A constant current source for extracellular microiontophoresis

There is evidence that some schizophrenic patients have deficits on tests of cognitive function, particularly tests of executive function, including the Wisconsin Card Sorting Test (WCST) and the Trail-making Test, Part B. This study was conducted to determine the generalizability of these findings across the schizophrenia spectrum to schizotypal personality disorder (SPD). Forty DSM-III SPD patients, 56 nonschizophrenia-related other personality disorder (OPD) patients, and 32 normal volunteers from two medical centers performed tests of executive function such as the WCST, Trail-making Part B, Stroop Word-Color Test, and Verbal Fluency, as well as tests of more general intellectual functioning such as the Wechsler Intelligence Scale-Revised Vocabulary and Block Design subtests, and Trail-making Part A. SPD patients performed more poorly on the WCST and on Trail-making Part B than did OPD patients or normal subjects; the groups did not differ on tests of general intellectual functioning. SPD patients may share some of the cognitive deficits observed in schizophrenia.     

Visual confrontation naming following left anterior temporal lobectomy: A comparison of surgical approaches.

Change in visual confrontation naming was examined following left (speech dominant) anterior temporal lobectomy (ATL) as a function of surgical technique and patient characteristics. Two hundred seventeen patients with intractable left temporal lobe epilepsy were selected according to standard criteria across 8 centers, and combined into 4 surgical approaches to ATL: (a) tailored resections with intraoperative mapping of eloquent cortex, (b) tailored resections with extraoperative mapping, (c) standard resections with sparing of superior temporal gyrus, and (d) standard resections including excision of superior temporal gyrus. Changes in visual confrontation naming were examined with an index of reliable change derived from an independent sample of 90 nonsurgical patients with complex partial seizures. Results showed significant decline in visual confrontation naming following left ATL, regardless of surgical technique. Across surgical approaches, the risk for decline in visual confrontation naming was associated with a later age of seizure onset and more extensive resection of lateral temporal neocortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing declarative memory in schizophrenia using Wisconsin Card Sorting Test stimuli: the Paired Associate Recognition Test

The Paired Associate Recognition Test (PART) was developed to measure declarative memory using Wisconsin Card Sorting Test (WCST) stimuli, so that both tasks could be administered during functional neuroimaging to differentiate memory and executive function, and associated frontal and temporal lobe activation in schizophrenia. The current study was designed to compare PART and WCST performance in schizophrenic patients and to examine effects of medication and symptomatology. The PART, WCST, and standard declarative memory tasks were administered to 30 chronic schizophrenic patients and 30 matched healthy control subjects. Supporting task validity was the finding that patients were equally impaired on the PART and the WCST. Neuroleptics did not appear to affect performance. The effect of anticholinergic medication correlated negatively with WCST performance in a small subsample. Severity of schizophrenia-specific symptoms measured at intake on the Brief Psychiatric Rating Scale correlated negatively with performance on the WCST. These results support the application of the PART and WCST in future functional neuroimaging studies.     

Neuropsychological outcome following anterior temporal lobectomy in patients with and without the syndrome of mesial temporal lobe epilepsy.

The nature, pattern, and degree of neuropsychological change following anterior temporal lobectomy (ATL) were examined as a function of the presence or absence of the syndrome of mesial temporal lobe epilepsy (MTLE). Fifty-four patients exhibited the syndrome of MTLE, while 34 patients were without the syndrome (non-MTLE). The test-retest performance of a group of 40 epilepsy patients who did not undergo surgery was used to derive regression based estimates of test-retest change. Overall, the MTLE group did not show significant cognitive decline following ATL. In contrast, the left non-MTLE group showed significant declines on verbal memory, confrontation naming, and verbal conceptual ability. Further, verbal memory was the most substantial area of decline, and was independent of seizure outcome. Clinical and theoretical implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frontotemporal cerebral blood flow change during executive and declarative memory tasks in schizophrenia: A positron emission tomography study.

