Journal of Consulting and Clinical Psychology 1977, Vol. 45, No. 4, 536-542
Relationship of Level of Education to Neuropsychological Measures in Brain-Damaged and Non-Brain-Damaged Adults M. A. J. Finlayson Hamilton Psychiatric Hospital, Ontario, Canada, and Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada
K. A. Johnson and R. M. Reitan University of Washington The present study investigated the effect of level of education upon measures of psychometric intelligence and neuropsychological adaptation in brain-damaged and control adults. The purpose was to determine whether, and to what extent, level of education would influence these measures. Fifty-one braindamaged and 51 control subjects were assigned to grade school, high school, or university groups, depending upon their level of education. All persons received the Wechsler-Bellevuc, Halstead's Neuropsychological Test Battery, and the Trail Making Test. The results indicated that both brain damage and level of education had a pronounced effect upon the measures. The nature of these results and their implications for clinical assessment are discussed. Level of education is invariably considered as a control variable in studies of psychological abilities. Investigations involving level of education as an independent variable have been generally in the context of criticisms of the methodology of cross-sectional research approaches to the study of aging effects (e.g., Birren & Morrison, 1961; Green, 1969). The relationship of level of education to intellectual abilities is well-known. In an excellent, review, Matarazzo (1972) pointed to a correlation of .70 as representing the relationship between level of education and 1Q in adults generally. Much less is known about the relationship between level of education and other measures of adaptive ability. Even less is known about these relationships in adults with well-documented brain lesions. Benton, Levin, and Van Allen (1974) found that education influenced performance This research was supported by a grant from the Ontario Mental Health Foundation to the first author and by Grant HD-022V4 from the National Institute of Health to the Child Development and Mental Retardation Center, University of Washington. Requests for reprints should be sent to M. Alan J. Finlayson, Neuropsychiatry Programme, Hamilton Psychiatric Hospital, Hamilton, Ontario, Canada, L9C 3N6.
on a test of geographic orientation in braindamaged and control persons. They also found an interaction between education and diagnostic categories. The low-education braindamaged group performed less well relative to its appropriate control group than did the brain-damaged group with higher education. Vega and Parsons (1967) reported that level of education was positively correlated with performance on several of Halstead's tests in their control group but not among their brain-damaged subjects. In view of the increasing application of Halstead's tests and related measures to clinical questions in the area of brain-behavior relationships, it was felt that a systematic evaluation of the effects of education upon these measures should be undertaken. It seemed reasonable, therefore, to compose groups of people with and without brain lesions who differ in level of education and to compare their performances on the Wechsler-Bellevue Scale, Halstead's tests, and the Trail Making Test, Parts A and B. Method Subjects Fifty-one persons with unequivocal evidence of brain damage (based on detailed neurological pro-
536
537
NEUROPSYCHOLOGICAL MEASURES
Table 1 Means and Standard Deviations for Age, Education, and IQ Values for Each Group Grade school Variable Age Brain-damaged Control Education Brain damaged Control Full Scale IQ Brain damaged Control Verbal IQ Brain damaged Control Performance IQ Brain damaged Control
University
High school
M
SD
M
SD
M
SD
3S.S3 34.12
8.19
8.72
34.53 34.47
7.07 7.36
34.76 35.22
9.05 7.78
7.82 7.94
1.63 1.71
12.00 12.00
0 0
17.06 17.35
1.78 1.66
87.00 101.88
17.90 10.23
92.20 112.71
13.50 12.21
103.00 129.53
17.40 7.58
89.35 98.12
19.11 9.53
92.50 110.00
15.10 11.40
108.00 127.71
15.80 8.22
86.80 106.24
17.70 10.38
94.20 113.00
19.40 12.80
97.60 126.88
18.50 7.31
ccdures) and 51 control persons were assigned to pairs of groups on the basis of number of years of formal education that each had completed. Persons with at least 3 years of college credit formed the university groups; persons who had completed Grade 12 but who had not gone to college constituted the high school groups; and persons with less than 10 years of education composed the grade school groups. All persons were male. Each group contained 15 righthanded and 2 left-handed persons. The groups did not differ in mean age, and at each education level the brain-damaged and control groups did not differ in mean years of education. Table 1 contains a summary of the descriptive variables for each group. Essentially conservative procedures were used in forming the groups. To avoid confounding the results with the effects of aging, only persons less than 50 years old were included in the study. Also, in addition to normally functioning individuals, the control groups contained hospitalized medical and psychiatric patients. In forming the brain-damaged groups, patients were included on the basis of clear evidence of brain damage, established by detailed neurological investigations. Patients with traumatic, neoplastic, and cerebral vascular damage were equally represented in the three brain-damaged groups. This last procedure was adopted to avoid the confounding effects of the type, and possibly of the extent of the lesions.
However, mention of the individual measures will be made at this time. The Wechsler-Bellevue Scale provides summary measures of Verbal IQ, Performance IQ, and Full Scale IQ, based upon scores on six verbal and five performance subtests. The following Halstead variables were studied: Category Test, Tactual Performance Test (Total Time, Memory, and Localization components), Seashore Rhythm Test, Speech-Sounds Perception Test, and the Finger Oscillation Test (scores on the nondominant side were also available for 84 of the 102 persons). Additionally, Parts A and B of the Trail Making Test were administered to each person.
Data Analysis The combined raw score distributions for the six groups were converted into a normalized T-score distribution with a mean of 50 and a standard deviation of 10 for each of the variables used in the study. The original six groups were analyzed by means of separate 2 X 3 analyses of variance. Tests of a posteriori significance were conducted using the NewmanKeuls procedure. The comparisons of interest were between the brain-damaged groups and their appropriate control groups and among the levels of education within the brain-damagcd-control dimension.
