Journal of Clinical and Experimental Neuropsychology
ISSN: 0168-8634 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/ncen19
Generalized cognitive function after stroke Jim Hom & Ralph M. Reitan To cite this article: Jim Hom & Ralph M. Reitan (1990) Generalized cognitive function after stroke, Journal of Clinical and Experimental Neuropsychology, 12:5, 644-654, DOI: 10.1080/01688639008401008 To link to this article: http://dx.doi.org/10.1080/01688639008401008
Published online: 04 Jan 2008.
Submit your article to this journal
Article views: 38
View related articles
Citing articles: 22 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ncen20 Download by: [University of Birmingham]
Date: 06 November 2015, At: 00:54
H 1990, Vol. 12, NO.5, pp. 644-654
Q Swets & zeitlinger
Generalized Cognitive Function after Stroke* Jim Hom University of Texas Southwestern Medical Center, Dallas, TX
Downloaded by [University of Birmingham] at 00:54 06 November 2015
Ralph M. Reitan Reitan Neuropsychology Laboratory, Tucson, AZ
ABSTRACT The present investigation was designed to determine the effect of cerebrovascular lesions upon general neuropsychological function. The performances of 60 patients with lateralized or diffuse cerebrovascular lesions were compared to 20 controls on cognitive and intellectual measures. Multivariate analyses indicated markedly poorer performances by the cerebrovascular groups on measures of generalized cerebral function, and no differences on such measures were found between the left- and right-damaged groups. The lateralized CVD groups demonstrated a differential tendency towards lower performances on VIQ for the left group and on PIQ for the right group. The results indicate significant neuropsychological impairment which extends beyond the expected lateralized dysfunctions, or selected deficits, associated with the damaged hemisphere. These findings indicate the importance of evaluating generalized as well as specific cognitive functions in clinical assessment of cerebrovascular lesions.
After heart disease and cancer, cerebrovascular disease (CVD) is the third most common cause of death in the United States (Adams & Victor, 1985; Kurtzke, 1985). The type and severity of the neurologic deficit resulting from stroke depends upon such factors as the location, size, temporal sequence, and mechanism of the stroke. The neurologic sequelae resulting from disruption in blood flow can vary tremendously, from a comatose state and hemiplegia to negligible neurologic symptoms of a transitory duration. Symptoms of mental confusion, sensorimotor deficits. aphasia, apraxia, seizures, and other dysfunctions are other clinical manifestations of stroke. Considering the frequency and importance of this neurological problem, there are surprisingly few studies concerned with intellectual, cognitive, and neuropsychological deficits associated with stroke. The primary focus of neuro-
* Address for reprints: Jim Hom, Ph.D.. Neuropsychology Laboratory, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard. Dallas, TX 752359070, USA.
Accepted for publication: October 12, 1989.
Downloaded by [University of Birmingham] at 00:54 06 November 2015
COGNITIVE FUNCTION A F E R STROKE
645
psychological investigations in stroke has been upon specific cognitive deficits, such as language, praxic, or sensorimotor function. This is likely due to the fact that the clinical symptoms of stroke have significantly aided in the diagnosis and identification of the cerebrovascular condition and, in fact, various neurovascular syndromes have been formulated which reflect the types of cerebrovascular insults to the major cerebral arteries (Adams & Victor, 1985). Reitan and Fitzhugh (1971) completed one of the first comprehensive studies of sensorimotor functioning associated with cerebrovascular lesions. A relatively consistent and orderly pattern of impairment of sensorimotor function was found that related to the lateralization of the cerebral damage, with motor and somatosensory functions more impaired contralateral to the side of the cerebral damage. Similar findings have been reported by other investigators (Finlayson & Reitan, 1980; Haaland & Delaney, 1981; Hom & Reitan, 1982; Reitan, 1970). In addition, Hom and Reitan (1 982) found greater bilateral deficits following rightcerebral-hemisphere than left-hemisphere cerebrovascular lesions. In addition to these findings, Reitan and Fitzhugh (1971) have demonstrated a relatively consistent pattern of intellectual