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Biomedical subjects

A L Benton

Publications and source records attributed to A L Benton.

At least 19 recordsLinked to original sources
PubMed1992

Gerstmann's syndrome.

Recent case reports describe the occurrence of a more or less pure Gerstmann syndrome in association with a focal lesion in the posterior perisylvian territory of the brain's left hemisphere. In addition, an electrocortical stimulation study reported the Gerstmann symptom combination and a number of other symptom combinations on stimulation of small areas in the left posterior parietotemporal cortex. The neuropsychological implications of these and other recent findings are considered in light of the variety of "syndromes" produced by lesions in this region, the rare occurrence of Gerstmann's syndrome, and its appearance as a consequence of lesions in diverse cerebral areas.

Adolescent↗
PubMed1979

Facial recognition in patients with focal brain lesions.

The performances of patients with radiologically or surgically verified focal lesions on a test requiring the identification of unfamiliar faces were investigated. Nonaphasic patients with posterior right hemisphere lesions and aphasic patients with substantial impairment in language comprehension showed a notably high frequency of defect. The frequency of defective performance in nonaphasic patients with right anterior lesions was higher than normal but less than that of the previously mentioned groups. Nonaphasic patients with left hemisphere lesions and aphasic patients without substantial impairment in language comprehension performed on a level comparable with that of control subjects. It is concluded that the identification of unfamiliar faces is a bihemispheric process, possibly involving linguistic as well as visuoperceptive components.

Adult↗
PubMed1979

Impairment of hand movements under visual guidance.

Impairment of object-bound movements of the hand performed under visual guidance ("optic ataxia") was a prominent sign in a patient with bilateral circumscribed infarctions in the posterior watershed territory. The sign was interpreted as resulting from defective integration of panoramic visual information with proprioceptive information concerning the upper extremity, and as being related either to damage of structures in the parietooccipital junction or their neural outflow to the premotor region.

Agnosia↗
PubMed1978

Interactive effects of age and cerebral disease on cognitive performances.

A battery of mental tests was given to groups of younger (16--44 years) and older (48--60 years) control and cerebral diseased patients. Each patient in the younger cerebral diseased group was matched individually with an older cerebral diseased patient for type and site of lesion. Each patient with cerebral disease was matched individually with a control patient for age, educational level and sex. Differences in level of test performance related to age were generally greater for cerebral diseased than for control patients. Differences in level of test performance related to diagnostic category were generally greater for older than for younger patients. Analysis disclosed a significant overall interactive effect of age and cerebral disease on the performance of mental tests, supporting the hypothesis that acquired cerebral disease has more severe behavioral consequences in older than in younger persons.

Adolescent↗
PubMed1978

Visuospatial judgment. A clinical test.

We constructed and developed a brief test assessing capacity for discriminating the direction of lines. Application of the test to patients with unilateral brain disease disclosed a remarkably high frequency of defective performance in those with right hemisphere lesions. The performance of patients with left hemisphere lesions was comparable to that of control patients. Brevity and ease of administration make the test convenient for clinical use.

Adolescent↗
PubMed1977

Historical notes on hemispheric dominance.

The evolution of knowledge of hemispheric cerebral dominance is sketched and some possible reasons for the relatively late recognition of asymmetry in hemispheric function are considered. The early clinical contributions pointing to the distinctive functional properties of the right hemisphere are described.

Aphasia↗
PubMed1977

Interactive effects of age and brain disease on reaction time.

Simple visual and auditory reaction time (RT) was studied in younger (16 to 44 years old) and older (46 to 63 years old) control and brain-diseased patients. Differences in RT related to age were larger for brain-diseased than control patients. Differences in RT related to diagnostic category were larger for older than younger patients. Analysis indicated an interactive effect of age and brain disease on RT supporting the suggestion that acquired brain disease leads to a more pronounced retardation in RT in older patients.

Acoustic Stimulation↗
PubMed1977

The reliability of reaction time determinations.

The reliability of simple and two-choice reaction time (RT) as a function of number of trials and measure of central tendency was examined. It was found that, within the particular conditions of the study, 18 trials were sufficient to obtain a highl reliable determination of simple RT but 30 trials were required for a highly reliable determination of two-choice RT. The selection of measure of central tendency was not related to degree of reliability.