Schizophrenia affects prefrontal and temporal-limbic networks. These regions were examined by contrasting regional cerebral blood flow (rCBF) during executive (Wisconsin Card Sorting Test [WCST]), and declarative memory tasks (Paired Associate Recognition Test [PART]). The tasks, and a resting baseline, were administered to 15 patients with schizophrenia and 15 healthy controls during 10 min positron emission tomography 1?O-water measures of rCBE Patients were worse on both tasks. Controls activated inferior frontal, occipitotemporal, and temporal pole regions for both tasks. Similar results were obtained for controls matched to level of patient performance. Patients showed no activation of hypothesized regions during the WCST and activated the dorsolateral prefrontal cortex during the PART. On the PART, occipitotemporal activation correlated with better performance for controls only. Better WCST performance correlated with CBF increase in prefrontal regions for controls and in the parahippocampal gyrus for patients. Results suggest that schizophrenia may involve a breakdown in the integration of a frontotemporal network that is responsive to executive and declarative memory demands in healthy individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term follow-up after temporal lobe resection for lesions associated with chronic seizures

A follow-up study was conducted on 60 patients who had standard en bloc anterior temporal lobe resection, including mesiotemporal structures, as treatment for temporal lobe lesions associated with chronic, medically intractable seizures. Lesions were identified as glial tumors, hamartomas, or vascular malformations. Long-term outcome was assessed in terms of seizure frequency and certain psychosocial sequelae. Seizure onset occurred at an average age of 15 years (median = 13.5 years), and patients experienced seizures for an average of 13 years prior to surgery. The mean time of follow-up was 8.4 years postsurgery (median = 6 years). The Kaplan-Meier curve at median follow-up showed a seizure-free rate of 80%. Late seizure recurrence was documented for three patients; two had been seizure-free for 10 years and one for 15 years after surgery, before re-onset of seizures in the absence of tumor recurrence. A prolonged history of seizures prior to surgery was associated with a poorer seizure outcome (p = 0.06), suggesting that secondary epileptogenesis at sites distant to the lesion may develop with years of uncontrolled seizures. There was a low tumor recurrence rate of 3.3% (two cases). The psychosocial outcome was generally good, with 67% working or engaged in educational studies, and improvement noted in 59% of cases for one or more of the psychosocial factors investigated. This study confirms that anterior temporal lobe resection for temporal lesions associated with chronic seizures is a successful treatment with a high seizure-free rate following surgery and good psychosocial outcome.     

Epilepsy surgery in the first three years of life

PURPOSE: Partial seizures in early postnatal life may be catastrophic and associated with poor long-term outcome. Epilepsy surgery can alleviate partial seizures in older children and adults, but there is little experience with surgical therapy in infancy apart from hemispheric epilepsy syndromes. METHODS: We analyzed the results of cortical resection to treat medically refractory partial epilepsy in 31 children (16 boys, 15 girls) aged <3 years (mean, 18.3 months). Subjects were included only if seizure relief was the primary indication for surgery. RESULTS: Follow-up of at least 1 year (mean, 4.6 years) in 26 patients revealed that 16 were seizure-free, 4 had >90% seizure reduction, and 6 had <90% reduction. There was no significant difference in seizure outcome between hemispherectomy/multilobar resections and lobar resections or temporal versus extratemporal resection. Seizure outcome was independent of the amount of cortex removed in nonlesional patients. Only the presence of a discrete lesion on preoperative neuroimaging correlated with a favorable outcome. Family perceptions of accelerated development in seizure-free patients were not confirmed on developmental assessment. CONCLUSIONS: We conclude that cortical resection often benefits very young children with catastrophic partial seizures, but does not guarantee enhanced neurological development. The location and extent of the excised cortex may not be critical as long as the entire epileptogenic region and lesion are removed.     

