Memory, emotional and vocational impairments before and after anterior temporal lobectomy for complex partial seizures

PURPOSE: To assess the pre- and postsurgical frequency of memory, emotional, and vocational impairments in patients who underwent anterior temporal lobectomy (ATL), and to assess the relationship between emotional disturbance and memory abilities after ATL. METHODS: Retrospective analysis of data was performed on 90 patients with medically intractable complex partial seizures who underwent ATL between 1981 and 2003. Patients were evaluated an average of 5 months before surgery and 11.3 months after surgery. RESULTS: A moderate to high frequency of memory impairment (44.4%; verbal or nonverbal), emotional disturbance (38.9%) and unemployment (27.8%) existed in the same individuals both before and after surgery. There were small to moderate rates of new onset memory (18.9%), emotional (11.1%), and vocational (7.8%) difficulties after surgery often regardless of seizure control outcome. Patients who underwent left-ATL and had emotional disturbance after surgery had the lowest verbal memory test scores. CONCLUSIONS: Results highlight the importance of taking into account emotional status when assessing memory abilities after ATL. Results replicate the finding of moderate to high frequencies of memory impairment, emotional disturbance, and unemployment both before and after ATL. Results provide support for the rationale that cognitive, psychiatric and vocational interventions are indicated to mitigate the problems that exist before and persist after ATL.     

A comparison of two fMRI methods for predicting verbal memory decline after left temporal lobectomy: Language lateralization versus hippocampal activation asymmetry

Purpose: Language lateralization measured by preoperative functional magnetic resonance imaging (fMRI) was shown recently to be predictive of verbal memory outcome in patients undergoing left anterior temporal lobe (L‐ATL) resection. The aim of this study was to determine whether language lateralization or functional lateralization in the hippocampus is a better predictor of outcome in this setting. Methods: Thirty L‐ATL patients underwent preoperative language fMRI, preoperative hippocampal fMRI using a scene encoding task, and pre‐ and postoperative neuropsychological testing. A group of 37 right ATL (R‐ATL) surgery patients was included for comparison. Results: Verbal memory decline occurred in roughly half of the L‐ATL patients. Preoperative language lateralization was correlated with postoperative verbal memory change. Hippocampal activation asymmetry was strongly related to side of seizure focus and to Wada memory asymmetry but was unrelated to verbal memory outcome. Discussion: Preoperative hippocampal activation asymmetry elicited by a scene encoding task is not predictive of verbal memory outcome. Risk of verbal memory decline is likely to be related to lateralization of material‐specific verbal memory networks, which are more closely correlated with language lateralization than with overall asymmetry of episodic memory processes.     

Gender,Memory, and Hippocampal Volumes: Relationships in Temporal Lobe Epilepsy

Previous research has suggested bilateral hippocampal support for verbal memory in women with early left-hemisphere injury and that women experience better verbal memory outcome following anterior temporal lobectomy (ATL). The present study investigated two issues: (1) Do women have better verbal memory outcome following ATL compared with men? (2) Are verbal memory abilities differentially supported by the right and left hippocampus in males and females? Verbal memory performance [Wechsler Memory Scale: Logical Memory (LM) savings score] was assessed in 70 patients who underwent ATL. MRI volumetric measurements of the left and right hippocampus were performed. No LM savings score difference was found between groups preoperatively although a statistically significant gender effect (P < 0.04) was found for postoperative LM savings scores. Females displayed better postoperative memory performance, regardless of side of surgery. Preoperative verbal memory performance was not associated with right or left hippocampal volumes in either left or right ATL females, although the right hippocampus was positively associated with memory performance for left ATL males. Hippocampal volumes were not associated with postoperative LM savings scores for any group. Results suggest that prose recall was only modestly influenced by gender and that bilateral hippocampal support for prose recall was not present in our female patients.     

Presurgical neuropsychological testing predicts cognitive and seizure outcomes after anterior temporal lobectomy

We sought to determine significant predictors of seizure and cognitive outcome following surgery for epilepsy. Participants included 41 patients who had undergone anterior temporal lobectomy (ATL). Higher presurgical verbal/language scores and lower nonverbal memory scores were predictive of seizure-free status following ATL. Overall, the presurgical predictors were 93% accurate in discriminating between seizure-free and non-seizure-free patients postsurgery. Surgery in the nondominant-for-language hemisphere was predictive of higher postsurgical verbal/language and verbal memory scores. Higher presurgical visual/construction, nonverbal memory, and verbal/language scores were predictive of better postsurgical verbal/language functioning. Better presurgical verbal/language functioning was predictive of the same skills postsurgically as well as visual/construction outcomes. Exploratory analyses in a subset of participants (n = 25) revealed that dominant and nondominant intracarotid amobarbital (Wada) memory scores added unique variance only for predicting nonverbal memory following ATL. Presurgical neuropsychological testing provides significant and unique information regarding postsurgical seizure freedom and cognitive outcome in patients who have undergone ATL.     

