Reports by patients and their families of memory change after left anterior temporal lobectomy: relationship to degree of hippocampal sclerosis

Amygdalohippocampotomy for mesial temporal lobe sclerosis: Epilepsy outcome 5 years after surgery

BACKGROUND

The goal of the present study is the evaluation of the long-term clinical outcome of epilepsy in patients with mesial temporal lobe sclerosis (MTLS) submitted to amygdalohippocampotomy (AHCo). AHCo consists of the lateral ablation of the amygdala and the peri-hippocampal disconnection instead of amygdalohippocampectomy (AHC), which involves the removal of both structures. We previously reported the short-term results of AHCo, so we here present the long-term results (> 5 years of follow-up) of the patients operated on with AHCo.

METHOD

Since 2007, 35 patients (22 females) aged 20-61 years (mean: 42 years) were operated on with the AHCo technique, 17 patients on the left side and 18 on the right. Of these patients, 21 (14 females) have been followed up > 5 years (5 to 7.5 years, mean 6.5 years). We compare the present results with those observed shortly after surgery and with the patients operated on with AHC.

FINDINGS

In all 21 cases, the diagnosis was mesial temporal lobe sclerosis (histology confirmed in 20), 11 on the left side and 10 on the right. Epilepsy results after 5 years were good/very good in 18 patients (85.7%), with Engel class IA-B in 15 (71.4%) and II in 3 (14.3%), and bad in 3 patients, with Engel Class III in 2 (9.5%) and class IV in 1 (4.8%). Concerning morbidity, one patient had hemiparesis (hypertensive capsular hemorrhage 24 h after surgery), two verbal memory worsening, two quadrantanopia and three late depression that was reversed with medication. Comparatively, the AHC long-term results were 87% Engel class I, 8% Engel class II and 5% Engel class III-IV. The morbidity was equally small.

CONCLUSIONS

The good/very good results of AHCo 5 years after surgery are 86%, which is not distinct from the AHC results. So AHCo seems to be effective and potentially safer than AHC in long-term follow-up.

Minimally invasive techniques for epilepsy surgery: stereotactic radiosurgery and other technologies

Minimally invasive surgical techniques for the treatment of medically intractable epilepsy, which have been developed by neurosurgeons and epileptologists almost simultaneously with standard open epilepsy surgery, provide benefits in the traditional realms of safety and efficacy and the more recently appreciated realms of patient acceptance and costs. In this review, the authors discuss the shortcomings of the gold standard of open epilepsy surgery and summarize the techniques developed to provide minimally invasive alternatives. These minimally invasive techniques include stereotactic radiosurgery using the Gamma Knife, stereotactic radiofrequency thermocoagulation, laser-induced thermal therapy, and MRI-guided focused ultrasound ablation.

Amygdalohippocampotomy: surgical technique and clinical results

OBJECT

The removal of mesial temporal structures, namely amygdalohippocampectomy, is the most efficient surgical procedure for the treatment of epilepsy. However, disconnection of the epileptogenic zones, as in temporal lobotomy or, for different purposes, hemispherotomy, have shown equivalent results with less morbidity. Thus, authors of the present study began performing selective amygdalohippocampotomy in cases of refractory mesial temporal lobe epilepsy (TLE) to treat mesial temporal lobe sclerosis (MTLS).

METHOD

The authors conducted a retrospective analysis of all cases of amygdalohippocampotomy collected in a database between November 2007 and March 2011.

RESULTS

Since 2007, 21 patients (14 males and 7 females), ages 20-58 years (mean 41 years), all with TLE due to MTLS, were treated with selective ablation of the lateral amygdala plus perihippocampal disconnection (anterior one-half to two-thirds in dominant hemisphere), the left side in 11 cases and the right in 10. In 20 patients the follow-up was 2 or more years (range 24-44 months, average 32 months). Clinical outcome for epilepsy 2 years after surgery (20 patients) was good/very good in 19 patients (95%) with an Engel Class I (15 patients [75%]) or II outcome (4 patients [20%]) and bad in 1 patient (5%) with an Engel Class IV outcome (extratemporal focus and later reoperation). Surgical morbidity included hemiparesis (capsular hypertensive hemorrhage 24 hours after surgery, 1 patient), verbal memory worsening (2 patients), and quadrantanopia (permanent in 2 patients, transient in 1). Late psychiatric depression developed in 3 cases. Operative time was reduced by about 30 minutes (15%) on average with this technique.

