Detection of visual field defects in patients after anterior temporal lobectomy for mesial temporal sclerosis-establishing eligibility to drive.
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AIMS: The aim of this study is to quantify visual field defects after temporal lobectomy for mesial temporal sclerosis and to establish eligibility for driving. METHODS: Automated static perimetry was performed on 14 patients who had undergone anterior temporal lobectomy for mesial temporal sclerosis. Perimetry consisted of monocular Humphrey Field Analyser (HFA) 30-2 test and a binocular Esterman 120 test. RESULTS: Of the 14 patients, three had no loss or non-specific loss, eight had partial homonymous quadrantanopia, one had complete homonymous quadrantanopia and two had concentric loss attributable to vigabatrin, which may have masked any loss occurring due to surgery. Of these, only seven passed the standardised DVLA visual fields. Of the seven who failed DVLA visual field, one had complete quadrantanopia, four had partial quadrantanopia and two had concentric loss (due to vigabatrin). CONCLUSIONS: Visual field defects contribute a great deal in the reduction of the quality of life in patients who have had surgery for mesial temporal sclerosis. Potential surgically induced visual field defects that could preclude driving need to be discussed with each patient preoperatively. In our study 50% of patients did not meet the required DVLA standards. (+info)
Emotional facial paresis in temporal lobe epilepsy: its prevalence and lateralizing value.
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The selection of patients with medically refractory temporal lobe epilepsy (TLE) for surgery depends on the concordance of data from clinical, imaging and electroencephalographic evaluation. Though clinical examination is often normal, emotional facial paresis has been described in patients with TLE. Utilizing a well-characterized group of mesial TLE (MTLE) patients, who have achieved excellent seizure outcome following anterior temporal lobectomy with amygdalohippocampectomy (ATL), we investigated the prevalence, predictive value and associations of emotional facial paresis. When compared to 8 out of 50 control subjects (16%), 36 out of 50 MTLE patients (72%) exhibited unilateral emotional facial paresis; the difference was highly significant (P<0.0001). The presence of contralateral emotional facial paresis correctly predicted the side of ATL in 86.1% patients. The occurrence of emotional facial paresis was significantly associated with longer duration of epilepsy prior to ATL and left ATL. Our observations confirm that emotional facial parersis contralateral to the side of mesial temporal sclerosis (MTS) is a valuable localizing sign in correctly predicting the epileptogenic temporal lobe. We hypothesize that the presence of an intact right hemisphere and pathological changes more extensive than MTS may be required for emotional facial paresis to readily manifest. (+info)
Unexpected amnesia: are there lessons to be learned from cases of amnesia following unilateral temporal lobe surgery?
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Cases of amnesia following unilateral temporal lobe surgery are rare, but they may provide important insights into human brain functioning. Such cases are reconsidered here in the light of recent developments in clinical and cognitive neuroscience. Descriptions of preoperative seizure activity in these cases indicate the potentially valuable role of ictal semiology in localizing the source of epileptiform discharges. Cases of amnesia after unilateral temporal lobectomy illustrate the complexity of intra- and inter-hemispheric propagation of epileptiform discharges and highlight possible neurophysiological mechanisms underlying false localization of abnormal EEG activity. This review points to the value of preoperative neuropsychological assessment in providing information on the likely primary locus of pathology and in predicting outcome after surgery. The analysis of cases upholds the benefits of the Wada procedure, but it highlights the variability in Wada test procedures and the fact that Wada test scores themselves may be open to varying interpretation. These cases of postoperative amnesia are further considered in the context of the cognitive neuroscience of human memory and, in particular, mechanisms underlying the human amnesic syndrome. They confirm the critical role of bilateral medial temporal lobe structures in anterograde memory, but they also highlight the complexity in teasing apart neural mechanisms underlying remote memory loss. (+info)
A specific role for the human amygdala in olfactory memory.
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The medial temporal lobe is known to play a role in the processing of olfaction and memory. The specific contribution of the human amygdala to memory for odors has not been addressed, however. The role of this region in memory for odors was assessed in patients with unilateral amygdala damage due to temporal lobectomy (n = 20; 11 left, 9 right), one patient with selective bilateral amygdala damage, and in 20 age-matched normal controls. Fifteen odors were presented, followed 1 h later by an odor-name matching test and an odor-odor recognition test. Signal detection analyses showed that both unilateral groups were impaired in their memory for matching odors with names, these patients were not significantly impaired on odor-odor recognition. Bilateral amygdala damage resulted in severe impairment in both odor-name matching as well as in odor-odor recognition memory. Importantly, none of the patients were impaired on an auditory verbal learning task, suggesting that these findings reflect a specific impairment in olfactory memory, and not merely a more general memory deficit. Taken together, the data provide neuropsychological evidence that the human amygdala is essential for olfactory memory. (+info)
Emotional memory and perception in temporal lobectomy patients with amygdala damage.
