Biomedical subjects

J T Becker

Publications and source records attributed to J T Becker.

At least 19 recordsLinked to original sources

PubMed1999

Functional neuroanatomy of semantic memory: recognition of semantic associations.

In an effort to examine the functional neuroanatomy of semantic memory, we studied the relative cerebral blood flow of eight healthy young subjects using 15O-water positron emission tomography (PET). Relative to a visual baseline control condition, each of four visual matching-to-sample tasks activated components of the ventral visual processing stream, including the inferior occipital and temporal cortices. Contrasting the task with the highest semantic component, a variation on the Pyramids and Palm Trees paradigm, with a size discrimination task resulted in focal activation in the anterior inferior temporal lobe, focused in the parahippocampal gyrus. There was additional activation in BA47 of the inferior frontal cortex. These data replicate and extend previously reported results using similar paradigms, and are consistent with cognitive neuropsychological models that stress the executive role of BA47 in semantic processing tasks.

Adolescent↗

PubMed1999

Combined effects of HIV-infection status and psychosocial vulnerability on mental health in homosexual men.

The present study examines psychiatric symptomatology and syndromal depression among 174 HIV+ and 760 HIV- homosexual men enrolled in the Pittsburgh site of the Multicenter AIDS Cohort Study (MACS). A central study goal was to determine whether men's psychosocial status in the areas of demographics, social supports, and coping, in combination with their HIV-infection status, was associated with mental health. Cross-sectional analyses indicated that HIV+ men had significantly higher levels of psychiatric symptomatology and syndromal depression than HIV- men. However, multivariate analyses showed that these associations only appeared among HIV+ men with certain psychosocial characteristics. HIV+ men who were younger, lacked full-time employment, claimed relatively high support from their relatives, and demonstrated high use of active behavioral coping strategies were at greater risk for psychiatric symptomatology and/or syndromal depression. Further, sense of mastery and frequent use of avoidant coping strategies were highly predictive of psychiatric outcomes irrespective of HIV status. The findings suggest that knowledge of an individual's HIV status per se will be inadequate for valid assessment of psychological risks. Rather, any association of HIV status and mental health will depend largely on other psychosocial characteristics that foster vulnerability or resistance to distress in these men.

Adaptation, Psychological↗

PubMed1999

Neuropsychological test performance in the acquired immunodeficiency syndrome: independent effects of diagnostic group on functioning.

Individuals infected with the acquired immunodeficiency syndrome (AIDS) are at risk for developing cognitive impairment. The extent to which the impairment represents the results of a single factor accounting for a wide degree of cognitive dysfunction, or is the result of the combined effects of multiple factors, has not been determined. In the present study, we analyzed data from 134 patients with AIDS and 105 HIV- controls using a recently developed analytical procedure. The results revealed that, by and large, the test variables shared a significant amount of variance related to disease status. Hence the AIDS-related influences on cognition are shared and thus cannot be considered independent. Two tests, Digit Symbol Substitution, and the primary measure of verbal free recall, had a direct relationship with the group variable (AIDS vs. controls). These results suggest that a single factor is sufficient to account for a large proportion of the AIDS-related variance on a wide variety of neuropsychological tests.

AIDS Dementia Complex↗

PubMed1999

Neurological characteristics of HIV-infected men and women seeking primary medical care.

We examined the neurological differences between human immunodeficiency virus (HIV)-infected men (n = 193) and women (n = 41) receiving primary medical care. There was no difference between men and women in the rate of HIV-related neurological syndromes (i.e. polyneuropathy, myelopathy, myopathy, HIV- dementia [HAD]). A logistic regression analysis indicated that low CD4+ cell count predicted all neurological syndromes. In addition, HAD was predicted by intravenous-drug use and lower education level, while neuropathy was associated with older age and with race. These findings indicate that there are no differences in the rate of neuropsychiatric disorders attributable to gender. The presence of other factors (e.g. drug abuse) could explain previously reported gender differences in neurological manifestations of HIV infection.

AIDS Dementia Complex↗

PubMed1999

Plasma viral load and CD4 lymphocytes predict HIV-associated dementia and sensory neuropathy.

