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Biomedical subjects

J Grafman

Publications and source records attributed to J Grafman.

158 records · Page 9Linked to original sources
PubMed1986

The effects of lateralized frontal lesions on mood regulation.

A group of Vietnam veterans with penetrating brain wounds to the orbitofrontal, dorsofrontal, and nonfrontal cortex were compared with a stratified control group of self-report and observed measures of mood state and cognition. In particular, hypotheses regarding the regulation of anxiety by frontal cortical mechanisms were evaluated. Results indicated that patients with right orbitofrontal lesions were prone to abnormally increased 'edginess'/anxiety and depression, whereas patients with left dorsofrontal lesions were prone to abnormally increased anger/hostility. A working model of mood state regulation is presented which represents the thesis that mood sensations are subject to numerous cognitive and biological influences that result in a variety of expressions of a particular mood disorder.

Adult↗
PubMed1986

Penetrating war injuries of the basal forebrain: neurology and cognition.

We compared the neurologic and cognitive performance of 15 young veterans who suffered unilateral penetrating missile wounds to the basal forebrain 15 years ago in the Vietnam War with uninjured controls and patients with lesions elsewhere in the brain. The subjects performed worse on tests of episodic memory, reasoning, and arithmetic and had more prolonged unconsciousness after injury; but their performance usually compared favorably with that of uninjured controls on tests of intelligence, attention, and language and was not consistent with that of a demented patient. The data suggest that the basal forebrain is functionally related to the reticular formation and to the basal forebrain is functionally related to the reticular formation and to the limbic-hippocampal memory system.

Basal Ganglia↗
PubMed1986

Face memory and discrimination: an analysis of the persistent effects of penetrating brain wounds.

This study was designed to examine the effects of penetrating head injury upon face discrimination and memory in 213 brain-injured Vietnam veterans and 49 normal controls. Impairment on tests of face memory was most associated with bilateral lesions and with unilateral lesions of the temporal lobe. Impairment on a test of face discrimination was most associated with right hemisphere, and with bilateral lesions which included either frontal or parietal lobe involvement. Performance on these tasks appeared independent of other visuospatial or verbal tasks. Cluster analysis revealed a dissociation between performance on facial memory and facial discrimination tasks.

Adult↗
PubMed1986

The relationship of brain-tissue loss volume and lesion location to cognitive deficit.

We examined the relationship of preinjury intelligence, a lesion-severity variable (brain-tissue loss volume), and lesion location to the persistence of cognitive deficits in Vietnam veterans with penetrating brain wounds. Using stepwise multiple linear regression procedures, we found that preinjury intelligence predicted a significant amount of the variance on postinjury cognitive testing, being a better predictor for tests requiring a number of complementary cognitive processes (e.g., intelligence tests) than for tests measuring a specific cognitive process (e.g., face recognition). Brain-tissue volume loss was found to play a larger role when a global cognitive measure was used, but a smaller role when a specific cognitive process was measured. Finally, lesion location was shown to be a significant predictor of performance only for specific cognitive processes. Nevertheless, preinjury intelligence/education appears to play an even larger role in postinjury performance than either brain-tissue loss volume or a particular structural loss.

Adult↗
PubMed1985

Isolated impairment of memory following a penetrating lesion of the fornix cerebri.

Persistent memory problems were reported by a 39-year-old man who suffered a penetrating brain wound while serving in Vietnam 15 years earlier. Neuropsychological testing indicated an unusually isolated memory impairment. Computed tomography revealed transection of the columns of the fornix cerebri with no temporal-lobe involvement and minimal thalamic damage. We suggest that the fornix cerebri has a role in the maintenance of information accessibility to both encoding and recall during post-working memory processing and in the organization of verbal information during encoding and/or retrieval for declarative (recall) purposes. These processes are not essential for verbal recognition but can result in decrements on specific laboratory tasks and in social adjustment.

Adult↗
PubMed1985

Epilepsy after penetrating head injury. I. Clinical correlates: a report of the Vietnam Head Injury Study.

Of 421 veterans who had penetrating brain wounds in Vietnam 15 years ago, 53% had posttraumatic epilepsy, and one-half of those still had seizures 15 years after injury. The relative risk of developing epilepsy dropped from about 580 times higher than the general age-matched population in the first year to 25 times higher after 10 years. Patients with focal neurologic signs or large lesions had increased risk of epilepsy, and site of the lesion may have been more important than size in determining occurrence. Family history of epilepsy or preinjury intelligence had no effect on seizure occurrence. Seizure frequency in the first year predicted future severity of seizures. Phenytoin therapy in the first year after injury did not prevent later seizures.

