Biomedical subjects

M Oscar-Berman

Publications and source records attributed to M Oscar-Berman.

At least 19 recordsLinked to original sources

PubMed2006

Bioequivalence study of two fluoxetine capsule formulations in healthy Middle Eastern volunteers.

OBJECTIVE: To assess the bioequivalence of two fluoxetine hydrochloride capsule (20 mg) formulations (Fluoxicare capsule from Pharmacare Ltd., Chemicals and Cosmetics, Ramallah, Palestine, as test formulation, and Prozac from Eli Lilly Ltd., Basingstoke, UK, as reference formulation). DESIGN AND METHODS: The study was conducted open with a randomized 2-period crossover design and a 6-week washout period. Participants were 24 healthy male volunteers aged 18-28 years, divided into 2 groups of 12 subjects. One group was given the originator drug (reference formulation), and the other was given the test formulation. Blood samples were obtained at baseline and at 14 time points during the interval 0-96 hours after drug administration. The concentrations of the samples were assayed spectrophotometrically at 220 nm using a Shimadzu 160 A UV-visible spectrometer. We calculated the plasma concentration-time curve (AUC), maximum plasma concentration (Cmax), and time of maximum plasma concentration (tmax) for each subject. Logarithmic transformation of the AUC and Cmax was used for the statistical analyses and to assess the bioavailability of the two formulations, using analyses of variance (ANOVA) and Satherwait t-tests for unequal variances. The ANOVA performed of tmax in Cmax, and in AUC provided the appropriate intra-subject variance estimates to evaluate the 90% confidence intervals for the differences between study variables after administration of the test and reference formulations. Statistical analyses were conducted on AUC 0-4 as the extrapolated part of the AUC, a truncated area approach was adapted. RESULTS: The mean pharmacokinetic parameters for both of the drugs under study were as follows: Cmax = 61.24 (+/- 12.96) ng/ml for the test formulation, and for the reference formulation Cmax = 61.39 (+/- 14.1) ng/ml, the effects were statistically equivalent. The tmax for the test formulation was 8.25 (+/- 1.7) and 7.33 (+/- 0.96) for the reference formulation. The area under the curve to infinity (AUC 0-infinity (ng, day/ml)) for the test formulation and for the reference formulation were 293.02 (+/- 52.69) and 296.15 (+/- 61.69), respectively. CONCLUSIONS: The two formulations had equivalent pharmacokinetic parameters, were well-tolerated, and their relative bioavailability was 98.94%.

Adult↗

PubMed2001

Measures of prefrontal system dysfunction in posttraumatic stress disorder.

Clinical observations have suggested that individuals who have suffered traumatic stressful events exhibit disruption in abilities mediated by frontal brain systems. Therefore, this study employed tasks sensitive to frontal lobe dysfunction, including delayed response (DR), delayed alternation (DA), object alternation (OA), delayed matching-to-sample (DMTS), and delayed nonmatching-to-sample (DNMTS), with participants having posttraumatic stress disorder (PTSD). Compared to controls, the PTSD participants were unimpaired on DA and DMTS, but they showed deficits on DR, OA, and DNMTS tasks. This pattern of results suggests disruption of functioning in selective prefrontal brain systems. Results are discussed in the context of the neuropsychological features of PTSD, as well as possible neuropathological and etiological underpinnings of this disorder.

Adult↗

PubMed2001

Selective attentional processing and the right hemisphere: effects of aging and alcoholism.

Thirty-seven nonalcoholic individuals (22 women, 15 men), ages 26-76, and 36 abstinent alcoholic individuals (11 women, 25 men), ages 31-74, participated in a cued-detection task that assessed right hemisphere (RH) functioning associated with aging and alcoholism. Young controls were less reliant on cues following RH activation, which is consistent with the view that the RH has an advantage because it has the ability to attend to a broader spatial array than does the left hemisphere (LH). This RH advantage was not obtained in older controls or alcoholic participants. The pattern of results for the older nonalcoholic participants indicated that they neither benefited from valid cues following LH activation nor exhibited enhanced processing on invalid cue trials following RH activation. The results for the alcoholic participants were consistent with RH functional decline, but did not support the view that alcoholism and aging have synergistic effects.