impairment. Intragroup comparisons based upon VIQ minus PIQ values demonstrated significant differences between the lateralized stroke groups. Left cerebral strokes were found to impair VIQ more than PIQ. The reverse was found for the right stroke group: PIQ was more impaired than VIQ. No intragroup differences were found for the group with diffuse cerebrovascular lesions; their mean difference between VIQ and PIQ occupied an intermediate position between the lateralized stroke groups. Heilman (1974) has summarized some of the major language and praxic deficits found in stroke. In general, left-hemisphere cerebrovascular lesions have resulted in impairment of language-oriented functions, while right-hemisphere lesions have been associated with impairment of visual-spatial functions. As noted earlier, the primary focus of investigations in stroke has been upon specific cognitive deficits. This focus is useful in providing information about the localization of maximal cerebral damage. However, it does not provide information about more subtle cognitive deficits or about functions which are dependent upon the general integrity of the brain. In fact, impairment of cognitive functions not specifically associated with each cerebral hemisphere but that are dependent upon the general integrity of the brain has been relatively ignored. Goodglass and Kaplan (1979) and Reitan (1986) have cited the importance of the effect of cerebral lesions upon the general, as well as the specific, functions of the brain. According to these investigators, except for some rare “pure” cases, some degree of general or nonspecific deficit occurs whenever there are specific ones. Whereas measures of specific functions are dependent upon specific sites or areas in the brain, general measures are relatively independent of a particular location of impairment and reflect the overall status of brain functioning. Thus, lesions that impair various specific functions also cause some degree of impairment of the general functions. A number of investigators have advocated more extensive investigation of
Downloaded by [University of Birmingham] at 00:54 06 November 2015
646
JIM HOM AND RALPH M.REITAN
generalized cognitive and behavioral changes as opposed to focusing only on the primary motor and sensory neurologic deficits (DUMe, Leedman, & Edis, 1986; Heilman, 1974; Reinvang & Sundet, 1985; Reitan & Wolfson, 1985). The purpose of the present study was to determine whether cerebrovascular lesions cause generalized neuropsychological losses (affecting functions which are not specifically associated with a single cerebral hemisphere). It was hypothesized that cerebrovascular lesions, lateralized or diffuse, will impair performances of abilities dependent upon the general integrity of the brain. In addition, it was believed that generalized cerebral dysfunction would occur regardless of lateralization of the cerebrovascular lesion.
METHOD Subjects Three groups of 20 adult patients each with cerebrovascular disease were composed for the study: a group with left-hemisphere lesions, one with right-hemisphere lesions. and a group with diffuse or generalized lesions. The left stroke group consisted of patients with the following types of neurological involvement: 16 occlusive disease - anterior or middle cerebral artery, internal carotid artery, or internal capsule; 1 arteriovenous malformation; 2 aneurysm; and 1 intracranial hemorrhage. The right-lesion group included cerebrovascular patients: 18 occlusive disease - anterior or middle cerebral artery, internal carotid artery, or internal capsule; and 2 arteriovenous malformations. Patients with diffuse or generalized cerebrovascular lesions composed the third stroke group; they had hypertensive encephalopathy, bilateral carotid artery insufficiency, basilar artery occlusion. or generalized atherosclerosis. A control group of 20 adult subjects was also included; it consisted of 7 patients with psychiatric disorders, 3 patients with noncerebrovascular medical or neurological problems, and 10 normal controls. The cerebrovascular disease (CVD) groups consisted of patients referred to R.M.R. for neuropsychological evaluation as part of a cerebrovascular disease research program. Extensive evaluations of cerebral vascular disease were done in two clinical research units for cerebrovascular and cardiovascular disease, and no patients were included in this study unless diagnoses, based upon thorough neurological and medical evaluations, were unequivocal. These evaluations included physical neurological examination, cerebral angiography. electroencephalography, brain scan, and surgical reports, when available. Patient medical histories included chronic hypertension, cardiovascular disease, stroke, and carotid insufficiencies. The four groups were matched for age, education, and gender, and there were no significant group differences on these variables. The mean ages (SDs), in years, of the groups were as follows: right, 52.0 (9.7);left, 51.8 (8.5); diffuse, 54.0 (8.2); and controls, 54.2 (9.4) years. Their education levels (SDs), in years, were as follows: 11.9 (3.3), 11.8 (4.7). 