IQ and Scores on the Mini-Mental State Examination (MMSE): Controlling for Effort and Education Among Geriatric Inpatients

ABSTRACT

The Mini-Mental State Examination (MMSE) and the Peabody Picture Vocabulary Test, Third Edition (PPVT-III) were administered to 76 Extended Care Center inpatients of a Veterans Affairs Medical Center, 56 of whom did not carry a diagnosis associated with brain impairment, and 20 of whom had a diagnosis associated with degenerative or cerebrovascular conditions. MMSE and PPVT-III scores, the latter of which estimates verbal IQ, were significantly correlated in both groups, even when controlling for the effects of education. This correlation was attenuated, but remained significant, in the face of varying levels of patient effort. The findings of this study support earlier findings, which also suggest that interpretation of “impaired” performance on the MMSE for those with IQ scores below 90 should be interpreted with caution. Average MMSE scores for Wechsler IQ classifications are provided.     

IQ and Scores on the Mini-Mental State Examination (MMSE)

The Mini-Mental State Examination (MMSE) and the Peabody Picture Vocabulary Test-Revised (PPVT-R) were administered to 217 Veterans Affairs (VA) Nursing Home patients, 104 of whom did not carry a diagnosis associated with brain impairment, and 113 who had a diagnosis associated with degenerative or cerebrovascular conditions. MMSE and IQ scores were significantly correlated in both groups, even controlling for the effects of education. It is suggested that although previous normative studies of the MMSE may provide good general clinical guidance, interpretation of “impaired” performance on the MMSE for those with IQ scores below 90 should be approached with caution. Average MMSE scores for Wechsler IQ classifications are provided.     

A simple syllogism-solving test: Empirical findings and implications for g research

It has been reported that the ability to solve syllogisms is highly g-loaded. In the present study, using a self-administered shortened version of a syllogism-solving test, the BAROCO Short, we examined whether robust findings generated by previous research regarding IQ scores were also applicable to BAROCO Short scores. Five syllogism-solving problems were included in a questionnaire as part of a postal survey conducted by the Keio Twin Research Center. Data were collected from 487 pairs of twins (1021 individuals) who were Japanese junior high or high school students (ages 13–18) and from 536 mothers and 431 fathers. Four findings related to IQ were replicated: 1) The mean level increased gradually during adolescence, stayed unchanged from the 30s to the early 50s, and subsequently declined after the late 50s. 2) The scores for both children and parents were predicted by the socioeconomic status of the family. 3) The genetic effect increased, although the shared environmental effect decreased during progression from adolescence to adulthood. 4) Children's scores were genetically correlated with school achievement. These findings further substantiate the close association between syllogistic reasoning ability and g.     

Concurrent validity of the Peabody Picture Vocabulary Test-Third Edition as an intelligence and achievement screener for low SES African American children

Authors tested the validity of the Peabody Picture Vocabulary Test-Third Edition (PPVT-III) as a screening measure for intelligence and achievement. The PPVT-III and Kaufman Assessment Battery for Children (KABC) were administered to 416 African American children of low socioeconomic status in a counterbalanced design. Results indicated that the PPVT-III correlated .58 with the KABC Mental Processing Composite (MPC) score; however, participants scored significantly lower (M = 8.3 points) on the PPVT-III than on the MPC. Although receiver operating characteristic (ROC) analyses supported the use of the PPVT-III as a valid intellectual and achievement screener, the selection of a single cutoff score for the PPVT-III was problematic. The purpose of the screening program should guide selection of a cutoff score for the PPVT-III.     

Intellectual, behavioral, and personality correlates of violent vs. non-violent juvenile offenders

