Ferreira-Atuesta et al reported 2 nomograms for predicting seizure freedom following antiseizure medication withdrawal after epilepsy surgery. The second nomogram is complete seizure freedom. The authors are from multiple institutions from around the world.
Patient selection: adult with seizures status post epilepsy surgery
Parameters:
(1) febrile seizure before surgery
(2) number of years between surgery and start of drug withdrawal, from 0 to 20
(3) focal to bilateral tonic clonic seizures before surgery
(4) seizure frequency before surgery
(5) duration of epilepsy, from 0 to 6.5 years (no mention for longer period, so will cap at 6.5)
points for time to begin =
= 100 - (4.55 * (years))
points for duration of epilepsy =
= MIN(23.63, 3.635 * (years))
|
Parameter
|
Finding
|
Points
|
|
febrile seizure before surgery
|
no
|
0
|
|
|
yes
|
6.54
|
|
focal to bilateral tonic clonic seizures
|
no
|
0
|
|
|
yes
|
18.54
|
|
seizure frequency
|
less than once a year
|
0
|
|
|
at least once per year
|
7.67
|
|
|
at least once per month
|
15.34
|
|
|
at least once per week
|
23.01
|
|
|
daily
|
30.68
|
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 179.39
value of X for 2-year complete seizure freedom =
= (-0.00009821*((score)^2)) - (0.01388 * (score)) + 4.881
probability of 2-year complete seizure frequency =
= 1 / (1 + EXP((-1) * X))
value of Y for 4-year complete seizure freedom =
= (-0.0001252 * ((score)^2)) - (0.01062 * (score)) + 4.328
probability of 4-year complete seizure freedom =
= 1 / (1 + EXP((-1) * Y))
Performance:
• The c-statistic is 0.68 in an external validation cohort.
