Measure Of Premorbid Intelligence Research Articles

Polygenic risk for schizophrenia and measured domains of cognition in individuals with psychosis and controls

Psychotic disorders including schizophrenia are commonly accompanied by cognitive deficits. Recent studies have reported negative genetic correlations between schizophrenia and indicators of cognitive ability such as general intelligence and processing speed. Here we compare the effect of polygenetic risk for schizophrenia (PRSSCZ) on measures that differ in their relationships with psychosis onset: a measure of current cognitive abilities (the Brief Assessment of Cognition in Schizophrenia, BACS) that is greatly reduced in psychotic disorder patients, a measure of premorbid intelligence that is minimally affected by psychosis onset (the Wide-Range Achievement Test, WRAT); and educational attainment (EY), which covaries with both BACS and WRAT. Using genome-wide single nucleotide polymorphism (SNP) data from 314 psychotic and 423 healthy research participants in the Bipolar-Schizophrenia Network for Intermediate Phenotypes (B-SNIP) Consortium, we investigated the association of PRSSCZ with BACS, WRAT, and EY. Among apparently healthy individuals, greater genetic risk for schizophrenia (PRSSCZ) was significantly associated with lower BACS scores (r = −0.17, p = 6.6 × 10−4 at PT = 1 × 10−4), but not with WRAT or EY. Among individuals with psychosis, PRSSCZ did not associate with variations in any of these three phenotypes. We further investigated the association between PRSSCZ and WRAT in more than 4500 healthy subjects from the Philadelphia Neurodevelopmental Cohort. The association was again null (p > 0.3, N = 4511), suggesting that different cognitive phenotypes vary in their etiologic relationship with schizophrenia.

The Wechsler Test of Adult Reading as a Measure of Premorbid Intelligence Following Traumatic Brain Injury

The current study sought to determine whether the Wechsler Test of Adult Reading (WTAR) provides a stable estimate of premorbid intellectual ability in acutely injured patients recovering from traumatic brain injury (TBI). A total of 135 participants (43 mild TBI [mTBI], 40 moderate/severe TBI [msevTBI], 52 healthy controls) were administered the WTAR at 1 and 12 months post-injury. Despite similar demographic profiles, participants with msevTBI performed significantly worse than controls on the WTAR at both time points. Moreover, the msevTBI group had a significant improvement in WTAR performance over the 1-year period. In contrast, those participants with mTBI did not significantly differ from healthy controls and both the mTBI and control groups demonstrated stability on the WTAR over time. Results indicate that word-reading tests may underestimate premorbid intelligence during the immediate recovery period for patients with msevTBI. Clinicians should consider alternative estimation measures in this TBI subpopulation.

Cognitive reserve and Aβ1-42 in mild cognitive impairment (Argentina-Alzheimer’s Disease Neuroimaging Initiative)

BackgroundThe purpose of this study was to investigate the relationship between cognitive reserve and concentration of Aβ1-42 in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment, those with Alzheimer’s disease, and in control subjects.MethodsThirty-three participants from the Argentina-Alzheimer’s Disease Neuroimaging Initiative database completed a cognitive battery, the Cognitive Reserve Questionnaire (CRQ), and an Argentinian accentuation reading test (TAP-BA) as a measure of premorbid intelligence, and underwent lumbar puncture for CSF biomarker quantification.ResultsThe CRQ significantly correlated with TAP-BA, education, and Aβ1-42. When considering Aβ1-42 levels, significant differences were found in CRQ scores; higher levels of CSF Aβ1-42 were associated with higher CRQ scores.ConclusionReduced Aβ1-42 in CSF is considered as evidence of amyloid deposition in the brain. Previous results suggest that individuals with higher education, higher occupational attainment, and participation in leisure activities (cognitive reserve) have a reduced risk of developing Alzheimer’s disease. Our results support the notion that enhanced neural activity has a protective role in mild cognitive impairment, as evidenced by higher CSF Aβ1-42 levels in individuals with more cognitive reserve.

