Categorization of novel animals by patients with Alzheimer's disease and corticobasal degeneration.

We taught a novel animal category by rule-based and similarity-based processes to participants with Alzheimer's disease (AD), corticobasal degeneration (CBD), and healthy age-matched participants. Healthy participants successfully categorized by either process. AD patients' rule-based categorization was impaired, while their similarity-based categorization resembled that of healthy participants.

Fear sensitivity and the psychological profile of patients with psychogenic nonepileptic seizures.

Psychogenic nonepileptic seizures (PNES) remain a poorly understood phenomenon for both patients and their physicians. Recent work has begun to focus on the possible psychological underpinnings of this diagnosis, but few studies have focused on specific emotional pathologies. This study sought to investigate the impact of a specific emotional measure: self-reported fear sensitivity.

Object perception impairments predict instrumental activities of daily living dependence in Alzheimer's disease.

This study examined the contribution of object perception and spatial localization to functional dependence among Alzheimer's disease (AD) patients. Forty patients with probable AD completed measures assessing verbal recognition memory, working memory, object perception, spatial localization, semantic knowledge, and global cognition. Primary caregivers completed a measure of activities of daily living (ADLs) that included instrumental and basic self-care subscales (i.

Cognitive functioning in sporadic amyotrophic lateral sclerosis: a six month longitudinal study.

Objective: To observe changes in cognition over six months in subjects with recently diagnosed sporadic amyotrophic lateral sclerosis (ALS).

Methods: The study used a between-group and within-group longitudinal design. Nineteen ALS subjects and eight matched caregivers were recruited to participate in baseline neuropsychological assessments that were repeated six months later.

Neuropsychological and perfusion MR imaging correlates of revascularization in a case of moyamoya syndrome.

Serial neurocognitive and perfusion MR imaging findings are described in the perioperative course of a 48-year-old woman with a superficial temporal artery to middle cerebral artery bypass for right hemispheric ischemia due to moyamoya syndrome. Neurocognitive testing reflected both global and focal cerebrovascular dysfunction, which suggests that perfusion augmentation following surgical revascularization may engender cognitive and neurologic improvement beyond focal regions of established ischemia.

The role of sensory-motor information in object recognition: evidence from category-specific visual agnosia.

The role of sensory-motor representations in object recognition was investigated in experiments involving AD, a patient with mild visual agnosia who was impaired in the recognition of visually presented living as compared to non-living entities. AD named visually presented items for which sensory-motor information was available significantly more reliably than items for which such information was not available; this was true when all items were non-living. Naming of objects from their associated sound was normal.

Earlier onset of Alzheimer disease symptoms in latino individuals compared with anglo individuals.

Background: Latino individuals are the largest minority group and the fastest growing population group in the United States, yet there are few studies comparing the clinical features of Alzheimer disease (AD) in this population with those found in Anglo (white non-Latino) patients.

Objective: To compare the age at AD symptom onset in Latino and Anglo individuals.

Design: Cross-sectional assessment using standardized methods to collect and compare age at AD symptom onset, demographic variables, and medical variables.

The neural basis for novel semantic categorization.

We monitored regional cerebral activity with BOLD fMRI during acquisition of a novel semantic category and subsequent categorization of test stimuli by a rule-based strategy or a similarity-based strategy. We observed different patterns of activation in direct comparisons of rule- and similarity-based categorization. During rule-based category acquisition, subjects recruited anterior cingulate, thalamic, and parietal regions to support selective attention to perceptual features, and left inferior frontal cortex to helps maintain rules in working memory.

Validation of the WMS-III Facial Memory subtest with the Graduate Hospital Facial Memory Test in a sample of right and left anterior temporal lobectomy patients.

A number of studies have shown visuospatial memory deficits following anterior temporal lobectomy (ATL) in the right, nondominant temporal lobe (RATL). The current study examines 26 patients with intractable temporal lobe epilepsy who underwent ATL in either the right (RATL, n = 16) or left temporal lobe (LATL, n = 10) on two tests of facial memory abilities, the Wechsler Memory Scale-III (WMS-III) Faces subtest and the Graduate Hospital Facial Memory Test (FMT). Repeated measures ANOVA on the FMT indicated a significant main effect of side of surgery.

