRIL

, topiramate Some Trade Names
TOPAMAX

, zosinamide) are no more effective than the established drugs. However, the newer drugs tend to have fewer adverse effects and to be better tolerated.
Infantile spasms, atonic seizures, and myoclonic seizures are difficult to treat. Valproate Some Trade Names
DEPAKENE

is preferred, followed by clonazepam Some Trade Names
KLONOPIN

. For infantile spasms, corticosteroids for 8 to 10 wk are often effective. The optimal regimen is controversial. ACTH 20 to 60 units IM once/day may be used. A ketogenic diet (a very high fat diet that induces ketosis) may help but is difficult to maintain.
For juvenile myoclonic epilepsy, life-long treatment is usually recommended. Carbamazepine Some Trade Names
TEGRETOL

, oxcarbazepine Some Trade Names
TRILEPTAL

, or gabapentin Some Trade Names
NEURONTIN

can exacerbate the seizures.
For febrile seizures, drugs are not recommended unless children have a subsequent seizure in the absence of febrile illness. Previously, many physicians gave phenobarbital Some Trade Names
LUMINAL

or other anticonvulsants to children with complicated febrile seizures to prevent nonfebrile seizures from developing, but this treatment does not appear effective, and long-term use of phenobarbital Some Trade Names
LUMINAL

reduces learning capacity.
For seizures due to alcohol withdrawal, drugs are not recommended. Instead, treating the withdrawal syndrome tends to prevent seizures. Treatment usually includes a benzodiazepine.

Adverse drug effects: All anticonvulsants may cause an allergic scarlatiniform or morbilliform rash, and none is completely safe during pregnancy at the HealingWell.com web site [in Table 2].)
For patients taking carbamazepine Some Trade Names
TEGRETOL

, CBC should be monitored routinely for the first year of therapy. Decreases in WBC count and dose-dependent neutropenia neutrophil count <> 2 times the upper limit of normal), the drug should be stopped. An increase in ammonia up to 1.5 times the upper limit of normal can be tolerated safely.
Carbamazepine Some Trade Names
TEGRETOL

, phenytoin Some Trade Names
DILANTIN

, and valproate Some Trade Names
DEPAKENE

are pregnancy category D drugs (ie, teratogenicity occurs in animal and human pregnancies). Risk of neural tube defects is somewhat greater with valproate Some Trade Names
DEPAKENE

than other commonly used anticonvulsants. The newer drugs are category C (ie, teratogenicity occurs in animals, but human risk is unknown).
Fetal antiepileptic drug syndrome (cleft lip, cleft palate, cardiac defects, microcephaly, growth retardation, developmental delay, abnormal facies, limb or digit hypoplasia) occurs in 4% of children of women who take anticonvulsants during pregnancy. Yet, because uncontrolled generalized seizures during pregnancy can lead to fetal injury and death, continued treatment with drugs is generally advisable). The risk should be put in perspective: Alcohol is more toxic to the developing fetus than any anticonvulsant. Taking folate supplements before conception helps reduce risk of neural tube defects and should be recommended to all women who are of childbearing age and who take anticonvulsants.
Surgery: About 10 to 20% of patients have intractable seizures refractory to medical treatment and are potential surgical candidates. If seizures originate from a focal, resectable area in the brain, resection of the epileptic focus usually improves seizure control markedly. If the focus is in the anteromesial temporal lobe, resection eliminates seizures in about 60% of patients. After surgical resection, some patients remain seizure-free without taking anticonvulsants, but many still require the drugs, but in reduced doses and possibly as monotherapy. Because surgery requires extensive testing and monitoring, these patients are best treated in specialized epilepsy centers.
Vagus nerve stimulation: Intermittent electrical stimulation of the left vagus nerve with an implanted pacemaker-like device (vagus nerve stimulator) is used as an adjunct to drug therapy in patients who have intractable seizures and are not candidates for epilepsy surgery. This procedure reduces the number of partial seizures by = 50% in about 40%. After the device is programmed, patients can activate it with a magnet to abort an imminent seizure. Adverse effects include deepening of the voice during stimulation, cough, and hoarseness. Complications are minimal. Duration of effectiveness is unclear.