Sex differences in olfactory identification and Wisconsin Card Sorting performance in schizophrenia: relationship to attention and verbal ability

We investigated the hypothesis that different prefrontal brain systems (i.e., dorsal vs. ventral) and sex contribute differentially to cognitive deficit in schizophrenia. Performance was assessed among clinically stable, chronic schizophrenic outpatients and matched normal control subjects on olfactory identification [on the University of Pennsylvania Smell Identification Test (UPSIT)] and on executive functions [using the Wisconsin Card Sorting Test (WCST)]. Patients were impaired on both tests compared to controls, and male schizophrenics were impaired on the WCST compared to female schizophrenics. The pattern of results suggests that gender differences on the UPSIT are mildly accentuated in schizophrenia. The data support our previous study indicating that UPSIT performance is largely independent of the executive or attentional deficits typically associated with schizophrenia, with the exception of verbal ability. Further research with larger samples is required to test the hypothesis that there is a severely impaired subgroup of male patients with diffuse prefrontal dysfunctions.     

Association of combined MRI, interictal EEG, and ictal EEG results with outcome and pathology after temporal lobectomy

PURPOSE: Magnetic resonance imaging, interictal scalp EEG, and ictal scalp EEG each have been shown to localize the primary epileptic region in most patients with mesial-basal temporal lobe epilepsy (MBTLE), but the association of surgical outcome and pathology with each combination of these test results is not known. METHODS: We reviewed the MRI, interictal scalp EEG, and ictal scalp EEG results of 90 consecutive patients with MBTLE. Twelve patients were excluded from the analysis because inconclusive bitemporal intracranial EEG results precluded anterior temporal lobectomy (ATL); none had concordant MRI and interictal scalp EEG results. We compared all combinations of presurgical MRI, interictal EEG, and ictal EEG results to seizure outcome and tissue pathology in the 78 patients who underwent an ATL. RESULTS: Forty-eight (61%) patients had concordant lateralized MRI and interictal EEG temporal lobe abnormalities, with no discordant ictal EEG results; 77% of these patients were seizure-free after ATL. Concordance of MRI and interictal EEG abnormalities correlated with seizure cessation (p < 0.05), compared to all combinations with discordant or nonlateralizing MRI and interictal EEG results. Mesial temporal sclerosis (MTS) was confirmed pathologically in about 80% of both groups (p = 0.5). Outcome in patients with concordant MRI and ictal EEG with nonlateralizing interictal EEG was significantly worse than combinations with concordant MRI and interictal EEG (p < 0.02). CONCLUSIONS: Compared to other combinations of test results, concordance of MRI and interictal EEG is most closely associated with surgical outcome in MBTLE. However, most selected patients have pathologic confirmation of MTS regardless of test results or outcome. This information may be useful for planning the presurgical evaluation of patients with medically intractable MBTLE.     

Incomplete psychometric equivalence of scores obtained on the manual and the computer version of the Wisconsin Card Sorting Test?

The Wisconsin Card Sorting Test (WCST) assesses executive and frontal lobe function and can be administered manually or by computer. Despite the widespread application of the 2 versions, the psychometric equivalence of their scores has rarely been evaluated and only a limited set of criteria has been considered. The present experimental study (N = 100 healthy adults) therefore examined the psychometric equivalence of 4 scores (i.e., Total Correct, Percentage of Errors, Perseverative Errors, and Failure-to-Maintain-Set) obtained on the 2 versions of the WCST in terms of 4 key criteria identified within the framework of classical test theory. The results showed considerable differences in variances, small to modest parallel-forms reliability coefficients, and small to modest temporal stability coefficients. Taken together, our results suggest that scores on the manual version and the computer version of the WCST show incomplete psychometric equivalence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of executive function in patients with mild traumatic brain injury

BACKGROUND: The nature of functional deficit after mild traumatic brain injury (TBI) defined by Glasgow Coma Score of 13-15 is not fully described. This study explored the sensitivity of several neuropsychological tests to identify sequelae of mild traumatic brain injury (TBI). METHODS: Eleven adult patients with mild TBI admitted to a Level 1 trauma center were studied. The battery of tests included the Wechsler Intelligence Scale for Children -Revised: Mazes Subtest, Trails A and B, the Boston Naming Test, The Multilingual Aphasia Examination: Controlled Oral Word Association Test, and the Paced Auditory Serial Addition Task. RESULTS: Control subjects performed significantly better than patients with mild TBI on Trails A and B, the Controlled Oral Word Association Test, and Paced Auditory Serial Addition Task (subtests 2-4). No significant differences in performances between patients and controls was found for the Wechsler Intelligence Scale for Children -Revised: Mazes Subtest, Boston Naming Test, and Paced Auditory Serial Addition Task Subtest 1. CONCLUSION: The results suggest that tests of specific frontal lobe executive functions are valuable in diagnosing and monitoring recovery from mild TBI.     