Adult↗
PubMed1985

Effects of left-hand preference on postinjury measures of distal motor ability.

The relationship of preinjury left-hand dominance for motor performance to postinjury distal motor skills following penetrating brain wounds in patients without overt hemiplegia was examined. We studied 13 controls, 13 right-hemisphere brain-damaged patients, and 11 left-hemisphere brain-damaged patients on motor tasks measuring reaction time, strength, and coordination. Our results indicated that no persistent deficits were seen on distal motor tasks in left-handed adults who suffered a penetrating brain wound. These findings are compatible with the relative sparing of persistent neuropsychological deficits in left-handers following brain damage.

Adult↗
PubMed1983

Forms of memory failure.

Memory may fail in a variety of ways. Patients with Korsakoff's syndrome demonstrate global memory deficits similar to those seen in patients with early progressive dementia. Korsakoff's patients, however, may recall rules and principles for organizing information and can gain access to their previously acquired knowledge (semantic memory), whereas recent memory may be grossly impaired. In contrast, dementia patients may have little access to previously acquired knowledge and therefore have great difficulty in organizing and encoding ongoing events. These contrasting forms of memory failure have implications for understanding the structure and mechanisms of memory and learning, particularly the relationship between episodic and semantic memory, as well as the development of therapeutic strategies for cognitive impairments.

Alcohol Amnestic Disorder↗
PubMed1983

Acalculia: historical development and current significance.

Acalculia is a loss of calculating abilities occurring as a result of cerebral damage. This paper reviews the development of the notion of acalculia from an expected concomitant of aphasia or dementia to that of a sometimes autonomous disorder. Current evidence indicates that acalculia tends to occur particularly in lesions of the left posterior hemispheric areas.

Aphasia↗
PubMed1982

Calculation disturbances in adults with focal hemispheric damage.

It has been suggested that hemisphere-damaged patients with calculation disorders can be subdivided into 3 groups: agraphia or alexia for numbers, spatial dyscalculia and anarithmetia. The purpose of the present study was to evaluate the role played by visuospatial disorders and by anarithmetia in subjects with impaired calculation abilities. Seventy-six patients with focal hemispheric lesions and 26 normal controls with demonstrated ability to read and write numbers were given a written calculation task, the Token Test, the Crosses Test, a test of Constructional Apraxia and Raven's Progressive Matrices. In the calculation task, a quantitative score represented the number of digits that were correct numerically and put in correct position. A qualitative score with emphasis on visuospatial factors was obtained by scoring each problem with the criteria used in Benton's Visual Retention Test. Analysis of the results showed that both left and right hemisphere-damaged patients performed significantly worse than controls and that patients with left posterior lesions were particularly impaired even after correction of the acalculia scores by the results of the other neuropsychological tests. These results suggest that even though different factors may contribute to calculation disorders (impairment of intelligence, visuoconstructive difficulties and above all aphasia), left posterior lesions are particularly prone to produce an impairment in calculating abilities which is partially independent from the above disorders.

Aphasia↗
PubMedDate not supplied

Conceptualizing functional neuroplasticity.

There are at least four major forms of functional neuroplasticity that can be studied in humans: homologous area adaptation, cross-modal reassignment, map expansion, and compensatory masquerade. Homologous area adaptation is the assumption of a particular cognitive process by a homologous region in the opposite hemisphere. Cross-modal reassignment occurs when structures previously devoted to processing a particular kind of sensory input now accepts input from a new sensory method. Map expansion is the enlargement of a functional brain region on the basis of performance. Compensatory masquerade is a novel allocation of a particular cognitive process to perform a task. By focusing on these four forms of functional neuroplasticity, several fundamental questions about how functional cooperation between brain regions is achieved can be addressed.

Brain↗
PubMedDate not supplied

Cognitive and mood-state changes in patients with chronic fatigue syndrome.

In this paper the cognitive and psychiatric impairments associated with chronic fatigue syndrome (CFS) and related disorders are reviewed. It is concluded that while acute mononucleosis and infection with Epstein-Barr virus occasionally result in impaired cognition, such changes have not yet been objectively verified in patients with CFS. However, when patients with CFS are carefully studied, concurrent or premorbid psychiatric disorders are revealed at a greater than chance level. Finally, some suggestions are offered regarding improved neuropsychological assessment of fatigue, concentration, and attention for patients with CFS. The findings to date, while suggesting that psychological predisposition may play a role in the expression of CFS, are still inconclusive regarding the etiology of CFS.

Cognition Disorders↗