10.3 (3.1). and 11.8 (2.0) years, respectively. The groups had comparable gender distributions (right, 16 males, 4 females; left, 18 males. 2 females; diffuse, 19 males, 1 female; and controls, 17 males, 3 females; x2 = 2.29, df = 3, n.s.). All subjects were right handed. Procedure Each patient was given an extensive battery of neuropsychological tests by technicians who had no knowledge of the diagnoses or of the research plan. The tests included the complete Halstead-Reitan Neuropsychological Test Battery for Adults (HRB; Reitan &
Downloaded by [University of Birmingham] at 00:54 06 November 2015
COGNITIVE FUNCTION AFIER STROKE
647
Wolfson, 1985) and the Wechsler Adult Intelligence Scale (WAIS; Wechsler, 1955). The variables were grouped in terms of the broader functions which they measure, based upon functional groupings used by Horn and Reitan (1982; 1984) and Hom and Fulbright (1987). The functional groupings are as follows: WAIS FSIQ, VIQ, PIQ; Verbal IQ subtests; Performance IQ subtests; Overall Brain Impairment - Halstead Impairment Index (HII); Attention and concentration - Speech-Sounds Perception Test, Seashore Rhythm Test, Trail Making Test, Part A (TMTA), and Digit Span and Arithmetic from the WAIS; Abstraction - Halstead Category Test, Tactual Performance Test Total Time (TPT Total), Trail Making Test, Part B (TMTB),and Digit Symbol from the WAIS; Incidental Memory - Tactual Performance Test Memory (TFT Memory) and Localization (TPT Localization) components; and, Motor - Halstead Finger Oscillation Test, dominant and nondominant hands. The following functional groupings are considered to be representative of the specific functions of the brain: WAIS FSIQ, VIQ, PIQ; Verbal IQ subtests; Performance IQ subtests; and, Motor. Previous studies have shown these functions to be somewhat dependent upon specific sites or areas in the brain (Doehring. Reitan, & Klove, 1961; Hom & Reitan, 1982, 1984; Klfive. 1959; Klfive & Reitan, 1958; Reitan, 1955; Reitan & Fitzhugh, 1971). The measures considered to represent the more generalized function of the brain are as follows: Overall Brain Impairment; Attention and Concentration; Abstraction; and, Incidental Memory. These functions have been shown to be relatively independent of a particular location or laterality of impairment and reflect generalized brain functioning (Doehring & Reitan, 1962; Horn & Reitan, 1984; Reitan & Wolfson, 1985, 1989; Reitan. Hom, & Wolfson, 1988).
RESULTS Multivariate analyses of variance (MANOVA) were computed to determine intergroup differences among the CVD groups and the matched control group for each functional grouping. For the Overall Brain Impairment grouping, univariate analysis of variance (ANOVA) was computed to determine differences among the groups. For statistically significant MANOVAs, a posteriori ANOVAs and Scheffd tests for multiple comparisons were computed to determine the locus of the differences within each grouping. In addition, intragroup intelligence differences were computed using the following formula: VIQ minus PIQ. Tables 1 and 2 give the raw score means, standard deviations, and ANOVA significance levels for the individual intellectual and neuropsychological measures for the C V D groups and for the control group. More detailed statistical results are presented in the text below.
Intelligence Multivariate analyses of variance yielded significant differences among the groups for the summary IQ scores (VIQ, PIQ, FSIQ), and Verbal and Performance subtest scores, F (9,180) = 7 . 3 7 , ~< .01; F (18, 201) = 1.68, p < .05; and F (15, 199) = 3.65, p < .001, respectively. Univariate analyses indicated the locus of the significant differences as being between the stroke groups and the controls for each functional grouping. Table 1 gives the raw score means, standard deviations, and the ANOVAs for each intellectual measure.