OBJECTIVE: To determine the predictive value of plasma HIV RNA and CD4 lymphocytes for HIV-associated dementia and sensory neuropathy. METHODS: A total of 1,604 AIDS-free HIV seropositive men from the Multicenter AIDS Cohort Study were followed over a 10-year period (1985 to 1995). HIV-associated dementia and sensory neuropathy were diagnosed according to standard definitions. Baseline samples were used to measure plasma HIV RNA levels with a branched DNA assay and levels of beta2-microglobulin, CD4 lymphocyte counts, and hemoglobin levels. RESULTS: Seventy-seven patients with HIV-associated dementia and 213 patients with sensory neuropathy were identified. Baseline HIV RNA levels above 3,000 copies/mL and CD4 counts below 500 cells/mm3 were predictive of both neurologic outcomes, but neither hemoglobin, body mass index, nor beta2-microglobulin were independently predictive. After adjusting for age and level of education, individuals with baseline plasma HIV RNA >30,000 copies/mL had a relative hazard for dementia 8.5 times (p < 0.001) that of those with <3,000 copies/mL, and those with CD4 counts <200 cells/mm3 had a 3.5-fold (p = 0.003) greater hazard relative to those with CD4 counts >500 cells/mm3. Individuals with HIV RNA >10,000 copies/mL had a 2.3-fold (p = 0.008) greater hazard of sensory neuropathy than those with <500 copies/mL, and men with <750 CD4 cells/mm3 had a 1.4-fold (p = 0.03) greater hazard than those with >750 CD4 cells/mm3. CONCLUSIONS: High levels of systemic HIV replication may "drive" the initiation of neurologic disease; effective suppression of HIV may reduce the incidence of dementia and neuropathy. Levels of plasma HIV RNA and CD4 counts, determined before the initiation of antiretroviral therapy, were predictive of HIV-associated dementia and sensory neuropathy.

AIDS Dementia Complex↗

PubMed1998

An examination of regional cerebral blood flow during object naming tasks.

The purpose of this study was to examine regional cerebral blood flow using positron emission tomography (PET) during the performance of tasks related to visual confrontation naming. Ten healthy, young participants were scanned twice in each of 5 conditions; blood flow was measured using standard PET [15O]-water technology. Two major findings have replicated previous studies. First, the naming of visually presented objects, whether covert or overt, requires a region of the left inferior cortex including the fusiform gyrus. Second, during overt naming, there is an increase in activity in the inferior or frontal cortex and insula as a consequence of generating speech code. These data are consistent with other studies demonstrating the importance of the inferior temporal regions for semantic processing, and the frontal cortex for word form generation.

Adult↗

PubMed1998

Independent effects of Alzheimer's disease on neuropsychological functioning.

A new analytical procedure, single common factor analysis, was carried out on the data from a relatively large sample of normals (n = 101) and patients with Alzheimer's disease (AD; n = 180) to examine the extent to which there were independent effects of disease status on different neuropsychological variables. This technique uses structural equation methods to determine what all of the variables have in common, and then controls this common factor when examining the relationship between diagnostic group and each individual test variable. To the extent that AD represents the sum of independent breakdowns of different information processing domains, then there should be sets of variables that have weak or nonexistent links to the other variables. However, the results revealed that a large proportion of the AD-related effects on test scores was shared and was not independent of the AD-related effects on other variables.

Aged↗

PubMed1998

Slowed information processing in HIV-1 disease. The Multicenter AIDS Cohort Study (MACS).

This investigation examined the effects of HIV-1 infection on speeded complex cognitive processing in a group of HIV-negative (n = 666), HIV-positive symptomatic (n = 156), and HIV-positive asymptomatic (n = 623) participants while controlling for the effects of slowed motor functioning, peripheral neuropathy, and several other putative confounds. Stroop Interference and reaction-time tasks served as anchor procedures to assess cognitive processing. The present findings suggest that HIV-1 infection is capable of compromising CNS-mediated cognitive processes (speeded processing) infringing upon their efficacy in the symptomatic stages of the disease while sparing individuals in the asymptomatic stage. The detrimental effects observed on information-processing mechanisms associated with HIV infection persisted despite the use of procedures to control for peripheral nerve integrity and other potential confounds.

AIDS Dementia Complex↗

PubMed1998

Apolipoprotein E polymorphism in Alzheimer's disease: a comparative study of two research populations from Spain and the United States.

We examined the distribution of the apolipoprotein E (APOE) polymorphism in two Caucasian populations of Alzheimer's disease (AD) patients referred to dementia clinics; one in Gerona, Spain (66 AD patients, 49 controls), and the other in Pittsburgh, Pa., USA (209 AD patients, 58 controls). The presence of the APOE*4 allele was a significant risk for developing AD in both cohorts: Gerona (odds ratio = 2.34, CI: 1.03-5.55) and Pittsburgh (odds ratio = 3.64, CI: 1.78-7.69). The proportion of AD with the APOE*4 allele was greater in the Pittsburgh cohort than in the Gerona cohort (p = 0.02). However, no statistical difference was noted between the two populations in nondemented controls (p = 0.41). These data emphasize the importance of geographical and ethnic variations in the study of APOE genotypes.