CONCLUSIONS

Amygdalohippocampotomy is as effective as amygdalohippocampectomy to treat MTLS and is a potentially safer, time-saving procedure.

Awareness, overestimation, and underestimation of cognitive functions in epilepsy

This study estimated cognitive awareness and the predictors of self-rating in patients with epilepsy (PWE). The Multiple Ability Self-Report Questionnaire (MASQ), State-Trait Anxiety Inventory, and Beck Depression Inventory were used for self-evaluation. Neuropsychological assessment yielded five single-domain scores (Long-Term Memory, Mental Speed, Working Memory, Set Shifting, and Visuospatial Matching) and a total composite score. Awareness was computed as the concordance between the neuropsychological and MASQ scores. In 37 patients with full awareness, self-ratings were predicted by Long-Term Memory, Working Memory, and Mental Speed. In 58 patients with incomplete or no awareness, self-ratings related to depression and seizure frequency. Compared with overestimation, underestimation was associated with higher test scores, better education, and younger age. Brain lesion and the type of epilepsy showed no effect. Therefore, PWE may appear unaware of their cognitive abilities due to negative affect and clinical burden. Understanding patients' awareness of their cognitive deficits can help clarify the clinical pattern provoked by epilepsy, as well as patients' compliance with treatment for seizures or cognitive difficulties.

Neuropsychological outcomes after Gamma Knife radiosurgery for mesial temporal lobe epilepsy: a prospective multicenter study

PURPOSE

To assess outcomes of language, verbal memory, cognitive efficiency and mental flexibility, mood, and quality of life (QOL) in a prospective, multicenter pilot study of Gamma Knife radiosurgery (RS) for mesial temporal lobe epilepsy (MTLE).

METHODS

RS, randomized to 20 Gy or 24 Gy comprising 5.5-7.5 ml at the 50% isodose volume, was performed on mesial temporal structures of patients with unilateral MTLE. Neuropsychological evaluations were performed at preoperative baseline, and mean change scores were described at 12 and 24 months postoperatively. QOL data were also available at 36 months.

KEY FINDINGS

Thirty patients were treated and 26 were available for the final 24-month neuropsychological evaluation. Language (Boston Naming Test), verbal memory (California Verbal Learning Test and Logical Memory subtest of the Wechsler Memory Scale-Revised), cognitive efficiency and mental flexibility (Trail Making Test), and mood (Beck Depression Inventory) did not differ from baseline. QOL scores improved at 24 and 36 months, with those patients attaining seizure remission by month 24s accounting for the majority of the improvement.

SIGNIFICANCE

The serial changes in cognitive outcomes, mood, and QOL are unremarkable following RS for MTLE. RS may provide an alternative to open surgery, especially in those patients at risk of cognitive impairment or who desire a noninvasive alternative to open surgery.

Are depression and cognitive performance related in temporal lobe epilepsy?

PURPOSE

The degree to which depression interacts with the cognitive deficits of epilepsy to alter cognitive skill and general functioning is unknown. Depression has significant negative effects on adaptive functioning including cognitive skills. Temporal lobe epilepsy (TLE) patients are known to possess cognitive dysfunction. Thus, TLE patients who are depressed may suffer a double burden of cognitive deficits.

METHODS

We examined whether depressed patients show increased cognitive deficits relative to nondepressed TLE patients (n = 59). We then sought to determine if this effect varied for left versus right TLE patients utilizing preoperative depression and neuropsychological data. To accurately study the lateralization of any observed effects, we selected only patients with definitive evidence of unilateral pathology and seizure focus and utilized a two-year seizure-free postsurgical outcome to capture this.

RESULTS

The data suggested that cognitive performance was not related to depression, and that depression did not reliably mediate the cognitive presentation of either our left or right TL patients. The notion of a double burden on cognition did not receive support from our data. The data did produce the expected advantage on verbal memory measures for right TLE patients.

CONCLUSIONS

The reasons for the limited statistical effects are discussed and issues in unraveling the causal relationships between depression, cognition, and TLE are considered. We discussed the potential role depression may play in the cognitive skills of TLE patients, but the major implication is that depression and neurocognitive performance appear to bear a limited relationship in the context of TLE.