The overall aim of this study was to examine the relationship between offender status (violent vs. nonviolent) and selected predictor variables from personality, behavioral, and intellectual domains. The two main sub goals were (a) to determine which variables from these domains were most closely associated with offender status, and (b) to construct a stepwise logistic regression model that could help identify which juveniles were more likely to be incarcerated for violent vs. nonviolent offenses. The participants for this investigation were juvenile offenders referred to the Juvenile Court Assessment Center by the Juvenile Justice Division of the Eleventh Judicial Circuit. The court-ordered assessment included the following measures: (a) The Millon Adolescent Clinical Inventory (MACI), (b) the Behavior Assessment System for Children (BASC), (c) the Peabody Picture Vocabulary Test-Third Edition (PPVT-III), (d) the Wide Range Achievement Test-Third Edition (WRAT-III), (e) the Kaufman Brief Intelligence Test (K-BIT), and (f) records of school achievement. The ten variables that had the strongest association with offender status were entered into the stepwise logistic regression analysis; five of these strategically chosen predictor variables accurately differentiated violent from nonviolent offenders 86.3% of the time. Reading Percentile (β=-.051), PPVT-III (β=-.059), MACI-Inhibition (β=-.033), MACI-Eating Dysfunction (β=.051), and BASC-Sense of Inadequacy (β=-.072). Gender differences were explored.     

A longitudinal study of bilingual and cognitive development(1)

This paper presents the findings of a longitudinal study of IQ data collected over a 5-year period (Grades K-4) on pupils enrolled in a French immersion program (anglophone pupils receiving all instruction in French except English language arts) and pupils in the regular English program. Although year-by-year results may fail to show IQ differences between the two groups, repeated measures analysis indicates that the immersion group has a higher IQ measure over the 5-year period. However, considering Grades 1–3 only, which involved the administration of the same test, the two groups do not score differentially with respect to either overall IQ measure or specific subtest scores (classification/categorization, analogies, following of verbal directions) when scores are adjusted for initial IQ (and age) differences, thus failing initially to support studies which show positive relationships between bilingualism and cognitive functioning. However, supportive of those studies is a further analysis on the data of immersion pupils classified as “high” French achievers vs. “low” French achievers. The high French achievers obtain significantly higher IQ measures and subtest scores (analogies and following of verbal directions) than the low French achievers, even when scores are adjusted for initial IQ and age differences. These findings are interpreted in the context of Cummins' (1976) “threshold” hypothesis relating to level of competence in the second language.     

Do the Wechsler scales underestimate the difference between verbal and performance abilities in children with language–related disorders?

The present paper examines the validity of the Wechsler scales with children with language-related disorders, with whom the scales were not originally normed. The general question is whether we can take measures of IQ, normed with a normal sample, and then validly use them as indicators of the same constructs with samples significantly different from the normed sample. In previous papers it was pointed out that the pattern structurally simple > moderately complex > complex tests can be observed in their IQ profiles within both the Verbal scale and the Performance scale. In this paper, it is hypothesized that this scatter of scores leads to an underestimation of the global V-P IQ differences for children with language-related disorders because there are more structurally complex tests on the Performance scale than on the Verbal scale. To test this hypothesis, "purer" V-P IQ differences were calculated by comparing the scores on Verbal and Performance tests of equal structural complexity. WPPSI and WISC-R data from four groups of children were analyzed: language-impaired children (n = 128), reading-impaired children (n = 112), children from dyslexic families (n = 51), and normal children (n = 49). When the effect of the difference in structural complexity was controlled for, it was found that the distribution of the revised V-P IQ difference was significantly more toward the negative end of the spectrum than the traditional V-P IQ differences for language-impaired and reading-impaired children, and approaching a significant level for children from dyslexic families. As hypothesized, there were no significant differences between the two distributions of V-P IQ differences for normal children. Practical and theoretical implications are discussed.     

Influence of IQ in interpreting MMSE scores in patients with multiple sclerosis

The Mini-Mental State Examination (MMSE) and Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) were administered to 46 outpatients diagnosed with multiple sclerosis (MS). MMSE total raw score was significantly and positively correlated with all WAIS-IV indexes, even when controlling for the effects of participant educational level, with the strongest relationship being with Full Scale IQ. These results suggest that clinicians consider patient intellectual functioning, in particular Full Scale IQ, when diagnosing neurocognitive impairment based on screening with the MMSE in individuals with MS.     