Dependent Variables The Wechsler-Bellevue Scale (Form I), Halstead's Neuropsychological Test Battery, and the Trail Making Test, Parts A and B, were administered individually to each person by examiners specially trained in neuropsychological testing procedures. These measures are in routine clinical use and have been more fully described elsewhere (Reitan & Davison, 1974).
Results
The results have been subdivided to facilitate their presentation. Figure 1 is a graphic representation of the mean T-score performance for each of the six groups on the summary
538
A. FINLAYSON, K. JOHNSON, AND R. REITAN
VIO
PIQ Control A - - A University n a High Sclinol O---O Gride Sttel
Brain Damagi A A • • • •
Figure 1. Mean T scores for each group on the Wechsler-Bellevue Scale. (VIQ = Verbal IQ; PIQ = Performance IQ; FSIQ = Full Scale IQ; 1 = Information; C = Comprehension; DS = Digit Span; A = Arithmetic; S = Similarities; V = Vocabulary; PA = Picture Arrangement; PC = Picture Completion; BD = Block Design; OA = Object Assembly; DSy = Digit Symbol.)
and subtest measures of the Wechsler-Bellevue Scale. The scores on each of these variables were analyzed by means of separate 3 X 2 analyses of variance. Table 2 contains the summary of the a posteriori tests (Newman-Keuls procedure). For these comparisons a significance level of p < .05 was accepted as being beyond chance expectations. The main effect for the brain-damagedcontrol dimension was highly significant for each measure. The differences were beyond chance expectations (p < .001) for all comparisons except the Vocabulary subtest (p < .005). Level of education also had a significant effect upon the obtained results, failing to reach significance only in the case of the Object Assembly subtest. By and large these factors were additive or independent. However, the interaction effects were significant (p < .05) for Performance IQ, Vocabulary, and Digit Symbol comparisons. These effects seemed to obtain because of the large differences among the control groups and the relatively small differences among the braindamaged groups. Inspection of Table 2 and Figure 1 indicates that there was no overlap of the mean performances of the brain-damaged and control groups for Performance IQ and the
Performance subtests. The differences between control and brain-damaged groups for each level of education were significant (p < .05) in every instance on these measures. On these same measures, level of education did not differentiate among the brain-damaged groups. Among the control groups, however, level of education separated all groups on the Digit Symbol subtest: the university from high school and grade school groups on Performance IQ and Block Design and the university and grade school groups on Picture Completion. However, level of education did not separate the groups on Picture Arrangement and Object Assembly. There was some overlap of the braindamaged and control groups on the remaining Wechsler-Bellevue variables (Full Scale IQ, Verbal IQ, and the Verbal subtests). This was particularly evident on Vocabulary, Information, Similarities, and Comprehension. Table 2 indicates that for these remaining measures, statistically significant differences between the control and brain-damaged grade school groups were found only on the Arithmetic subtest and Full Scale IQ. However, the remaining comparisons of brain-damaged and control groups were statistically significant (p < .05) except for Similarities with the high school groups. Among the brain-damaged
NEUROPSYCHOLOGICAL MEASURES
groups, level of education had a consistent effect on Verbal IQ, Full Scale 1Q, and the verbal subtests. For all of these measures, the high school and grade school groups were not significantly different from each other, but both were significantly different from the university group. Among the control groups the effect of level of education was least for the Arithmetic subtest. (University and grade school groups differed significantly.) The university group significantly exceeded the high school and grade school groups on Comprehension and Similarities, and all three groups were separated on Verbal IQ, Full Scale IQ, and the Information, Digit Span, and Vocabulary subtests. Figure 2 presents the mean T-score performance of each of the groups on the Halstead and related measures. The results on these measures were analyzed by means of 3 X 2 analyses of variance for each measure separately. The main effect of the braindamaged-control dimension was highly significant (p < .001) in each of the 10 instances. Level of education had a significant main effect for the Seashore Rhythm and SpeechSounds Perception tests (p < .001), the Category test (p < .005), the Trail Making Test, Part A (p < .01), and the Trail Making Test, Part B (p < .05). The nonsignificant F ratios for the interaction terms imply that these factors had independent or additive effects. Table 3 contains a summary of the a posteriori comparisons (Newman-Keuls procedure). At each level of education, the braindamaged groups were significantly different than their appropriate control group, except in the case of the grade school groups for the dominant hand tapping and the Memory component of the Tactual Performance Test. Among the brain-damaged groups, level of education had a significant effect only for the Seashore Rhythm Test (university group exceeded both the high school and grade school groups) and the Speech-Sounds Perception Test (university group exceeded the grade school group). Among the control groups level of education was not a significant variable on the Total Time, Memory, or Location components of the Tactual Performance Test or the measures of finger tapping speed. Significant differences were found on the
539
Table 2 Summary of the Newman-Keuls Analysis for Each of the Wechsler-Bellevue Variables Variable Verbal IQ Brain damaged Controls Performance IQ Brain damaged Controls Full Scale IQ Brain damaged Controls Information Brain damaged Controls Comprehension Brain damaged Controls Digit Span Brain damaged Controls Arithmetic Brain damaged Controls Similarities Brain damaged Controls Vocabulary Brain damaged Controls Picture Arrangement Brain damaged Controls Picture Completion Brain damaged Controls Block Design Brain damaged Controls Object Assembly Brain damaged Controls Digit Symbol Brain damaged Controls
Grade school
High school
University
42.29a 46.18
43.53al 51.651 52.82 J 63.29 J
41.88.1 44.76al 46.35al 50.35. J 54.06.J 62.94 J 41.06.1 43.82al 49.001 48.29 J 53.76 J 63.94 J 42.12a 43.82
45.29al 52.761 53.06 J 61.35 J
44.41. 47.29 0
44.35al 51.881 50.35aJ 61.76 J
44.65a 45.82
44.65.1 52.711 53.79 J 60.59 J
43.65a~| 43.650 1 49.59 1 49.24aJ 54.65a,hJ 59.47bJ 41.82, 46.12n
46.71a 51.00.