Determining empirically based self-reported cognitive change: development of reliable change indices and standardized regression-based change norms for the multiple abilities self-report questionnaire in an epilepsy sample

PURPOSE

Reliable change indices (RCIs) and standardized regression-based (SRB) change score norms were calculated for a measure of self-reported cognitive function, the Multiple Abilities Self-Report Questionnaire (MASQ), in patients with complex partial seizures. Establishment of such standardized change scores could be useful in determining the magnitude and direction of self-appraised cognitive change after epilepsy surgery or other treatment interventions. The primary study objective was to calculate RCI and SRB values for the MASQ. A secondary objective was to report SRB change scores in patients who had undergone anterior temporal lobectomy (ATL) and to assess relationships between self-reported cognitive change, seizure outcome, objective memory test performance, and mood.

METHODS

The MASQ was administered to 36 patients with complex partial seizures on two occasions (mean test-retest interval, 6 months). This group did not have major psychopathology and were on stable antiepileptic drugs. RCI and SRB change scores were calculated. Adjustments for baseline ratings, age, education, gender, age at seizure onset, and seizure duration were made with the SRB method. A confidence interval cutoff score (90% level) was calculated for the five MASQ cognitive domains (Language, Visual Perception, Verbal Memory, Visual-Spatial Memory, Attention/Concentration). MASQ SRB scores were computed for a second sample of 50 patients who had undergone ATL.

RESULTS

Test-retest reliabilities for the MASQ domains ranged from a low of 0.63 (Attention/Concentration) to a high of 0.87 (total score). Baseline MASQ score was the single largest contributor to the regression equations. Left and right ATL groups demonstrated similar magnitudes of self-reported cognitive change across all five MASQ domains. Individual base rate change distributions were similar across four of the five domains. with a higher proportion of right ATL patients reporting worsening attention function. Both postoperative mood and SRB-based verbal memory outcome were significantly correlated to self-reported cognitive change in the patients who had undergone ATL.

CONCLUSIONS

SRB methodology provides a standardized technique with which to establish patient perception of cognitive change and may be of use when examining change across individual- and group-level ratings of cognitive functioning in clinical and research settings. These techniques also provide a common metric for direct comparison between subjective self-report ratings of cognitive function and objective cognitive test instruments.

Patients' Perceptions of Memory Functioning Before and After Surgical Intervention to Treat Medically Refractory Epilepsy

PURPOSE

One risk associated with epilepsy surgery is memory loss, but perhaps more important is how patients perceive changes in their memories. This longitudinal study evaluated changes in memory self-reports and investigated how self-reports relate to changes on objective memory measures in temporal or extratemporal epilepsy patients who underwent surgery.

METHODS

Objective memory (Wechsler Memory Scale-Revised) and subjective memory self-reports (Memory Assessment Clinics Self-Rating Scale) were individually assessed for 136 patients approximately 6 months before and 6 months after surgery. A measure of depressive affect (Beck Depression Inventory-2nd Edition) was used to control variance attributable to emotional distress.

RESULTS

Despite a lack of significant correlational relationships between objective and subjective memory for the entire sample, significant correlations between objective memory scores and self-reports did emerge for a subset of patients who evidenced memory decline. Differences also were found in the subjective memory ratings of temporal lobe versus extratemporal patients. Temporal lobe patients rated their memories more negatively than did extratemporal patients and were more likely to report significant improvements in their memory after surgery.

CONCLUSIONS

In general, patients were not accurate when rating their memories compared to other adults. However, patients with significant declines in their memories were sensitive to actual changes in their memories over time relative to their own personal baselines.

Bilateral hippocampal volume predicts verbal memory function in temporal lobe epilepsy

The present study used quantitative volume estimates of the hippocampus based on structural magnetic resonance imaging (MRI) to predict memory performance of individuals with epilepsy of temporal lobe origin (TLE). Twenty individuals with TLE completed standardized neuropsychological tests and a quality of life inventory, and participated in a brain MRI protocol designed to obtain high-resolution images of the hippocampus. The combined volume of the left and right hippocampi was found to be the best predictor of objective verbal memory performance. This finding is consistent with the functional adequacy model of hippocampal function. In contrast, the asymmetry between right and left hippocampal volume was the best predictor of subjective ratings of cognitive functioning, which is consistent with the functional reserve model. The collective and complementary functions of the left and right hippocampi merit further exploration in prospective studies of memory function and TLE.

