164 AJMONE-MARSAN
input to the amplifier of one EEG recording channel. This provided a
signal that would permit the identification and synchronization of each
single frame with the corresponding event in the tracing.^20 Furthermore,
because the seizures were induced, the investigator who performed the
activation test could continuously dictate all clinical observations. Both
the dictation and the patient’s answers, or lack thereof, to questions were
recorded on the same audio tape for later analysis. This permitted the
monitoring of subjective feelings, sensations, aphasic signs, etc., that
may have been missed in video monitoring when the observer was not
always present.
In the research project dealing with the pre-operative workup for the
selection of potential surgical candidates, Van Buren and I placed great
importance on the electrographic manifestations of the ictal episode for
the correct localization and lateralization of an epileptogenic process.
On the other hand, with either scalp or direct electrography, the interictal
phenomena were never ignored, and were considered significant, not so
much for reaching the correct diagnosis, but rather to decide on progno
sis or possible contraindication to surgery. Thus, in the common situa
tion in which there was extensive interictal evidence for bilateral, active
and independent epileptogenic processes, a patient might eventually
be classified as a poor candidate or as a noncandidate for local temporal
ablation, even if the onset of seizures was proven to be consistently only
on one side.
Of those involved in surgical treatment of epilepsy, Van Buren et al.
were among the first to emphasize the need for a reasonably long post
operative follow-up period, before reliable conclusions can be drawn on
the potentially successful results of surgery.^21 Still, at the present time,
most published data, with the exception of the MNI school, include a
predominance of cases with post-operative follow-ups of from six months
to less than two years. The NINDS experience, derived from the study of
over 120 temporal lobe epileptics, seems to suggest that a minimum of
four years of follow-up is required, before concluding the surgical proced
ure was a “total success.” Indeed one may find up to 63 percent of patients
seizure-free during the first post-operative year. However, this percent
age may fall to less than 25 percent after 10 years or longer of follow-up.