Impairment of executive function induced by hypertension in the Rhesus monkey (Macaca mulatta).

The effects of chronic, untreated hypertension on executive function were investigated in a nonhuman primate model of hypertensive cerebrovascular disease. Executive function was assessed with the Conceptual Set-Shifting Task (CSST), a task adapted from the human Wisconsin Card Sorting Test (WCST). Like the WCST, the CSST requires abstraction of a stimulus set, followed by a series of set shifts. Performance on the CSST by 7 young adult monkeys (Macaca mulatta) with surgically induced hypertension was compared with that of 6 normotensive monkeys. The hypertensive group was significantly impaired relative to the normotensive group in abstraction and set shifting. Although the neural basis of this impairment is unclear, evidence from studies with humans and monkeys suggests that the prefrontal cortex may be the locus for this effect of hypertension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association between striatal reduction and poor Wisconsin card sorting test performance in patients with schizophrenia

Several findings support the hypothesis that the striatum is implicated in executive functions and in the modulation of goal-directed behavior, and could play a key role in the pathophysiology and in the production of symptoms and signs in schizophrenia. We have studied the relationship between the objective measures of the striatal structures, as evaluated by magnetic resonance imaging (MRI), and the Wisconsin Card Sorting Test (WCST) performance in a schizophrenic sample. Thirty-five schizophrenic patients underwent MRI scans of striatal structure and neuropsychological evaluation of executive functions by WCST. Poor WCST performers had a reduction of the left caudate nucleus and putamen, and right total striatum when compared to 24 healthy controls. Significant correlation coefficients were also observed between neuropsychological indexes and left striatal measures. The findings suggest the existence of a relationship between abnormalities of striatal structure and abnormal executive-type or organizational cognitive functions.     

Declarative memory following anterior temporal lobectomy in humans.

Hypothesized that verbal memory decline following anterior temporal lobectomy (ATL) is associated with a lack of significant neuropathology in resected left, but not right, hippocampus and is limited to measures of episodic memory only. Tests of immediate (digit span), semantic (visual naming), and episodic memory as measured by the California Verbal Learning Test (CVLT) were administered before and 6 mo after resection of the anterior left (n?=?36) or right (n?=?26) temporal lobe. There were no effects of hippocampal pathology on measures of immediate or semantic memory for either ATL group or for episodic memory for the right ATL group. Left ATL patients who demonstrated no/mild hippocampal sclerosis exhibited significantly greater postoperative decline in episodic memory compared with those with moderate/marked hippocampal sclerosis on multiple CVLT indices (recall measures, learning characteristics, and contrast measures). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cerebral blood flow velocity decreases during cognitive stimulation in Huntington's disease