648
JIM HOM A M )RALPH M. REITAN
Table 1. Group mean raw scores and ANOVA comparisons for intellectual abilities of patients with cerebrovasculardisease. Measure
Right
Left
Diffuse
91.05 24.90 100.25 14.03 93.40 20.68
96.05 17.14 98.65 14.81 94.95 17.26
114.85 6.61 122.25 8.12 119.15 6.43
Control F (3.76)
p c
Intelligence
VIQ PIQ
Downloaded by [University of Birmingham] at 00:54 06 November 2015
FSIQ
M 104.85 SD 16.08 M 95.55 SD 17.24 M 98.80 SD 15.79
7.20
.OOO5
15.30
.OOO1
11.21
.OOO1
Verbal Subtests
Information Comprehension Digit Span Arithmetic Similarities Vocabulary
M SD M SD M SD M SD M SD M SD
9.95 2.11 10.60 3.40 7.15 3.72 8.75 4.40 10.35 2.96 10.30 3.05
7.45 4.95 8.25 5.69 4.80 4.06 5.80 5.38 7.60 5.00 7.75 5.39
9.20 3.04 8.60 3.99 5.95 3.80 6.50 4.81 7.55 4.05 9.OO 3.1 1
11.35 1.57 13.15 2.28 9.30 3.36 10.85 2.80 11.85 1.81 12.65 1.87
M
5.55 3.03 7.40 4.15 5.60 3.39 5.75 3.61 5.45 2.48
6.40 2.98 7.20 3.82 7.00 3.31 8.15 3.34 5.30 3.79
5.00 3.10 7.20 3.97 6.10 2.36 7.05 3.85 4.95 3.38
9.75 2.55 11.10 2.55 11.35 2.41 11.50 1.47 9.15 I .76
5.20
.005
6.24
.001
5.28
.002
5.31
.002
6.75
.OOO1
6.81
.OOO1
10.61
.OOO1
Performance Subtests
Picture Arrangement Picture Completion Block Design Object Assembly Digit Symbol
SD M SD M SD M SD M SD
5.45
.005
16.26
.OOO1
11.78
.OOO1
8.87
.OOO1
For VIQ, the control group was found to be significantly superior in intellectual functioning to the left and diffuse CVD groups. However, no significant difference was in evidence between the right CVD group and the controls. PIQ and FSIQ were found to be significantly worse in all the CVD groups compared to the controls. No significant differences were found among the CVD groups on any of the summary IQ measures. In terms of the individual Verbal subtests, the left CVD group had the lowest mean scores on 4 of the 5 measures (except Similarities) followed by the diffuse CVD group. The right CVD group had the best mean performances compared to
Downloaded by [University of Birmingham] at 00:54 06 November 2015
COGNITIVE FUNCTION A F E R STROKE
649
the other CVD groups on all individual verbal subtests. The left CVD group’s mean scores were significantly poorer on all the individual Verbal subtests as compared to the matched controls. In addition, the scores of the diffuse CVD group were found to be significantly worse than the controls on the Comprehension, Arithmetic, and Similarities subtests. No significant differences were found between the right CVD group and the controls or among the CVD groups. For the Performance subtests, all three CVD groups were found to have significantly poorer scores on all individual subtests as compared to the matched controls. However, no significant differences were found among the CVD groups, indicating similar degrees of perceptual-motor IQ impairment among the stroke groups. Major differences were found among groups on Verbal and Performance IQ discrepancies (VIQ minus PIQ). Univariate ANOVA indicated a highly significant difference among the groups ( F (3, 76) = 7 . 8 2 , < ~ .001). Verbal IQ abilities were lower relative to perceptual-motor IQ abilities in the left CVD group (M = -9.20, SD = 16.84), diffuse CVD group (M = -2.60, SD = 9.50), and controls (M = -7.40, SD = 8.76). In contrast, the right CVD group had lower perceptualmotor IQ abilities relative to verbal IQ abilities (M = 9.30, SD = 16.10). Scheffd multiple comparisons indicated significant differences between the left and right CVD groups and between the right CVD group and the matched controls at the .05 level of statistical significance.
Overall Brain Impairment Statistical comparison of the HI1 values for the groups yielded significantly worse HI1 values for all three stroke groups as compared to the matched controls, F (3, 76) = 27.51, p < .0001. No significant differences were found among the stroke groups. These findings clearly indicate a considerable degree of brain dysfunction in stroke. The lateralization of the cerebrovascular lesions did not differentially affect the level of overall brain impairment. Apparently, regardless of side of cerebral lesion, stroke can cause significant impairment of higher cognitive abilities in a generalized manner. Attention and Concentration The multivariate analysis of the measures in this grouping demonstrated the presence of significant intergroup differences among the CVD and control groups in attention and concentration abilities, F (15, 199) = 2 . 2 5 , < ~ .01. Table 2 presents the group performance means and standard deviations along with the significance level for ANOVAs for each measure. On each of the five measures, the matched control group’s mean scores were better than those of the stroke groups. Univariate analyses indicated statistically significant differences in the following comparisons with controls: (1) versus left CVDs on Digit Span; (2) versus left and diffuse CVDs on Arithmetic; (3) versus all three CVD groups on Seashore Rhythm; (4) versus left and diffuse CVDs on Speech-Sounds Perception; and, (5) versus diffuse CVDs on TMTA.