Self-report of cognitive abilities in temporal lobe epilepsy: cognitive, psychosocial, and emotional factors

Self-report of cognitive functioning using the Multiple Abilities Self-Report Questionnaire (MASQ) was examined in 57 left (LTLE) and 36 right (RTLE) temporal lobe epilepsy patients. The MASQ is a 38-item self-report measure assessing five domains of self-perceived cognitive functioning: Language, Visual-Perceptual Abilities, Verbal Memory, Visual-Spatial Memory, and Attention/Concentration. Overall, LTLE patients self-reported more cognitive difficulties across all domains. Language was the only domain to emerge as a robust indicator of seizure lateralization (LTLE patients reporting more problems). Neuropsychological test performance did not emerge as a significant predictor for any domain, whereas measures of psychosocial and emotional functioning accounted for a significant but modest amount of variance in all of them. The results suggest caution in using such self-report measures as an ecological extension of objective testing, but suggest a role in assessing self-appraisal of deficits.

Memory deficits after resection from left or right anterior temporal lobe in humans: a meta-analytic review

PURPOSE

Memory deficits in epileptic patients have been found in some, but not all studies assessing the effects of side of seizures and resection from a temporal lobe on cognitive performance. The purpose of this study was to provide a quantitative review of previous studies on this issue.

METHODS

Based on conventional meta-analytic procedures, we identified 33 studies that assessed verbal and nonverbal memory performance before and after anterior temporal lobectomy. The Logical Memory and Visual Reproduction subtests from the Wechsler Memory Scale were used. These studies were then subjected to two levels of analyses: (a) vote-counting procedure, and (b) effect-size calculations and comparisons.

RESULTS

Overall, the data confirmed previous findings that verbal memory tasks are sensitive to left hemisphere dysfunction. The efficacy of a "nonverbal" task for tapping function in the nondominant (right) hemisphere was not confirmed, although a trend supporting this speculation was observed. With regard to the comparison of changes in verbal and nonverbal memory before and after resection from a temporal lobe, a clear trend was observed for decline in verbal memory function after resection from the left, especially significant for immediate verbal recall. A trend for contralateral improvement on nonverbal memory also was observed. The pattern of memory change after resection from the right temporal lobe was less clear.

CONCLUSIONS

The findings of this study suggest that side of epileptic seizure and surgical resection from a temporal lobe affect verbal memory functions. The relations between the laterality of epileptic seizure, surgical resection from the temporal lobe, and nonverbal memory are to be verified by further research.

The perception of memory failures in patients with epilepsy

The aim of the study is to evaluate the correlation between subjective memory complaints and neuropsychological tests in the epilepsy population. We administered a Self Report Memory Questionnaire, based on possible everyday memory failures, two questionnaires on anxiety and depression and a battery of cognitive tests to 150 patients with epilepsy (n=100 with partial epilepsy, n=50 with idiopathic generalized epilepsy) and a control group (n=50). A discrepancy between the results of the memory questionnaire and the cognitive tests was found in the epilepsy patients: the Self Report Memory Questionnaire did not show any correlation with the psychological tests. The same discrepancy was not seen in the controls, where the memory questionnaire was related to two verbal memory tests. Furthermore, patients with epilepsy reported greater difficulties on the Self Report Memory Questionnaire than the controls (P < 0.05). It appeared that the tendency to overstate memory problems was mainly related to anxiety and depression, but was not connected with the type of epilepsy, nor with its duration (in years). Seizure frequency, on the other hand, seemed to greatly influence mood, which in turn is probably affect subjective memory perception.

Does neuroticism influence cognitive self-assessment after epilepsy surgery?

PURPOSE

To examine how cognitive, personality, and seizure outcome variables influence the subjective cognitive functioning of patients with refractory temporal lobe seizures after epilepsy surgery.

METHODS

Thirty-three consecutive patients with drug-resistant partial epilepsy who underwent surgical treatment at a tertiary referral university epilepsy center were tested before surgery and 1 year after surgery. Objective cognitive and subjective cognitive functioning tests were used, and personality was assessed. Seizure control was operationalized as a dichotomous variable.

