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M Oscar-Berman

Publications and source records attributed to M Oscar-Berman.

At least 37 records · Page 2Linked to original sources
PubMed1990

Repetition priming of words and pseudowords in divided attention and in amnesia.

Repetition priming of novel stimuli (pseudowords) and stimuli with preexisting representations (words) was compared in two experiments. In one, 19 normal male subjects performed a lexical decision task with either focused or divided attention. In another, lexical decision performance was compared between 8 male Korsakoff patients and 8 alcoholic control subjects. In control conditions, repetition speeded responses to both stimulus types. Experimental conditions that minimized the contribution of episodic memory to task performance eliminated reaction time priming for pseudowords but not for words. However, in these same conditions, repetition increased the likelihood that pseudowords would be incorrectly classified. These results indicate that preserved repetition priming effects in amnesia do not solely reflect activation of representations in semantic memory.

Alcohol Amnestic Disorder↗
PubMed1990

Emotional perception and memory in alcoholism and aging.

The ability to identify and recognize emotional materials was studied in 10 male alcoholic Korsakoff patients, 27 male non-Korsakoff alcoholics, and 31 male nonalcoholic controls, across a wide age range (23 to 77 years). Stimulus materials were presented in two sensory modalities; the materials were photographs of faces expressing one of four emotions (happy, sad, angry, or neutral), and recordings of sentences with emotional intonations or semantic meanings expressing the same four emotions. Results of the experiments showed consistently severe deficits in emotional functions in the Korsakoff patients, but only minor alterations in the non-Korsakoff alcoholics. Older subjects, whether or not they had a history of alcoholism, also exhibited significant deficits on most of the tasks. Results of the study did not provide strong support for the premature aging hypothesis of alcoholism, which suggests that alcoholism accelerates aging, beginning either at the onset of heavy drinking early in adult life, or later in life after the normal manifestations of aging have begun to appear. Results are related to brain mechanisms in emotional perception and memory functions.

Adult↗
PubMed1989

Spatial and visual learning deficits in Alzheimer's and Parkinson's disease.

Experimental paradigms adopted from animal models were used to compare the neuropsychological mechanisms underlying the dementias of Alzheimer's and Parkinson's diseases. Two tasks were selected because characteristic profiles of impairment in nonhuman primates are seen following selective lesions of frontal cortex, temporal cortex, and fornix. The tasks consisted of a spatial and a visual learning problem, each with two components: (1) original learning and (2) reversal of the original learning. The Alzheimer's patients were significantly impaired on original learning and reversal learning in the visual modality compared with demented Parkinson's patients, even though both groups were equated for severity of dementia. On the spatial tasks, both the Alzheimer's and the demented Parkinson's patients were impaired on reversal learning but not on original learning. The profile of deficits on the visual tasks may serve to differentiate Alzheimer's from Parkinson's dementia and may reflect selective orbitofrontal system lesions in the former.

Aged↗
PubMed1989

Alcoholism, aging, and functional cerebral asymmetries.

Reviews research concerning the possible relationship between cognitive decline and abnormal hemispheric asymmetries in alcoholic and aging individuals. Because the deteriorative effects of alcoholism on the central nervous system have suggested greater visuospatial than language-related functional impairments, numerous investigators had hypothesized that right-hemisphere integrity may be selectively disrupted (rather than the left hemisphere). Furthermore, performance on diverse perceptual and cognitive tests used to measure right-hemisphere functions in alcoholics had been observed to decline with normal chronological aging as well, thereby raising the possibility that certain neuropsychological deficits associated with alcoholism (presumably related to right-hemispheric decline) are identical to those associated with aging. However, an extensive review of empirical research findings on cerebral asymmetries both in alcoholics and in aging individuals suggested that their patterns of functional laterality are similar to those of normal controls.

Age Factors↗
PubMed1989

Links between clinical and experimental neuropsychology.

The goals of both experimental and clinical neuropsychology involve qualitative analyses of the behavioral sequelae of brain damage in humans. Both of these subdisciplines attempt to delineate and clarify perceptual, cognitive, linguistic, affective, and other changes in individuals with neurological disease--particularly as these disorders contribute to our understanding of normal brain function and its modification by pathology. Thus, an interest in brain-behavior relations is coupled with diagnostic studies of brain-damaged individuals. Frequently, this collaboration leads to increased awareness of pathological symptomatology. Sometimes it leads to important insights about the nature of normal cognitive abilities, and to improved therapeutic outcomes for individual patients themselves.

Brain Damage, Chronic↗
PubMed1988

Cognitive deficits in olivopontocerebellar atrophy: implications for the cholinergic hypothesis of Alzheimer's dementia.