650
JIM HOM AND RALPH M. REITAN
Table 2. Group mean raw scores and ANOVA comparisons for general neuropsychological and motor abilities. Measure
Right
Left
Diffuse
Control
F (3.76)
p
ISSN: 0168-8634 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/ncen19
Generalized cognitive function after stroke Jim Hom & Ralph M. Reitan To cite this article: Jim Hom & Ralph M. Reitan (1990) Generalized cognitive function after stroke, Journal of Clinical and Experimental Neuropsychology, 12:5, 644-654, DOI: 10.1080/01688639008401008 To link to this article: http://dx.doi.org/10.1080/01688639008401008
Published online: 04 Jan 2008.
Submit your article to this journal
Article views: 38
View related articles
Citing articles: 22 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ncen20 Download by: [University of Birmingham]
Date: 06 November 2015, At: 00:54
H 1990, Vol. 12, NO.5, pp. 644-654
Q Swets & zeitlinger
Generalized Cognitive Function after Stroke* Jim Hom University of Texas Southwestern Medical Center, Dallas, TX
Downloaded by [University of Birmingham] at 00:54 06 November 2015
Ralph M. Reitan Reitan Neuropsychology Laboratory, Tucson, AZ
ABSTRACT The present investigation was designed to determine the effect of cerebrovascular lesions upon general neuropsychological function. The performances of 60 patients with lateralized or diffuse cerebrovascular lesions were compared to 20 controls on cognitive and intellectual measures. Multivariate analyses indicated markedly poorer performances by the cerebrovascular groups on measures of generalized cerebral function, and no differences on such measures were found between the left- and right-damaged groups. The lateralized CVD groups demonstrated a differential tendency towards lower performances on VIQ for the left group and on PIQ for the right group. The results indicate significant neuropsychological impairment which extends beyond the expected lateralized dysfunctions, or selected deficits, associated with the damaged hemisphere. These findings indicate the importance of evaluating generalized as well as specific cognitive functions in clinical assessment of cerebrovascular lesions.
After heart disease and cancer, cerebrovascular disease (CVD) is the third most common cause of death in the United States (Adams & Victor, 1985; Kurtzke, 1985). The type and severity of the neurologic deficit resulting from stroke depends upon such factors as the location, size, temporal sequence, and mechanism of the stroke. The neurologic sequelae resulting from disruption in blood flow can vary tremendously, from a comatose state and hemiplegia to negligible neurologic symptoms of a transitory duration. Symptoms of mental confusion, sensorimotor deficits. aphasia, apraxia, seizures, and other dysfunctions are other clinical manifestations of stroke. Considering the frequency and importance of this neurological problem, there are surprisingly few studies concerned with intellectual, cognitive, and neuropsychological deficits associated with stroke. The primary focus of neuro-
* Address for reprints: Jim Hom, Ph.D.. Neuropsychology Laboratory, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard. Dallas, TX 752359070, USA.
Accepted for publication: October 12, 1989.
Downloaded by [University of Birmingham] at 00:54 06 November 2015
COGNITIVE FUNCTION A F E R STROKE
645
psychological investigations in stroke has been upon specific cognitive deficits, such as language, praxic, or sensorimotor function. This is likely due to the fact that the clinical symptoms of stroke have significantly aided in the diagnosis and identification of the cerebrovascular condition and, in fact, various neurovascular syndromes have been formulated which reflect the types of cerebrovascular insults to the major cerebral arteries (Adams & Victor, 1985). Reitan and Fitzhugh (1971) completed one of the first comprehensive studies of sensorimotor functioning associated with cerebrovascular lesions. A relatively consistent and orderly pattern of impairment of sensorimotor function was found that related to the lateralization of the cerebral damage, with motor and somatosensory functions more impaired contralateral to the side of the cerebral damage. Similar findings have been reported by other investigators (Finlayson & Reitan, 1980; Haaland & Delaney, 1981; Hom & Reitan, 1982; Reitan, 1970). In addition, Hom and Reitan (1 982) found greater bilateral deficits following rightcerebral-hemisphere than left-hemisphere cerebrovascular lesions. In addition to these findings, Reitan and