RESULTS

A significant inverse relationship was found between neuroticism and subjective cognitive functioning. None of the other pre- and postoperative cognitive and surgery outcome variables were significant predictors of subjective cognitive functioning, even after controlling for the effect of neuroticism.

CONCLUSIONS

Subjective and objective memory functioning are independent in patients with epilepsy after surgical treatment. Subjective memory functioning appears to be related not to seizure relief but to neuroticism. These data suggest that psychological factors such as personality traits predisposing to emotional distress should be taken into consideration in the clinical management and counseling of patients undergoing epilepsy surgery.

Neuropsychological assessment for temporal lobe epilepsy surgery

Neuropsychological assessment consists of a comprehensive evaluation of cognitive functioning and most often some evaluation of motor skills and sensory status also. Cognitive functions sampled typically include "intelligence" (IQ tests), attention, language skills, visuospatial abilities, "executive skills" and other abilities associated with frontal-lobe function, and learning and memory. Thus, the assessment samples vary widely among a variety of functions, providing a comprehensive picture of an individual's strengths and weaknesses. The resulting pattern points to the probable site of epileptic focus. Neuropsychological findings also serve to predict the risk for postsurgical cognitive decline and, when performance before and after operation is compared, they provide data on the impact of surgery upon cognitive functioning. Comprehensive evaluation of learning and memory is particularly important in this context, because of the frequency of temporal lobe epilepsy and the prominence of memory dysfunction associated with it. In addition, patients slated for elective surgery may also undergo an intracarotid amobarbital procedure (IAP), which is performed to determine the side of cerebral dominance for language and to test the memory capabilities of each hemisphere alone. All of these specialized neuropsychological tools are discussed in this paper.

Confrontation naming after anterior temporal lobectomy is related to age of acquisition of the object names

Decline in visual confrontation naming ability may occur as a postacute complication of left anterior temporal lobectomy (ATL) for the treatment of intractable mesial temporal lobe epilepsy. In this study of 26 left ATL patients who demonstrated postsurgery decline on a standardized naming measure, it was hypothesized that naming performance would be significantly associated with specific attributes of the object names. We investigated the relation between performance on the Boston Naming Test (BNT) and the following attributes of the test items: living versus nonliving category (L/NL), word length (WL), written word frequency (WF), and age of acquisition (AoA). Regression analyses revealed that AoA and WF were significant predictors of preoperative group performance. AoA was the only significant predictor of performance after left ATL. For the 17 individuals who demonstrated a statistically meaningful decline on the BNT, as indicated by a Reliable Change Index, individual logistic regressions demonstrated that AoA was the strongest and most consistent predictor of postoperative success/failure for items that had been named correctly preoperatively. Consistent with the literature on naming errors in elderly normals and patients with aphasia or semantic dementia, the results provide evidence that object names learned in late childhood are among the most vulnerable when there is a decline in object naming ability. Investigation of additional attributes and semantic knowledge for the concepts represented by the pictured objects will be necessary to determine whether the naming deficit associated with TLE and ATL reflects an impairment of phonological word-form retrieval, semantics, or both.

An analysis of neuropsychological change scores following selective temporal resection of the non-dominant temporal lobe

Reliable change in neuropsychological test scores was examined in patients undergoing right-sided, selective temporal resections for the relief of intractable epilepsy. Measures were taken prior to surgery, 1-month post-operatively and 1-year post-operatively. Non-verbal memory performance was more robustly measured than in previous studies. Results failed to replicate previous studies which report verbal memory deficits even following right-sided surgery. No strong evidence of a material-specific, non-verbal memory deficit was found on commonly used tests of non-verbal memory. The majority of patients failed to show reliable decline in performance following surgery indicating that fears of post-operative memory decline may be unfounded.