Are Shunt Revisions Associated with IQ in Congenital Hydrocephalus? A Meta -Analysis

Although it is generally acknowledged that shunt revisions are associated with reductions in cognitive functions in individuals with congenital hydrocephalus, the literature yields mixed results and is inconclusive. The current study used meta-analytic methods to empirically synthesize studies addressing the association of shunt revisions and IQ in individuals with congenital hydrocephalus. Six studies and three in-house datasets yielded 11 independent samples for meta-analysis. Groups representing lower and higher numbers of shunt revisions were coded to generate effect sizes for differences in IQ scores. Mean effect size across studies was statistically significant, but small (Hedges’ g = 0.25, p < 0.001, 95 % CI [0.08, 0.43]) with more shunt revisions associated with lower IQ scores. Results show an association of lower IQ and more shunt revisions of about 3 IQ points, a small effect, but within the error of measurement associated with IQ tests. Although clinical significance of this effect is not clear, results suggest that repeated shunt revisions because of shunt failure is associated with a reduction in cognitive functions.     

Meta-Analysis of Intelligence Quotient (IQ) in Obsessive-Compulsive Disorder

Obsessive compulsive disorder (OCD) is associated with a moderate degree of underperformance on cognitive tests, including deficient processing speed. However, despite little research focusing on Intelligence Quotient (IQ) in OCD, it has long been speculated that the disorder is associated with elevated intellectual capacity. The present meta-analytic study was, therefore, conducted to quantitatively summarize the literature on IQ in OCD systematically. We identified 98 studies containing IQ data among individuals with OCD and non-psychiatric comparison groups, and computed 108 effect sizes for Verbal IQ (VIQ, n = 55), Performance IQ (PIQ, n = 13), and Full Scale IQ (FSIQ, n = 40). Across studies, small effect sizes were found for FSIQ and VIQ, and a moderate effect size for PIQ, exemplifying reduced IQ in OCD. However, mean IQ scores across OCD samples were in the normative range. Moderator analyses revealed no significant moderating effect across clinical and demographic indices. We conclude that, although lower than controls, OCD is associated with normative FSIQ and VIQ, and relatively lowered PIQ. These results are discussed in light of neuropsychological research in OCD, and particularly the putative impact of reduced processing speed in this population. Recommendations for utilization of IQ tests in OCD, and directions for future studies are offered.     

Note on locus of control and academic achievement in institutionalized juvenile delinquents

The previously reported relationship between internal locus of control and academic achievement was explored with the Nowicki-Strickland Locus of Control Scale for Children (Nowicki & Strickland, 1973) and seven measures of academic achievement in a random sample of 45 male residents of seven state learning centers for juvenile delinquents. Correlations between overall locus of control scores and all seven measures were significant, but with intelligence controlled in a partial correlation, locus of control scores were found to add little to the prediction of academic achievement from IQ scores alone. Discussion addressed possible explanations for the current findings in terms of the meaning of the scale for a nonnormal group and the effects of situations on responses of subjects.Appreciation is expressed to Mobile Psychiatric Clinic staff psychologists, to the U.S. General Accounting Office, and to Kingsbury Center, consultants, Washington, D.C., for their assistance in data collection.     

What Does the DAP:IQ Measure?: Drawing Comparisons between Drawing Performance and Developmental Assessments

Human figure drawing tasks such as the Draw-a-Person test have long been used to assess intelligence (F. Goodenough, 1926). The authors investigate the skills tapped by drawing and the risk factors associated with poor drawing. Self-portraits of 345 preschool children were scored by raters trained in using the Draw-a-Person Intellectual Ability test (DAP:IQ) rubric (C. R. Reynolds & J. A. Hickman, 2004). Analyses of children's fine motor, gross motor, social, cognitive, and language skills revealed that only fine motor skill was an independent predictor of DAP:IQ scores. Being a boy and having a low birth weight were associated with lower DAP:IQ scores. These findings suggest that although the DAP:IQ may not be a valid measure of cognitive ability, it may be a useful screening tool for fine motor disturbances in at-risk children, such as boys who were born at low birth weights. Furthermore, researchers who use human figure drawing tasks to measure intelligence should measure fine motor skill in addition to intelligence.     