Risk to verbal memory following anterior temporal lobectomy in patients with severe left-sided hippocampal sclerosis

BACKGROUND: Previous investigations indicate low risk for memory loss following anterior temporal lobectomy (ATL) in patients with severe hippocampal sclerosis (HS) compared with patients with mild HS. However, these conclusions have been established primarily with group-level analyses. OBJECTIVE: To investigate individual base rate risk for verbal memory loss following ATL in patients who have pathologically verified mild, moderate, or severe HS. PATIENTS AND METHODS: One hundred fifteen patients with unilateral temporal lobe epilepsy (68 with left-sided and 47 with right-sided epilepsy) were included. Acquisition, retrieval, and recognition components of verbal memory, as measured by the California Verbal Learning Test, were assessed before and after ATL. Postoperatively, the degree of neuronal loss and reactive gliosis of the hippocampus was assessed via a 3-tiered rating system establishing mild, moderate, and severe pathologic features. Patients with preoperative magnetic resonance imaging-based evidence of lesions outside the mesial temporal area (side of surgical resection) were excluded. RESULTS: Neither seizure laterality nor severity of HS was associated with preoperative verbal memory performance. Postoperatively, the left-sided ATL group demonstrated significant decline across the acquisition (P<.01), retrival (P<.001), and recognition (P<.001) verbal memory components compared with the right-sided ATL group. Patients who underwent left-sided ATL and had mild HS displayed the largest magnitude and percentage proportion of postoperative decline across all verbal memory components. However, 28 (48%) of the 58 patients who underwent left-sided ATL and who had moderate and severe HS displayed statistically reliable declines on retrieval aspects of verbal memory. Most patients undergoing right-sided ATL, regardless of the extent of hippocampal pathologic features, displayed no postoperative memory change. CONCLUSIONS: Substantial individual heterogeneity of memory outcome exists across groups of patients undergoing ATL, with various degrees of pathologically verified HS. Patients undergoing left-sided ATL who have mild HS seem at greatest risk for broad-spectrum verbal memory decline. However, when examining outcome on a patient-by-patient basis, many patients undergoing left-sided ATL who have moderate to severe HS were also vulnerable to verbal memory loss. This risk seems selective to a retrieval-based aspect of verbal memory.     

Cognitive Consequences of Two-Thirds Anterior Temporal Lobectomy on Verbal Memory in 144 Patients: A Three-Month Follow-Up Study

Previous studies have shown that left temporal lobectomy for intractable epilepsy can lead to verbal memory deficits. However, patients with left temporal lobe epilepsy (LTLE) frequently have impaired verbal memory preoperativel. The present analysis of 144 patients who underwent temporal lobe resections for either left (n = 68) or right (n = 76) temporal lobe epilepsy (LTLE, RTLE) addressed the questions of (a) whether a left two-thirds anterior temporal lobectomy (ATL) increases deficits in these qualitative aspects of verbal memory already impaired preoperatively, and (b) whether other aspects of verbal memory are additionally affected. We also evaluated possible determinants of preoperative abilities and postoperative changes, using multiple regression analysis. Preoperatively, patients with LTLE differed from patients with RTLE only in poorer performance on measures of long-term consolidation/retrieval (delayed recall). This was related to hippocampal pathology and seizure severity. Only left temporal lobe resections resulted in significant deterioration in verbal learning and memory. Acquisition over learning trials and recognition deteriorated most markedly, whereas performance in long-term consolidation/retrieval showed only minor changes. Preoperative performance levels, chronological age, the extent of the en bloc resection, preoperative performance on figural memory, and preoperative seizure severity were valuable determinants of postoperative changes in acquisition and recognition. In contrast, changes in consolidation/retrieval related only to preoperative ability. Left two-thirds ATL leads to new impairment in addition to preexisting memory deficits. The finding that left temporal lobectomy affects verbal acquisition and recognition more than long-term consolidatiodretrieval, including the different determinants of these changes, most likely reflects the differential effects of surgery on mesial temporal and neocortical temporal functions.     