Fitzhugh (1971) have demonstrated a relatively consistent pattern of intellectual impairment. Intragroup comparisons based upon VIQ minus PIQ values demonstrated significant differences between the lateralized stroke groups. Left cerebral strokes were found to impair VIQ more than PIQ. The reverse was found for the right stroke group: PIQ was more impaired than VIQ. No intragroup differences were found for the group with diffuse cerebrovascular lesions; their mean difference between VIQ and PIQ occupied an intermediate position between the lateralized stroke groups. Heilman (1974) has summarized some of the major language and praxic deficits found in stroke. In general, left-hemisphere cerebrovascular lesions have resulted in impairment of language-oriented functions, while right-hemisphere lesions have been associated with impairment of visual-spatial functions. As noted earlier, the primary focus of investigations in stroke has been upon specific cognitive deficits. This focus is useful in providing information about the localization of maximal cerebral damage. However, it does not provide information about more subtle cognitive deficits or about functions which are dependent upon the general integrity of the brain. In fact, impairment of cognitive functions not specifically associated with each cerebral hemisphere but that are dependent upon the general integrity of the brain has been relatively ignored. Goodglass and Kaplan (1979) and Reitan (1986) have cited the importance of the effect of cerebral lesions upon the general, as well as the specific, functions of the brain. According to these investigators, except for some rare “pure” cases, some degree of general or nonspecific deficit occurs whenever there are specific ones. Whereas measures of specific functions are dependent upon specific sites or areas in the brain, general measures are relatively independent of a particular location of impairment and reflect the overall status of brain functioning. Thus, lesions that impair various specific functions also cause some degree of impairment of the general functions. A number of investigators have advocated more extensive investigation of
Downloaded by [University of Birmingham] at 00:54 06 November 2015
646
JIM HOM AND RALPH M.REITAN
generalized cognitive and behavioral changes as opposed to focusing only on the primary motor and sensory neurologic deficits (DUMe, Leedman, & Edis, 1986; Heilman, 1974; Reinvang & Sundet, 1985; Reitan & Wolfson, 1985). The purpose of the present study was to determine whether cerebrovascular lesions cause generalized neuropsychological losses (affecting functions which are not specifically associated with a single cerebral hemisphere). It was hypothesized that cerebrovascular lesions, lateralized or diffuse, will impair performances of abilities dependent upon the general integrity of the brain. In addition, it was believed that generalized cerebral dysfunction would occur regardless of lateralization of the cerebrovascular lesion.
METHOD Subjects Three groups of 20 adult patients each with cerebrovascular disease were composed for the study: a group with left-hemisphere lesions, one with right-hemisphere lesions. and a group with diffuse or generalized lesions. The left stroke group consisted of patients with the following types of neurological involvement: 16 occlusive disease - anterior or middle cerebral artery, internal carotid artery, or internal capsule; 1 arteriovenous malformation; 2 aneurysm; and 1 intracranial hemorrhage. The right-lesion group included cerebrovascular patients: 18 occlusive disease - anterior or middle cerebral artery, internal carotid artery, or internal capsule; and 2 arteriovenous malformations. Patients with diffuse or generalized cerebrovascular lesions composed the third stroke group; they had hypertensive encephalopathy, bilateral carotid artery insufficiency, basilar artery occlusion. or generalized atherosclerosis. A control group of 20 adult subjects was also included; it consisted of 7 patients with psychiatric disorders, 3 patients with noncerebrovascular medical or neurological problems, and 10 normal controls. The cerebrovascular disease (CVD) groups consisted of patients referred to R.M.R. for neuropsychological evaluation as part of a cerebrovascular disease research program. Extensive evaluations of cerebral vascular disease were done in two clinical research units for cerebrovascular and cardiovascular disease, and no patients were included in this study unless diagnoses, based upon thorough neurological and medical evaluations, were unequivocal. These evaluations included physical neurological examination, cerebral angiography. electroencephalography, brain scan, and surgical reports, when available. Patient medical histories included chronic hypertension, cardiovascular disease, stroke, and carotid insufficiencies. The four groups were matched for age, education, and gender, and there were no significant group differences on these variables. The mean ages (SDs), in years, of the groups were as follows: right, 52.0 (9.7);left, 51.8 (8.5); diffuse, 54.0 (8.2); and controls, 54.2 (9.4) years. Their education levels (SDs), in years, were as follows: 11.9 (3.3), 11.8 (4.7). 