52.411 61.18J
43.71. 42.94
47.29al 51.821 52.47 J 62.53 J
42.59a1 46.12al 47.88al 52.47J 52.76aJ 58.47nJ 43.41.1 46.29a I47.24al 49.180J 53.76a,bJ 59.35bJ 43.6Sal 44.59.1 46.76,1 S0.53J S4.00aJ 60.65 J 42.24a~| 47.35al 47.35al S3.06aJ 54.41J 56.76aJ 42.29al 44.24al 46.28a~| 48.53 J 54.82 J 62.76 J
Note. Values (reading horizontally) that share a common subscript do not differ significantly. A bracket (reading vertically) between two values indicates that they differ beyond the .05 level.
Category test (university group exceeded both of the other two groups); Seashore Rhythm Test (university group exceeded the grade school group); Speech-Sounds Perception test (grade school was poorer than both of the other two groups); Trail Making Test, Part A
540
A. FINLAYSON, K. JOHNSON, AND R. REITAN
CAT
TPT-T TPT-M
TPT-l
FT-0
FT-NO
TrA
TrB
Control Brain Damage £,--& University D---CD High School O---O Grade School Pigme 2. Mean 7"-score performance on Halstcad's tests and the Trail Making Test. (CAT = Category Test; TPT-T = Tactual Performance, Total Time component; TPT-M = Tactual Performance Test, Memory component; TPT-L = Tactual Performance Test, Localization component; SRT = Seashore Rhythm Test; SPT = Speech-Sounds Perception Test; F'T-D = Finger Oscillation Test, dominant side; FT-NI) = Finger Oscillation Test, nondominant side; TrA = Trail Making Test, Form A; TrB = Trail Making Test, Form B.)
(university group exceeded both of the other groups); and Trail Making Test, Part B (university group exceeded the grade school group). Discussion The clearest finding that emerged from the present investigation was the separation of the brain-damaged and control groups on the measures used. In effect, this demonstrates the sensitivity of these measures to the integrity of the cerebral cortex. This was not unexpected (e.g., K10vc, 1974; Reitan, 1955, 1956, 1958, 1975; Vega & Parsons, 1967). The main effect was highly significant for every dependent variable. Furthermore, on every comparison, the university control group performed significantly better than the university brain-damaged group; the high school control group exceeded the braindamaged group (high school) on every measure
except Similarities. The separation of the grade school groups was not as complete, since the groups did not differ significantly on Verbal IQ; Information; Comprehension; Vocabulary; Tactual Performance Test, Memory component; and dominant hand finger tapping. Level of education also had an effect upon the data. However, it did not appear to exert as consistent an effect as did brain damage. Among the control groups, the university-educated persons clearly exceeded the other two groups. This was most apparent on the Verbal subtests of the WechslerBellevue Scale. These differences were less clear-cut on the Halstead and Trail Making Test measures. On 10 of the 14 Wechsler variables, the university control group exceeded both of the other control groups, whereas on only 2 of the 10 other variables did this occur. It has been demonstrated
NEUROPSYCHOLOGICAL MEASURES
that the Halstead measures are more sensitive to the integrity of the brain than are the Wechsler-Bellevue measures (Reitan, 1959, 1975). Thus, the striking differences for education on the Wechsler tests are considerably reduced on measures that more clearly relate to the adequacy of brain functioning. Level of education also had an effect among the brain-damaged groups, albeit to a lesser degree. It was most pronounced on the verbal aspects of the Wechsler-Bellevue and the Seashore Rhythm Test. On these measures the university brain-damaged group exceeded both of the other groups. On the SpeechSounds Perception Test, the university braindamaged group exceeded only the grade school group. On the remaining measures the effects of level of education were not demonstrated for the brain-damaged groups. The measures on which level of education had an influence have in common auditory-verbal and language requirements. It may be the case that these abilities are more highly developed or overlearned in the university population and hence are more resistant to the deleterious effects of cerebral dysfunction. In this connection, it was observed that the magnitude of the F ratios for level of education was larger on the Wechsler verbal subtests and somewhat smaller on the remaining variables, whereas the opposite relationship obtained for the effects of brain damage. Reed and Fitzhugh (1966) and Reitan (1972, 1975) have maintained that tests most sensitive to the effects of brain damage are those that require immediate problem-solving skills. On the other hand, tests that tap abilities which have been developed over a number of years are much less sensitive to the effects of brain lesions. The pattern of results in the present study supports this position. In fact, it could be argued that the effects of education, as might be expected, are most pronounced on the measures of stored information and have little relationship to immediate problem-solving tasks. Vega and Parsons (1967) reported no relationship between level of education and the Halstead variables for their brain-damaged subjects and several significant correlations for their medical-surgical control group. Prigatano and Parsons (1976), also using a
541
Table 3 Summary oj the Newman-Keuls Analyses of the Halstead Measures and Parts A and B oj the Trail Making Test Variable
Grade school
High school
University
Halstead measure CAT