Performance of a sample of patients with Mild Cognitive Impairment (MCI), Alzheimer's Disease (AD) and healthy elderly on a lexical decision test (LDT) as a measure of pre-morbid intelligence.

ObjectiveThe objective of this study was to describe the performance of healthy elderly patients with aging-related pathologies (MCI) and patients with AD on a lexical decision test.MethodsThe study included 38 healthy elderly subjects, 61 MCI and 26 AD patients from the Neurology Department of the Hospital das Clinicas, Behavioral and Cognitive Neurology Group. The neuropsychological instruments included the episodic memory test (RAVLT), subtests from the WAIS-III (Matrix Reasoning and Vocabulary) to determine estimated IQ, the Boston naming test (BNT) and Lexical Decision Test (LDT).ResultsAll groups differed on the MMSE, as expected according to their pathologies, memory tests, naming and estimated IQ. For the vocabulary and the LDT – measures of crystalized intelligence no differences were found.ConclusionThe LDT demonstrated that lexical decision can be used as a measure of pre-morbid IQ among the individuals assessed in a Brazilian sample.

C-58 * Using Multimodal Magnetic Resonance Imaging to Explore Biomarkers of Veterans with Post-Traumatic Stress Disorder after Blast Injury

OBJECTIVE: This study aims to compare neuroimaging measures of gray matter thickness and volume in the medial prefrontal and parietal areas of combat veterans with and without Post-Traumatic Stress Disorder (PTSD) and blast exposure. Secondary objectives include investigating the relationship between neuropsychological and imaging data. METHOD: Twenty post-9/11 male combat veterans were recruited from the Philadelphia Veterans Affairs Medical Center. All participants had been deployed, 13 had a history of PTSD and blast exposure, and seven did not endorse PTSD or blast. Veterans completed measures of emotional and neuropsychological functioning and one MRI scan. RESULTS: Volumetric measures of the caudal and rostral anterior cingulate cortex (ACC) and precuneus areas were normalized using total gray matter volume. Group differences in gray matter volume across hemispheres were examined using repeated measures analyses of variance and no significant differences were found. Independent samples t-tests also did not find significant group differences in thickness for these areas. Controls outperformed those with TBI and PTSD on a measure of premorbid intelligence, t(18) = 2.65, p =.02, 95% CI [3.77, 32.47]), but no other significant differences in neuropsychological performance were observed. CONCLUSION(S): These initial findings are unexpected, as previous research has found significantly smaller anterior cingulate cortex volumes in those with PTSD. However, these areas are relatively unexplored in relation to PTSD and blast injury. This study may provide evidence that the medial prefrontal and parietal areas do not serve as biomarkers for the presence of PTSD and blast trauma, but more data are needed to draw firm conclusions. Language: en

Vocabulary is an appropriate measure of premorbid intelligence in a sample with heterogeneous educational level in Brazil.

Crystallized intelligence refers to one's knowledge base and can be measured by vocabulary tests. Fluid intelligence is related to nonverbal aspects of intelligence, depends very little on previously acquired knowledge, and can be measured by tests such as Block Design (BD) and Raven Colored Matrices (RCM). Premorbid intelligence quotient (IQ) refers to one's intellectual ability level previous to the onset of disorders like mild cognitive impairment (MCI) and Alzheimer's disease (AD) and it is important to estimate disease severity. The objective was to compare performance in tests that measure crystallized and fluid intelligence in healthy subjects and patients with amnestic MCI (aMCI) and AD. One hundred forty-four participants (aMCI (n = 38), AD (n = 45), and healthy controls (n = 61)) were submitted to neuropsychological tests (WAIS-III vocabulary, BD, and RCM). There were significant among groups, except for vocabulary, indicating a relative stability of crystallized intelligence in the continuum from normal to pathological cognitive decline. Vocabulary seems to be stable during the progression of the disease and useful as a measure of premorbid intelligence, that is, to estimate previous function in relation to the level of education and, as a collateral measure of cognition in people with low education.