Is body mass index in old age related to cognitive abilities? The Lothian Birth Cohort 1936 Study

We tested the hypothesis that the previously reported association between a higher body mass index (BMI) and poorer cognition in later adulthood is an artifact of confounding by previous cognitive ability and socioeconomic status. Participants were 1,079 adults aged about 70 years in the Lothian Birth Cohort 1936 Study, on whom there are IQ data from age 11. Cognitive outcome measures included: IQ at age 70 using the same test that was administered at age 11; composite measures of general cognitive ability (g factor), speed of information processing, and memory; and two tests of verbal ability. People classified as overweight or obese in later adulthood had significantly lower scores on tests of childhood IQ, age 70 IQ, g factor, and verbal ability. There was no significant association with processing speed or memory performance. After adjusting for childhood IQ and social class in general linear models, associations with age 70 IQ and g factor were nonsignificant or attenuated. However, throughout the models, there was a persistent (inverse) relationship between BMI and performance on the National Adult Reading Test (NART) and Wechsler Test of Adult Reading (WTAR), which remained significant after full adjustment for all sociodemographic and health covariates (for the NART, p = .025; for the WTAR, p = .011). The findings suggest that the previously reported BMI-cognition associations in later adulthood could be largely accounted for by prior ability and socioeconomic status, and by the possible influence of these factors on the adoption of health behaviors in adulthood.     

Intelligence: new findings and theoretical developments

We review new findings and new theoretical developments in the field of intelligence. New findings include the following: (a) Heritability of IQ varies significantly by social class. (b) Almost no genetic polymorphisms have been discovered that are consistently associated with variation in IQ in the normal range. (c) Much has been learned about the biological underpinnings of intelligence. (d) "Crystallized" and "fluid" IQ are quite different aspects of intelligence at both the behavioral and biological levels. (e) The importance of the environment for IQ is established by the 12-point to 18-point increase in IQ when children are adopted from working-class to middle-class homes. (f) Even when improvements in IQ produced by the most effective early childhood interventions fail to persist, there can be very marked effects on academic achievement and life outcomes. (g) In most developed countries studied, gains on IQ tests have continued, and they are beginning in the developing world. (h) Sex differences in aspects of intelligence are due partly to identifiable biological factors and partly to socialization factors. (i) The IQ gap between Blacks and Whites has been reduced by 0.33 SD in recent years. We report theorizing concerning (a) the relationship between working memory and intelligence, (b) the apparent contradiction between strong heritability effects on IQ and strong secular effects on IQ, (c) whether a general intelligence factor could arise from initially largely independent cognitive skills, (d) the relation between self-regulation and cognitive skills, and (e) the effects of stress on intelligence.     

Relations Among Preschool Children's Understanding of Visual Perspective Taking,False Belief,and Lying

This study investigated the relations among preschool children's ability to understand that other people see things differently than they do, that other people can believe things differently than the children know to be true, and that they can manipulate others' beliefs through intentional lying. Children between the ages of 3 and 5 were given tasks that tested their knowledge of Level 2 visual perspective taking, understanding of false belief, and the discriminative use of deceptive ploys. The Peabody Picture Vocabulary Test (PPVT-III) was administered as a measure of language proficiency. The children's scores on the three types of tasks were correlated with each other and with children's age, but not with scores on the PPVT-III. Most children either passed all the tasks or failed all the tasks. Regression analyses indicated that scores on visual perspective taking and false belief independently predicted each other, and scores on false belief and the discriminative use of deception independently predicted each other. The results provide evidence that advances in visual perspective taking, false belief understanding, and the discriminative use of deceptive ploys are developmentally related and occur in close synchrony.     

Learning mnemonics: roles of aging and subtle cognitive impairment

Previously validated methods of memory training were used in conjunction with the Folstein Mini-Mental State Examination (MMSE) to explore the relationship between complexity of learned mnemonic, aging, and subtle cognitive impairment. Subjects were 218 community-dwelling elderly. Treatment included imagery mnemonics for remembering names and faces and lists. There was a significant interaction among age, type of learning task (face-name vs. list), and improvement when controlling for MMSE score. There was also a significant interaction among MMSE score, type of learning task, and improvement when controlling for age. Scores on the more complex list-learning mnemonic were more affected by age and MMSE scores than were scores on the face-name mnemonic. Implications of the findings for cognitive training of the old old and the impaired are discussed.     

