Assessment of everyday memory after severe head injury

This study investigates two everyday memory questionnaires: the Subjective Memory Questionnaire (SMQ) and the Everyday Memory Questionnaire (EMQ). Both self-ratings and relatives' ratings were collected from a severe head injured group and a control group. Head injured subjects were also assessed on the Rivermead Behavioural Memory Test (RBMT). On the SMQ, there was a significant difference between the head injured and control groups for both self and relatives' ratings. On the EMQ only relatives' ratings differed significantly between the two groups. When head injured subjects, which were rated as non-impaired by the RBMT, were excluded from group comparisons, all questionnaire measures showed significant differences between groups. Both EMQ and SMQ scores for relatives and self-ratings correlated significantly with RBMT scores. The utility of the everyday memory measures is discussed.     

Short-term cognitive changes after unilateral temporal lobectomy or unilateral amygdalo-hippocampectomy for the relief of temporal lobe epilepsy.

Forty two patients who had unilateral temporal lobe surgery (either temporal lobectomy or amygdalo-hippocampectomy) were evaluated using a selection of cognitive tests before and soon after surgery, to examine whether the amygdalo-hippocampectomy produces less cognitive impairment than the standard en bloc resection. On specific indices of cognitive functioning an amygdalo-hippocampectomy rather than a temporal lobectomy, undertaken on the temporal lobe thought to mediate that particular function, produced less impairment, in terms of change in cognitive function resulting from the operation. An amygdalo-hippocampectomy carried out on the temporal lobe not thought to mediate such skills, however, resulted in less improvement or more deterioration in these functions than a temporal lobectomy, except in the case of delayed prose recall, where a right amygdalo-hippocampectomy led to more improvement than a right temporal lobectomy. Overall there were few scores which distinguished between the different surgical procedures for cognitive outcome.     

Self-report of memory function in patients with temporal lobe epilepsy and temporal lobectomy

Thirty-one surgical candidates with a unilateral temporal lobe seizure focus, 72 temporal lobectomy patients, 63 non-epileptic controls and their relatives, respectively, filled in the Memory Observation Questionnaire. The two patient groups rated their current memory similarly, but significantly worse than controls rated their own memory. Memory status was judged to be improved approximately three years after a temporal lobectomy. The relatives' ratings agreed with those of the patients. Thus patients who underwent surgical resection for relief of temporal lobe epilepsy did not report further subjective deterioration in memory compared to pre-operative cases. Laterality of excision did not affect self-report of general memory function. Nevertheless, a brief Verbal memory subscale yielded the expected material specific pattern after unilateral temporal lobectomy.     

The relationship between quantitative T2 relaxometry and memory in nonlesional temporal lobe epilepsy

PURPOSE: We investigated the relationship between preoperative quantitative magnetic resonance imaging (MRI) T2 relaxometry and volumetry of the hippocampi and pre- and postoperative verbal memory in temporal lobectomy patients who had nonlesional temporal lobe epilepsy. METHODS: Pre- and postoperative memory data based on the Logical Memory (LM) subtest of the Wechsler Memory Scale-Revised (WMS-R) and the 30-min delayed recall trial of the Rey Auditory Verbal Learning Test (AVLT) were obtained from 26 left and 15 right temporal lobectomy patients. Coronal MRI T2 maps were generated for these 41 temporal lobectomy patients as well as 61 control patients. Hippocampal T2 relaxation times and hippocampal volumes, converted to z scores using control group data, were correlated with neuropsychological performance in the patients. RESULTS: In left temporal lobe-onset patients, high T2 in the left hippocampal body predicted higher LM performance after surgery. Asymmetrically high T2 in the left hippocampal body (i.e., the right-minus-left difference), compared with the right hippocampal body, also predicted higher LM performance after surgery. In right temporal lobe-onset patients, high T2 in the left hippocampal body predicted relatively lower AVLT performance after surgery. Multiple regression analysis in left temporal-onset patients revealed that high T2 in the left hippocampal body together with higher preoperative LM performance predict higher postoperative LM performance. CONCLUSIONS: Our findings suggest that elevated (i.e., abnormal) hippocampal T2 signal is associated with memory ability (or hippocampal functional capacity) independent of MRI-determined hippocampal atrophy. Therefore, our findings support the use of quantitative T2 relaxometry as an independent predictor of verbal memory outcome in both left and right TLE patients who are candidates for temporal lobectomy.     