Effect of Wada Memory Stimulus Type in Discriminating Lateralized Temporal Lobe Impairment

Summary: Purpose : To examine the effects of memory stimulus type on Wada memory performance.
Method : Ninety-six patients (left, 47; right, 49) from four epilepsy centers who were candidates for anterior temporal lobectomy (ATL) and who have subsequently undergone surgery were studied. Patients with atypical cerebral language lateralization or with evidence on magnetic resonance imaging (MRI) to suggest a lesion other than hippocampal sclerosis were excluded. Wada memory performance was obtained by using both real objects and line drawings as memory stimuli.
Results : Wada memory laterality scores with either real objects or line drawings as memory stimuli discriminated left from right-ATL groups. However, objects were superior to line drawings in making this differentiation. Further, objects were superior to line drawings in individual patient classification of candidates for left ATL, with no difference in the classification rates using either objects or line drawings in candidates for right ATL.
Conclusions : Type of memory stimuli is an important factor affecting memory results during the Wada test.     

Quantitative magnetic resonance imaging in temporal lobe epilepsy: relationship to neuropathology and neuropsychological function.

Magnetic resonance images (MRIs) were obtained from 25 patients with medically refractory epilepsy of temporal lobe origin (12 on the left, 13 on the right) and 14 right-handed control subjects. The hippocampi and temporal lobes were traced by computer on successive coronal images and the resulting measurements of area were summed for each region. The left and right hippocampi were symmetrical in the control subjects; however, for patients the hippocampus was smaller on the side of the seizure focus. Moreover, the left-right hippocampal ratio significantly differentiated the control subjects from each patient group. The left temporal lobe was significantly smaller than the right in control subjects. The epileptics' temporal lobes were smaller on the side of the seizure focus, compared to the temporal lobes in the control subjects. MRI hippocampal measurements were compared to hippocampal neuronal densities obtained postoperatively. Significant correlations were obtained between the ratio (side ipsilateral to focus/side contralateral to focus) of MRI hippocampal measurements and neuronal densities in all hippocampal subfields except CA2. Prior to surgery, patients were administered the Wechsler Memory Scale and the verbal Selective Reminding Test. Significant correlations existed between MRI measurements of the left hippocampus and the Wechsler logical memory percent retention scores and between the left temporal lobe measurements and the verbal Selective Reminding Test scores for patients with seizure foci in the left temporal lobe.     

Neuropsychological Effect of Temporal Lobe Resection in Preadolescent Children with Epilepsy

Summary: Purpose : Numerous studies have demonstrated changes in cognitive, memory, and language functioning in adults and adolescents after temporal lobectomy, yet little information is available regarding neuropsychological outcome in preadolescent children.
Methods : We studied pre-and postoperative neuropsychological test results from 14 children who underwent temporal lobe resection for intractable epilepsy at age 7–12 years (mean 9.4 years).
Results : Thirteen patients (93%) had no seizures or less than one seizure a year at follow-up 23-48 months (mean 34 months) after operation. Postoperative neuropsychological testing was performed 6–9 months (mean 7 months) after surgery in 13 patients and 36 months after the first operation in 1 patient who underwent two-stage resection of a tumor. Verbal, Performance, and Full Scale IQ were initially in the low-average range, with no significant change across the pre-and postoperative evaluations. Immediate verbal memory performance decreased significantly in children who initially performed above the median preoperatively and tended to decrease in children who had left rather than right temporal lobe resection. Significant postoperative decreases in delayed memory scores were independent of preoperative ability or side of resection.
Conclusions : Our small study suggests vulnerability to postoperative decline in immediate verbal memory scores in preadolescent children who have higher baseline immediate memory function or undergo left rather than right temporal lobe resection, similar to that observed in adolescents in adults. The entire group exhibited a statistically significant decrease in delayed verbal memory. Study of larger series of patients will be important to clarify further the short-and long-term risks and benefits of temporal lobe resection in childhood.     

Poor presurgical performance on both verbal and visual memory measures is associated with low risk for memory decline following left temporal lobectomy for intractable epilepsy

Studies have shown a lower risk for verbal memory decline following dominant anterior temporal lobectomy (ATL) among patients with poor, presurgical verbal memory scores. It is unclear however, if the risk of decline is increased in patients who also have reduced visual memory. Objective and subjective memory outcome following left ATL was examined in twelve patients with reduced presurgical visual and verbal memory scores. Only one patient demonstrated a meaningful decline in memory scores, with a decline in visual memory following surgery. Presurgically, this patient demonstrated poor memory bilaterally on Wada testing and small discrepancy in hippocampal volumes. She was also one of two patients who continued to have seizures post-surgery. This preliminary study suggests that patients with unilateral, left TLE and poor verbal and visual memory are unlikely to show meaningful memory declines following left ATL, particularly if they demonstrate expected patterns on Wada testing, hippocampal volume discrepancy (left < right), and postsurgical seizure-freedom.     