Adult↗

PubMed2000

Hypoperfusion of inferior frontal brain regions in abstinent alcoholics: a pilot SPECT study.

OBJECTIVE: This pilot study evaluated hypotheses concerning the relationship between cerebral hypoperfusion and residual deficits in the functioning of frontal brain systems in abstinent long-term alcoholics. METHOD: The participants (N = 22) were 10 healthy, abstinent alcoholics (9 men) and 12 age-equivalent nonalcoholic controls (10 men). Cerebral blood flow was observed through the use of regionally specific computer-derived quantitative analysis of single photon emission computed tomography (SPECT) perfusion images. Measures of alcohol use, abstinence and neuropsychological functioning were also obtained to relate to SPECT findings. RESULTS: A positive relationship was observed between perfusion levels in the left inferior frontal brain region and years of sobriety. Alcoholics with less than 4 years of sobriety had significantly reduced left inferior frontal perfusion compared with both nonalcoholic controls and alcoholics having longer periods of sobriety. CONCLUSIONS: The findings support the hypothesis that frontal brain abnormalities in alcoholics may subside with extended abstinence.

Adult↗

PubMed1999

Comparing visual perception on conventional cabinet tachistoscopes and computer monitor tachistoscopes.

Computer monitor-based tachistoscopes (using a cathode ray tube, CRT) and conventional tachistoscopes differ in experimental control over stimulus continuity, duration, and timing accuracy. This study evaluated the perception of visual stimuli presented with the two different types of devices. An experiment was conducted to compare recognition of visuospatial stimuli (random shapes) presented laterally and centrally in the visual fields for short exposure durations (14, 29, and 43 msec), first with one device and then with another. Results indicated that the subjects' error rates and laterality patterns were similar on both types of tachistoscopes. It was concluded that perception of visual stimuli presented as continuous images on a conventional tachistoscope may be equivalent to perception of visual stimuli presented as pulsating images on a CRT. Further studies are needed using other types of visual materials to determine the range of visual stimuli for which both types of tachistoscopes measure equivalent perceptual processes.

Adolescent↗

PubMed1999

Hypoperfusion of the cerebellum and aging effects on cerebral cortex blood flow in abstinent alcoholics: a SPECT study.

BACKGROUND: This study evaluated hypotheses concerning alcoholism, aging, and the relationship between cerebral hypoperfusion and residual deficits in the functioning of cerebellar and neocortical brain systems. METHODS: The participants were 10 healthy abstinent alcoholics (9 men, 1 woman) and 12 nonalcoholic controls (10 men, 2 women) ranging in age from 35 to 67 years. Cerebral blood flow was observed through the use of regionally specific computer-derived quantitative analysis of single photon emission computed tomography (SPECT) perfusion images. Cerebellar perfusion was measured and compared with cerebral cortex perfusion in age-equivalent subgroups of alcoholics and controls (under 55 years; 55 years and over). RESULTS: In abstinent alcoholics under age 55, cerebellar perfusion ratios were significantly reduced compared with the controls. In alcoholics and nonalcoholic controls 55 years old and older, this relationship was reversed, probably as a result of diminished cortical perfusion with aging in the alcoholics and of cerebellar decline in the controls. CONCLUSIONS: The findings support hypotheses that the residual effects of alcoholism include cerebellar brain abnormalities and that aging combined with long-term alcoholism leads to cerebral cortical decline.

Adult↗

PubMed1997

Association learning and recognition memory in alcoholic Korsakoff patients.

