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J T Becker

Publications and source records attributed to J T Becker.

At least 55 records · Page 3Linked to original sources
PubMed1997

Regional cerebral blood flow during word and nonword reading.

The purpose of this study was to examine changes in regional cerebral blood flow (rCBF) using positron emission tomography (PET) during overt word and nonword reading tasks to determine structures involved in semantic processing. Ten young, healthy, right-handed subjects were scanned 12 times, twice in each of six specific conditions. Blood flow was measured by 15O-water using standard PET imaging technology. The rCBFs during different cognitive conditions were compared by using analysis of covariance (SPM94), which resulted in three-dimensional maps of those brain regions more active in one condition relative to another. When the subjects read aloud words with difficult or unusual grapheme-phoneme translations (i.e., third-order approximation to English or irregularly spelled real words), increases in activation were seen in the inferior frontal cortex. When subjects were reading aloud regular and irregular words (which had important semantic components relative to nonwords), activation of the fusiform gyrus was seen. These data are broadly consistent with brain regions generally associated with reading based on other neuropsychological paradigms, and they emphasize the multicomponent aspects of this complex cognitive process.

Adolescent↗
PubMed1997

Prevalence and predictors of depressive, anxiety and substance use disorders in HIV-infected and uninfected men: a longitudinal evaluation.

BACKGROUND: There is little agreement on whether the prevalence of psychiatric disorder is elevated in HIV-seropositive (HIV+) populations compared with uninfected persons. However, evaluation of this issue has been limited difficulties of sampling, study design and failure to control for other risk factors for disorder. METHODS: Prevalence and clinical characteristics of DSM-III-R major depressive disorder (MDD), generalized anxiety disorder, adjustment disorder, and alcohol and substance abuse/dependence were evaluated in a representative sample of HIV+ men attending primary care physicians' offices in a defined geographical area. Lifetime prevalence at baseline and 1-year rates during longitudinal follow-up were determined for the 113 HIV+ men, as well as 57 HIV-men, via standardized interview. Multivariate analyses considered unique and combined effects of HIV serostatus and other risk factors on likelihood of disorder. RESULTS: Although there were no differences in lifetime rates prior to baseline, HIV+ men were at greater risk for disorders during the prospective study period. For MDD, this effect was maintained even after controlling for other risk factors. Several of these other factors bore their own effects: regardless of HIV serostatus, men were susceptible to psychopathology if at baseline they were younger, had a lifetime psychiatric history, or had poor social supports or a low sense of personal mastery. CONCLUSIONS: The risk of certain psychiatric disorders appears uniquely elevated in HIV+ men. Since other factors also influence risk, interventions designed to minimize psychopathology during HIV infection should attend to both HIV-related and non-HIV-related risk factors.

Adaptation, Psychological↗
PubMed1997

Neuropsychological abnormalities among HIV-infected individuals in a community-based sample.

The purpose of this study was to determine the nature and extent of neuropsychological abnormalities among HIV-infected individuals and to examine the interrelationships between measures of cognitive functions and the factors that predict neuropsychological abnormalities. The study focused on cross-sectional data gathered in a multidisciplinary research clinic form 200 HIV-infected (HIV +) men and women recruited from primary medical care settings. Composite scores representing six cognitive domains were derived from the neuropsychological test data. Scores of memory, fluency, spatial, and frontal functions could be predicted by independent assessment of participants' verbal and psychomotor speed abilities. Basic verbal ability itself was predicted by education, race, and handedness, whereas speed was predicted by age, CD4+ cell counts, and a lifetime history of major depression. This model of effects is consistent with the hypothesis that psychomotor slowing is central to mild cognitive disorder in HIV infection and that such changes are associated with markers of the severity of systemic infection.

Adult↗
PubMed1997

Psychiatric correlates of MR deep white matter lesions in probable Alzheimer's disease.

The authors examined the relationship between psychiatric symptoms and the presence of of MR deep white matter lesions (DWMLs) in 28 probable Alzheimer's disease (AD) patients with mild to moderate dementia. The difference in frequency of psychiatric symptoms between patients with and without DWMLs was not statistically significant. However, MR global scores of severity correlated with the presence of ideational disturbances (such as low self-esteem and suicidal ideation). Analysis of specific cerebral regions indicated that the highest correlation occurred in the frontal white matter. Thus, DWMLs are correlated with specific symptoms of depression in AD. Whether DWMLs are etiologically related to these symptoms remains to be determined.

Aged↗
PubMed1997

EEG spectral abnormalities and psychosis as predictors of cognitive and functional decline in probable Alzheimer's disease.