41.82*1 41.53»1 46.12al Brain damaged S3.94aJ SS.18*J 61.41 J Controls TPT-T 42.29*1 45.00*1 43.47*1 Brain damaged S4.06*J 56.24*J 58.82*J Controls TPT-M 46.24* 46.41*1 46.53*1 Brain damaged 49.65* 54.24*J 55.59*J Controls TPT-L 44.76*1 48.24*1 43.65al Brain damaged 51.53*J 54.41*J 56.47aJ Controls SRT 42.76al 43.47a 1 50.75 1 Brain damaged Controls 49.18aJ 54.00a,bJ 57.52bJ SPT Brain damaged 41.47*1 45.18*bl 48.65bl 48.24 J 56.05* J 60.17J Controls FT-D 46.35a 45.41al 47.00al Brain damaged 51.06a 54.00* J 55.00* J Controls FT-ND 45.65*1 46.00*1 46.53*1 Brain damaged 55.77 a J 55.81*J 56.10*J Controls Making Test Trail Form A 42.76*1 44.41*1 44.76*1 Brain damaged 52.35*J S4.41*J 61.52 J Controls Form B 43.00*1 42.12* 1 44.76*1 Brain damaged Controls S0.94»J 56.11a,bJ 61.17bJ Note. Values (reading horizontally) that share a common subscript do not differ significantly. A bracket (reading vertically) between two values indicates that they differ beyond the .05 level. CAT = Category Test; TPT-T = Tactual Performance Test, Total Time component; TPT-M = Tactual Performance Test, Memory component; TPT-L = Tactual Performance Test, Localization component; SRT = Seashore Rhythm Test; SPT = Speech-Sounds Perception Test; FT-D = Finger Oscillation Test, dominant side; FT-ND = Finger Oscillation Test, nondominant side.
correlational design, reported similar findings of no correlation between Halstead's tests and education for a psychiatric population, but a positive correlation was obtained on the Seashore Rhythm Test for the braindamaged group. Generalizations to the present investigation are difficult because of differ-
542
A. FINLAYSON, K. JOHNSON, AND R. REITAN
ences in composition of the control and brain-damaged groups and also in the statistical analyses. However, two points are demonstrated: (a) the sensitivity of the Halstead Neuropsychological Test Battery to the effects of brain damage in differing populations and (b) the need for the clinician to consider other methods of inference than level of performance in rendering clinical judgments. In this latter context our results suggest a moderate influence of education in ordering some of the data among the brain-damaged and control groups. The present study was concerned with the investigation of intergroup differences, a level of performance approach. The fact that education did order some of the data highlights one of the problems in an adherence to this type of inference alone when making clinical judgments as to the presence or nature of brain damage (e.g., Reitan, 1966; Rourke, 1975). Presumably, other methods of inference might be less affected by educational level. However, acceptance of such a hypothesis requires an empirical demonstration. References Benton, A. L., Levin, H. S., & Van Allen, M. W. Geographic orientation in patients with unilateral cerebral disease. Neuropsyclwlogia, 1974, 12, 183-191. Birren, J. K., & Morrison, D. F. Analysis of the WAIS subtests in relation to age and education. Journal of Gerontology, 1961, 16, 363-369. Green, R. F. Age-intelligence relationship between ages sixteen and sixty-four: A rising trend. Developmental Psychology, 1969, 1, 618-627. K10ve, H. Validation studies in adult clinical neuropsychology. In R. M. Reitan & L. A. Davison (Eds.), Clinical neuropsychology: Current status and applications. Washington, IXC.: V. H. Winston, 1974.
Matarazzo, J. IX Wechsler's measurement and appraisal of adult intelligence. Baltimore: Williams & Wilkins, 1972. Prigatano, G. P., & Parsons, 0. A. Relationship of age and education to Halstead test performance in different patient populations. Journal of Cansuiting and Clinical Psychology, 1976, 44, 527-533. Reed, H. «. C., Jr., & Fitzhugh, K. B. Patterns of deficit in relation to severity of cerebral dysfunction in children and adults. Journal of Consulting and Clinical Psychology, 1966, 30, 98-102. Reitan, R. M. An investigation of the validity of Halstead's measures of biological intelligence. Archives of Neurology and Psychiatry, 1955, 73, 28-35. Reitan, R. M. Investigation of the relationship between "psychometric" and "biological" intelligence. Journal of Nervous and Mental Disease, 1956, 123, 536-541. Reitan, R. M. Validity of the Trail Making Test as an indicator of organic brain damage. Perceptual and Motor Skills, 1958, 8, 271-276. Reitan, R. M. The comparative effects of brain damage on the Halstead Impairment Index and the Wechsler-Bellevue Scale. Journal of Clinical Psychology, 1959, IS, 281-285. Reitan, R. M. A research program on the psychological effect of brain lesions in human beings. In N. R. Ellis (Kd.), International review of research in mental retardation (Vol. 1). New York: Academic Press, 1966. Reitan, R. M. Verbal problem solving as related to cerebral damage. Perceptual and Motor Skills, 1972, 34, 515-524. Reitan, R. M. Human neuropsychology: Assessment of brain-behavior relationships. In P. McReynolds (Kd.), Advances in psychological assessment (Vol. 3). San Francisco: Jossey-Bass, 1975. Reitan, R. M., & Davison, L. A. Clinical neuropsychology: Current status and applications. Washington, D.C.: V. H. Winston, 1974. Rourke, B. P. Brain-behavior relationship in children with learning disabilities: A research program. American Psychologist, 1975, 30, 911-920. Vega, A., & Parsons, O. A. Cross-validation of the Halstead-Reitan tests for brain damage. Journal of Consulting Psychology, 1967, 31, 619-625. Received January 28, 1976 •
Relationship of Level of Education to Neuropsychological Measures in Brain-Damaged and Non-Brain-Damaged Adults M. A. J. Finlayson Hamilton Psychiatric Hospital, Ontario, Canada, and Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada
K. A. Johnson and R. M. Reitan University of Washington The present study investigated the effect of level of education upon measures of psychometric intelligence and neuropsychological adaptation in brain-damaged and control adults. The purpose was to determine whether, and to what extent, level of education would influence these measures. Fifty-one braindamaged and 51 control subjects were assigned to grade school, high school, or university groups, depending upon their level of education. All persons received the Wechsler-Bellevuc, Halstead's Neuropsychological Test Battery, and the Trail Making Test. The results indicated that both brain damage and level of education had a pronounced effect upon the measures. The nature of these results and their implications for clinical assessment are discussed. Level of education is invariably considered as a control variable in studies of psychological abilities. Investigations involving level of education as an independent variable have been generally in the context of criticisms of the methodology of cross-sectional research approaches to the study of aging effects (e.g., Birren & Morrison, 1961; Green, 1969). The relationship of level of education to intellectual abilities is well-known. In an excellent, review, Matarazzo (1972) pointed to a correlation of .70 as representing the relationship between level of education and 1Q in adults generally. Much less is known about the relationship between level of education and other measures of adaptive ability. Even less is known about these relationships in adults with well-documented brain lesions. Benton, Levin, and Van Allen (1974) found that education influenced performance This research was supported by a grant from the Ontario Mental Health Foundation to the first author and by Grant HD-022V4 from the National Institute of Health to the Child Development and Mental Retardation Center, University of Washington. Requests for reprints should be sent to M. Alan J. Finlayson, Neuropsychiatry Programme, Hamilton Psychiatric Hospital, Hamilton, Ontario, Canada, L9C 3N6.
on a test of geographic orientation in braindamaged and control persons. They also found an interaction between education and diagnostic categories. The low-education braindamaged group performed less well relative to its appropriate control group than did the brain-damaged group with higher education. Vega and Parsons (1967) reported that level of education was positively correlated with performance on several of Halstead's tests in their control group but not among their brain-damaged subjects. In view of the increasing application of Halstead's tests and related measures to clinical questions in the area of brain-behavior relationships, it was felt that a systematic evaluation of the effects of education upon these measures should be undertaken. It seemed reasonable, therefore, to compose groups of people with and without brain lesions who differ in level of education and to compare their performances on the Wechsler-Bellevue Scale, Halstead's tests, and the Trail Making Test, Parts A and B. Method Subjects Fifty-one persons with unequivocal evidence of brain damage (based on detailed neurological pro-
536
537
NEUROPSYCHOLOGICAL MEASURES
Table 1 Means and Standard Deviations for Age, Education, and IQ Values for Each Group Grade school Variable Age Brain-damaged Control Education Brain damaged Control Full Scale IQ Brain damaged Control Verbal IQ Brain damaged Control Performance IQ Brain damaged Control
University
High school
M
SD
M
SD
M
SD
3S.S3 34.12
8.19
8.72
34.53 34.47
7.07 7.36
34.76 35.22
9.05 7.78
7.82 7.94
1.63 1.71
12.00 12.00
0 0
17.06 17.35
1.78 1.66
87.00 101.88
17.90 10.23
92.20 112.71
13.50 12.21
103.00 129.53
17.40 7.58
89.35 98.12
19.11 9.53
92.50 110.00
15.10 11.40
108.00 127.71
15.80 8.22
86.80 106.24
17.70 10.38
94.20 113.00
19.40 12.80
97.60 126.88
18.50 7.31
ccdures) and 51 control persons were assigned to pairs of groups on the basis of number of years of formal education that each had completed. Persons with at least 3 years of college credit formed the university groups; persons who had completed Grade 12 but who had not gone to college constituted the high school groups; and persons with less than 10 years of education composed the grade school groups. All persons were male. Each group contained 15 righthanded and 2 left-handed persons. The groups did not differ in mean age, and at each education level the brain-damaged and control groups did not differ in mean years of education. Table 1 contains a summary of the descriptive variables for each group. Essentially conservative procedures were used in forming the groups. To avoid confounding the results with the effects of aging, only persons less than 50 years old were included in the study. Also, in addition to normally functioning individuals, the control groups contained hospitalized medical and psychiatric patients. In forming the brain-damaged groups, patients were included on the basis of clear evidence of brain damage, established by detailed neurological investigations. Patients with traumatic, neoplastic, and cerebral vascular damage were equally represented in the three brain-damaged groups. This last procedure was adopted to avoid the confounding effects of the type, and possibly of the extent of the lesions.
However, mention of the individual measures will be made at this time. The Wechsler-Bellevue Scale provides summary measures of Verbal IQ, Performance IQ, and Full Scale IQ, based upon scores on six verbal and five performance subtests. The following Halstead variables were studied: Category Test, Tactual Performance Test (Total Time, Memory, and Localization components), Seashore Rhythm Test, Speech-Sounds Perception Test, and the Finger Oscillation Test (scores on the nondominant side were also available for 84 of the 102 persons). Additionally, Parts A and B of the Trail Making Test were administered to each person.
Data Analysis The combined raw score distributions for the six groups were converted into a normalized T-score distribution with a mean of 50 and a standard deviation of 10 for each of the variables used in the study. The original six groups were analyzed by means of separate 2 X 3 analyses of variance. Tests of a posteriori significance were conducted using the NewmanKeuls procedure. The comparisons of interest were between the brain-damaged groups and their appropriate control groups and among the levels of education within the brain-damagcd-control dimension.