OBJECTIVE: To examine whether activation of cerebral blood flow velocity during cognitive stimulation, as measured by transcranial Doppler ultrasonography (TCD), is altered in patients with Huntington's Disease (HD). BACKGROUND: Previous research suggests that resting cerebral blood flow in symptomatic and asymptomatic HD patients is reduced from expected premorbid levels. The effects of cognitive activation on this relative hypoperfusion in HD has not been studied extensively. METHODS: We measured TCD flow velocity during rest and cognitive testing with the Porteus Maze Test and the Trails Test in 12 normal control subjects and 10 gene-positive HD patients. Percent change (i.e., flow during testing/resting) of flow velocity in the anterior and middle cerebral arteries were compared between groups. Correlations among percent flow velocity change, a disability rating scale, and cognitive test scores were calculated. RESULTS: In control subjects, anterior cerebral artery flow velocity and middle cerebral artery velocity increased during cognitive testing (p=0.001). HD patients showed a smaller blood flow velocity increase in the anterior cerebral arteries during the Porteus Maze Test (p < 0.001) and the Trails Test, Part B (p < 0.001). In the left anterior cerebral artery, flow velocity fell an average of 4.2% below resting baseline levels during the Porteus Maze Test, and 1.2% below resting levels during the Trails Test. The magnitude of the cerebral blood flow velocity changes in the anterior cerebral artery correlated with a number of cognitive test scores and with a rating scale of functional disability. In addition, logistic regression was able to discriminate the HD patients from the control group based on blood flow velocity changes (p=0.0025). When HD patients were divided into more (i.e., HD with chorea; n=4) and less impaired (i.e., without chorea; n=6) groups, both showed significant decreases in left anterior cerebral artery flow velocity during visual spatial executive cognition testing compared with control subjects. CONCLUSIONS: These results suggest that activation of visual spatial executive functions cause decreased flow velocity in the anterior cerebral artery, but not the middle cerebral artery, in HD patients. These changes are related to test performance and functional capabilities.     

Use of positron emission tomography for presurgical localization of eloquent brain areas in children with seizures

Successful surgical management of a neoplastic or nonneoplastic seizure focus in close proximity to or within eloquent brain areas relies on precise delineation of the relationship between the lesion and functional brain areas. The aim of this series was to validate the usefulness and test the efficacy of noninvasive presurgical PET mapping of eloquent brain areas to predict surgical morbidity and outcome in children with seizures. To identify eloquent brain areas in 15 children (6 female and 9 male; mean age 11 years) with epileptogenic lesions PET images of regional cerebral blood flow were performed following the administration of [(15)O]water during motor, visual, articulation, and receptive language tasks. These images with coregistered magnetic resonance (MR) images were then used to delineate the anatomic relationship of a seizure focus to eloquent brain areas. Additional PET images using [18F]fluoro-2-deoxy-D-glucose (FDG) and [11C]methionine (CMET) were acquired to help localize the seizure focus, as well as characterize the lesion. Patient surgical management decisions were based on PET mapping in combination with coregistered MR images, PET-FDG findings, and the anatomic characteristics of the lesion. At follow-up 1-26 months after surgery, all patients that underwent temporal lobectomy (9 patients) and extratemporal resection (4 patients) for a neoplastic or nonneoplastic seizure focus are seizure-free with minimal postoperative morbidity. Of prime importance, no child sustained a postoperative speech or language deficit. PET imaging was also well tolerated without procedural complications. Based on PET mapping, a nonoperative approach was used for 2 children and a biopsy only was used in one child. When cortical injury involved prenatally determined eloquent cortex, PET demonstrated reorganization of language areas to new adjacent areas or even to the contralateral hemisphere. Integration of anatomical and functional data enhanced the surgical safety, defined optimal surgical approach, delineated the seizure focus from eloquent brain areas, facilitated maximum resection and optimized the timing of surgery, thereby minimizing surgical morbidity while maximizing surgical goals. PET measurements of FDG and CMET uptake were also helpful in localizing the seizure focus and grading the tumors. PET used for brain mapping in children provides the surgeon with strategic preoperative information not readily attainable with traditional invasive Wada testing or intraoperative cortical stimulation. PET mapping may also improve the outcome of extratemporal resections by allowing aggressive seizure focus resection. In addition, serial brain maps may optimize timing for surgical intervention by demonstrating reorganization of eloquent cortex often seen in younger children after cortical injury. Our results suggest that noninvasive presurgical brain mapping has the potential to reduce risk and improve neurologic outcome.     

Reliability and construct validity of the Paired-Associate Recognition Test: A test of declarative memory using Wisconsin Card Sorting stimuli.