We examined whether either psychotic features (e.g., delusions and hallucinations) or EEG abnormalities are associated with more rapid progression of Alzheimer's disease (AD). AD patients with psychosis have exhibited more EEG abnormalities than those without psychosis, and both abnormal EEG and psychosis have been noted to be predictors of functional and cognitive decline in AD. Ninety-five probable AD patients participating in a longitudinal study of dementia had an EEG and a semistructured psychiatric interview at baseline. Using EEG spectral analysis, we classified records as normal/abnormal based on the parasagittal mean frequency. Patients with abnormal EEGs were more functionally (e.g., Blessed Rating Scale for activities of daily living) and cognitively (e.g., Mini-Mental State) impaired than patients with normal EEG. AD patients with psychosis were only more functionally impaired than patients without psychosis. A two-factor analysis showed no interaction between abnormal EEG and psychosis. In addition, using a Cox proportional hazard model adjusted for age and education, the presence of an abnormal EEG or psychotic symptom at study entry was associated with higher risk of reaching severe cognitive and functional impairment during follow-up. Neither abnormal EEG nor the presence of psychosis predicted death. These results indicate that both abnormal EEG and psychosis are independent predictors of disease progression but not of physical survival.

Aged↗
PubMed1997

The apolipoprotein E epsilon 4 allele is not associated with psychiatric symptoms or extrapyramidal signs in probable Alzheimer's disease.

The objective of our study was to examine the relationship between the presence of the apolipoprotein E (apo E) epsilon 4 allele, psychiatric symptoms, and extrapyramidal signs (EPS) in probable Alzheimer's disease (AD). The apo E epsilon 4 allele modifies the risk and age at onset of AD. However, it still needs to be determined whether it is a marker for specific clinical subgroups. The frequency of clinical signs and symptoms was examined in 194 AD patients with the apo E epsilon 3/3 (N = 79), epsilon 3/4 (N = 96), and epsilon 4/4 (N = 19) genotypes participating in a longitudinal study of dementia. Each patient was assessed with semistructured psychiatric and neurologic examinations. Patients with the epsilon 4/4 genotype had an earlier age at onset of dementia (p = 0.03). However, no individual psychiatric symptom or neurologic sign was associated with the presence of the apo E epsilon 4 allele, including major depression (odds ratio [OR], 1.14; CI, 0.50 to 2.45; p = 0.78), psychosis (e.g., delusions and hallucinations) (OR, 0.66, CI, 0.35 to 1.25; p = 0.20), and EPS (in neuroleptic-free patients) (OR, 0.82, CI, 0.45 to 1.49; p = 0.52), after controlling by age at onset, duration of the symptoms, education, and severity of dementia. The presence of the apo E epsilon 4 allele has limited utility in the characterization of neurologic and psychiatric subgroups in probable AD patients. The apo E epsilon 4/4 genotype appears to be related to age at onset of AD, consistent with previous findings.

Age of Onset↗
PubMed1997

Do homosexual and bisexual men who place others at potential risk for HIV have unique psychological profiles?

Prevention of HIV infection requires individuals to attend not only to their own risk but also whether they place others at risk. To design appropriate interventions, however, it is important to determine whether HIV positive and HIV negative individuals who place others at potential risk differ in their psychological profiles. Such differences would suggest the need for specially tailored interventions for each group. We studied 525 homosexual and bisexual men (156 HIV positive, 369 HIV negative) from the Multicenter AIDS Cohort Study (Pittsburgh site) to (a) identify correlates of risky behavior and (b) determine whether these correlates differed by HIV serostatus. Although HIV positive men were somewhat less likely than HIV negative men to have engaged in high-risk sexual activity in the past 6 months (e.g., unprotected insertive anal intercourse), the correlates of such activity were identical across groups. Regardless of serostatus, men placing others at potential risk were younger, less educated, had less psychological distress and greater feelings of mastery, employed fewer active behavioral coping strategies, and were heavier users of alcohol and amyl nitrate (poppers).

Adaptation, Psychological↗
PubMed1997

On the relationship between knowledge and memory for pictures: evidence from the study of patients with semantic dementia and Alzheimer's disease.

Current views of long-term memory presume that both the hippocampal complex and the neocortex play interactive, but separate, roles in the storage of memories. While the neocortex is considered the eventual and permanent store for our memories, the encoding of recently experienced events is thought to be initially dependent upon the hippocampus and closely related structures. Neuropsychological studies have demonstrated that damage to the medial temporal lobe results in a retrograde amnesia extending back in time, with better preservation of older memories. The converse pattern has been shown in patients with semantic dementia, who have focal atrophy of the inferolateral temporal neocortex, but relative sparing of the hippocampal complex (Graham & Hodges, 1997). Here we demonstrate that such patients can show relatively preserved new learning on a forced-choice recognition memory test (based on real and chimeric animals), while patients in the early amnestic phase of Alzheimer's disease show severely impaired learning on the same test. This result provides support for the view that new learning is primarily dependent upon the hippocampus and related structures.