Functional MRI predicts post-surgical memory following temporal lobectomy.

Temporal lobectomy is an effective therapy for medically refractory temporal lobe epilepsy (TLE), but may be complicated by amnestic syndromes. Therefore, pre-surgical evaluation to assess the risk/benefit ratio for surgery is required. Intracarotid amobarbital testing (IAT) is currently the most widely used method for assessing pre-surgical memory lateralization, but is relatively invasive.

Dissociation of numbers and objects in corticobasal degeneration and semantic dementia.

Background: Semantic memory is thought to consist of category-specific representations of knowledge that may be selectively compromised in patients with neurodegenerative diseases, but this has been difficult to demonstrate reliably across object categories.

Methods: The authors evaluated performance on several simple measures requiring number representations (including addition and magnitude judgments of single digits), and on a task that requires object representations (an object naming task) in patients with corticobasal degeneration (CBD; n = 13) and semantic dementia (SD; n = 15). They also examined regional cortical atrophy using voxel-based morphometric analyses of high resolution structural MRI in subgroups of five CBD patients and three SD patients.

Visual processing impairments and decrements in regional brain activity in Alzheimer's disease.

The relationships between intermediate visual processes, involving object and space perception, and regional brain activity using positron emission tomography and single photon emission tomography were investigated in 16 patients with Alzheimer's disease. Significant region specific correlations were found between unfamiliar face matching and cerebral activity in the left occipito-temporal region and middle/inferior temporal regions bilaterally. Letter-word identification correlated significantly with brain activity in the angular gyri and occipital association cortices bilaterally, as well as a broad region of activation in the left hemisphere temporal, parietal and occipital lobes.

What's in a name: voxel-based morphometric analyses of MRI and naming difficulty in Alzheimer's disease, frontotemporal dementia and corticobasal degeneration.

Confrontation naming is impaired in neurodegenerative conditions like Alzheimer's disease (AD), frontotemporal dementia (FTD) and corticobasal degeneration (CBD). Some behavioural observations suggest a common source of impaired naming across these patient groups, while others find partially unique patterns of naming difficulty. We hypothesized that a large-scale neural network underlies naming, and that patterns of impaired naming in AD, FTD and CBD reflect cortical atrophy that interrupts this network in a manner that is partially shared and partially unique across these patient groups.

Memory for faces dissociates from memory for location following anterior temporal lobectomy.

It has been suggested that the right and left mesial temporal lobes are specialized for processing different types of information for long-term memory (LTM). Although findings have been consistent in regard to the dominant role of the left mesial temporal lobe (MTL) in verbal memory, the role of the right MTL in non-verbal memory remains debatable. Given the existence of two cortical pathways specialized for processing different types of visuospatial information, we examined whether memory processing for these two types of information might also be differentially localized.

Neural basis for verb processing in Alzheimer's disease: an fMRI study.

Patients with probable Alzheimer's disease (AD) have difficulty understanding verbs. To investigate the neural basis for this deficit, the authors used functional magnetic resonance imaging to examine patterns of neural activation during verb processing in 11 AD patients compared with 16 healthy seniors. Subjects judged the pleasantness of verbs, including MOTION verbs and COGNITION verbs.

Assessing nonverbal memory with the Biber Figure Learning Test-Extended in temporal lobe epilepsy patients.

Material-specific memory dysfunction was assessed using a nonverbal, visuospatial, supraspan learning test, the Biber Figure Learning Test-Extended (BFLT-E), in 71 left-hemisphere language-dominant epilepsy patients prior to anterior temporal lobectomy (ATL) and in 48 age-matched healthy subjects. Two matched forms of the BFLT-E yielded comparable scores, indicating that this task may be used to track memory performance over time in individual patients. Right temporal lobe epilepsy (RTLE) and left temporal lobe epilepsy (LTLE) patients performed below healthy subjects on all free-recall measures.

Whole-brain N-acetylaspartate level and cognitive performance in HIV infection.

Background And Purpose: In the brain of HIV-infected patients, proton MR spectroscopic studies are typically used to examine small volumes of tissue with single-voxel methods. Since brain disease is diffuse in patients with HIV, such studies preclude assessment of the true extent of the metabolic burden. To assess this extent, the relationship between global neuronal integrity, reflected by the whole-brain N-acetylaspartate (WBNAA) concentration, was correlated with neuropsychological function and the AIDS dementia complex (ADC) stage score.