Bilateral hippocampal atrophy: consequences to verbal memory following temporal lobectomy

BACKGROUND: Bilateral hippocampal damage is a risk factor for memory decline after anterior temporal lobectomy (ATL). OBJECTIVE: To investigate verbal memory outcome in patients with temporal lobe epilepsy (TLE) with either unilateral or bilateral hippocampal atrophy as measured by MRI. METHODS: The authors selected 60 patients with TLE who had undergone ATL (left = 31, right = 29). They determined normalized MRI hippocampal volumes by cursor tracing 1.5-mm slices from three-dimensional MRI acquisition. Hippocampal volumes were defined as atrophic if the volumes were below 2 SD for control subjects. Bilateral hippocampal atrophy was present in 10 patients with left TLE and 11 patients with right TLE. The authors assessed acquisition, retrieval, and recognition components of verbal memory both before and after ATL. RESULTS: Groups did not differ across age, education, intelligence, age at seizure onset, or seizure duration. Seizure-free rates after ATL were 70% or higher for all groups. Before surgery, patients with left TLE displayed worse verbal acquisition performance compared with patients with right TLE. Patients with left TLE with bilateral hippocampal volume loss displayed the lowest performance across all three memory components. After surgery, both groups of patients with left TLE exhibited worse verbal memory outcome compared with patients with right TLE. Bilateral hippocampal atrophy did not worsen outcome in the patients with right TLE. A higher proportion of patients with left TLE with bilateral hippocampal atrophy experienced memory decline compared with the other TLE groups. CONCLUSION: Bilateral hippocampal atrophy in the presence of left TLE is associated with worse verbal memory before and after ATL compared with patients with unilateral hippocampal volume loss or right TLE with bilateral hippocampal volume loss.     

Memory and intelligence outcome following surgery for intractable temporal lobe epilepsy: relationship to seizure outcome and evaluation using a customized neuropsychological battery

The main objectives of this prospective study were to (1) assess memory and intelligence outcome following surgery for intractable temporal lobe epilepsy, (2) correlate this with seizure outcome and side of surgery, and (3) perform (1) and (2) using an indigenously developed battery customized to the Indian population. Prior to use in our epilepsy surgery program, the test-retest and interexaminer variance reliability of this battery had been established in both normal and cognitively compromised populations. The memory scores were overall rather than material-specific. The battery was administered to right-handed adults undergoing surgery for intractable temporal lobe epilepsy without any evidence of opposite temporal lobe abnormality, both presurgery and postsurgery at a mean follow-up of 8 months. Twenty-five consecutive patients were included; 13 underwent right and 12 underwent left temporal surgery. Seizure outcome was assessed using Engel's classification. Among 13 patients who underwent right temporal surgery, although 4 patients with poor seizure outcome had insignificant changes in scores, 7 of 9 patients with good seizure outcome exhibited considerable (> 20% over preoperative) improvement in their memory and intelligence scores. Statistical analysis using Student's t test and the Mann-Whitney test revealed that the patients who underwent right temporal surgery with good seizure outcome had significant improvement in both memory (P = 0.007) and intelligence (P = 0.043) scores compared with those with poor seizure outcome. In contrast, patients who underwent left temporal surgery had no significant change in cognitive scores irrespective of seizure outcome. Cognitive improvement seems to occur in patients with good seizure outcome following nondominant temporal lobe surgery for intractable epilepsy with no evidence of pathology in the opposite temporal lobe. The same finding was not observed in patients undergoing left temporal surgery.     

Verbal memory impairment correlates with hippocampal pyramidal cell density

Thirty-five patients with medically refractory epilepsy localized to the temporal lobe (18 left, 17 right) completed the verbal Selective Reminding Test before surgery. Verbal memory impairments existed before surgery regardless of the lateralization of the seizure focus, but patients with left temporal seizure foci were significantly more impaired. After surgical removal of the mesial temporal lobe structures, 2 blinded observers established volumetric cell densities for hippocampal subfields CA1, CA2, CA3, the hilar area, and the granule cell layer of the area dentata. Statistically significant correlations existed between presurgical memory impairment and cell counts (in CA3 and the hilar area, only) for patients with left temporal seizure foci. These findings support the hippocampal model of memory and complement prior research documenting the memory impairments present after surgical removal of the mesial temporal structures.     

