Psychological Aspects of Focal Epilepsy and Its Neurological Management Brenda Milner Background · This paper focuses on observing patients who have remained seizure free after undergoing a cortical excision for epilepsy relief · Doing so will serve to delineate the residual effects of a known brain lesion The Patient Sample · Patients: 955 cases of unilateral brain operation carried out to control seizures arising from long-standing atrophic lesions, excluding cases where seizures were secondary to a brain tumour · Nearly all of the remaining patients had lesions invading more than one lobe of the brain · These patients were divided into two groups: 1) The Central/Rolandic Group - comprises 117 patients, including 12 with focal lesions of the precentral or post central gyrus, or both, as well as cases of more massive brain injury 2) The Non-Central Group - comprises 101 patients, most of whom had circumscribed removals of parieto-temporal, temporo-occipital, or fronts-temporal cortex Salient Findings and Their Diagnostic Implications (300) · Few patients showed any lasting post-operative impairment of intelligence · Research has uncovered specific changes related to damage to particular cortical areas, and to whether or not the damage is in the speech-dominant hemisphere . Although these deficits tend to be mild and interfere very little (if at all) with the patient's daily life, they have lateralizing and localizing significance ; the fact that they are detectable pre-operatively explains why psychological examination now plays an increasing role in the assessment of patients who are candidates for seizure surgery; they may provide clues for areas of damage · Another purpose of pre-operative psychological tests is to draw attention to possible instances of right-hemisphere speech representation that would otherwise have been missed because the patients were right handed · Patients at risk are those few right-handers who are right-hemisphere dominant for speech and yet have a right hemisphere lesion · In this case, the Sodium amobarbital Amytal test of lateralization can be carried out BEFORE surgery
Risk to Memory · In rare cases, the operation of unilateral temporal lobectomy (including the hippocampus) has produced a global and persistent amnesic syndrome that is a more serious handicap than the epilepsy itself - To account for this unexpected result in two cases of left temporal lobectomy, Penfield and Milner suppose that in each case there was an additional and possible more extensive lesion in the hippocampal region of the opposite hemisphere - Thus surgical removal of the partially functioning (though epileptogenic) hippocampus on the LEFT deprived the patient of hippocampal function bilaterally - This is consistent with the fact that bilateral surgical destruction of the hippocampus and hippocampal gryus causes severe and lasting memory loss · Such cases of memory loss have led researchers to look carefully for possible signs of bilateral temporal lobe abnormality in all patients being considered for a unilateral temporal lobectomy · The researchers have been testing memory in patients with evidence of bilateral temporal abnormality after the intracartoid injection of sodium Amytal; this has allowed them to