Conceptual development in learning-disabled and normal boys

In two related studies, a pictorial sorting task served as the means of measuring conceptual development in LD and normal boys. The studies found no differences in the bases on which groups were formed (perceptible attributes, function, or nominal class membership) or in the manner in which groups were structured (thematically, in complexive groups or superordinate groups). Furthermore, parallel developmental trends were found in both LD and normal subjects groups. These findings are not consistent with early studies of concept formation in brain-damaged subjects, most of whom were retarded. Subjects in the present studies were selected on the basis of clinical diagnosis of LD and average IQ. The findings of the present studies suggest that generalizations about conceptual abilities of LD children of normal intelligence should not be based on early studies of the effects of brain damage.     

Skull size and intelligence, and King Robert Bruce's IQ

An estimate of someone's IQ is a potentially informative personal datum. This study examines the association between external skull measurements and IQ scores, and uses the resulting regression equation to provide an estimate of the IQ of King Robert I of Scotland (Robert Bruce, 1274–1329). Participants were 48 relatively healthy Caucasian men (age 71–76 years) resident in Scotland. Using magnetic resonance imaging data, intracranial volume estimated from external skull length and width correlated greater than .5 (p < .001) with measured intracranial area, which correlates very highly with brain volume. IQ scores estimated from the National Adult Reading Test (NART) correlated .56 (p < .001) with measured intracranial area, and .49 (p < .01) with estimated intracranial volume based on external skull width and length. The partial correlation coefficient of this latter association was .25 (p = .09) after adjustment for measured intracranial area. Thus, actual intracranial area accounts for about 74% of the variance shared by NART and estimated intracranial volume. A cast of the skull of Robert Bruce was measured and its intracranial volume estimated. A regression equation between IQ and estimated intracranial volume, based on data from the 48 subjects, estimated the IQ of Robert Bruce at about 128 (95% confidence interval 106 to  130), i.e. almost two standard deviations above the mean. NART scores show a ceiling effect, so this estimated IQ might be an underestimate. Robert Bruce's estimated high IQ is congruent with his military, political and other intellectual achievements.     

Correlates of intelligence in computer measured aspects of prose vocabulary: word length, diversity, and rarity

Computer measured aspects of prose vocabulary as correlates of intelligence are of interest because they offer the potential of assessing intelligence in situations where more direct assessment (e.g. through IQ tests) is either impractically expensive or (as in the case of populations that lived in the past) impossible. This study assessed a word-length measure (average number of letters), two word-diversity measures (ratio of number of different to number of total words, and Yule's Characteristic K, which indicates the repeat rate for words), and a word-rarity measure (proportion of words present on a rare-words list). In the first part of the study, essays of 120 students in Grade 11 and 12 in a private American high-school for whom Cooperative School and College Ability Test (SCAT) scores (which correlate with IQ test scores) were available, were assessed in terms of the vocabulary measures. Only the word-rarity and word-length measures correlated significantly with SCAT scores, and the highest correlations were manifested by the word-rarity measure. In the study's second part, the vocabulary measures were applied to articles selected from American newspapers representing African American (119 articles), general (110 articles), and Jewish-American (109 articles) communities, among which, for whatever reasons, reliable average IQ performance differences have been found. Only the word-rarity measure discriminated in the predicted way among the three sorts of newspapers. Implications for other potential uses of the computerized word-rarity measure for assessing temporal, social, and geographic group differences in intelligence are discussed.     

The comparability of intelligence test results: Group- and individual-level comparisons of seven intelligence tests

A significant body of research has demonstrated that IQs obtained from different intelligence tests substantially correlate at the group level. Yet, there is minimal research investigating whether different intelligence tests yield comparable results for individuals. Examining this issue is paramount given that high-stakes decisions are based on individual test results. Consequently, we investigated whether seven current and widely used intelligence tests yielded comparable results for individuals between the ages of 4–20 years. Results mostly indicated substantial correlations between tests, although several significant mean differences at the group level were identified. Results associated with individual-level comparability indicated that the interpretation of exact IQ scores cannot be empirically supported, as the 95% confidence intervals could not be reliably replicated with different intelligence tests. Similar patterns also appeared for the individual-level comparability of nonverbal and verbal intelligence factor scores. Furthermore, the nominal level of intelligence systematically predicted IQ differences between tests, with above- and below-average IQ scores associated with larger differences as compared to average IQ scores. Analyses based on continuous data confirmed that differences appeared to increase toward the above-average IQ score range. These findings are critical as these are the ranges in which diagnostic questions most often arise in practice. Implications for test interpretation and test construction are discussed.