A cerebral cortical cholinergic reduction in dominantly inherited olivopontocerebellar atrophy (OPCA) was recently described. Although the magnitude of the cholinergic reduction was similar to that observed in Alzheimer's disease (AD), none of the OPCA patients was reported to have been demented. We now describe a comprehensive neuropsychological assessment of 11 patients from one of the OPCA pedigrees which we examined biochemically. Detailed neuropsychological testing disclosed previously unrecognized deficits in verbal and nonverbal intelligence, memory, and frontal system function which were positively correlated with the severity of cerebellar ataxia. However, our OPCA patients appeared to be at most only mildly disabled by their cognitive impairment and scored within or close to the normal range on a simple mental status screening examination. This, as well as an absence of any aphasia, apraxia, or agnosia, contrasts with the profile and severity observed in advanced AD dementia, characterized by a similar cortical cholinergic deficit. This finding also suggests that cholinergic reduction may explain only part of the pathophysiology underlying the dementia of AD.

Adult↗
PubMed1987

Tactile discrimination learning deficits in Alzheimer's and Parkinson's diseases.

Neuropsychological mechanisms of dementia in Alzheimer's and Parkinson's diseases were compared using a tactile discrimination learning paradigm adopted from animal models. There were two components to the task: tactile original learning (TOL), which is sensitive to parietal lobe damage in nonhuman primates; and tactile reversal of original learning (TRL), a measure of perseveration. The patients with Alzheimer's disease were significantly impaired on TOL compared with demented patients with Parkinson's disease, even though both groups were equated for severity of dementia. On TRL, the patients with Alzheimer's disease and demented patients with Parkinson's disease were both significantly impaired, but the patients with Alzheimer's disease showed significantly more perseverative errors. The mechanisms underlying TOL and TRL deficits may serve to differentiate Alzheimer's from Parkinson's dementia, and may involve selective parietal system lesions.

Aged↗
PubMed1987

Cognitive deficits related to memory impairments in alcoholism.

Cognitive impairments related to alcoholism are examined in terms of input, intervening, and output variables. Respectively, the dysfunctions are represented by visuospatial/perceptual abnormalities, affective/conative deficits, and strong perseverative response tendencies. Defects in one or more of these aspects of cognitive functioning may appear as problems of memory. Functional differences between subgroups of alcoholics who do and do not develop severe anterograde amnesia characteristic of Korsakoff's syndrome presumably are attributable to differences in the distribution and extent of brain pathology. Both subgroups have widespread cortical pathology, which may play an important role in stimulus-processing deficiencies observed in both. Korsakoff's have demonstrated a more significant degree of pathology in diencephalic and basal forebrain structures than that observed in non-Korsakoff alcoholics; this may contribute to the greater memory and affective impairments in the former. However, in no subgroup of alcoholics can a single functional system or brain region be implicated as the major contributory factor. Rather, damage to multiple brain regions likely is responsible for the plethora of cognitive difficulties reported in the alcoholism literature.

Alcohol Amnestic Disorder↗
PubMed1987

Lack of laterality effect for monaural categorization of VOT and TOT stimuli.

Sixteen right-handed males were tested for lateral preference and consistency of identification of stimuli differing in voice-onset time (VOT) or tone-onset time (TOT). A continuum of 10 stimuli of each type was presented monaurally to the right and left ears, and reaction times (RTs) were recorded each time a participant indicated a choice between a voiced [da] and a voiceless [ta] alternative for VOT, or between the presence of one type of tone or another for TOT. Results indicated that both classes of stimuli were perceived as having unique boundaries, with the TOT boundary being lower than that of the VOT continuum. VOTs were identified more quickly than TOTs, and the two ears did not differ in consistency or speed of identification for either condition. Results cannot be used to support the idea that the two hemispheres process voice-onset time differently than tone-onset asynchronies. In view of the absence of a right ear advantage for VOT, however, the use of a monaural task for eliciting hemispheric asymmetries is not recommended.

Adolescent↗
PubMed1986

Selective delayed response deficits in Parkinson's and Alzheimer's disease.

Experimental paradigms adopted from animal models were used to contrast the functional anatomy of frontal systems involved in Alzheimer's disease and the dementia of Parkinson's disease. Patients with Parkinson's disease with dementia were compared with patients with Alzheimer's disease, and nondemented patients with Parkinson's disease, and normal controls. The tasks administered, delayed alternation and delayed response (DR), are sensitive to frontal system damage. Different aspects of each task are mediated by separate frontosubcortical neuronal networks. Patients with Parkinson's disease with dementia were significantly impaired only on DR, whereas patients with Alzheimer's disease were impaired on DR and delayed alternation, even though both groups were equated for severity of dementia. Although dysfunction in the frontal lobes, and/or their subcortical connections, is implicated in both Parkinson's and Alzheimer's disease, dorsolateral frontal systems appear primarily impaired in Parkinson's disease, whereas dorsolateral frontal impairment combined with other regions, possibly orbitofrontal, are prominent in Alzheimer's disease.

Aged↗
PubMed1986

Comparative neuropsychology of cortical and subcortical dementia.