Verbal novelty detection within the human hippocampus proper

Animal studies and neuropsychological tests of patients with temporal lobe epilepsy have demonstrated the importance of human medial temporal lobes for memory formation. In addition, more recent studies have shown that the human hippocampal region is also involved in novelty detection. However, the exact contribution of the hippocampus proper to these processes is still unknown. To examine further its role we compared event-related potentials recorded within the medial temporal lobes in 29 temporal lobe epilepsy patients with and 21 without hippocampal sclerosis. While in patients with extrahippocampal lesions but without hippocampal sclerosis event-related potentials to first presentations and repetitions of words were reduced on the side of the epileptogenic focus, in patients with hippocampal sclerosis only those to first presentations but not to repetitions were affected. Because sclerosis of the hippocampus proper selectively reduced event-related potentials to new but not old verbal stimuli, it can be concluded that the human hippocampus proper contributes to verbal novelty detection.

Anterior temporal lobectomy, hippocampal sclerosis, and memory: recent neuropsychological findings

Anterior temporal lobectomy (ATL) is an effective and increasingly utilized treatment for nonlesional, intractable mesial temporal lobe epilepsy. However, this surgery results in domain-specific neuropsychological morbidity for a subset of patients. Within the past decade, multidisciplinary studies have revealed that left ATL patients without significant sclerosis in the resected hippocampus are most at risk for a substantial postacute decline in the ability to encode new verbal information. These patients are also at risk for a significant decrement in confrontation naming and other retrieval-based language abilities. The memory deficit is not attributable to this disruption of language. A relationship between hippocampal sclerosis (HS) status and memory performance has not been identified consistently in right ATL patients, but investigation of new visuospatial measures continues. The influence of variables other than HS on neuropsychological outcome is also discussed.

Self-reporting of everyday memory in patients with epilepsy: relation to neuropsychological, clinical, pathological and treatment factors

Patients with epilepsy frequently complain of memory problems, but neuropsychological tests sometimes fail to detect consistent deficits; this may be because laboratory tests are poor indicators of everyday memory problems, or because subjective memory difficulties may be provoked by a variety of factors. To address these issues, we compared 100 patients with epilepsy and 57 healthy controls by means of our Questionnaire of Memory Efficiency, the State-Trait Anxiety Inventory, the Self-Rating Depression Scale and a battery of tests. The Chronbach test showed the Questionnaire of Memory Efficiency to be satisfactorily reliable. Patients reported significantly greater memory difficulties and higher levels of anxiety and depression than controls. Questionnaire of Memory Efficiency scores correlated with anxiety and depression levels, as well as with memory and learning test scores and regression analysis showed that anxiety, depression and visual learning had the most consistent explanatory power. No correlation was found with clinical variables or the presence of detectable brain lesion. Patients undergoing polytherapy or treatment for long periods reported the greatest memory difficulties. These findings suggest that subjective perception of memory failure reflects objective memory impairment. However, emotional factors and low self-esteem may bloat the reporting of everyday memory difficulties. The Questionnaire of Memory Efficiency seems able to provide information about everyday memory problems in patients with epilepsy that may be useful for planning neuropsychological counselling or rehabilitation.

The imaging of epilepsy

Based on the experience of a university neurological epilepsy center, the neurological classification and the gradation of neurological evaluation of patients with epilepsy are described. Into this the nature and the significance of the imaging of the brain are interwoven. The object, illustrated by several illustrative patients, is to stress the importance of the MRI and to note that based on the MRI findings and the clinical findings, the battery of sophisticated electroencephalographic evaluation is determined. Epilepsy is an area where imaging and all aspects of the clinical neurological evaluation integrate very well and in which correlation is most important.

Does naming contribute to memory self-report in temporal lobe epilepsy?

The present study evaluated the hypothesis (Mayeux et al., 1980) that visual confrontation naming deficits may underlie the memory complaint in patients with temporal lobe epilepsy (TLE). Thirty-nine patients with medically refractory left (n = 23) and right (n = 16) TLE were compared with an epilepsy control group with idiopathic primary generalized epilepsy (n = 38). All subjects completed selected subtests of the Multilingual Aphasia Examination and Wechsler Memory Scale (Form 1) together with a measure specifically designed for quantification of the memory complaint in TLE. Objective verbal memory test performance, confrontation naming, repetition, and comprehension were unrelated to memory self-report. Controlled Oral Word Association was the only measure to exert an influence on memory self-ratings, and this relationship was specific to the TLE group. The hypothesis of Mayeux et al. (1980) was not specifically supported, but the present findings do suggest that cognitive processes reflected in orthographically based and internally generated word retrieval play a role in memory self-report.