Association learning and recognition memory were examined in 8 male alcoholic Korsakoff patients (mean age 58), and in the following 4 groups of 10 men: non-Korsakoff alcoholics (mean age 59), nonalcoholic controls (mean age 64), younger alcoholics (mean age 36), and nonalcoholic controls (mean age 37). The tasks were modeled after those used for testing memory functioning in nonhuman primates. Association learning, defined as the ability to distinguish rewarded from equally familiar nonrewarded visual stimuli, was impaired in Korsakoff patients. Korsakoff patients also were impaired on recognition memory-the ability to discriminate familiar from novel items. Results support the view of loss of multiple memory functions in alcoholic amnesia. An effect of aging was indicated by differences in performance levels between younger and older groups of non-Korsakoff participants, although the latter were superior to the Korsakoff patients.

Adult↗

PubMed1997

Impairments of brain and behavior: the neurological effects of alcohol.

Chronic heavy drinking and alcoholism can have serious repercussions for the functioning of the entire nervous system, particularly the brain. These effects include changes in emotions and personality as well as impaired perception, learning, and memory. Neuropathological and imaging techniques have provided evidence of physical brain abnormalities in alcoholics, such as atrophy of nerve cells and brain shrinkage. At the cellular level, alcohol appears to directly affect brain function in a variety of ways, primarily by interfering with the action of glutamate, gamma-aminobutyric acid, and other neurotransmitters. Neurological disorders also can result from vitamin deficiency and liver disease, two health problems that commonly occur with alcoholism. Other hypotheses, based on factors such as aging, gender, and genetics, have been developed to explain various alcohol-related neurological consequences. Many pharmacological treatments to improve neuropsychological functioning in alcoholics have been tested, but none has proved entirely successful. With prolonged abstinence, however, slow recovery of cognitive functioning can occur in some cases.

Alcohol Drinking↗

PubMed1997

Breakdown of cross-modal function in dementia.

To evaluate the possibility that specific language abnormalities in dementia are related to impaired cross-modal ability, the authors studied patients with Alzheimer's disease (which is characterized by a generalized language breakdown or aphasia) and patients with Parkinson's disease and dementia (a disorder associated more with selective deficits in naming than with aphasia). Both groups were initially equated for severity of dementia. Compared with nondemented patients with Parkinson's disease and age-equivalent healthy controls, patients with Alzheimer's disease and Parkinson's disease with dementia showed significant deficits in cross-modal ability. Moreover, the cross-modal deficits were significantly associated with object-naming ability. Results support the concept that language capacity and cross-modal functions are interrelated.

Aged↗

PubMed1996

Measures of prefrontal dysfunction after closed head injury.

Tasks sensitive to frontal lobe dysfunction (delayed response, delayed alternation, object alternation, and Wisconsin Card Sort) were administered to 20 patients with post-acute closed-head injury (CHI). Time since injury varied (6 to 280 months; mean, 48 months), as did length of coma (2 hr to 120 days; mean, 38 days). Compared to normal controls, CHI patients showed no deficits on delayed response tasks, but were impaired on delayed alternation, object alternation, and the Wisconsin Card Sort Test. Analyses of the performance profiles of the CHI patients suggested that they may have difficulty in establishing set (a consequence of damage to the orbitofrontal system).

Adult↗

PubMed1996

Visual laterality patterns for the perception of emotional words in alcoholic and aging individuals.

OBJECTIVE: This study evaluated hypotheses concerning alcohol-related cerebral dysfunction: (1) alcoholism, like normal chronological aging, has a more detrimental effect upon functions controlled by the right hemisphere of the brain than functions controlled by the left hemisphere; (2) interhemispheric transfer dysfunction is associated with alcoholism and aging; and (3) alcoholism and aging act synergistically. METHOD: The participants were 61 right-handed men: 18 young (ages 30 to 49 years) and 14 older (50 to 69 years) detoxified abstinent alcoholics and 14 young and 15 older healthy nonalcoholic controls. In a perceptual laterality paradigm, emotional and nonemotional words were presented to the left or right visual fields, followed by a visual masking stimulus. The participants were asked to judge the emotional valence of each word (positive, negative or neutral) and to respond verbally or manually (button presses). The dependent variable was the Critical Interstimulus Interval needed to escape the backward-masking effect. RESULTS: The alcoholics showed a significant right visual field advantage in both response mode conditions, whereas the controls did not. In addition, older alcoholics showed a selective impairment in processing negative words. CONCLUSIONS: The findings support the suggestion that alcoholics may have deficient right-hemisphere functioning. Since both the young and older alcoholic groups showed similar right visual field advantages, the idea of synergism between alcoholism and aging with respect to perceptual asymmetries was not supported.