Olfactory memory in patients with anterior temporal lobectomy.

Right and left temporal lobectomy patients, matched in age and intelligence, made more errors in odor recall than a control group. Patients with right temporal lobe excisions recalled significantly fewer odors correctly than patients with left temporal lobe excisions. Olfactory memory scores were not related to other memory deficits associated with left or right temporal lobe dysfunction or to intelligence or lesion size. However, in patients with right temporal lobectomy, percent of odors recalled correctly correlated positively with a general memory index. The findings presented are consistent with previous reports that the right temporal lobe is more involved with nonverbal memory than the left temporal lobe.     

Pre- and postoperative verbal memory in pediatric patients with temporal lobe epilepsy

Outcome studies concerning memory after pediatric temporal lobe surgery in the treatment of epilepsy are rare and have not yielded consistent results. In the present study, 55 children and adolescents with temporal lobe epilepsy (TLE; 26 left, 29 right, 6-17 years) performed a verbal memory test before and 3 as well as 12 months after different types of temporal lobe resections (anterior lobectomy, amygdalo-hippocampectomy (AH), lesionectomy (LX)). Groups did not significantly differ before surgery. Three months after surgery, the left resected group showed a decline in learning and delayed recall, and performed significantly lower than the right resected group. Recoveries were evident 1 year after surgery. The postoperative memory declines were associated with a left-sided resection and a higher preoperative performance. Comparisons on the different resection types suggest a special risk in patients undergoing a left-sided AH. In summary, our results indicate a functional association of verbal memory functions with the left temporal lobe similar to findings in adult patients. Declines after left-sided temporal resections seem to be reversible at least for part of the children, perhaps due to the greater plasticity of the immature brain.     

Interaction of cognitive aging and memory deficits related to epilepsy surgery

Temporal lobe epilepsy surgery can cause significant memory impairment. This study was intended to examine whether surgery also could affect prognosis of memory in older age. Age regression of verbal memory was examined in 187 patients (before and 1 year after left temporal lobe surgery) and 264 healthy controls. Eighty patients underwent selective amygdalohippocampectomy, and 107 patients underwent anterior two-thirds temporal lobectomy. Amygdalohippocampectomy patients had mesiotemporal epilepsy; anterior two-thirds temporal lobectomy patients had more extramesial or diffuse seizure onset zones. Memory was assessed by word list learning for its more mesial (consolidation/retrieval) and more neocortical (learning) aspects. Patients showed significant preoperative memory impairment. Independent of seizure outcome and surgical approach, surgery had significant negative effects on learning and consolidation/retrieval. In the amygdalohippocampectomy group, preoperative and postoperative age regressions of learning and consolidation/retrieval were not different from those of controls. In the anterior two-thirds temporal lobectomy group, age regression of verbal learning became steeper after surgery, and consolidation/retrieval was negatively correlated with older age and later onset of epilepsy even before surgery. The data confirm that age regression of verbal memory in left temporal lobe epilepsy is similar to that in healthy controls. Both left anterior two-thirds temporal lobectomy and amygdalohippocampectomy worsen verbal learning and memory and bring patients closer to cognitive disability. Particularly in anterior two-thirds temporal lobectomy patients, surgery and reduced capacities for compensation cause acceleration of lifetime memory decline. The results support earlier and tailored epilepsy surgery and suggest that memory prognosis in older age should be considered if more extensive temporal resections would be inevitable.     

Crossed aphasia in a patient with complex partial seizures: evidence from intracarotid amobarbital testing, functional cortical mapping, and neuropsychological assessment.

We report a right-handed patient who became transiently aphasic following a right temporal lobectomy for control of intractable complex partial seizures. Preoperative intracarotid amobarbital testing revealed right-hemisphere language dominance, although bilateral language representation was present. Memory testing during unilateral electrical hippocampal simulation with depth electrodes indicated reliance on left-hemisphere mesial temporal lobe structures for verbal memory. Functional mapping for language during surgery established several right perisylvian regions that, when stimulated, produced speech arrest and/or paraphasic substitution. One-year follow-up neuropsychological assessment demonstrated an increase in verbal learning and decrease in visual memory, a pattern associated with patients who have undergone right temporal lobectomy. These data demonstrate that (1) right cerebral language dominance can be observed when ipsilateral seizure onset is present (2) verbal memory and language dominance are not necessarily linked, and (3) some reported cases of crossed aphasia may in fact have bilateral language representation.     