Differential Effects of Left and Right Anterior Temporal Lobectomy on Verbal Learning and Memory Performance

The California Verbal Learning Test (CVLT) was utilized to identify the quantitative and qualitative alterations in verbal learning and memory performance that discriminated between patients following partial resection of the left (dominant) (n = 26) or right (nondominant) (n = 31) temporal lobe. Patients were administered the CVLT preoperatively and 6 months postoperatively, and the differential effects of laterality of resection on verbal learning and memory performance were determined. Following left temporal resection, patients showed significantly more serial clustering, a lower proportion of words recalled from the middle of the list, and more intrusion errors in free recall. Patients who underwent right temporal resection showed significantly greater recall of words from the middle and fewer words from the end of the list, more semantic clustering, and greater ability to recall verbal material after a short delay. These findings suggest that anterior temporal lobectomy (ATL) results in changes in the way verbal material is acquired, and affects the rate of forgetting. Patients who undergo left ATL become more dependent on less effective and efficient learning strategies, and forget the material that they have acquired at a faster rate. The opposite tendencies characterize patients who undergo right ATL.     

Material-specific memory changes after anterior temporal lobectomy as predicted by the intracarotid amobarbital test

Summary: Purpose: The intracarotid amobarbital test (IAT) has been shown to predict verbal memory changes after anterior temporal lobectomy (ATL). Seeking to extend these findings, we examined two questions: (a) What is the relationship between material‐specific aspects of IAT memory and material‐specific memory changes after ATL? and (b) Which IAT memory score(s) optimally predict memory changes after surgery, the memory score after injection ipsilateral to the seizure focus, the memory score after injection contralateral to the seizure focus, or the IAT asymmetry score, comprising the ipsilateral minus contralateral injection scores? Methods: Seventy left hemisphere language‐dominant patients undergoing ATL for treatment of medically refractory seizures were administered a verbal and visuospatial recognition memory test before surgery and 3 weeks after surgery. IAT memory recognition scores for words and designs were used to predict verbal and visuospatial memory changes after surgery. Results: After surgery, left ATL patients declined in verbal memory, whereas right ATL patients declined in visuospatial memory. IAT total recognition memory scores (collapsed across all types of materials) and IAT word memory scores were associated with postoperative verbal memory decline. This relationship was significant for the IAT ipsilateral injection memory scores and the IAT hemispheric asymmetry scores. IAT memory performances were not related to visuospatial memory changes. Conclusions: Results indicate IAT memory measures to be related to postoperative verbal, but not visuospatial, memory change. A specific relationship was found between postoperative verbal memory change and IAT verbal memory after injection ipsilateral to the seizure focus, when relying primarily on the contralateral hemisphere. This finding is consistent with the functional reserve model of memory change in ATL.     

The effects of cognitive rehabilitation on memory outcome after temporal lobe epilepsy surgery

OBJECTIVE: Epilepsy surgery is a valuable treatment option for patients with pharmacoresistant epilepsy, but seizure freedom is often achieved at the cost of cognitive impairments caused by surgery. The aim of this study was to investigate the short-term effects of cognitive rehabilitation on memory outcome after temporal lobe epilepsy surgery. METHODS: Two groups of patients who underwent temporal lobe resection, one followed (n=55) and one not followed (n=57) by postoperative rehabilitation, were evaluated with respect to memory and attention before and 3 months after temporal lobe surgery. The groups came from different epilepsy centers, but were largely matched with respect to age, sex, type of surgery, and seizure outcome. RESULTS: After surgery, 78% of the patients were seizure-free. Repeated-measures MANOVA revealed a significant "side x surgery" effect on verbal recognition and a "rehabilitation x surgery" effect on verbal learning and recognition. There were no effects for loss in verbal delayed recall or figural memory. Detailed analyses indicated gains as a result of rehabilitation, particularly after right temporal lobe surgery. Attention generally improved. The risk of manifesting losses in verbal memory was about four times higher without than with rehabilitation. CONCLUSIONS: Rehabilitation can counteract the verbal memory decline that is normally seen after temporal lobe resection. Its positive effects were evident particularly with respect to the more cortically associated aspects of verbal learning rather than to the mesial aspects of long-term consolidation/retrieval. Figural memory was not affected at all, and attention improved independent of rehabilitation. Interestingly, left temporal lobe-resected patients, who were most in need of an efficacious rehabilitation, profited less than right temporal lobe-resected patients, indicating that left-sided surgery may reduce the capacity needed for efficient training of verbal memory. Thus, rehabilitation has a positive effect on memory outcome, but its usefulness for risk groups and the question of whether training should be performed after or possibly before surgery are debatable. Further research should also address different interventions, longer-term outcome, and the carryover effects on everyday functioning.     

