Long‐term outcome in children with infantile spasms treated with vigabatrin: A cohort of 180 patients

To the Editors: I have read with great interest the article of Djuric et al.,1 "Long-term outcome in children with infantile spasms treated with vigabatrin: A cohort of 180 patients." They describe the largest reported cohort of patients with infantile spasms treated by vigabatrin followed for the longest period of time, and from a single tertiary epilepsy center. According to this report, the long-term outcome (at 2.4–18, 9 [mean 10] years) is amazingly good: normal cognitive outcome (intelligence testing score [IQ] > 70) in 60 (40%) of 149 patients and freedom from seizures in 69 (46%) of 149 patients. It should be noted that IQ > 70 is not the same as IQ > 90, which is usually used for normal intelligence. These figures are seemingly much better than in the long-term follow-up in patients treated with adrenocorticotropic hormone (ACTH).2, 3 The corresponding numbers in the latter study are 36 (24.5%) of 147 and 48 (33%) of 147, respectively. Because the results of Djuric et al. have been compared with my studies of long-term outcome of children treated for infantile spasms, I would like to correct some erroneous information presented about my study. Finally, it is difficult, if not impossible, to compare the results of clinical series of infantile spasms, because of their nonhomogeneity and different definitions of response used in the series. A good response should include both total cessation of the spasms and disappearance of the hypsarrhythmia in the sleep EEG. Some authors have treated only children whose outcome is likely to be favorable, with a high number of dropouts from the series. Furthermore, there might be difference of study design due to age at onset of the spasms, extension of etiologic investigations, different treatment schedules, concomitant drugs, rate of relapses, definition of cognitive impairment and length of follow-up. The author has no conflicts of interest to disclose. I confirm that I have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.