Throughout this decade Dr. Williamson, as well as Dr. Susan Spencer and others on the team, reported the semiology of multiple partial seizure types based on site of origin and in particular helped define complex partial seizures of frontal, temporal, parietal and occipital origin. Drs. Susan and Dennis Spencer and colleagues also assembled experience with corpus callosotomy and defined both the benefits and risks.
During the same period of the early 1980's Dr. Dennis Spencer introduced a new approach to temporal lobectomy that maximized removal of epileptic tissue in the hippocampus and spared important functional lateral cortex. The resected tissue was carefully studied by Drs. Nihal DeLanerolle, Jung Kim and Anne Williamson, among others to gain understanding of the pathology and pathophysiology of epilepsy, especially mesial temporal sclerosis.
During that period Dr. John Ebersole returned to Yale from the NIH and joined the team. With a primary interest in neurophysiology he was a pioneer in use of 24-hour ambulatory monitoring. He then turned his expertise to both conventional EEG and magnetoencephalography and utilized dipole source localization to refine the likely site of interictal and ictal discharges.
Although maintaining an interest in intensive monitoring and pre-surgical evaluation, Dr. Mattson, with Joyce Cramer, had increasingly directed their research efforts to pharmacokinetics and pharmacology of antiepileptic drugs. By the mid 1970's they had designed, developed and led the two large VA Multi-center COOP Studies comparing the standard antiepileptic drugs from the mid 1970's to the early 1990's with support from Dr. Williamson and later Dr. Ebersole.
By the mid 1980's, in view of the surgical emphasis of the epilepsy monitoring unit, Dr. Mattson appointed Dr. Peter Williamson to replace him as Director. Throughout most of that decade, 24-hour EEG recording was recorded on paper and required hours of exhaustive review for interictal and ictal events. The 24-hour attendance by expert nurses provided preliminary identification of important data which facilitated the review. By the end of the 1980's technical advances allowed the EEG to be digitized and recorded on a portion of the videotape thus locking the clinical and EEG events. This previously had been done on a split-screen but the number of channels and the resolution were limited.
Despite new equipment, increased efficiency of operation and the addition of two beds, the VA monitoring unit had a waiting time for admission of almost a year. It became clear for many reasons the VA would not expand the unit further because the hospital had begun a process of reducing, not increasing, bed size and plans were started to develop another epilepsy unit at Yale-New Haven Hospital.
In addition to the limited bed situation, many studies required patients to be transported to Yale-New Haven Hospital and back for diagnostic tests such as MRI and surgery because by that time the majority of patients were Yale "sharing" not VA patients. Further, although all epilepsy physicians worked and had appointments and responsibilities at both Yale and the VA, Drs. Susan and especially Dennis Spencer had primary appointments and responsibilities on the Yale rather than the VA campus making daily travel difficult.
For all these reasons initiatives were set in motion to develop an epilepsy monitoring unit with a surgical emphasis at Yale-New Haven Hospital. Initially, a small surgical unit was established in the Neuro-intensive Care Unit for intracranial recording and surgery. Extensive planning simultaneously was undertaken to build a unit comparable to but larger than that at the VA in Yale-New Haven Hospital. Opening in 1990, under the direction of Drs. Dennis and Susan Spencer, the unit coexisted with the unit at the VA under the Directorship of Dr. Peter Williamson.
Also in the mid 1980's, Dr. Williamson began a formal epilepsy fellowship with the training of Dr. Paul Boon followed by Dr. Jacqueline French, both of whom have become internationally recognized epileptologists.