Dependent Variables The Wechsler-Bellevue Scale (Form I), Halstead's Neuropsychological Test Battery, and the Trail Making Test, Parts A and B, were administered individually to each person by examiners specially trained in neuropsychological testing procedures. These measures are in routine clinical use and have been more fully described elsewhere (Reitan & Davison, 1974).
Results
The results have been subdivided to facilitate their presentation. Figure 1 is a graphic representation of the mean T-score performance for each of the six groups on the summary
538
A. FINLAYSON, K. JOHNSON, AND R. REITAN
VIO
PIQ Control A - - A University n a High Sclinol O---O Gride Sttel
Brain Damagi A A • • • •
Figure 1. Mean T scores for each group on the Wechsler-Bellevue Scale. (VIQ = Verbal IQ; PIQ = Performance IQ; FSIQ = Full Scale IQ; 1 = Information; C = Comprehension; DS = Digit Span; A = Arithmetic; S = Similarities; V = Vocabulary; PA = Picture Arrangement; PC = Picture Completion; BD = Block Design; OA = Object Assembly; DSy = Digit Symbol.)
and subtest measures of the Wechsler-Bellevue Scale. The scores on each of these variables were analyzed by means of separate 3 X 2 analyses of variance. Table 2 contains the summary of the a posteriori tests (Newman-Keuls procedure). For these comparisons a significance level of p < .05 was accepted as being beyond chance expectations. The main effect for the brain-damagedcontrol dimension was highly significant for each measure. The differences were beyond chance expectations (p < .001) for all comparisons except the Vocabulary subtest (p < .005). Level of education also had a significant effect upon the obtained results, failing to reach significance only in the case of the Object Assembly subtest. By and large these factors were additive or independent. However, the interaction effects were significant (p < .05) for Performance IQ, Vocabulary, and Digit Symbol comparisons. These effects seemed to obtain because of the large differences among the control groups and the relatively small differences among the braindamaged groups. Inspection of Table 2 and Figure 1 indicates that there was no overlap of the mean performances of the brain-damaged and control groups for Performance IQ and the
Performance subtests. The differences between control and brain-damaged groups for each level of education were significant (p < .05) in every instance on these measures. On these same measures, level of education did not differentiate among the brain-damaged groups. Among the control groups, however, level of education separated all groups on the Digit Symbol subtest: the university from high school and grade school groups on Performance IQ and Block Design and the university and grade school groups on Picture Completion. However, level of education did not separate the groups on Picture Arrangement and Object Assembly. There was some overlap of the braindamaged and control groups on the remaining Wechsler-Bellevue variables (Full Scale IQ, Verbal IQ, and the Verbal subtests). This was particularly evident on Vocabulary, Information, Similarities, and Comprehension. Table 2 indicates that for these remaining measures, statistically significant differences between the control and brain-damaged grade school groups were found only on the Arithmetic subtest and Full Scale IQ. However, the remaining comparisons of brain-damaged and control groups were statistically significant (p < .05) except for Similarities with the high school groups. Among the brain-damaged
NEUROPSYCHOLOGICAL MEASURES
groups, level of education had a consistent effect on Verbal IQ, Full Scale 1Q, and the verbal subtests. For all of these measures, the high school and grade school groups were not significantly different from each other, but both were significantly different from the university group. Among the control groups the effect of level of education was least for the Arithmetic subtest. (University and grade school groups differed significantly.) The university group significantly exceeded the high school and grade school groups on Comprehension and Similarities, and all three groups were separated on Verbal IQ, Full Scale IQ, and the Information, Digit Span, and Vocabulary subtests. Figure 2 presents the mean T-score performance of each of the groups on the Halstead and related measures. The results on these measures were analyzed by means of 3 X 2 analyses of variance for each measure separately. The main effect of the braindamaged-control dimension was highly significant (p < .001) in each of the 10 instances. Level of education had a significant main effect for the Seashore Rhythm and SpeechSounds Perception tests (p < .001), the Category test (p < .005), the Trail Making Test, Part A (p < .01), and the Trail Making Test, Part B (p < .05). The nonsignificant F ratios for the interaction terms imply that these factors had independent or additive effects. Table 3 contains a summary of the a posteriori comparisons (Newman-Keuls procedure). At each level of education, the braindamaged groups were significantly different than their appropriate control group, except in the case of the grade school groups for the dominant hand tapping and the Memory component of the Tactual Performance Test. Among the brain-damaged groups, level of education had a significant effect only for the Seashore Rhythm Test (university group exceeded both the high school and grade school groups) and the Speech-Sounds Perception Test (university group exceeded the grade school group). Among the control groups level of education was not a significant variable on the Total Time, Memory, or Location components of the Tactual Performance Test or the measures of finger tapping speed. Significant differences were found on the
539
Table 2 Summary of the Newman-Keuls Analysis for Each of the Wechsler-Bellevue Variables Variable Verbal IQ Brain damaged Controls Performance IQ Brain damaged Controls Full Scale IQ Brain damaged Controls Information Brain damaged Controls Comprehension Brain damaged Controls Digit Span Brain damaged Controls Arithmetic Brain damaged Controls Similarities Brain damaged Controls Vocabulary Brain damaged Controls Picture Arrangement Brain damaged Controls Picture Completion Brain damaged Controls Block Design Brain damaged Controls Object Assembly Brain damaged Controls Digit Symbol Brain damaged Controls
Grade school
High school
University
42.29a 46.18
43.53al 51.651 52.82 J 63.29 J
41.88.1 44.76al 46.35al 50.35. J 54.06.J 62.94 J 41.06.1 43.82al 49.001 48.29 J 53.76 J 63.94 J 42.12a 43.82
45.29al 52.761 53.06 J 61.35 J
44.41. 47.29 0
44.35al 51.881 50.35aJ 61.76 J
44.65a 45.82
44.65.1 52.711 53.79 J 60.59 J
43.65a~| 43.650 1 49.59 1 49.24aJ 54.65a,hJ 59.47bJ 41.82, 46.12n
46.71a 51.00.