Memory outcome 2 years after anterior temporal lobectomy in patients with drug-resistant epilepsy

PURPOSE: Memory decline is often observed after anterior temporal lobectomy (ATL), particularly in patients with dominant hemisphere resections. However, the follow-up length has been 1 year or less in most studies. Our aims were to examine postoperative memory changes over a longer period and to identify baseline demographic and clinical predictors of memory outcome. METHODS: We administered material-specific memory tests at baseline, and 1 and 2 years after surgery to 82 consecutive right-handed patients (52% males) who underwent ATL for drug-resistant temporal lobe epilepsy (TLE) (35 left, 47 right) after a non-invasive presurgical protocol. Repeated measures multivariate analysis of variance (RM-MANOVA) was used to examine the relationship between changes in memory tests scores over time and side of TLE and pathology. Also, standardized residual change scores were calculated for each memory test and entered in multiple linear regression models aimed at identifying baseline predictors of better memory outcome. RESULTS: RM-MANOVA revealed a significant change in memory test scores over time, with an interaction between time and side of surgery, as 2 years after surgery patients with RTLE were improved while patients with LTLE were not worse as compared with baseline. Pathology was not associated with changes in memory scores. In multiple regression analysis, significant associations were found between right TLE and greater improvement in verbal memory, younger age and greater improvement in visuospatial memory, and male gender and greater improvement in both verbal and visuospatial memory. CONCLUSIONS: Our results suggest that the long-term memory outcome of TLE patients undergoing ATL without invasive presurgical assessment may be good in most cases not only for right-sided but also for left-sided resections.     

Development of Two Spanish versions of the Verbal Selective Reminding Test

The Selective Reminding procedure has become a widely used test for evaluating verbal learning and memory. However, since this test was mainly devised for use in English speaking individuals, disadvantages could appear when translations of the test are applied to Spanish speaking patients. To overcome these difficulties, two Spanish versions of the Verbal Selective Reminding Test were devised and administered to 48 healthy individuals, 19-31 years in age, in two separate sessions. We found that performances on the two forms were comparable, except for one measure. All the variables on both forms yielded significant positive correlations. We also examined test-retest reliability separately for both possible orders, with Order 2 (Form 2 administered first) being more reliable than Order 1 (Form 1 administered first).     

Development of two spanish versions of the verbal selective reminding test

The Selective Reminding procedure has become a widely used test for evaluating verbal learning and memory. However, since this test was mainly devised for use in English speaking individuals, disadvantages could appear when translations of the test are applied to Spanish speaking patients. To overcome these difficulties, two Spanish versions of the Verbal Selective Reminding Test were devised and administered to 48 healthy individuals, 19-31 years in age, in two separate sessions. We found that performances on the two forms were comparable, except for one measure. All the variables on both forms yielded significant positive correlations. We also examined test-retest reliability separately for both possible orders, with Order 2 (Form 2 administered first) being more reliable than Order 1 (Form 1 administered first).     

Comparison of neuropsychological outcomes after selective amygdalohippocampectomy versus anterior temporal lobectomy

Transsylvian selective amygdalohippocampectomy (TSA) is an operative technique designed to spare unaffected brain tissue during surgical treatment for mesial temporal lobe epilepsy. In contrast to standard anterior temporal lobectomy (ATL), the advantages of TSA with respect to postoperative cognitive outcome are equivocal. We compared cognitive function before and after surgery in 49 patients with unilateral mesial temporal lobe seizures who underwent either ATL (n=17) or TSA (n=32). All patients received neuropsychological testing before and 1 year after surgery. The intelligence quotient (IQ) increased postoperatively in both surgical groups. Memory evaluation in the ATL group revealed a postoperative decline in nonverbal memory after right-sided resection and a postoperative decline in verbal memory after left-sided resection. In the TSA group, there was a slight postoperative decline only in verbal memory after left-sided resection, but other memory function was well preserved. In particular, there was significant postoperative improvement in verbal memory after right-sided resection. Overall, memory function was better preserved in the TSA group than in the ATL group.