Patients' aims for epilepsy surgery: desires beyond seizure freedom.

PURPOSE: To evaluate prospectively patient's aims for epilepsy surgery as previously outlined theoretically by Taylor et al. (Epilepsia 1997;3:625-30). METHODS: Ninety-three consecutive patients were interviewed by a psychiatrist as part of their evaluation for epilepsy surgery. Open-ended questions about the patient were asked, and carers' aims or ambitions for change as a result of putative relief of seizures were elicited. The interviewer aimed to obtain a maximum of five aims for later follow-up purposes. These questions were part of an extensive psychiatric interview that is described. RESULTS: The aims of 69 patients or carers were analyzed. The 204 statements of aims were grouped into 59 categories initially. The five most frequently cited constituted 50% of all the aims listed. These aims were desire for work, driving of motor vehicles, independence, socializing, and freedom from drugs. The patients rarely identified a desire for improvement in cognitive functioning as an aim for epilepsy surgery. A final analysis into six categories showed that changes in social process predominated, even over changes in personal behavior. CONCLUSIONS: The social and personal aims to accompany relief of epilepsy identified by patients are consistent with the literature on psychosocial adjustment to epilepsy.

Differential cognitive effects of colloid cysts in the third ventricle that spare or compromise the fornix.

A series of twelve cases, all of whom had received surgery for the removal of a colloid cyst in the third ventricle, was examined on a series of memory tests. The only consistent predictor of poor memory performance that could be detected from MRIs was the presence of bilateral interruption of the fornix, which occurred in three of the subjects. Although these three cases were poor on tests of learning and recall, there was evidence that recognition was less impaired. The subjects were also tested on a set of recognition and concurrent discriminations that closely matched tests given to non-human primates. Clear parallels were found between the apparent effects of fornix damage in these clinical cases and those observed following more selective surgery in non-human primates. These findings not only indicate that fornix damage is sufficient to induce anterograde amnesia but also support the validity of recent animal tests that are thought to capture aspects of episodic memory.

Prosodic preservation in Landau-Kleffner syndrome: a case report.

Landau-Kleffner syndrome (LKS) is a rare acquired condition of auditory verbal agnosia and convulsive disorder in children. It has been proposed that there is a functional relationship between electrical disturbance and the speech defect. Prosody or the melody of language, as described by Monrad-Krohn (1947), is one aspect of non-verbal communication which is distributed bilaterally in the brain. Prosodic parameters of expression and perception in one 7.5-year-old child were tested to see if they were preserved as a means of communication. The child was observed during video-electroencephalogram (EEG) monitoring over a 48-hour period. All utterances were recorded and subject to analysis for the salience and variation of acoustic correlates of prosody. Prosodic comprehension was measured using specific perceptual tasks previously presented to normal children between the ages of 5.5 and 8.5. Despite being unable to meaningfully use or perceive phonemes, the child was able to use variations in fundamental frequency, duration and intensity of utterances, to convey both emotional and propositional intent. Similarly, the child was able to discriminate prosodic contours of a male adult voice to an age equivalent to 5.5 to 6.5 years. This argues in favour of the notion for educating such children not only through the visual channel but also through the auditory channel.

Regional cerebral blood flow and language dominance: SPECT during intracarotid amobarbital testing.

We examined the relation between language dominance and regional cerebral blood flow (rCBF) during the intracarotid amobarbital procedure (IAP). A previous report limited to three patients suggested that dominant rather than nondominant hemisphere IAP may have a differential effect on rCBF. Behavioral assessment during the IAP also suggests that dominant hemisphere injection results in a differential effect on memory and affective symptoms rather than nondominant injection. Thirteen patients were assessed using single-photon emission CT (SPECT) brain imaging during both left and right IAP. The SPECTs were coregistered with the individual's MRI. Changes in rCBF during each IAP were compared with the patient's baseline SPECT. Nine patients had left hemisphere dominance, two were right dominant, and two had bilateral speech representation. In the left dominant subjects, left-hemisphere injection had a consistently greater effect on rCBF than right-hemisphere injection in the anterior (p < 0.005) and posterior (p < 0.01) temporal neocortex. There was also a trend for greater hypoperfusion in the frontal lobe of the left hemisphere. rCBF in the ipsilateral hippocampus was not significantly different after each injection (p > 0.05). In the two patients with right hemisphere speech, the reverse pattern was seen, with greater hypoperfusion after right (dominant) hemisphere injection. There was no consistent asymmetry in the two patients with bilateral speech. Dominant hemisphere IAP results in significantly greater hypoperfusion than does nondominant injection. These data provide a physiologic basis for behavioral differences noted after dominant versus nondominant IAP.

Contribution of medial versus lateral temporal-lobe structures to human odour identification.