The Family Pictures subtest of the WMS-III: relationship to verbal and visual memory following temporal lobectomy for intractable epilepsy

This study examined the extent to which the Family Pictures (FP) subtest of the Wechsler Memory Scale-Third Edition (WMS-III) is related to verbal memory measures and right mesial temporal integrity. Epilepsy patients who underwent temporal lobectomy did not differ in the extent to which FP scores changed from before to after surgery, although postoperative FP performance was worse in those who underwent right temporal lobectomy than in those who underwent left temporal lobectomy. FP was most strongly related to the Logical Memory subtest from the WMS-III. Results suggest that FP measures both verbal and visual memory and is minimally sensitive to lateralization of temporal lobectomy.     

Everyday memory self-assessed by adult patients with acquired brain damage and their significant others

Self-assessment of everyday memory dysfunction was examined in a sample of 48 patients with acquired brain injury. A modified version of the Everyday Memory Questionnaire (EMQ20) was used as an interview. Patients were compared to 30 persons without brain injury. EMQ20 was completed by significant others (SOs) to both patients and controls. Patients reported a higher frequency of memory problems (days per week) and more distress due to memory deficits compared to controls. A high degree of consistency was found between patient and SO ratings on these measures. No difference was found on the total usage of memory aids, but patients asked other people more for a reminder and used loose notes less than controls. Implications for rehabilitation and future research are discussed.     

Crossed aphasia in a patient with complex partial seizures: Evidence from intracarotid amobarbital testing,functional cortical mapping,and neuropsychological assessment

Abstract

We report a right-handed patient who became transiently aphasic following a right temporal lobectomy for control of intractable complex partial seizures. Pre-operative intracarotid amobarbital testing revealed right-hemisphere language dominance, although bilateral language representation was present. Memory testing during unilateral electrical hippocampal simulation with depth electrodes indicated reliance on left-hemisphere mesial temporal lobe structures for verbal memory. Functional mapping for language during surgery established several right perisylvian regions that, when stimulated, produced speech arrest and/or paraphasic substitution. One-year follow-up neuropsychological assessment demonstrated an increase in verbal learning and decrease in visual memory, a pattern associated with patients who have undergone right temporal lobectomy. These data demonstrate that (1) right cerebral language dominance can be observed when ipsilateral seizure onset is present (2) verbal memory and language dominance are not necessarily linked, and (3) some reported cases of crossed aphasia may in fact have bilateral language representation.     

Intracarotid Amobarbital Procedure as a Predictor of Material-Specific Memory Change After Anterior Temporal Lobectomy

Summary: Memory testing during the intracarotid amobarbital procedure (IAP) is used extensively to identify temporal lobe surgery candidates "at risk" for developing severe postoperative anterograde amnesia. However, the utility of the IAP in predicting commonly observed material-specific memory deficits has not been thoroughly investigated. We examined the utility of contralateral IAP memory testing, as an index of the functional capacity of the surgical temporal lobe, to predict postoperative material-specific memory changes on the Wechsler Memory Scale-Revised (WMS-R) in patients with left hemisphere speech dominance undergoing left (n = 32) and right (n = 31) temporal lobectomy (TL). Left TL patients who "passed" contralateral IAP memory testing (368% recognition of memory items) had significantly greater verbal memory decrements than those who "failed" the IAP, presumably as a result of removal of functional tissue. A similar relationship between contralateral IAP performance and visual memory performance was not observed among right TL patients. Thus, the functional adequacy of the tissue to be resected appears to be inversely related to postoperative verbal memory decrement, at least among left TL patients. This relationship is consistent with results of recent studies demonstrating an inverse relationship between verbal memory decrements after left TL and preoperative neuropsychological verbal memory performance, magnetic resonance imaging (MRI) hippocampal volumes, and degree of mesiotemporal sclerosis (MTS).     