Adult↗

PubMed1994

A comparative neuropsychological approach to alcoholism and the brain.

Comparative neuropsychology involves the study of brain-behavior relationships by applying experimental paradigms, used extensively in animal laboratories, for testing human clinical populations. Popular paradigms include delayed reaction tasks, discrimination and reversal learning tasks, and matching- and nonmatching-to-sample. Such tasks were perfected on experimental animals having well defined brain lesions, and adapted for the sensory and motor capabilities of human neurological patients. By holding task requirements constant for human and nonhuman primates, analogous measures can be made of neurobehavioral deficits associated with specific brain damage. Human and nonhuman primates solve many so-called animal-learning tasks, in similar ways. Moreover, many tasks, despite their apparent simplicity, already have proven to be sensitive to cognitive impairments after brain damage in humans and nonhumans alike. An important advantage of using paradigms from comparative neuropsychology, in conjunction with standard clinical neuropsychological assessments, is that the simplicity of the tasks makes them manageable for patients with severe cognitive impairments. In addition, since the tasks do not require linguistic strategies for performance, the problems can be solved by patients whose language skills are compromised. An example of the application of comparative neuropsychology to clinical populations is given: patients with a history of long term alcohol abuse were tested on delayed reaction paradigms, and the findings have been useful in clarifying the contribution of damaged frontal cortical-subcortical brains systems to their cognitive impairments.

Alcoholism↗

PubMed1992

Memory deficits in Alzheimer's patients: a comprehensive review.

Despite considerable experimental work on Alzheimer's disease (AD), the underlying cognitive mechanisms as well as the precise localization of neuropathological changes critical for memory loss remains undefined. A review of the neuropsychological literature on long-term memory deficits in AD patients suggests that AD patients display (a) a pervasive deficit of explicit memory, (b) a partial deficiency of implicit memory for verbal and visuoperceptual material (as measured by repetition priming procedures), and (c) a substantial sparing of implicit memory for visuomotor skills. The explicit memory loss is likely a result of encoding as well as consolidation difficulties. A faulty lexical-semantic knowledge structure appears responsible for deficient repetition priming effects. Since neuropathological changes diffusely affect the brain of AD patients, establishing a clear relationship between localization of cerebral lesions and memory deficits is particularly difficult. Nevertheless, data suggest that extensive involvement of the hippocampal-amygdala complex plays a major role in explicit memory loss. Damage to associative cortical areas likely is involved in repetition priming deficits. The relative integrity of primary motor and sensory cortical areas and of the basal ganglia likely subsume, by contrast, the normal learning of visuomotor skills.

Aged↗

PubMed1992

Visual and auditory spatial and nonspatial delayed-response performance by Korsakoff and non-Korsakoff alcoholic and aging individuals.

Thirty-six male alcoholics (13 with Korsakoff's syndrome) and 24 controls performed visual and auditory delayed-response tasks sensitive to prefrontal cortical damage in nonhuman primates. Korsakoff patients were consistently impaired compared with other subjects. Impairments by Korsakoff patients were evident when demands were placed on visual processing time (brief stimulus durations), and the deficits became exaggerated with increased demands on short-term memory. Under the most difficult experimental conditions, controls and non-Korsakoff alcoholics who were over 50 years old performed somewhat worse compared with younger groups 27-49 years old. Age-linked deficits were mild compared with Korsakoffs' deficits, and age-group differences disappeared with easier task demands. The results implicate cortical pathology in alcoholism and normal chronological aging and suggest that prefrontal damage accompanies alcoholic Korsakoff's syndrome.