52.411 61.18J
43.71. 42.94
47.29al 51.821 52.47 J 62.53 J
42.59a1 46.12al 47.88al 52.47J 52.76aJ 58.47nJ 43.41.1 46.29a I47.24al 49.180J 53.76a,bJ 59.35bJ 43.6Sal 44.59.1 46.76,1 S0.53J S4.00aJ 60.65 J 42.24a~| 47.35al 47.35al S3.06aJ 54.41J 56.76aJ 42.29al 44.24al 46.28a~| 48.53 J 54.82 J 62.76 J
Note. Values (reading horizontally) that share a common subscript do not differ significantly. A bracket (reading vertically) between two values indicates that they differ beyond the .05 level.
Category test (university group exceeded both of the other two groups); Seashore Rhythm Test (university group exceeded the grade school group); Speech-Sounds Perception test (grade school was poorer than both of the other two groups); Trail Making Test, Part A
540
A. FINLAYSON, K. JOHNSON, AND R. REITAN
CAT
TPT-T TPT-M
TPT-l
FT-0
FT-NO
TrA
TrB
Control Brain Damage £,--& University D---CD High School O---O Grade School Pigme 2. Mean 7"-score performance on Halstcad's tests and the Trail Making Test. (CAT = Category Test; TPT-T = Tactual Performance, Total Time component; TPT-M = Tactual Performance Test, Memory component; TPT-L = Tactual Performance Test, Localization component; SRT = Seashore Rhythm Test; SPT = Speech-Sounds Perception Test; F'T-D = Finger Oscillation Test, dominant side; FT-NI) = Finger Oscillation Test, nondominant side; TrA = Trail Making Test, Form A; TrB = Trail Making Test, Form B.)
(university group exceeded both of the other groups); and Trail Making Test, Part B (university group exceeded the grade school group). Discussion The clearest finding that emerged from the present investigation was the separation of the brain-damaged and control groups on the measures used. In effect, this demonstrates the sensitivity of these measures to the integrity of the cerebral cortex. This was not unexpected (e.g., K10vc, 1974; Reitan, 1955, 1956, 1958, 1975; Vega & Parsons, 1967). The main effect was highly significant for every dependent variable. Furthermore, on every comparison, the university control group performed significantly better than the university brain-damaged group; the high school control group exceeded the braindamaged group (high school) on every measure
except Similarities. The separation of the grade school groups was not as complete, since the groups did not differ significantly on Verbal IQ; Information; Comprehension; Vocabulary; Tactual Performance Test, Memory component; and dominant hand finger tapping. Level of education also had an effect upon the data. However, it did not appear to exert as consistent an effect as did brain damage. Among the control groups, the university-educated persons clearly exceeded the other two groups. This was most apparent on the Verbal subtests of the WechslerBellevue Scale. These differences were less clear-cut on the Halstead and Trail Making Test measures. On 10 of the 14 Wechsler variables, the university control group exceeded both of the other control groups, whereas on only 2 of the 10 other variables did this occur. It has been demonstrated
NEUROPSYCHOLOGICAL MEASURES
that the Halstead measures are more sensitive to the integrity of the brain than are the Wechsler-Bellevue measures (Reitan, 1959, 1975). Thus, the striking differences for education on the Wechsler tests are considerably reduced on measures that more clearly relate to the adequacy of brain functioning. Level of education also had an effect among the brain-damaged groups, albeit to a lesser degree. It was most pronounced on the verbal aspects of the Wechsler-Bellevue and the Seashore Rhythm Test. On these measures the university brain-damaged group exceeded both of the other groups. On the SpeechSounds Perception Test, the university braindamaged group exceeded only the grade school group. On the remaining measures the effects of level of education were not demonstrated for the brain-damaged groups. The measures on which level of education had an influence have in common auditory-verbal and language requirements. It may be the case that these abilities are more highly developed or overlearned in the university population and hence are more resistant to the deleterious effects of cerebral dysfunction. In this connection, it was observed that the magnitude of the F ratios for level of education was larger on the Wechsler verbal subtests and somewhat smaller on the remaining variables, whereas the opposite relationship obtained for the effects of brain damage. Reed and Fitzhugh (1966) and Reitan (1972, 1975) have maintained that tests most sensitive to the effects of brain damage are those that require immediate problem-solving skills. On the other hand, tests that tap abilities which have been developed over a number of years are much less sensitive to the effects of brain lesions. The pattern of results in the present study supports this position. In fact, it could be argued that the effects of education, as might be expected, are most pronounced on the measures of stored information and have little relationship to immediate problem-solving tasks. Vega and Parsons (1967) reported no relationship between level of education and the Halstead variables for their brain-damaged subjects and several significant correlations for their medical-surgical control group. Prigatano and Parsons (1976), also using a
541
Table 3 Summary oj the Newman-Keuls Analyses of the Halstead Measures and Parts A and B oj the Trail Making Test Variable
Grade school
High school
University
Halstead measure CAT
41.82*1 41.53»1 46.12al Brain damaged S3.94aJ SS.18*J 61.41 J Controls TPT-T 42.29*1 45.00*1 43.47*1 Brain damaged S4.06*J 56.24*J 58.82*J Controls TPT-M 46.24* 46.41*1 46.53*1 Brain damaged 49.65* 54.24*J 55.59*J Controls TPT-L 44.76*1 48.24*1 43.65al Brain damaged 51.53*J 54.41*J 56.47aJ Controls SRT 42.76al 43.47a 1 50.75 1 Brain damaged Controls 49.18aJ 54.00a,bJ 57.52bJ SPT Brain damaged 41.47*1 45.18*bl 48.65bl 48.24 J 56.05* J 60.17J Controls FT-D 46.35a 45.41al 47.00al Brain damaged 51.06a 54.00* J 55.00* J Controls FT-ND 45.65*1 46.00*1 46.53*1 Brain damaged 55.77 a J 55.81*J 56.10*J Controls Making Test Trail Form A 42.76*1 44.41*1 44.76*1 Brain damaged 52.35*J S4.41*J 61.52 J Controls Form B 43.00*1 42.12* 1 44.76*1 Brain damaged Controls S0.94»J 56.11a,bJ 61.17bJ Note. Values (reading horizontally) that share a common subscript do not differ significantly. A bracket (reading vertically) between two values indicates that they differ beyond the .05 level. CAT = Category Test; TPT-T = Tactual Performance Test, Total Time component; TPT-M = Tactual Performance Test, Memory component; TPT-L = Tactual Performance Test, Localization component; SRT = Seashore Rhythm Test; SPT = Speech-Sounds Perception Test; FT-D = Finger Oscillation Test, dominant side; FT-ND = Finger Oscillation Test, nondominant side.
