Arthur L. Benton

Differential behavioral effects in frontal lobe disease

Abstract The performances of groups of patients with left, right and bilateral frontal lesions were compared on a battery consisting of two tests presumed to be related specifically to left hemisphere function, two tests presumed to be related specifically to right hemisphere function, and two tests presumed to be related specifically to bilateral frontal lobe function. Eighteen predictions, based on both theoretical considerations and the indications of previous literature, were made concerning the differences in performance to be expected among the three groups. Fifteen of the 18 predictions were confirmed by the results. It is concluded that some of the interhemispheric differences in performance which have been found in comparisons of patients with unilateral post-Rolandic lesions are also demonstrable in patients with unilateral frontal lesions and that certain task performances are particularly susceptible to the effects of bilateral frontal lobe damage.

Word fluency and brain damage

Abstract A group of sixty-six adult subjects was given the task of producing as many words as possible beginning with specified letters of the alphabet. The number of words produced during a period of 60 sec correlated highly both with a frequency count derived from the Thorndike-Lorge norms and with estimates derived from the dictionary of the number of words in the English language beginning with each letter. In a second experiment, eight letters representing three levels of difficulty as found in normal subjects were given to thirty brain-damaged and thirty hospitalized control patients. Results in terms of verbal productivity indicated that, for patients of high intelligence, difficult letters (i.e. J and U) showed the greatest discrimination. On the other hand, for patients of low intelligence, easy letters (i.e. F, S, P and T) were more effective in differentiating the brain-damage and control groups. The findings also indicated that difficult letters may be particularly effective in distinguishing between patients with right and left hemisphere damage. An analysis of order of presentation indicated that practice and fatigue effects were not related to verbal fluency when as many as eight letters were administered. It is suggested that the addition of difficult letters to standard word fluency tests may yield more precise discriminations between brain-damaged and control patients when overall level of intellectual functioning is taken into account.

Visual perception of line direction in patients with unilateral brain disease

The accuracy of identifying the slope of briefly exposed lines was assessed in patients with lesions of the left or right hemisphere and in a group of control patients without history or evidence of brain disease. The frequency of impaired performance was remarkably high in the patients with right hemisphere lesions. In contrast, the patients with left hemisphere lesions did not perform differently from the control group. Visual field defect, aphasic disorder, and age were not related to performance level. The striking interhemispheric difference in performance on this visuospatial task suggests its further development for clinicodiagnostic purposes.

Aphasia, Alexia, and Agraphia

This monograph on the aphasic disorders is succinct yet remarkably comprehensive. The first section covers the neuropathologic basis of aphasia, problems of localization, and methods of testing. The second section describes the major aphasic syndromes and allied disorders. A detailed discussion of the neuroanatomical correlates of specific language performances composes the third section. The final section deals with associated clinical problems such as mutism, dementia, apraxia, and agnosia. This is a well-written exposition in which facts and theories are clearly presented. Though all students of aphasia will find it informative, it should prove to be particularly useful to residents in neurology and psychiatry as they cope with the formidable clinical and theoretical problems posed by the aphasic disorders. Dr Benson is to be congratulated on his achievement.

Impairment in Facial Recognition in Patients with Cerebral Disease

Summary A test requiring the identification of unfamiliar faces was developed and given to groups of patients with lesions of the left or the right hemisphere as well as to a large group of control patients. Performance level in the control group showed a slight decline with age but was not related to education or sex. The mean performance levels of both brain-damaged groups were significantly inferior to that of the control group. In addition, however, the mean performance level of the patients with right hemisphere lesions was significantly inferior to that of the patients with left hemisphere lesions and grossly defective performances were made mainly by patients with right hemisphere lesions. Performance level was not related to the presence of visual field defect, the presence of aphasia, type of lesion or intrahemispheric locus of lesion. A number of considerations suggested that the observed interhemispheric difference in performance was not related to a possible difference in the extent of lesion in the two groups. The observations clearly indicate that impairment in facial recognition, as assessed by the procedures utilized in the study, is rather closely associated with disease of the right hemisphere. The relationship of the findings to the clinical complaint of prosopagnosia and the nature of the basic disabilities underlying defective facial recognition are considered.