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BACKGROUND: The human amygdala is implicated in the formation of emotional memories and the perception of emotional stimuli--particularly fear--across various modalities. OBJECTIVES: To discern the extent to which these functions are related. METHODS: 28 patients who had anterior temporal lobectomy (13 left and 15 right) for intractable epilepsy were recruited. Structural magnetic resonance imaging showed that three of them had atrophy of their remaining amygdala. All participants were given tests of affect perception from facial and vocal expressions and of emotional memory, using a standard narrative test and a novel test of word recognition. The results were standardised against matched healthy controls. RESULTS: Performance on all emotion tasks in patients with unilateral lobectomy ranged from unimpaired to moderately impaired. Perception of emotions in faces and voices was (with exceptions) significantly positively correlated, indicating multimodal emotional processing. However, there was no correlation between the subjects' performance on tests of emotional memory and perception. Several subjects showed strong emotional memory enhancement but poor fear perception. Patients with bilateral amygdala damage had greater impairment, particularly on the narrative test of emotional memory, one showing superior fear recognition but absent memory enhancement. CONCLUSIONS: Bilateral amygdala damage is particularly disruptive of emotional memory processes in comparison with unilateral temporal lobectomy. On a cognitive level, the pattern of results implies that perception of emotional expressions and emotional memory are supported by separate processing systems or streams. (+info)
Schizophrenia-like psychosis arising de novo following a temporal lobectomy: timing and risk factors.
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OBJECTIVES: To clarify risk factors for the development of schizophrenia-like psychotic disorders following temporal lobectomy, and to explore the possibility that the early postoperative period is a time of high risk for the onset of such chronic psychotic disorders. METHODS: Patients who developed schizophrenia-like psychosis were identified from a series of 320 patients who had a temporal lobectomy for medically intractable epilepsy. The relationship of their disorders to both the operation and subsequent seizure activity was examined. Using a retrospective case-control design, risk factors for the development of schizophrenia-like psychosis were established. RESULTS: Eleven patients who developed schizophrenia-like psychosis postoperatively were identified and compared with 33 control subjects who remained free of psychosis postoperatively. The onset of de novo psychotic symptoms was typically in the first year following the operation. No clear relationship between postoperative seizure activity and fluctuations in psychotic symptoms emerged. Compared with the controls, patients who become psychotic had more preoperative bilateral electroencephalogram (EEG) abnormalities, pathologies other than mesial temporal sclerosis in the excised lobe and a smaller amygdala on the unoperated side. CONCLUSIONS: Temporal lobectomy for medically intractable epilepsy may precipitate a schizophrenia-like psychosis. Patients with bilateral functional and structural abnormalities, particularly of the amygdala, may be at particular risk for the development of such psychoses. (+info)
Temporal lobectomy: long-term seizure outcome, late recurrence and risks for seizure recurrence.
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There is little information available relevant to long-term seizure outcome after anterior temporal lobectomy, particularly at extended postoperative periods. The aim of this study was an in-depth examination of patterns of longitudinal outcome and potential risk factors for seizure recurrence after lobectomy, utilizing a large patient sample with long follow-up. Included were 325 patients who underwent anterior temporal lobectomy between 1978 and 1998 (mean follow-up 9.6 +/- 4.2 years). Retrospective data were analysed using survival analysis and multivariate regression with Cox proportional hazard models. The probability of complete seizure freedom at 2 years post-surgery was 55.3% [95% confidence interval (CI) 50-61]; at 5 years, 47.7% (95% CI 42-53); and at 10 postoperative years it was 41% (95% CI 36-48). Patients with discrete abnormalities preoperatively (i.e. lesions and hippocampal sclerosis) had a significantly higher probability of seizure freedom than patients without obvious abnormality. The latter group had a pattern of recurrence similar to that in patients with lesions outside the area of excision. After adjustment for preoperative pathology, only the presence of preoperative secondarily generalized seizures had a significant association with recurrence [occasional preoperative generalized seizures, hazard ratio (HR) 1.6, 95% CI 1.1-2.3; frequent seizures, HR 2.0, 95% CI 1.4-2.9 compared with absence of preoperative generalized seizures]. Duration of preoperative epilepsy, age of seizure onset and age at surgery did not have an effect on outcome. Patients with two seizure-free postoperative years had a 74% (95% CI 66-81) probability of seizure freedom by 10 postoperative years. This late seizure recurrence was not associated with any identified risk factors. Specifically, patients with hippocampal sclerosis were not at higher risk. Surprisingly, complete discontinuation of anti-epileptic drugs (AEDs) after two postoperative years was not associated with an increased risk of recurrence (HR 1.03, 95% CI 0.5-2.1). This may be because selection of patients for AED discontinuation is biased towards those individuals perceived as 'low risk'. The results of this study indicate that the lack of an obvious abnormality or the presence of diffuse pathology, and preoperative secondarily generalized seizures are risk factors for recurrence after surgery. Late recurrence after initial seizure freedom is not a rare event; risk factors specific to this phenomenon are as yet unidentified. (+info)
Cerebellar hemorrhage as a complication of temporal lobectomy for refractory medial temporal epilepsy: report of three cases.
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Cerebellar hemorrhage is listed among the potential complications following neurosurgical procedures. In this scenario it is usually reported as a rare condition. However, it seems that epilepsy surgery patients are somewhat more prone to this kind of complication, compared to other surgical groups. Head positioning, excessive cerebral spinal fluid draining and the excision of non-expanding encephalic tissue (or combinations among the three) are likely to be cause underlying remote cerebellar hemorrhage. Out of the 118 ATL/AH performed at our institution, between 1996 and 2002, we identified 3 (2.5%) patients presenting with cerebellar hemorrhage. We report on such cases and review the literature on the topic. (+info)