NEU ROPSYCHOLOGIICAL STUDIES OF BLACKS WITH CEREBROVASCULAR DISORDERS: A PRELIMINARY INVESTIGATION A. Brown, PhD, A. Campbell, PhD, D. Wood, MD, A. Hastings, MD, 0. Lewis-Jack, MS, G. Dennis, MD, P. Ford-Booker, MS, L. Hicks, PhD, A. Adeshoye, MD, R. Weir, MD, and T. Davis, MD Washington, DC
Very few studies have been conducted that examine brain behavior functions in blacks and other ethnic minorities. Recognizing that measures of higher cortical functions have cultural, experiential, and organic determinants, the present investigation was designed to ascertain whether findings reported in neuropsychologic studies of white patients with lateralized cerebral lesions are applicable to groups of black patients with lesions in similar locations. Thirty-seven patients with left (n =15) and right (n = 22) cerebrovascular lesions were administered the Michigan Neuropsychological Battery (MNB). This battery is comprised of a number of objective standardized measures of higher and lower-level cerebral functions. With one exception, the performance of patients in the brain-injured groups was not systematically different on tests of higher brain functions. As expected, tests of lower-level somatosensory and motor functions showed a pattern of greater impairment on the side of the body contralateral to the lesion. But, in contrast to neuropsychological studies of white paFrom the Howard University Psychology Department and College of Medicine, Washington, DC. Requests for reprints should be addressed to Dr Alfonso Campbell, Jr, Psychology Department, Howard University, Washington, DC 20059. JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 83, NO. 3
tients, a pattern of laterality specific deficits on verbal IQ and performance IQ was not observed. Methodological and theoretical implications of these findings are discussed. Key words * cerebrovascular disorders* neuropsychology
During the past decade, experimental and clinical literature in human neuropsychology has grown enormously. This trend reflects increased interest in brain-behavior issues and the potential this discipline offers in providing a better understanding of the cerebral organization of psychological processes in man. Today, researchers in clinical neuropsychology, a professional specialty in human neuropsychology, have become aware that current neuropsychological assessment procedures are not only sensitive to the presence of cerebral pathology, but also such demographic factors as culture, ethnicity, gender, social class, age, and education.1-8 When current neuropsychological instruments were developed and validated, use of these measures with ethnic minorities was not of prime importance. Since blacks and other ethnic minorities have not been included in these validation studies, uncritical acceptance of neuropsychological measures as diagnostically valid indices of brain functions in these populations is unwarranted and unwise. Failure to take ethnicity/culture into account as a potential 217
CEREBROVASCULAR DISORDERS IN BLACKS
moderator variable may lead to false interpretations of neuropsychological test findings. Recognizing that measures of higher cortical functions have cultural, experiential, and organic determinants, it is important to determine whether findings reported in neuropsychological studies of white patients with lateralized cerebral lesions are generalizable to groups of black patients with similarly placed lesions. The present study was undertaken to examine this important neuropsychological issue, and to create a data base that when expanded to include similar data from blacks with different types of neurologic disorders, can be used as a normative standard.
METHOD Thirty-seven patients, 18 men and 19 women from the Washington, DC metropolitan area participated in the present investigation. These patients (mean age = 56, mean years of education = 9.5) were selected from a population admitted to the Neurology Service at Howard University Hospital with a provisional diagnosis of stroke. Twenty-two patients (Group RBD) had sustained a right hemisphere stroke and 15 (Group LBD) had cerebrovascular lesions in the left hemisphere. Criteria used to select participants in the present investigation were: 1. a focal neurological deficit on clinical neurological examination and evidence of a cerebrovascular lesion in computer axial tomography (CT-scan), electroencephalographic (EEG), arteriographic and/ or brain-scan studies, 2. right-handed prior to stroke, and 3. no previous history of psychiatric disorder, brain insults, alcohol or other drug abuse. Patients with CT scans showing single or multiple lesions incompatible with the focal neurologic deficit were not included in this study. All patients were given the Michigan Neuropsychological Battery (MNB),9 comprised of objective standardized measures of a broad range of language, verbal, and nonverbal reasoning, auditory and visual memory functions, and selected somatosensory and motor skills. Administration time for these tests varied from 3 to 4 hours. If a patient was unable to complete the test in a single administration, the examiner administered the test in the immediate ensuing days. Most patients were tested in the Physical Medicine and Rehabilitation unit. Several patients who were released from the hospital before testing could begin, were tested in their homes. After the patients agreed to participate in the study, informed consent was obtained. 218