10.3 (3.1). and 11.8 (2.0) years, respectively. The groups had comparable gender distributions (right, 16 males, 4 females; left, 18 males. 2 females; diffuse, 19 males, 1 female; and controls, 17 males, 3 females; x2 = 2.29, df = 3, n.s.). All subjects were right handed. Procedure Each patient was given an extensive battery of neuropsychological tests by technicians who had no knowledge of the diagnoses or of the research plan. The tests included the complete Halstead-Reitan Neuropsychological Test Battery for Adults (HRB; Reitan &
Downloaded by [University of Birmingham] at 00:54 06 November 2015
COGNITIVE FUNCTION AFIER STROKE
647
Wolfson, 1985) and the Wechsler Adult Intelligence Scale (WAIS; Wechsler, 1955). The variables were grouped in terms of the broader functions which they measure, based upon functional groupings used by Horn and Reitan (1982; 1984) and Hom and Fulbright (1987). The functional groupings are as follows: WAIS FSIQ, VIQ, PIQ; Verbal IQ subtests; Performance IQ subtests; Overall Brain Impairment - Halstead Impairment Index (HII); Attention and concentration - Speech-Sounds Perception Test, Seashore Rhythm Test, Trail Making Test, Part A (TMTA), and Digit Span and Arithmetic from the WAIS; Abstraction - Halstead Category Test, Tactual Performance Test Total Time (TPT Total), Trail Making Test, Part B (TMTB),and Digit Symbol from the WAIS; Incidental Memory - Tactual Performance Test Memory (TFT Memory) and Localization (TPT Localization) components; and, Motor - Halstead Finger Oscillation Test, dominant and nondominant hands. The following functional groupings are considered to be representative of the specific functions of the brain: WAIS FSIQ, VIQ, PIQ; Verbal IQ subtests; Performance IQ subtests; and, Motor. Previous studies have shown these functions to be somewhat dependent upon specific sites or areas in the brain (Doehring. Reitan, & Klove, 1961; Hom & Reitan, 1982, 1984; Klfive. 1959; Klfive & Reitan, 1958; Reitan, 1955; Reitan & Fitzhugh, 1971). The measures considered to represent the more generalized function of the brain are as follows: Overall Brain Impairment; Attention and Concentration; Abstraction; and, Incidental Memory. These functions have been shown to be relatively independent of a particular location or laterality of impairment and reflect generalized brain functioning (Doehring & Reitan, 1962; Horn & Reitan, 1984; Reitan & Wolfson, 1985, 1989; Reitan. Hom, & Wolfson, 1988).
RESULTS Multivariate analyses of variance (MANOVA) were computed to determine intergroup differences among the CVD groups and the matched control group for each functional grouping. For the Overall Brain Impairment grouping, univariate analysis of variance (ANOVA) was computed to determine differences among the groups. For statistically significant MANOVAs, a posteriori ANOVAs and Scheffd tests for multiple comparisons were computed to determine the locus of the differences within each grouping. In addition, intragroup intelligence differences were computed using the following formula: VIQ minus PIQ. Tables 1 and 2 give the raw score means, standard deviations, and ANOVA significance levels for the individual intellectual and neuropsychological measures for the C V D groups and for the control group. More detailed statistical results are presented in the text below.
Intelligence Multivariate analyses of variance yielded significant differences among the groups for the summary IQ scores (VIQ, PIQ, FSIQ), and Verbal and Performance subtest scores, F (9,180) = 7 . 3 7 , ~< .01; F (18, 201) = 1.68, p < .05; and F (15, 199) = 3.65, p < .001, respectively. Univariate analyses indicated the locus of the significant differences as being between the stroke groups and the controls for each functional grouping. Table 1 gives the raw score means, standard deviations, and the ANOVAs for each intellectual measure.