To investigate possible distinct contributions of different temporal-lobe structures to odour identification, the University of Pennsylvania Smell Identification Test was administered monorhinally to seizure-free patients who had undergone one of three types of temporal-lobe resection practised in three different institutions for surgical treatment of epilepsy. The resections were neocorticectomy (Dublin), selective amygdalohippocampectomy (Zurich), or anterior temporal-lobe resection with encroachment on amygdala and hippocampus (Montreal). Resections, analysed from MRI scans, showed unexpected encroachment on medial structures in most patients of the neocorticectomy groups, and largest amygdala and hippocampal resections in the amygdalohippocampectomy groups. Impaired odour identification was observed in all patient groups, irrespective of surgical approach, with greatest impairment in the nostril ipsilateral to the resection. The finding of deficits in all three surgical groups suggests that damage in the anterior temporal area, perhaps in piriform cortex, is sufficient to disrupt performance on this task; it may be that function is disrupted in the medial temporal-lobe region by disconnection when the periamygdaloid area is damaged, even when amygdala and hippocampus are left intact. An alternative explanation for our results is that damage in any one of these areas disrupts a complex network involving several distinct temporal-lobe structures.

Learning and retention of words and designs following excision from medial or lateral temporal-lobe structures.

We sought to elucidate the contributions of the amygdala, hippocampus and temporal neocortex to learning and memory for verbal and visuospatial material. Two matched learning tasks, using abstract words versus abstract designs, were administered to patients with unilateral neocorticectomy (NCE; Dublin), selective amygdalohippocampectomy (AHE; Zurich) or anterior temporal-lobe resection invading the amygdala and hippocampus (ATL; Montreal). Data were analysed according to side and type of resection. Learning and recall for words was impaired in groups with resection from the left temporal lobe, irrespective of whether mediobasal structures were spared or temporal neocortex was spared. All right-resection groups were unimpaired. Learning for abstract designs was impaired across all trials in the right AHE and NCE groups, and on the last two trials in the right ATL group. Restricted deficits of lower magnitude were observed on some trials in left-resection groups. These results show a partial dissociation between side of excision and type of material, but the finding of similar deficits in all resection types was unexpected. We propose that excision from either the hippocampal region or temporal neocortex may result in a disconnection, giving a similar functional outcome, as both types of resection interrupt a circuit likely to be essential for normal storage and retrieval of information.

Assessment of the functional effect of the intracarotid sodium amobarbital procedure using co-registered MRI/HMPAO-SPECT and SEEG.

We studied the functional effect of injection of sodium amobarbital (SA) in 10 patients with intractable epilepsy. During the intracarotid amobarbital procedure, we measured delta activity in EEG recording from implanted electrodes and regional cerebral blood flow (rCBF) using HMPAO-SPECT co-registered with MRI. SA injection resulted in an increase in delta activity and a decrease in rCBF in all areas examined. Direct functional changes were observed in structures perfused by the carotid artery injected. In addition, we observed indirect effects, probably owing to deafferentation of neuronal pathways connecting these structures to ipsilateral and contralateral regions, including middle and posterior hippocampus.

Correlation of fornix damage with memory impairment in six cases of colloid cyst removal.

We studied six patients in whom colloid cysts had been removed surgically from the third ventricle. The patients were selected simply by availability for the study, not on grounds of clinically diagnosed amnesia or its absence. The outcomes of operation ranged from one patient who had postoperatively resumed a normal life without complaint of memory disorder at any stage, through four who complained of memory disorder since operation, to one who was so severely amnesic as to require constant supervision. Each patient was given psychometric tests of memory, and was also scanned by magnetic-resonance imaging. One of us examined the six scans and assessed the extent of damage to the fornix, and any other brain damage, in ignorance of the outcomes of the psychometric tests. The fornix in the right hemisphere had been destroyed in all six cases, and all showed evidence of moderate or severe impairment in nonverbal memory. The fornix in the left hemisphere was intact in only one patient; this was the patient who had resumed a normal life without complaint of memory disorder. The left fornix was damaged with some sparing in one further patient, and the remaining four patients showed destruction of the fornix in the left as well as in the right hemisphere. The severity of impairment in verbal memory in these six cases was related to the severity of the damage to the left fornix. No other evidence of brain damage appeared to be systematically related to memory ability. These results add to the evidence that bilateral fornix damage produces amnesia, and that sparing of the left fornix alone is sufficient to ensure a more favourable outcome.

Temporal neocorticectomy in management of intractable epilepsy: long-term outcome and predictive factors.

We report the results of a long-term follow-up study of 50 patients who underwent removal of temporal neocortex with preservation of deeper limbic structures as surgical therapy for intractable temporal lobe epilepsy. The follow-up period ranged from 3 to 15 years. Preoperative EEG investigations were based on interictal discharges alone. Three factors were predictive of a good outcome: (a) A clear unilateral anterior-midtemporal focus (p less than 0.01), (b) stereotypical onset of temporal lobe seizure (p less than 0.005), and (c) greater volume of tissue removed at operation (p less than 0.05). Overall results showed that 62% of patients experienced an outcome of "cure" or "almost cure," as classified according to a modified version of Crandall's criteria (Crandall's I and II). Those who experienced a significant reduction in seizures but who continued to have intractable epilepsy (Crandall's III) were not considered to have had a good result. Overall outcome compares favorably with other that of centers using different surgical approaches and indicates that neocorticectomy is a suitable procedure in a highly selected population even when limited resources are available.