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had a further one-year remission and by five years 90% had had a further two-year remission
period, indicating that the long-term prognosis was similar in both groups37.

A further analysis of the data from the MRC AED withdrawal study using regression
modelling has recently been reported38. The recurrence risk within the first 12 months
following AED withdrawal was 30% (95% CI 2535) while the risk of recurrence within the
next 12 months three months after AED withdrawal was 15% (95% CI 1019). For those
who had a seizure recurrence, three months after recommencing treatment the risk of seizure
recurrence within the next six months was 18% (95% CI 1027) and 26% (95% CI 1735)
within 12 months38.

An analysis of 14 AED withdrawal studies found that the recurrence rate following AED
discontinuation ranged from 12−66% (mean 34%) and reinstatement of treatment was
successful in obtaining further remission in, on average, 80% with no significant differences
between age groups. A second remission may, however, take many years to achieve, while
in an average of 19% the reintroduction of the medication did not control the seizures as
before. Up to 23% of those discontinuing treatment go on to develop intractable epilepsy.
Risk factors for subsequent poor treatment outcome were symptomatic partial epilepsy and
cognitive deficits39.

Despite the risk of seizure recurrence, patients may choose to discontinue treatment because
of the impact of continuing antiepileptic medication on quality of life. In one study40, the
effect of AED withdrawal on quality of life was assessed. At one year seizure recurrence had
occurred in 15% of the withdrawal group compared with 7% in the non-withdrawal group.
The proportion of patients having completely normal neuropsychological findings increased
from 11% to 28% in the withdrawal group while decreasing from 11% to 9% in the non-
withdrawal group. No differences in quality of life were observed between the two groups.
At 41 months’ follow-up, predictors of continued seizure freedom following treatment
withdrawal were prior use of carbamazepine (approximately three-fold increase in likelihood
of remaining seizure free compared with patients on any other drug) and a normal
neurological examination40.

Prognosis following epilepsy surgery

Only two randomised controlled trials have compared the outcomes of patients with temporal
lobe epilepsy randomised to either surgery or continued medical treatment41,42, the latter study
being of somewhat limited value due to difficulty recruiting suitable patients for inclusion in
the study42. In the earlier study, 80 patients with temporal lobe epilepsy were randomised to
have either epilepsy surgery or continued medical treatment for one year. A total of 90% of
patients in the surgery group underwent surgery with 64% free from seizures impairing
consciousness (42% completely seizure free) compared to 8% (3% completely seizure free
overall) in the medical group at one year. Quality of life was also improved in patients after
surgery compared to patients in the medical group (P < 0.001)41.

In a recent review of controlled studies (total 2734 patients, all but one study non-randomised)
44% of patients in the surgical group (mainly temporal lobe surgery) were seizure free
compared to 12% with medical treatment only. Moreover surgical patients were four times
more likely to be able to discontinue medication compared to non-surgical patients43.

In the long-term follow-up of 615 adults who underwent epilepsy surgery (497 anterior
temporal resections, 40 temporal lesionectomies, 40 extratemporal lesionectomies, 20 extra-
temporal resections, 11 hemispherectomies, and seven palliative procedures [corpus
callosotomy, subpial transection]), patients who had extra-temporal resections were more
likely to have seizure recurrence than were those who had anterior temporal resections