Adult↗
PubMed1977

Facial recognition in "pseudoneurological" patients.

A test of facial recognition was given to 44 patients whose symptoms raised a question of differential diagnosis between brain disease and functional psychiatric disorder. These "pseudoneurological" patients presented symptoms (e.g., memory impairment, headache, sensory disturbances) that were sufficiently suggestive of CNS disease to warrant thorough neurological evaluation. In each case, such evaluation disclosed no evidence of brain disease and the final diagnosis was some type of functional psychiatric disorder. Facial recognition performances of these patients were indistinguishable from those of medical patients without history or evidence of brain disease. The findings support the clinical application of this type of task in cases presenting problems of differential diagnosis.

Adult↗
PubMed1976

Proprioceptive feedback performance in patients with focal brain lesions.

Utilization of proprioceptive feedback in a manual tracking task was studied in patients with circumscribed unilateral brain lesions. Patients with posterior right hemisphere disease showed severe impairment in performance as compared to those with lesions in other areas of the brain. Increasing the intensity of proprioceptive feedback facilitated the tracking performance of left hemisphere damaged patients while patients with right hemisphere lesions failed to improve. The results were interpreted as supporting the view that the posterior right hemisphere plays a particularly important role in the utilization of proprioceptive information to maintain the position of body parts in space.

Brain Diseases↗
PubMed1976

Visual localization in patients with unilateral brain disease.

The accuracy of localization of briefly exposed single dots and pairs of dots was assessed in patients with lesions of the left and right hemispheres and in control patients without history or evidence of brain disease. A remarkably high frequency of impaired performance was found in the patients with right hemisphere lesions. The performance of the patients with left hemisphere lesions was comparable with that of the control patients. Visual field defect was associated with defective localization in the right hemisphere group but not in the left hemisphere group. Aphasic disorder and age were not related to performance level. The relationship of the findings to those of previous studies of visual localization in patients with unilateral brain disease is discussed.

Adult↗
PubMed1975

Reaction time to square-wave gratings as a function of spatial frequency, complexity and contrast.

Visuomotor reaction time (RT) of normal human subjects to briefly presented square-wave bar patterns were measured. The pattern varied with respect to magnitude and number of spatial frequencies (one cycle/degree of visual angle, 3 cycles/degree, and both combined) with each spatial frequency stimulus presented at 3 levels of contrast. Space-average luminance was held constant. RT increased with the higher spatial frequency and was intermediate in value for the combination stimulus at each level of contrast. RT increased with decreasing contrast levels for each spatial frequency stimulus. There was no interaction between the two parameters. The findings indicate that a behavioral response measure can be employed to study the multiple channel hypothesis of human vision. The results were compared with those of other investigators employing sine-wave gratings, perceptual response measures and the evoked potentials technique.

Adult↗
PubMed1975

Temporal orientation in patients with brain disease.

A brief schedule of questions, based on empirically derived norms, disclosed significant inaccuracy in temporal orientation in 24% of a groups of nonaphasic patients with brain disease. Conventional neurological examination detected temporal disorientation in only 15%. Patients with bilateral lesions showed a higher frequency of temporal disorientation than did those with inilateral lesions. In a group of 15 aphasic patients, 5 (33%) showed evidence of temporal disorientation according to the test while only 3 (20%) were detected on clinical examination. It is suggested that a schedule of questions scored on the basis of empirically derived norms should be incorporated into the neurological examination to assess temporal orientation.

Aphasia↗
PubMed1975

Relationship between monocular and binocular depth acuity.

Estimates of monocular and binocular depth acuity were obtained on two samples of subjects with adequate visual acuity and capacity for stereopsis. Both a method of average error and a modified method of limits were employed to secure the estimates. Eight ratios of binocular to monocular depth acuity ranged from 2.4:1 to 4.2:1 at a distance of 15 ft. The results contradict the familiar generalization that binocular depth perception is about 20 times as acute as monocular depth perception.

Adolescent↗