The list of tests administered is as follows: * Wechsler Adult Intelligence Scale Revised (WAIS-R). Includes six verbal and five performance subtests which yield a verbal, performance, and full-scale IQ, in addition to objective measures of the different mental functions tapped by each of 11 subtests.'0 * Raven Coloured Progressive Matrices (RCPM). Measures nonverbal reasoning in visual modes of thought. Patients are required to examine a pattern with one section missing, then choose one from six alternatives that would complete the pattern. The RCPM is untimed and consists of 36 items.11 * Visual Retention Test (VRT). Designed to measure visual memory and constructional abilities. Each of 10 cards (Form C) with one or more designs is exposed for 10 seconds (administration A) and then withdrawn, followed by immediate reproduction from memory by the patient. To differentiate impairment of visual memory from constructional disabilities, the patient is asked to copy each of the same designs (administration C).12 * Purdue Pegboard (Purdue). Determines the presence and laterality of cerebral lesions through manual dexterity. Patients are instructed to insert pegs for 60 seconds in a column of holes in a pegboard, one at a time and as rapidly as they can, starting with the preferred hand. The test is then repeated with the non-preferred hand, and then with both hands simultaneously, with the examiner recording the number of pegs inserted in 30 and 60 seconds.13 * Symbol Digit Modalities Test (SDMT). A simple substitution test, reversing the format of the WAIS Digit Symbol subtest. In the Digit Symbol test, substitution responses are geometric designs which can only be written, whereas responses to the SDMT consist of numbers. The patient is given 90 seconds to make as many written substitutions as possible. This is followed by the oral form in which the patient speaks instead of writing numbers for another 90-second interval, with the examiner recording the responses. Thus, the SDMT permits comparisons of efficiency in performance on the same mental test in two different modalities: writing and speaking. The SDMT has proven to be the most sensitive single indicator of cerebral dysfunction and changes in the clinical picture with time and/or therapeutic intervention in the Michigan Neuropsychological Battery. Such changes are usually in the form of increased or decreased speed and efficiency in written and oral substitutions, rather than increases or decreases in errors.'4 * Single and Double Simultaneous (Face-Hand) StimJOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 83, NO. 3
CEREBROVASCULAR DISORDERS IN BLACKS
ulation Test (SDSS). Developed and standardized by Centofanti and Smith,15 it tests somatosensory functions, and is a refinement of the earlier Double Simultaneous Test. The patient is seated, asked to close his/her eyes and place the palm of each hand on the ipsilateral thigh. Patients are then required to indicate by pointing where they had been touched by the examiner after single or double simultaneous stimulations of the right and/or left cheek and/or hand. TWenty trials (eight single and 12 double simultaneous stimulations) are administered.'6' * Memory for Unrelated Sentences (MUS). While the WAIS-R Digit Span subtest provides a measure of immediate auditory memory for nonmeaningful series of random numbers, the MUS measures immediate auditory memory for semantic/syntactic materials. Patients are requested to immediately repeat after the examiner each of 10 sentences of increasing length. The test is terminated after errors are made in two consecutive sentences, and the patient's scores consist of the larger number of syllables in any sentence (Osteicher H. 1973. Unpublished data). * Visual Organization Test (VOT). The Hooper VOT consists of line drawings of common objects (for example, fish, hammer, truck, broom) that have been cut up with the pieces rearranged in random patterns. Like the Wechsler Block Design and Object Assembly subtests, the VOT provides a measure of visual-spatial-organizational abilities. However, unlike these two subtests, the pieces shown on the picture of each cut-up object cannot be moved. The test is untimed and consists of 30 items.17 * Visual Retention Test: Multiple Choice Form. Assesses capacity for complex visual form discrimination. There are 16 designs which cover a fairly broad range in terms of difficulty. Each multiple-choice item includes one correct foil and three incorrect foils. In Administration A, the patient is presented with the stimulus card for 10 seconds. Then, the patient is asked to point to or call the number of the foil that matches the stimulus design. In Administration B, the patient is presented with the stimulus design and the multiple-choice response array simultaneously; the patient's task is to discriminate among the response choices in order to identify the one design that matches the stimulus design (Benton AL. 1977. Unpublished data).