correlational design, reported similar findings of no correlation between Halstead's tests and education for a psychiatric population, but a positive correlation was obtained on the Seashore Rhythm Test for the braindamaged group. Generalizations to the present investigation are difficult because of differ-
542
A. FINLAYSON, K. JOHNSON, AND R. REITAN
ences in composition of the control and brain-damaged groups and also in the statistical analyses. However, two points are demonstrated: (a) the sensitivity of the Halstead Neuropsychological Test Battery to the effects of brain damage in differing populations and (b) the need for the clinician to consider other methods of inference than level of performance in rendering clinical judgments. In this latter context our results suggest a moderate influence of education in ordering some of the data among the brain-damaged and control groups. The present study was concerned with the investigation of intergroup differences, a level of performance approach. The fact that education did order some of the data highlights one of the problems in an adherence to this type of inference alone when making clinical judgments as to the presence or nature of brain damage (e.g., Reitan, 1966; Rourke, 1975). Presumably, other methods of inference might be less affected by educational level. However, acceptance of such a hypothesis requires an empirical demonstration. References Benton, A. L., Levin, H. S., & Van Allen, M. W. Geographic orientation in patients with unilateral cerebral disease. Neuropsyclwlogia, 1974, 12, 183-191. Birren, J. K., & Morrison, D. F. Analysis of the WAIS subtests in relation to age and education. Journal of Gerontology, 1961, 16, 363-369. Green, R. F. Age-intelligence relationship between ages sixteen and sixty-four: A rising trend. Developmental Psychology, 1969, 1, 618-627. K10ve, H. Validation studies in adult clinical neuropsychology. In R. M. Reitan & L. A. Davison (Eds.), Clinical neuropsychology: Current status and applications. Washington, IXC.: V. H. Winston, 1974.
Matarazzo, J. IX Wechsler's measurement and appraisal of adult intelligence. Baltimore: Williams & Wilkins, 1972. Prigatano, G. P., & Parsons, 0. A. Relationship of age and education to Halstead test performance in different patient populations. Journal of Cansuiting and Clinical Psychology, 1976, 44, 527-533. Reed, H. «. C., Jr., & Fitzhugh, K. B. Patterns of deficit in relation to severity of cerebral dysfunction in children and adults. Journal of Consulting and Clinical Psychology, 1966, 30, 98-102. Reitan, R. M. An investigation of the validity of Halstead's measures of biological intelligence. Archives of Neurology and Psychiatry, 1955, 73, 28-35. Reitan, R. M. Investigation of the relationship between "psychometric" and "biological" intelligence. Journal of Nervous and Mental Disease, 1956, 123, 536-541. Reitan, R. M. Validity of the Trail Making Test as an indicator of organic brain damage. Perceptual and Motor Skills, 1958, 8, 271-276. Reitan, R. M. The comparative effects of brain damage on the Halstead Impairment Index and the Wechsler-Bellevue Scale. Journal of Clinical Psychology, 1959, IS, 281-285. Reitan, R. M. A research program on the psychological effect of brain lesions in human beings. In N. R. Ellis (Kd.), International review of research in mental retardation (Vol. 1). New York: Academic Press, 1966. Reitan, R. M. Verbal problem solving as related to cerebral damage. Perceptual and Motor Skills, 1972, 34, 515-524. Reitan, R. M. Human neuropsychology: Assessment of brain-behavior relationships. In P. McReynolds (Kd.), Advances in psychological assessment (Vol. 3). San Francisco: Jossey-Bass, 1975. Reitan, R. M., & Davison, L. A. Clinical neuropsychology: Current status and applications. Washington, D.C.: V. H. Winston, 1974. Rourke, B. P. Brain-behavior relationship in children with learning disabilities: A research program. American Psychologist, 1975, 30, 911-920. Vega, A., & Parsons, O. A. Cross-validation of the Halstead-Reitan tests for brain damage. Journal of Consulting Psychology, 1967, 31, 619-625. Received January 28, 1976 •