Age Factors↗

PubMed1992

Resource-limited information processing in alcoholism.

A concurrent-task paradigm was utilized to examine the availability of limited-capacity information-processing resources in long-term chronic alcoholism. Normal control subjects and detoxified long-term alcoholics did not differ in their performance of a primary task that required an assessment of the meaning of foveally-presented words. However, reaction time measures indicated that the abstinent alcoholics were relatively impaired in their ability to concurrently perform a secondary task that required them to detect randomly-occurring and spatially-distributed visual probe stimuli. This impairment is interpreted as reflecting an abnormal limitation in the attentional resources abstinent alcoholics have available for task performance. The relationship between this deficit and the types of biological abnormalities and neuropsychological impairments commonly observed in alcoholism is discussed.

Alcoholism↗

PubMed1991

Selective delayed alternation deficits in dominantly inherited olivopontocerebellar atrophy.

In order to characterize more completely the nature of the frontal lobe-type cognitive changes in patients with dominantly inherited olivopontocerebellar atrophy (OPCA) we administered two tasks sensitive to frontal system dysfunction, delayed alternation (DA) and delayed response (DR), to 12 patients from one OPCA family. Affected members from this family have previously been shown to have a marked and widespread cerebral (including frontal) cortical cholinergic reduction as severe as that observed in Alzheimer's disease. Performance on DA, but not on DR, was significantly impaired in the OPCA patients compared to that in the controls. We suggest that the DA deficits in OPCA could be a consequence of a loss of cholinergic innervation to orbitofrontal or possibly temporal cortical areas and/or damage to the integrity of the cerebello-frontal neuronal connections.

Adult↗

PubMed1991

Clinical and experimental approaches to varieties of memory.

Memory is described as a complex aspect of cognitive functioning. Memory is dependent upon input from the sensory modalities; it relies upon the passage of time; and it requires intervening processes for initial acquisition and subsequent access. Based upon questions posed concerning the relationship between clinical and experimental advances in memory and memory disorders, an example is given to illustrate the influence of research upon techniques for diagnosis and rehabilitation. Suggestions are provided about how to approach answering other related questions in neuropsychology. An integrated program is suggested with the aim of bringing together findings from neuroanatomy, neurochemistry, and neurobehavior. Emphasis is placed upon integrating results of research based upon human and nonhuman models of disordered memory and other cognitive functions. Neuroanatomical systems important for performing delayed-reaction tasks are reviewed, as are results of delayed response and delayed alternation testing in several human populations with neurological dysfunction suggestive of frontal lobe damage.

Adult↗

PubMed1990

Cross-modal functions in alcoholism and aging.

Two experiments were performed to measure separate aspects of cross-modal functions in normal and alcoholic research participants: matching, and utilization of concepts. In Experiment 1, cross-modal equivalence-matching was measured, i.e. the ability to select in a second modality (e.g. vision), the same stimulus that was first presented in a different modality (e.g. touch). Experiment 2 measured cross-modal transfer of information about stimulus dimensions, i.e. the ability to recognize and use the concepts of texture and form, based upon prior experience solving tactual problems, to solve visual problems. Fifty-five normal and alcoholic research participants comprised the following five groups: 13 young normals (YN) and 10 young alcoholics (YA), 28-48 years of age; 13 older normals (ON) and 14 older alcoholics (OA), 50-71 years of age; and 5 alcoholic Korsakoff patients (K), 55-68 years of age. Separate subgroups of 9 age-matched ONs and 9 OAs were devised for purposes of statistical analyses of data involving the 5 Ks. Results of the experiments indicated that aging is associated with decline in tactual discrimination ability. Further, cross-modal functions appear to be compromised by alcoholic Korsakoff's disease, and--to a lesser extent--by the combined effects of alcoholism and normal chronological aging. Brain mechanisms important for normal cross-modal functions are discussed.

Adult↗