Normative observations on neuropsychological test performances in old age

As part of a study of dementia, 162 normal volunteers in the age range of 65-84 years were given a battery of nine neuropsychological tests assessing temporal orientation, short-term memory, language functions, and visuoperceptive capacity. When compared to subjects less than 65 years of age, the groups showed little evidence of generalized decline in cognitive function before the age of 80 years. The 80-84 years subgroup showed a higher overall failure rate on the tests than the younger subgroups. Nevertheless, 70% of all subjects in the 80-84 years subgroup made no more than one failure on the nine tests. There were substantial differences among the tests in respect to their sensitivity to the effects of aging. The largest decline in performance was shown on tests of short-term visual memory, serial digit learning, and facial recognition. The other verbal, memory, and visuoperceptive tests were performed well up to the age of 80 years. The findings are interpreted as providing limited support for the hypothesis that normal aging does not necessarily involve a general decline in level of cognitive functioning. The clinical application of the tests that were sensitive or insensitive to the effects of aging is considered.

Developmental Outcomes after Early Prefrontal Cortex Damage.

The neuropsychological bases of cognitive, social, and moral development are minimally understood, with a seemingly wide chasm between developmental theories and brain maturation models. As one approach to bridging ideas in these areas, we review 10 cases of early prefrontal cortex damage from the clinical literature, highlighting overall clinical profiles and real life developmental outcomes. Based on these cases, there is preliminary evidence to support distinctive developmental differences after: (1) dorsolateral, (2) mesial, and (3) orbital-polar prefrontal lesions, for more profound impairments after bilateral damage, and possibly for recovery differences after very early vs. later childhood lesion onset. Further case and group studies are needed to confirm reliable effects of specific lesion locations, the influence of age of lesion onset, and related experiential and treatment variables in determining adult outcomes. Rather than a single underlying deficit associated with early prefrontal cortex damage, we interpret the findings to suggest that it is the altered integration and interplay of cognitive, emotional, self-regulatory, and executive/metacognitive deficits that contribute to diverse developmental frontal lobe syndromes. The findings support the fundamental importance of prefrontal cortex maturation in protracted cognitive, social-emotional, and moral development.

Prosopagnosia and facial discrimination

Abstract The relations between prosopagnosia and the ability to discriminate unfamiliar faces are reviewed and the performance of a prosopagnosic patient on a facial discrimination test as well as on other tasks requiring the processing and integration of visual information is described. The finding that this patient showed essentially normal ability to discriminate unfamiliar faces supports the contention that prosopagnosia cannot be solely explained in terms of a general visuoperceptive impairment. The present state of our understanding of the disabilities underlying both prosopagnosia and defective discrimination of unfamiliar faces is discussed.

Tactile perception of direction in relation to handedness and familial handedness.

Abstract The accuracy of tactile perception of the direction of tactile stimulation of brief duration applied to the palms of the hands was investigated in relation to hand preference and familial background in normal subjects. In confirmation of previous findings, perception of direction was significantly more accurate on the left hand than on the righthanded subjects. Lefthanded subjects showed no trend toward superior performance on either hand. Familial background in respect to handedness was found to be a significant and independent determinant of lateral pattern of performance. Righthanded subjects with a purely dextral familial background showed clear superiority on the left hand while those who had a lefthanded parent showed no lateral asymmetry in performance. Lefthanded subjects with righthanded parents show no lateral asymmetry in performance but those with a lefthanded parent show clear superiority on the right hand. The findings underscore the importance of familial background as a determinant of performances reflecting asymmetry in hemispheric function.

Prediction of outcome in anorexia nervosa from neuropsychological status

To evaluate the possibility that subtle brain dysfunction may exist in anorexia nervosa and indicate a poor prognosis, 20 anorexia nervosa patients received neuropsychological assessments covering a broad array of cognitive performances. The patients were examined at admission and again at the end of an inhospital treatment program when they were at normal weight for their age and height. Pretreatment performance on the assessment battery was not associated with outcome 1 year after discharge. However, posttreatment performance and significantly associated with outcome. A majority (71%) of patients with two or more cognitive deficits showed an unfavorable outcome (i.e., did not maintain their weight). In contrast, a majority (85%) of patients with less than two cognitive defects had a favorable outcome (i.e., maintained or increased their weight). The findings suggest that the hypothesis of a central nervous system disorder limiting the capacity for anorectics to recover deserves further exploration.