Effects of temporal lobe epilepsy on retrograde memory

PURPOSE: In a previous investigation (Lah et al., 2004), we found deficits in retrograde memory in patients who had undergone temporal lobectomy (TL). In this study, we set out to determine whether such deficits are present before surgery in patients with temporal lobe epilepsy (TLE). METHODS: Memory for public and autobiographic facts and events was assessed in patients with focal left-sided (n=15) or right-sided (n=14) TLE and healthy control subjects (n=15). The impact of epilepsy and underlying cognitive deficits on retrograde memory also was examined. RESULTS: Patients with left TLE demonstrated retrograde memory deficits across domains. Patients with right TLE showed defective recall only in the autobiographic domain. Young age at onset (younger than 14 years) was associated with greater difficulties in recall of famous events, and patients receiving polytherapy had significantly reduced recall of autobiographic events compared with those receiving monotherapy. In most cases, deficient memory for the past was associated with impairments in other cognitive skills, especially language abilities. CONCLUSIONS: In unoperated-on patients with TLE, we found deficits in retrograde memory that were similar to those seen after TL, with the pattern of deficits being influenced by side of lesion, anticonvulsant medication, and word-finding deficits. Unlike patients tested after right TL, patients with right TLE did not have difficulty recalling details of famous events, which raises the possibility that right TL results in a decline in this aspect of retrograde memory.     

Investigation of Everyday Memory in Normal Subjects Using the Subjective Memory Questionnaire (SMQ)

This study examined memory for everyday events by method of self-report using the Subjective Memory Questionnaire (SMQ). The purpose of the study was to repeat and extend existing normative data.The SMQ was found to be adequately reliable, but this finding needs to be replicated in a large sample of subjects. Data from 170—224 control subjects revealed no effects of age or sex on total SMQ scores. However, sex differences occurred in 50% of individual questions, possibly reflecting cultural sterotypes. Higher social classes rated their memory more optimistically than lower classes. Overall subjects estimated their memory as being above “average”.Principal Component Analysis revealed 10 factors with eigen-values greater than 1.0. These included factors for “male” and “female” memory that have not been found previously in studies using subjective measures of everyday memory. Factors identified as “absentmindedness”, “names” and “how to get somewhere” were similar to those reported elsewhere.     

Subjective versus objective memory change after temporal lobe epilepsy surgery.

OBJECTIVE: To examine subjective versus objective memory change after anterior temporal lobectomy (ATL). METHODS: A prospective, controlled study. Controls included 39 unoperated patients with intractable temporal lobe epilepsy (TLE) who were administered a series of cognitive and health-related quality of life measures at baseline and at 12-month follow-up intervals. The surgery sample included 65 patients with intractable, focal TLE who had undergone either a right or left ATL. These patients were tested preoperatively and at 6-month follow-up intervals. Subjective and objective memory change was quantified using a newly developed methodology to control for practice effect and regression to the mean. RESULTS: Measures of subjective and objective memory change were not significantly related in the surgery sample. Prevalence of significant subjective memory decline 1 year after surgery ranged from 3 to 7%, whereas prevalence of significant objective memory decline ranged from 26 to 55%. Postoperative levels of emotional distress significantly predicted self-reported memory decline 1 year after ATL. Postoperative medication side effect and seizure outcome were also related significantly to subjective memory change in patients who had undergone left ATL. CONCLUSIONS: Subjective and objective memory change after temporal lobectomy are not related. Complaints of significant memory decline after ATL are infrequent and may serve as a marker for depression or other mood disorder rather than organically based memory decline.     

Visual memory in patients after anterior right temporal lobectomy and adult normative data for the Brown Location Test

Several large meta-analytic studies have failed to support a consistent relationship between visual or “nonverbal” memory deficits and right mesial temporal lobe changes. The Brown Location Test (BLT), a recently developed dot location learning and memory test, uses a nonsymmetrical array and provides control over many of the confounding variables (e.g., verbal influence and drawing requirements) inherent in other measures of visual memory. In the present investigation, we evaluated the clinical utility of the BLT in patients who had undergone left or right anterior mesial temporal lobectomy. We also provide normative data of 298 healthy adults for standardized scores. Results revealed significantly worse performance on the BLT in the right as compared to the left lobectomy group and the healthy adult normative sample. The present findings support a role for the right anterior mesial temporal lobe in dot location learning and memory.     

Defining meaningful postoperative change in epilepsy surgery patients: measuring the unmeasurable?