Data Analyses Scores earned on MNB measures served as dependent variables, while side of the lesion and gender were JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 83, NO. 3
TABLE. MEAN MNB SCORES OF PATIENTS IN GROUP LBD AND RBD Neuropsychological RBD LBD Measures (n = 22) (n = 15) VIQ 80.70 72.50 PIQ 70.90 72.40 FSIQ 74.90 71.70 VOT 15.10 13.10 RAVENS 16.10 18.40 VRT (A) 2.73 2.50 VRT(C) 5.41 5.22 SDMT (W) 12.90 11.20 SDMT (0) 16.40 15.40 MUS 25.20 21.00 PPR30 7.86 4.30 PPR60 14.60 8.60 PPL30 2.82 9.67* PPL60 5.41 18.90* SDSSL 11.30 15.05 SDSSR 14.20 11.90 VRTMC (A) 4.70 7.10* VRTMC (C) 7.00 9.44
*P
Very few studies have been conducted that examine brain behavior functions in blacks and other ethnic minorities. Recognizing that measures of higher cortical functions have cultural, experiential, and organic determinants, the present investigation was designed to ascertain whether findings reported in neuropsychologic studies of white patients with lateralized cerebral lesions are applicable to groups of black patients with lesions in similar locations. Thirty-seven patients with left (n =15) and right (n = 22) cerebrovascular lesions were administered the Michigan Neuropsychological Battery (MNB). This battery is comprised of a number of objective standardized measures of higher and lower-level cerebral functions. With one exception, the performance of patients in the brain-injured groups was not systematically different on tests of higher brain functions. As expected, tests of lower-level somatosensory and motor functions showed a pattern of greater impairment on the side of the body contralateral to the lesion. But, in contrast to neuropsychological studies of white paFrom the Howard University Psychology Department and College of Medicine, Washington, DC. Requests for reprints should be addressed to Dr Alfonso Campbell, Jr, Psychology Department, Howard University, Washington, DC 20059. JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 83, NO. 3
tients, a pattern of laterality specific deficits on verbal IQ and performance IQ was not observed. Methodological and theoretical implications of these findings are discussed. Key words * cerebrovascular disorders* neuropsychology
During the past decade, experimental and clinical literature in human neuropsychology has grown enormously. This trend reflects increased interest in brain-behavior issues and the potential this discipline offers in providing a better understanding of the cerebral organization of psychological processes in man. Today, researchers in clinical neuropsychology, a professional specialty in human neuropsychology, have become aware that current neuropsychological assessment procedures are not only sensitive to the presence of cerebral pathology, but also such demographic factors as culture, ethnicity, gender, social class, age, and education.1-8 When current neuropsychological instruments were developed and validated, use of these measures with ethnic minorities was not of prime importance. Since blacks and other ethnic minorities have not been included in these validation studies, uncritical acceptance of neuropsychological measures as diagnostically valid indices of brain functions in these populations is unwarranted and unwise. Failure to take ethnicity/culture into account as a potential 217
CEREBROVASCULAR DISORDERS IN BLACKS
moderator variable may lead to false interpretations of neuropsychological test findings. Recognizing that measures of higher cortical functions have cultural, experiential, and organic determinants, it is important to determine whether findings reported in neuropsychological studies of white patients with lateralized cerebral lesions are generalizable to groups of black patients with similarly placed lesions. The present study was undertaken to examine this important neuropsychological issue, and to create a data base that when expanded to include similar data from blacks with different types of neurologic disorders, can be used as a normative standard.
METHOD Thirty-seven patients, 18 men and 19 women from the Washington, DC metropolitan area participated in the present investigation. These patients (mean age = 56, mean years of education = 9.5) were selected from a population admitted to the Neurology Service at Howard University Hospital with a provisional diagnosis of stroke. Twenty-two patients (Group RBD) had sustained a right hemisphere stroke and 15 (Group LBD) had cerebrovascular lesions in the left hemisphere. Criteria used to select participants in the present investigation were: 1. a focal neurological deficit on clinical neurological examination and evidence of a cerebrovascular lesion in computer axial tomography (CT-scan), electroencephalographic (EEG), arteriographic and/ or brain-scan studies, 2. right-handed prior to stroke, and 3. no previous history of psychiatric disorder, brain insults, alcohol or other drug abuse. Patients with CT scans showing single or multiple lesions incompatible with the focal neurologic deficit were not included in this study. All patients were given the Michigan Neuropsychological Battery (MNB),9 comprised of objective standardized measures of a broad range of language, verbal, and nonverbal reasoning, auditory and visual memory functions, and selected somatosensory and motor skills. Administration time for these tests varied from 3 to 4 hours. If a patient was unable to complete the test in a single administration, the examiner administered the test in the immediate ensuing days. Most patients were tested in the Physical Medicine and Rehabilitation unit. Several patients who were released from the hospital before testing could begin, were tested in their homes. After the patients agreed to participate in the study, informed consent was obtained. 218