The Paired-Associate Recognition Test (PART) was developed to test declarative memory using Wisconsin Card Sorting Test (WCST) stimuli, for use in physiologic neuroimaging studies of memory and executive function in schizophrenia. PART was administered to 55 healthy adults (30 male, 25 female) to establish reliability and construct validity. Reliability results indicate that PART performance was stable across trials and internally consistent. Convergent validity was confirmed by significant correlations between PART and standard measures of visual recall, and by PART loading on a memory factor. Divergent validity was established through low correlations between PART and WCST, and by a loading of WCST on a separate factor. Overall results indicate that PART can be administered reliably and that it requires declarative memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Outcome after temporal lobectomy in bilateral temporal lobe epilepsy

We determined how noninvasive presurgical data relate to prognosis after temporal lobectomy in patients with independent bilateral temporal lobe (IBTL) complex partial seizures on the intracranial electroencephalogram (EEG). Between 1986 and 1994, 28 patients had IBTL seizures on intracranial EEG. Fifteen of these 28 patients underwent temporal lobectomy and 13 were not offered surgery. Of the 15 patients who had surgery, 10 patients became seizure-free. Magnetic resonance imaging (MRI) and the Wada test were the only variables associated with a seizure-free outcome. Seven of 10 seizure-free patients had a lateralized Wada result or the presence of unilateral hippocampal sclerosis, whereas none of the patients with persistent seizures had either of these findings. Variables not found to be predictive of a seizure-free outcome included location of scalp interictal spikes, degree of seizure-onset laterality, presence of early epilepsy risk factor, duration of epilepsy, and full-scale intelligence quotient. We conclude that MRI and the Wada test provide information of prognostic value in patients with bilateral temporal seizures independent of intracranial EEG data.     

Individual memory change after anterior temporal lobectomy: a base rate analysis using regression-based outcome methodology

PURPOSE: To characterize patterns of base rate change on measures of verbal and visual memory after anterior temporal lobectomy (ATL) using a newly developed regression-based outcome methodology that accounts for effects of practice and regression towards the mean, and to comment on the predictive utility of baseline memory measures on postoperative memory outcome. METHODS: Memory change was operationalized using regression-based change norms in a group of left (n = 53) and right (n = 48) ATL patients. All patients were administered tests of episodic verbal (prose recall, list learning) and visual (figure reproduction) memory, and semantic memory before and after ATL. RESULTS: ATL patients displayed a wide range of memory outcome across verbal and visual memory domains. Significant performance declines were noted for 25-50% of left ATL patients on verbal semantic and episodic memory tasks, while one-third of right ATL patients displayed significant declines in immediate and delayed episodic prose recall. Significant performance improvement was noted in an additional one-third of right ATL patients on delayed prose recall. Base rate change was similar between the two ATL groups across immediate and delayed visual memory. Approximately one-fourth of all patients displayed clinically meaningful losses on the visual memory task following surgery. Robust relationships between preoperative memory measures and nonstandardized change scores were attenuated or reversed using standardized memory outcome techniques. CONCLUSIONS: Our results demonstrated substantial group variability in memory outcome for ATL patients. These results extend previous research by incorporating known effects of practice and regression to the mean when addressing meaningful neuropsychological change following epilepsy surgery. Our findings also suggest that future neuropsychological outcome studies should take steps towards controlling for regression-to-the-mean before drawing predictive conclusions.     

Role of the hippocampus in sex differences in verbal memory: Memory outcome following left anterior temporal lobectomy.

The authors examined the neural and cognitive bases for sex differences in verbal memory in 57 patients who underwent left anterior temporal lobectomy (ATL) for the treatment of intractable seizures. On the California Verbal Learning Test (D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1987), women recalled more words than men both before and after surgery, regardless of the extent of hippocampal damage. Extent of hippocampal sclerosis was related to memory loss in both men and women. Women's superiority in verbal memory appears to result in part from their use of an efficient encoding strategy. Women were more likely than men to use semantic clustering both before and after ATL, and sex differences in word recall were attenuated after scores were adjusted for semantic clustering. There was no effect of ATL on semantic clustering. Taken together, these results suggest that sex differences in verbal memory are not due to differences in the integrity of the left hippocampus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)