Two hundred and ninety epilepsy surgery patients completed the Hospital Anxiety and Depression Scale and were assessed on a list learning task preoperatively and 1 year postoperatively. Deterioration and improvement in verbal memory were determined using reliable change indices (RCIs) at 80 and 90% confidence limits. Almost one third of patients (27%) experienced a deterioration in verbal learning. The number of left temporal lobectomy patients who had deteriorated outnumbered the right temporal lobectomy patients by 2:1. Significant improvements in verbal learning were seen in 21% of the right temporal lobectomy group and 10% of the left temporal lobectomy group. Patients who were seizure-free postoperatively were not more likely to experience a postoperative deterioration or improvement in memory than those who continued to experience seizures. No significant relationships were found between subjective ratings of postoperative memory function and objective indices of change. Reliable, objective indices of postoperative deterioration in memory function may bear little relation to the patient's subjective experience. This should be considered when statistical predictions are used as the basis of preoperative counseling.     

Cognitive strategies in patients with unilateral temporal lobe excisions

The performance of patients with surgical excisions of either the left or right temporal lobe and a normal control group was compared on a hypothesis test. Subjects in both temporal lobectomy groups solved fewer problems than controls; and there was no difference in the performance of left and right lobectomy patients. However, analyses of cognitive patterns revealed specific strategies associated with subjects having undergone left temporal lobe excisions. These patients formulated fewer hypotheses than controls and tended to shift from a given hypothesis even when it was indicated to be correct. Conversely, right temporal lobectomy patients tended to retain a given hypothesis which was indicated to be incorrect. The same results were found with and without memory assistance, indicating that these cognitive strategies occur independent of overt memory deficits.     

Bilateral Magnetic Resonance Imaging-Determined Hippocampal Atrophy and Verbal Memory Before and After Temporal Lobectomy

Summary: We investigated pre- and postoperative verbal memory in temporal lobectomy patients who had volumetrically symmetric hippocampi. Pre- and postoperative verbal memory data based on the Logical Memory subtest of the Wechsler Memory Scale-Revised (WMS-R) were obtained from 15 left and 18 right temporal lobectomy patients. The difference between hippocampal volumes (R/L) was between -0.1 and 0.3 cm³, which is indeterminate for lateralizing hippocampal atrophy. Patients were divided into four groups based on side of operation and combined hippocampal volume expressed as a function of total intracranial volume (R + L volume/total intracranial volume). Patients with a combined hippocampal volume that was smaller than any combined hippocampal value of a normal control group were defined as bilaterally atrophic. Left temporal lobectomy patients demonstrated the expected decrease in verbal memory postoperatively regardless of whether the volumetrically symmetric hippocampi were nonatrophic or atrophic. Left temporal lobectomy patients with bilaterally atrophic hippocampi, however, had the poorest verbal memory before and after operation. Right temporal lobectomy patients tended to have improved verbal memory after operation whether or not the volumetrically symmetric hippocampi were atrophic. We conclude that side of operation is a more potent predictor of verbal memory outcome than is hippocampal atrophy when hippocampi are bilaterally symmetric and that left temporal lobectomy patients with bilateral atrophy may be at risk for greater functional deficits after operation.     

Language-related cognitive declines after left temporal lobectomy in children.

Presented is a case series demonstrating that clinically significant language-related cognitive declines not detected by intelligence quotient (IQ) testing occur after left temporal lobectomy in school-aged children. In this series, comprehensive preoperative and postoperative neuropsychologic evaluations were completed in eight school-aged patients who underwent temporal lobectomy (five left, three right) for temporal lobe epilepsy. Mean age at surgery was 13 years, 11 months +/- 2 years, 1 month. Testing included measurement of IQ, verbal learning, naming, visual memory, sight word recognition, reading comprehension, and calculation. All five left temporal lobectomy patients demonstrated significant language-related cognitive declines on postoperative neuropsychologic testing, including deficits in verbal IQ (one patient), verbal learning (four patients), naming (one patient), and reading comprehension (one patient). These deficits were clinically evident in four of the five left temporal lobectomy patients, leading to declines in educational performance. IQ testing alone did not reliably identify these deficits. No significant declines were found after surgery in three right temporal lobectomy patients. Average or high preoperative functioning may have predisposed patients to postoperative deficits in this series, whereas magnetic resonance imaging or pathologic abnormalities did not protect against postoperative deficits. Outcome studies of temporal lobectomy in childhood should use comprehensive neuropsychologic testing to identify cognitive deficits.