Aged↗

PubMed1998

Neurobehavioral correlates of perceived mental and motor slowness in HIV infection and AIDS.

The authors assessed 72 human immunodeficiency virus (HIV)-infected patients with a self-rating slowness scale (SRSS) concerning mental and motor slowness in their activities of daily living. In order to understand the relationship between complaints of slowness and predictor variables, the investigators developed a preliminary model using multiple regression analysis. Reports of slowness on the SRSS were independently associated with self-reported cognitive and neurological symptoms and with peripheral neurological syndromes (e.g., neuropathy, myopathy). Lesser contributions to self-perceived mental and motor slowness were found for neuropsychological measures of information processing speed, severity of the infection, depression, HIV encephalopathy, and sociodemographic factors (e.g., age, education). The relationship among the predictor variables showed that complaints of slowness reflect neurological, psychiatric/psychological, and cognitive symptomatology of the HIV infection.

AIDS Dementia Complex↗

PubMed1998

Cognition and aging in a complex work environment: relationships with performance among air traffic control specialists.

Chronological age affects the performance of demanding cognitive tasks within the aviation environment. Within the domain of air traffic control (ATC), the ability to handle simultaneous visual and auditory input, or to return to a task after a break to complete another task, is critical to success and is the sort of cognitive function most affected by age. The limited available data suggest a strong relationship between age and job performance among ATC specialists, whether measured at the time of entry into the system or during the working lifetime of a full-performance-level controller. An analysis of the distribution of the ages of controllers currently in the system, and a projection for the years 2001 and 2006, leads to the conclusion that a high proportion of the ATC work force will be at risk for displaying age-related changes in job performance efficiency over the next 10 yr. It seems important, therefore, to determine the nature and extent of the age-related cognitive changes that can occur during the lifespan of a controller (i.e., 25-55 yr of age) and how these changes may affect job performance. The results of such an analysis should aid in the design and implementation of new control systems to minimize any deleterious effects of aging on performance.

Adult↗

PubMed1997

Extrapyramidal signs in patients with probable Alzheimer disease.

OBJECTIVE: To examine whether extrapyramidal signs (EPSs) were associated with more rapid progression of Alzheimer disease (AD). DESIGN: Cross-sectional with longitudinal follow-up and the likelihood of arriving at 4 end points: Mini-Mental State Examination score of less than 9, Blessed Dementia Rating Scale score for activities of daily living of 15 or more, institutionalization, and death using a proportional hazard model with 6 variables: overall EPSs, bradykinesia, tremors, abnormal gait, cogwheel rigidity, and postural instability. SETTING: Multidisciplinary behavioral neurology research clinic. PATIENTS: We examined the individual EPS characteristics of 164 patients with mild-moderately probable AD, free of neuroleptic medication, participating in a longitudinal study of dementia. RESULTS: Patients with AD with EPSs (n= 51 [31%]) were older (P>.001) and had lower Mini-Mental State Examination scores (P=.003) than those without EPSs at study entry. Bradykinesia was present in 35 (69%) of the 51 patients with EPSs, abnormal gait in 18 (35%), rigidity in 10 (20%), postural instability in 10 (20%), tremors in 7 (14%), and oral-mandibular dyskinesia in 2 (4%). Using proportional hazard analysis with time-dependent covariates for overall EPSs and individual EPSs, adjusted by age at study entry, education, Mini-Mental State Examination score, and Blessed Dementia Rating Scale score for activities of daily living, the development of EPSs was associated with time to institutionalization (P<.001) but not with cognitive (eg, Mini-Mental State Examination score <9) or functional (eg, Blessed Dementia Rating Scale score > or = 15) decline or death. However, when we examined severity of the EPSs, as measured by the New York University Parkinson's Disease Scale, the development of EPSs was associated with functional decline (P=.005). Of the individual EPSs, rigidity predicted death (P<.001) and institutionalization (P=.03), whereas tremors predicted functional decline (P=.02). CONCLUSIONS: In this cohort, the presence or absence of EPSs is related to time to institutionalization, but not to severe cognitive or functional impairment or death. However, when severity of the extrapyramidal phenomenon is taken into account, EPSs are related to functional decline. Further, it appears that a subgroup of patients with AD with EPSs, where cogwheel rigidity and tremors are the core signs, can have a worse outcome.

Aged↗

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↗