Alzheimer Disease↗
PubMed1996

Alterations in functional neuroanatomical connectivity in Alzheimer's disease. Positron emission tomography of auditory verbal short-term memory.

Conscious recall of past events which have specific temporal and spatial contexts, termed episodic memory, is mediated by a system of interrelated brain regions. In Alzheimer's disease (AD) this system breaks down, resulting in an inability to recall events from the immediate past. Studies of normal human auditory-verbal short-term memory suggest that the brain system underlying these processes has distinct components, and the present study utilized the methods of functional brain mapping to determine the nature and extent of the breakdown that occurs in AD. Using subtraction techniques of PET-acquired images of regional cerebral blood flow we demonstrate that AD patients show a compensatory hyperactivation of various regions of cerebral cortex normally involved in these tasks, as well as activation of cortical areas not activated by normal elderly subjects. These results provide clear evidence of functional plasticity in the AD patient's brain even if those changes do not result in normal memory function.

Aged↗
PubMed1996

Functional connectivity in auditory-verbal short-term memory in Alzheimer's disease.

Alzheimer's disease (AD) patients show normal patterns of regional cerebral blood flow during performance of subspan verbal memory tasks, but appear to allocate new brain regions when performing supraspan recall tasks. To understand the relationships among these interconnected brain regions, their functional connectivity was considered using principal components analysis (PCA). AD patients and controls were scanned in four conditions: visual fixation only and visual fixation with one-word recall, three-word recall, and eight-word recall. When applied to the data from the three recall task conditions (i.e., eliminating fixation), PCA revealed a significant first component accounting for 75.8% of the variance in the control data and 66.8% of the variance in the patient data. The one-word recall condition had a high positive component score, and the eight-word condition a high negative score. The correlations of individual voxels on this factor (i.e., spatial modes) were very similar between the patients and the controls. The overall similarity in the results of the PCAs between the patients and the controls suggests that they have similar functional connectivity. This would suggest that, at least in the early course of the dementia, the functional CNS organization of verbal memory systems remains normal.

Aged↗
PubMed1996

Development of subtle neurological signs after systemic illness in HIV-infected individuals.

Thirty human immunodeficiency virus (HIV) infected individuals entered a longitudinal study without signs of dysfunction of the central nervous system (CNS). Nine of these individuals developed a systemic illness between study visits, and 7 of these 9 patients (78%) had neurological signs at the next examination (e.g., action-intention tremors, abnormal gait, release signs, abnormal deep tendon reflexes). Only 2/21 (9.5%) of the subjects who did not develop systemic illness showed such signs. These data are consistent with the hypothesis that other factors (e.g. cytokines) as well as the HIV may cause subtle CNS dysfunction.

AIDS Dementia Complex↗
PubMed1996

Focal temporal lobe dysfunction in probable Alzheimer's disease predicts a slow rate of cognitive decline.

The memory disorder in Alzheimer's disease (AD) can be described as having two components: one primarily a defect in secondary memory and the other a defect in executive processes. We compared and contrasted the pattern of neuropsychological impairment in AD patients as a function of their memory and executive deficits. A K-Means cluster analysis identified four groups of patients. All four groups had impaired episodic and semantic memory and three had progressively more severe impairments in executive functions. The fourth group had normal executive functions; this group (N=32), described as having a "temporal lobe" pattern of impairment, had a significantly slower rate of progression of their dementia, with visual-construction skills virtually spared. These data demonstrate the existence of a subgroup of AD patients with a consistent pattern of impairment who progress more slowly than other patients over the course of 2 years and who maintain some specific cognitive abilities. This suggests that the mechanism of their disease may be different.

Aged↗
PubMed1996

Compensatory reallocation of brain resources supporting verbal episodic memory in Alzheimer's disease.

Conscious recall of past events that have specific temporal and spatial contexts, termed episodic memory, is mediated by a system of interrelated brain regions. In Alzheimer's disease (AD) this system breaks down, resulting in an inability to recall events from the immediate past. Using subtraction techniques with PET-acquired images of regional cerebral blood flow, we demonstrate that AD patients show a greater activation of regions of cerebral cortex normally involved in auditory-verbal memory, as well as activation of cortical areas not activated by normal elderly subjects. These results provide clear evidence of functional plasticity in the AD patient's brain even if those changes do not result in normal memory function, and provide insights into the mechanism by which the AD brain attempts to compensate for neurodegeneration.