The list of tests administered is as follows: * Wechsler Adult Intelligence Scale Revised (WAIS-R). Includes six verbal and five performance subtests which yield a verbal, performance, and full-scale IQ, in addition to objective measures of the different mental functions tapped by each of 11 subtests.'0 * Raven Coloured Progressive Matrices (RCPM). Measures nonverbal reasoning in visual modes of thought. Patients are required to examine a pattern with one section missing, then choose one from six alternatives that would complete the pattern. The RCPM is untimed and consists of 36 items.11 * Visual Retention Test (VRT). Designed to measure visual memory and constructional abilities. Each of 10 cards (Form C) with one or more designs is exposed for 10 seconds (administration A) and then withdrawn, followed by immediate reproduction from memory by the patient. To differentiate impairment of visual memory from constructional disabilities, the patient is asked to copy each of the same designs (administration C).12 * Purdue Pegboard (Purdue). Determines the presence and laterality of cerebral lesions through manual dexterity. Patients are instructed to insert pegs for 60 seconds in a column of holes in a pegboard, one at a time and as rapidly as they can, starting with the preferred hand. The test is then repeated with the non-preferred hand, and then with both hands simultaneously, with the examiner recording the number of pegs inserted in 30 and 60 seconds.13 * Symbol Digit Modalities Test (SDMT). A simple substitution test, reversing the format of the WAIS Digit Symbol subtest. In the Digit Symbol test, substitution responses are geometric designs which can only be written, whereas responses to the SDMT consist of numbers. The patient is given 90 seconds to make as many written substitutions as possible. This is followed by the oral form in which the patient speaks instead of writing numbers for another 90-second interval, with the examiner recording the responses. Thus, the SDMT permits comparisons of efficiency in performance on the same mental test in two different modalities: writing and speaking. The SDMT has proven to be the most sensitive single indicator of cerebral dysfunction and changes in the clinical picture with time and/or therapeutic intervention in the Michigan Neuropsychological Battery. Such changes are usually in the form of increased or decreased speed and efficiency in written and oral substitutions, rather than increases or decreases in errors.'4 * Single and Double Simultaneous (Face-Hand) StimJOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 83, NO. 3
CEREBROVASCULAR DISORDERS IN BLACKS
ulation Test (SDSS). Developed and standardized by Centofanti and Smith,15 it tests somatosensory functions, and is a refinement of the earlier Double Simultaneous Test. The patient is seated, asked to close his/her eyes and place the palm of each hand on the ipsilateral thigh. Patients are then required to indicate by pointing where they had been touched by the examiner after single or double simultaneous stimulations of the right and/or left cheek and/or hand. TWenty trials (eight single and 12 double simultaneous stimulations) are administered.'6' * Memory for Unrelated Sentences (MUS). While the WAIS-R Digit Span subtest provides a measure of immediate auditory memory for nonmeaningful series of random numbers, the MUS measures immediate auditory memory for semantic/syntactic materials. Patients are requested to immediately repeat after the examiner each of 10 sentences of increasing length. The test is terminated after errors are made in two consecutive sentences, and the patient's scores consist of the larger number of syllables in any sentence (Osteicher H. 1973. Unpublished data). * Visual Organization Test (VOT). The Hooper VOT consists of line drawings of common objects (for example, fish, hammer, truck, broom) that have been cut up with the pieces rearranged in random patterns. Like the Wechsler Block Design and Object Assembly subtests, the VOT provides a measure of visual-spatial-organizational abilities. However, unlike these two subtests, the pieces shown on the picture of each cut-up object cannot be moved. The test is untimed and consists of 30 items.17 * Visual Retention Test: Multiple Choice Form. Assesses capacity for complex visual form discrimination. There are 16 designs which cover a fairly broad range in terms of difficulty. Each multiple-choice item includes one correct foil and three incorrect foils. In Administration A, the patient is presented with the stimulus card for 10 seconds. Then, the patient is asked to point to or call the number of the foil that matches the stimulus design. In Administration B, the patient is presented with the stimulus design and the multiple-choice response array simultaneously; the patient's task is to discriminate among the response choices in order to identify the one design that matches the stimulus design (Benton AL. 1977. Unpublished data).
Data Analyses Scores earned on MNB measures served as dependent variables, while side of the lesion and gender were JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 83, NO. 3
TABLE. MEAN MNB SCORES OF PATIENTS IN GROUP LBD AND RBD Neuropsychological RBD LBD Measures (n = 22) (n = 15) VIQ 80.70 72.50 PIQ 70.90 72.40 FSIQ 74.90 71.70 VOT 15.10 13.10 RAVENS 16.10 18.40 VRT (A) 2.73 2.50 VRT(C) 5.41 5.22 SDMT (W) 12.90 11.20 SDMT (0) 16.40 15.40 MUS 25.20 21.00 PPR30 7.86 4.30 PPR60 14.60 8.60 PPL30 2.82 9.67* PPL60 5.41 18.90* SDSSL 11.30 15.05 SDSSR 14.20 11.90 VRTMC (A) 4.70 7.10* VRTMC (C) 7.00 9.44
*P