Categorization of object descriptions in Alzheimer's disease and frontotemporal dementia: limitation in rule-based processing.

Studies of semantic memory in probable Alzheimer's disease (AD) have focused on the degradation of semantic knowledge, but other work in AD suggests an impairment in the semantic categorization processes that operate on this knowledge. We examined the categorization of object descriptions, where semantic category membership judgments were based on rule-based or similarity-based categorization processes. We found that AD patients were selectively limited in their semantic categorization under conditions requiring a rule-based approach.

Category-specific medial temporal lobe activation and the consolidation of semantic memory: evidence from fMRI.

Semantic memory consolidation was studied by comparing medial temporal lobe (MTL) fMRI activation to ANIMAL, IMPLEMENT and ABSTRACT nouns in healthy seniors to that of young adults. Relative to healthy seniors, young adults were predicted to show greater MTL activation for IMPLEMENTS, but not ANIMALS, because the ANIMALS category consists of highly intercorrelated and overlapping features that should require less MTL-mediated binding than IMPLEMENTS over a shorter period of time during concept consolidation. ABSTRACT meanings are context-dependent and do not consist of fixed feature sets.

Naming and recognizing famous faces in temporal lobe epilepsy.

Objective: To assess naming and recognition of faces of familiar famous people in patients with epilepsy before and after anterior temporal lobectomy (ATL).

Methods: Color photographs of famous people were presented for naming and description to 63 patients with temporal lobe epilepsy (TLE) either before or after ATL and to 10 healthy age- and education-matched controls.

Results: Spontaneous naming of photographed famous people was impaired in all patient groups, but was most abnormal in patients who had undergone left ATL.

Brain metabolism in the cerebellum and visual cortex correlates with neuropsychological testing in patients with Alzheimer's disease.

This study was designed to measure glucose metabolic deficits in areas not typically recognized as abnormal on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans in patients with Alzheimer's disease (AD), and to correlate such findings with subtle neuropsychological impairment. FDG-PET scans on 38 AD patients with no clinical evidence of visual, spatial or motor deficits were acquired on the PET HEAD scanner 40 min following the intravenous administration of 115 microCi.kg-1 of FDG.

Characteristics of patients initiated on the new antiepileptic drugs: a PADS study.

Whereas randomized controlled trials remain a standard for evaluating and comparing efficacy and safety of the new antiepileptic drugs (AEDs), postmarketing drug research offers a useful means of comparing efficacy and safety of new AEDs. However, differences in baseline characteristics of patients in different drug groups create the potential for bias in drug comparison studies. In this study, baseline demographic characteristics of 1,386 patients initiating lamotrigine (LTG), tiagabine (TGB), or topiramate (TPM) were compared to identify patient characteristics that may influence AED use in epilepsy patients.

Neural basis for semantic memory difficulty in Alzheimer's disease: an fMRI study.

Patients with probable Alzheimer's disease are thought to have a semantic memory deficit. We used functional MRI to evaluate the neural basis for impaired semantic memory for ANIMALS and IMPLEMENTS in 11 patients with Alzheimer's disease and 16 healthy seniors. For both categories of knowledge, Alzheimer's disease patients show reduced activation in the left posterolateral temporal-inferior parietal cortex compared with healthy seniors.

The neural basis for categorization in semantic memory.

We asked young adults to categorize written object descriptions into one of two categories, based on a rule or on overall similarity, while we monitored regional brain activity with functional magnetic resonance imaging (fMRI). We found significantly greater recruitment of left dorsolateral prefrontal cortex for rule-based categorization in direct comparison with similarity-based categorization. Recruitment of right ventral frontal cortex and thalamus was uniquely associated with rule-based categorization as well.

Visual perceptual functions predict instrumental activities of daily living in patients with dementia.

Objective: To assess relations between discrete visual perceptual functions commonly affected in patients with neurodegenerative dementia and the performance of instrumental activities of daily living (IADL).

Background: Neuropsychologic measures are often used to predict IADL performances in dementia patients. Prior studies have focused on the contribution of higher-level memory and executive deficits to IADL.