648
JIM HOM A M )RALPH M. REITAN
Table 1. Group mean raw scores and ANOVA comparisons for intellectual abilities of patients with cerebrovasculardisease. Measure
Right
Left
Diffuse
91.05 24.90 100.25 14.03 93.40 20.68
96.05 17.14 98.65 14.81 94.95 17.26
114.85 6.61 122.25 8.12 119.15 6.43
Control F (3.76)
p c
Intelligence
VIQ PIQ
Downloaded by [University of Birmingham] at 00:54 06 November 2015
FSIQ
M 104.85 SD 16.08 M 95.55 SD 17.24 M 98.80 SD 15.79
7.20
.OOO5
15.30
.OOO1
11.21
.OOO1
Verbal Subtests
Information Comprehension Digit Span Arithmetic Similarities Vocabulary
M SD M SD M SD M SD M SD M SD
9.95 2.11 10.60 3.40 7.15 3.72 8.75 4.40 10.35 2.96 10.30 3.05
7.45 4.95 8.25 5.69 4.80 4.06 5.80 5.38 7.60 5.00 7.75 5.39
9.20 3.04 8.60 3.99 5.95 3.80 6.50 4.81 7.55 4.05 9.OO 3.1 1
11.35 1.57 13.15 2.28 9.30 3.36 10.85 2.80 11.85 1.81 12.65 1.87
M
5.55 3.03 7.40 4.15 5.60 3.39 5.75 3.61 5.45 2.48
6.40 2.98 7.20 3.82 7.00 3.31 8.15 3.34 5.30 3.79
5.00 3.10 7.20 3.97 6.10 2.36 7.05 3.85 4.95 3.38
9.75 2.55 11.10 2.55 11.35 2.41 11.50 1.47 9.15 I .76
5.20
.005
6.24
.001
5.28
.002
5.31
.002
6.75
.OOO1
6.81
.OOO1
10.61
.OOO1
Performance Subtests
Picture Arrangement Picture Completion Block Design Object Assembly Digit Symbol
SD M SD M SD M SD M SD
5.45
.005
16.26
.OOO1
11.78
.OOO1
8.87
.OOO1
For VIQ, the control group was found to be significantly superior in intellectual functioning to the left and diffuse CVD groups. However, no significant difference was in evidence between the right CVD group and the controls. PIQ and FSIQ were found to be significantly worse in all the CVD groups compared to the controls. No significant differences were found among the CVD groups on any of the summary IQ measures. In terms of the individual Verbal subtests, the left CVD group had the lowest mean scores on 4 of the 5 measures (except Similarities) followed by the diffuse CVD group. The right CVD group had the best mean performances compared to
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the other CVD groups on all individual verbal subtests. The left CVD group’s mean scores were significantly poorer on all the individual Verbal subtests as compared to the matched controls. In addition, the scores of the diffuse CVD group were found to be significantly worse than the controls on the Comprehension, Arithmetic, and Similarities subtests. No significant differences were found between the right CVD group and the controls or among the CVD groups. For the Performance subtests, all three CVD groups were found to have significantly poorer scores on all individual subtests as compared to the matched controls. However, no significant differences were found among the CVD groups, indicating similar degrees of perceptual-motor IQ impairment among the stroke groups. Major differences were found among groups on Verbal and Performance IQ discrepancies (VIQ minus PIQ). Univariate ANOVA indicated a highly significant difference among the groups ( F (3, 76) = 7 . 8 2 , < ~ .001). Verbal IQ abilities were lower relative to perceptual-motor IQ abilities in the left CVD group (M = -9.20, SD = 16.84), diffuse CVD group (M = -2.60, SD = 9.50), and controls (M = -7.40, SD = 8.76). In contrast, the right CVD group had lower perceptualmotor IQ abilities relative to verbal IQ abilities (M = 9.30, SD = 16.10). Scheffd multiple comparisons indicated significant differences between the left and right CVD groups and between the right CVD group and the matched controls at the .05 level of statistical significance.
Overall Brain Impairment Statistical comparison of the HI1 values for the groups yielded significantly worse HI1 values for all three stroke groups as compared to the matched controls, F (3, 76) = 27.51, p < .0001. No significant differences were found among the stroke groups. These findings clearly indicate a considerable degree of brain dysfunction in stroke. The lateralization of the cerebrovascular lesions did not differentially affect the level of overall brain impairment. Apparently, regardless of side of cerebral lesion, stroke can cause significant impairment of higher cognitive abilities in a generalized manner. Attention and Concentration The multivariate analysis of the measures in this grouping demonstrated the presence of significant intergroup differences among the CVD and control groups in attention and concentration abilities, F (15, 199) = 2 . 2 5 , < ~ .01. Table 2 presents the group performance means and standard deviations along with the significance level for ANOVAs for each measure. On each of the five measures, the matched control group’s mean scores were better than those of the stroke groups. Univariate analyses indicated statistically significant differences in the following comparisons with controls: (1) versus left CVDs on Digit Span; (2) versus left and diffuse CVDs on Arithmetic; (3) versus all three CVD groups on Seashore Rhythm; (4) versus left and diffuse CVDs on Speech-Sounds Perception; and, (5) versus diffuse CVDs on TMTA.
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Table 2. Group mean raw scores and ANOVA comparisons for general neuropsychological and motor abilities. Measure
Right
Left
Diffuse
Control
F (3.76)
p
