Improving quality of life with epilepsy surgery

In this issue of Neurology, Langfitt et al.¹ examine the effect of surgical outcome on quality of life in patients with intractable partial epilepsy. An estimated 30 to 40% of patients with epilepsy have medically refractory seizures.^2,3 Many of these individuals have an “intractable” disorder that is disabling, affecting the patient's quality of life.^2,3 The initial response to medication is of prognostic importance.^2,3 Multiple drug trials are unlikely to render an individual seizure free if the patient failed the initial two antiepileptic drugs (AEDs).² Approximately 80% of patients with partial seizure disorders have temporal lobe epilepsy.⁴ The comorbidity associated with intractable epilepsy may include progressive cognitive impairment, depression, AED-induced adverse effects, physical trauma related to seizures, status epilepticus, and sudden death.^2–6

Surgical resection of the epileptogenic zone, i.e., site of seizure onset and initial propagation, may be performed as an alternative to medication in patients with intractable partial epilepsy.^4–8 The effectiveness of surgery for temporal lobe epilepsy has been confirmed in a randomized controlled study comparing medical therapy and surgical treatment in 80 patients.⁷ The results indicated that 58% of 40 patients treated surgically were not experiencing seizures with loss of awareness at 1 year compared to 8% of 40 patients receiving AED medication (p < 0.001).⁷ The surgical group was also significantly more likely to have an improvement in quality of life (p < 0.001).⁷ Patients with unilateral MRI-identified mesial temporal sclerosis concordant with unilateral temporal lobe epileptiform discharges are candidates for a “curative” operative procedure with 94% of these patients in one study having an excellent seizure outcome.⁸ Operative morbidity occurred in 2 of 175 patients (1%) undergoing surgery for temporal lobe epilepsy.⁸

A verbal memory loss may develop following temporal lobe resection in the language-dominant hemisphere in an estimated 25 to 40% of patients.¹ The effect of amygdalohippocampectomy on memory outcome was evaluated in 140 patients.⁴ Verbal memory was reduced in ≤51% of 66 patients with left temporal lobe epilepsy and ≤32% of 74 patients with right temporal lobe epilepsy after surgery.⁴ Two percent and 7% of the left and right temporal lobe patients had an improvement in delayed recall.⁴ Individuals at greater risk for a verbal memory decline include those with left temporal lobe epilepsy, normal MRI, bilateral hippocampal pathology, later age at seizure onset, or normal preoperative memory.⁹ A severe global amnestic syndrome following unilateral temporal lobe surgery for epilepsy, however, is very rare.¹⁰ There have been nine documented patients with this unexpected adverse event.¹⁰

The study by Langfitt et al.¹ evaluates the importance of seizure outcome and memory decline on health-related quality of life (HRQOL) in 138 patients undergoing surgery for partial epilepsy. The HRQOL was evaluated using the QOLIE-89.¹ Fifty patients (36%) experienced a reduction in memory performance after surgery. A total of 113 patients (82%) were in a seizure remission at 2 or 5 years, or both, following epilepsy surgery. Thirty-nine of the 113 patients (35%) had a memory decline. Twenty-five patients (18%) were surgical failures. Eleven of the 138 patients (8%) were “double losers,” i.e., poor seizure outcome and memory deficit. The quality of life of the 113 individuals with a favorable seizure outcome improved regardless of any acquired memory decline. The 11 individuals (8%) who were surgical failures and sustained memory loss were the only patient group to experience a reduction in measures of HRQOL.

There is compelling evidence that most individuals with temporal lobe epilepsy have a marked reduction in seizure tendency following surgical treatment.^1,7,8 The psychosocial limitations of intractable epilepsy are often related to the presence of spontaneous seizures.¹ Preoperative assessments are available to counsel potential operative candidates. Factors that need to be considered in selecting candidates include preoperative memory, employment or educational activities, the pathology underlying the epileptogenic zone, the lateralization of the temporal lobe, and MRI findings. An intracarotid amobarbital procedure (IAP) is useful to assess language function and identify the very rare patient at risk for a global amnestic syndrome.¹ The utility of IAP for material-specific memory decline such as verbal memory loss after unilateral temporal lobe surgery is controversial. The potential for verbal memory loss after surgery needs to be weighed against the natural history of the disease which may include progressive cognitive impairment. The postoperative memory deficit is usually material-specific and not a global amnestic syndrome and may not interfere with the individual's quality of life with an excellent seizure outcome.¹ Ultimately, the patient should be considered for surgical treatment, even if at risk for verbal memory loss, earlier rather than later in the presence of an intractable seizure disorder because rendering the individual seizure free is required to be a participating and productive member of society.