The terms "cortical" and "subcortical" dementia are controversial; however, the clinical distinction between them is real. For example, although Alzheimer's and Parkinson's disease (prototypical of cortical and subcortical dementia, respectively) share clinical features, they differ in the presence of aphasia, apraxia, and agnosia in Alzheimer's disease but not in Parkinson's dementia. We review our studies aimed at clarifying the mechanisms underlying the differences between these neurological disorders. Experimental paradigms adopted from animal models were used to study the functional anatomy and neuropsychological characteristics of Alzheimer's and Parkinson's disease. The tasks administered include delayed alternation (DA) and delayed response (DR), which are sensitive to frontal system damage, and tactile discrimination learning (TOL) and reversal (TRL) paradigms sensitive to parietal system damage. Alzheimer's patients were significantly impaired on all tasks whereas Parkinsonians with dementia were impaired only on DR and TRL. Consideration of neuroanatomical and neuropsychological mechanisms involved in DA, DR, TOL, and TRL appears to have sharpened the distinction between Alzheimer's and Parkinson's dementia. Dementia in Alzheimer's disease may involve dorsolateral frontal, orbitofrontal and parietal systems. In contrast, dementia in Parkinson's disease may involve prominent dorsolateral frontal system damage.

Dementia↗
PubMed1986

Bilateral frontal lobe disease and selective delayed response deficits in humans.

The performance of patients with frontal lobe disease was compared with that of amnesic patients (with etiology of alcoholic Korsakoff's disease or surgically treated ruptured anterior communicating artery aneurysm) on tasks known to be sensitive to frontal lobe damage in nonhuman primates: delayed alternation (DA) and delayed response (DR). Alcoholic patients with no clinical memory impairment served as controls. Results showed that bilateral frontal lobe damage in humans is associated with impairment on both tasks. In addition, there was no relation between performances on DA and DR and performance on standardized tests of memory, a result strengthening the suggestion that the former tasks are not sensitive to anterograde amnesia in humans.

Alcohol Amnestic Disorder↗
PubMed1985

Matching- and delayed matching-to-sample performance as measures of visual processing, selective attention, and memory in aging and alcoholic individuals.

Visual processing time, selective attention to visual cues, and memory for those cues were measured in groups of normal and alcoholic research participants within three different age ranges: young (35-45 yr), middle (46-59 yr) and older (60-70 yr). Performance across groups also was compared to that of alcoholic Korsakoff patients, known to have processing and attentional abnormalities. The matching-to-sample task was employed in which participants are required to match one of two laterally located response choices with a stimulus displayed in the center between them. Duration of the center sample stimulus varied between 20 and 500 msec, and delay between sample offset and response-choice (match) onset varied between 0 and 30 sec. Complexity of the sample stimulus also was varied, containing one or two dimensions (color and/or form). Levels of performance for all groups improved with increased sample stimulus durations, and were negatively related to a stimulus complexity and length of delay. Significant group differences in accuracy were evident with short stimulus exposures; the Korsakoff and older groups made more errors than the younger groups. Similarly, response times were influenced differentially by stimulus duration, stimulus complexity, and the delay between sample and matching stimuli, with young participants (alcoholics and controls) responding fastest. Results emphasize the contribution of processing deficits to other cognitive impairments in aging and alcoholic individuals, as well as the relative independence of aging and alcoholism.

Adult↗
PubMed1983

Bimanual tactual discrimination in aging alcoholics.

Somesthesis and perceptual laterality were studied in normal aging and in aging alcoholic populations. The bimanual (dichhaptic) stimulation technique that was employed required participants to recognize and identify items traced onto the palms of both hands simultaneously, thereby eliciting competition for analysis by the two cerebral hemispheres. Performance of five groups of participants was compared (younger and older alcoholics and age-matched normal controls, and alcoholic Korsakoff patients); within each of the groups, the ability to identify verbal stimuli (letters) was compared with nonverbal stimuli (lines differing in orientation) for the right and the left hands separately. The results suggest that tactile discrimination accuracy for nonverbal information is disrupted by aging, but that alcoholism per se does not have this effect. The combined effects of alcohol abuse and aging were seen only on the tactual tasks that required identification of verbal items. Lateralization measures based upon performance by the two hands separately did not differentiate among the groups.

Adult↗
PubMed1982

Comparative neuropsychology and Korsakoff's syndrome. III--Delayed response, delayed alternation and DRL performance.

Performance of alcoholic Korsakoff patients was compared with that of patients with Huntington's disease. Broca's aphasia or alcoholism (without clinical signs of memory impairment) on delayed alternation (DA) and delayed response (DR) tests. Korsakoffs were impaired on both tasks, and Huntington patients were impaired on DA only. In a separate experiment, performance by Korsakoffs was compared to that of alcoholic and normal controls on four DRL schedules. Korsakoffs tended to be overresponsive, making errors of commission early within a schedule, and consequently, obtaining fewer reinforcements than the controls.

Adult↗