Aged↗
PubMed1995

Computed tomography--but not magnetic resonance imaging--identified periventricular white-matter lesions predict symptomatic cerebrovascular disease in probable Alzheimer's disease.

OBJECTIVE: To examine the clinical consequences of periventricular white-matter lesions on computed tomography (CT) and magnetic resonance imaging (MRI) scans in probable Alzheimer's disease. DESIGN: Case series, 12-month follow-up. SETTING: Multidisciplinary behavioral neurology research clinic. PATIENTS: We longitudinally evaluated the clinical characteristics of 27 patients with probable AD for whom both CT and MRI scans had been performed at baseline. INTERVENTIONS: None. MAIN OUTCOME MEASURE: The presence of abnormal neurological signs was examined at baseline and at a 12-month examination. RESULTS: Periventricular white-matter lesions were observed with CT in 12 patients (44%) and with MRI in 21 patients (78%). Computed tomography did not detect lesions of 1 to 3 mm, as were seen on MRI scans, and CT also did not detect lesions of 4 to 10 mm when they occurred in the deep subcortical white matter and were not part of a greater confluent lesion. There was no relationship between the severity of periventricular white-matter lesions with either neuroimaging method and the presence of abnormal neurological signs. However, there was a greater frequency of periventricular white-matter lesions shown on CT scans than on MRI scans at baseline in patients in whom abnormal neurological signs (eg, abnormal gait, asymmetric deep tendon reflexes, focal motor deficits, abnormal plantar response) developed at 12-month follow-up. CONCLUSION: Although MRI may be more sensitive in detecting periventricular white-matter lesions, CT is more specific in predicting subsequent symptomatic cerebrovascular disease.

Aged↗
PubMed1995

Understanding impaired analysis of faces by patients with probable Alzheimer's disease.

The purpose of this study was to analyze the facial recognition skills of patients diagnosed with Probable Alzheimer's Disease (AD). The performance of 181 AD patients was evaluated to address their ability to: analyze visual forms, to discriminate individual faces, and to recognize and name familiar famous faces. The results of the study demonstrate that the ability to analyze visual information is more vulnerable early in dementia than is the ability to discriminate individual faces. The inability to recognize familiar faces among the AD patients was related to impairments of their lexical/semantic system, rather than to a specific defect in facial discrimination. These data are fully consistent with existing models of face processing and recognition, and suggest that the recognition defect in AD is related to the naming component of face recognition, rather than the perceptual component.

Aged↗
PubMed1995

Methodological considerations in estimating speed of cognitive operations.

Individuals infected with Human Immunodeficiency Virus (HIV) and having cognitive impairment have been described as having slow mentation. Data supporting this proposition come from a variety of sources, including Sternberg's (1966) item recognition memory task. The procedure nominally provides an index of speed of mental operations, independent from input/output demands. However, since the original use of this procedure in the 1960s, advances in cognitive psychology have revealed many of its limitations. The purpose of the present study was to examine the psychometric characteristics of this task. Each participant performed the Sternberg item recognition task twice, 6 mo apart. The stability of the estimate of the slope of regression equations and for zero intercept ranged from excellent (r = .87) to poor (r = .30), and the data from many individual subjects could not be reliably modelled using multiple linear regression techniques. These data, as well as those from previous research, demonstrate the limited practical use of this task in clinical samples. Furthermore, as cognitive psychological theory has advanced in the past 30 yr, the conceptual underpinnings of the procedure have essentially evaporated.

AIDS Dementia Complex↗
PubMed1995

Qualitative features of the memory deficit associated with HIV infection and AIDS: cross-validation of a discriminant function classification scheme.

The neuropsychological defects associated with late stage HIV infection and AIDS have been characterized as being similar to those seen in patients with dementia syndromes of subcortical etiologies. The purpose of this paper is to report on the cross-center replication of the classification of HIV-infected subjects' neuropsychological status based on a discriminant function generated from other HIV-related and unrelated cognitively impaired subjects. Of the HIV-control subjects, 42/46 (91.3%) were classified as "Normal", with only two subjects in each of two "dementia" groups: subcortical and cortical. However, similar to other HIV+ samples, a large proportion (36%) of our HIV-infected subjects were classified as "Subcortical", with 61% classified as "Normal", and one (3%) in the "Cortical" group. These data demonstrate that not only does the cognitive performance of some HIV+ subjects have distinct features relative to that of HIV-control subjects, but that the features are consistent with previous suggestions that such patients have a "Subcortical" pattern of impairment.

Acquired Immunodeficiency Syndrome↗