Poster 26: Word Reading Compared to Demographics-Based Estimates of Premorbid IQ in Early Huntington Disease

Background Irregular word pronunciation is a common method of estimating premorbid intellect, because it is resistant to neurological insult/deterioration. However, emerging research suggests word reading ability declines in some neurodegenerative diseases, resulting in an underestimation of premorbid IQ. Misrepresentation of predisease intellect may affect clinical diagnosis and confound the selection of participants for clinical trials. An alternative method is the use of a demographically-based equation to estimate intelligence. Aim To compare the WRAT Reading Subtest (a pronunciation measure) and the Barona Index (a demographically-based regression equation) as estimates of premorbid IQ in individuals with mild to moderate Huntington disease (HD). Method Using participants (n = 73) pooled from two clinical trials and an outpatient HD clinic, we examined WRAT and Barona standard scores and their discrepancy, along with demographic and clinical characteristics. Results Mean age was 47.6 years (SD = 11.7), total functional capacity (TFC) was 9.6 (SD = 3.0), and total motor score (TMS) was 32.7 (SD = 15.8). Average WRAT standard score was 91.9 (SD = 11.9), while Barona was 108.0 (SD = 7.2), with a mean discrepancy of 16.1 (SD = 10.7; range –42.3 to +6.3). Although true premorbid IQ is unknown, this sample overrepresented higher levels of education (i.e., ∼22% of the sample had 16+ years, while ∼8% had p Discussion The WRAT produced premorbid IQ estimates lower than the Barona for 93% of participants and was below expectations given the sample's mean education. Unlike the Barona, the WRAT was associated with impaired motor functioning, suggesting that it may decline with disease. Therefore, the Barona Index may be a more appropriate measure of premorbid intelligence in persons with HD and should be considered for subject selection in clinical trials and clinical evaluation.

The WRAT-3 Reading Subtest as a Measure of Premorbid Intelligence Among Persons With Brain Injury.

Objective: To examine whether the Wide Range Achievement Test–3 (WRAT-3) Reading subtest (S. Jastak & G. S. Wilkenson, 1984; G. S. Wilkinson, 1993) measures premorbid intelligence in persons with traumatic brain injury (TBI). Participants: Sixty individuals (63% male, 78% Caucasian, mean age 38 years) tested during acute rehabilitation hospitalization following TBI and 1 year later. Results: Slight (4.4 points) increase in WRAT-3 Reading scores was observed but with greater, although nonsignificant (p .12), increase for those with greater injury severity. Conclusions: The WRAT-3 Reading subtest is a better hold test for individuals who sustain mild TBI.

Armed Forces Qualification Test as a Measure of Premorbid Intelligence

Estimating the premorbid abilities of individuals who sustained brain injury is a vital part of neuropsychological assessments. Military providers are in a unique position in that a great many of their patients have on record a measure of ability obtained prior to onset of their medical condition. For enlisted personnel, this is the Armed Forces Qualification Test (AFQT; U.S. Department of Defense, 1984). In this study, we examined the relation between this test and a standardized test of intelligence, the Multidimensional Aptitude Battery (Jackson, 1984). A regression equation was computed that allows estimation of intelligence from AFQT scores, providing clinicians a useful method of assessing premorbid cognitive ability in brain-injured patients.

Nithsdale schizophrenia surveys 21: a longitudinal study of National Adult Reading Test stability.

The stability of the National Adult Reading Test (NART) as a measure of pre-morbid intelligence in schizophrenia has not yet been satisfactorily established despite the widespread use of the NART in schizophrenia research. We examined NART stability in a diverse group of 45 schizophrenic patients in a prospective longitudinal study over 6.5-7.5 years. The results showed that NART performance does not decline significantly with increasing duration of schizophrenic illness and that test-retest reliability, even over 6.5-7.5 years, is extremely high. Our results provide the necessary evidence that the NART can be used as a stable measure of pre-morbid intelligence in schizophrenia.

Nithsdale schizophrenia surveys 21: A longitudinal study of national adult reading test stability

Background. The stability of the National Adult Reading Test (NART) as a measure of pre-morbid intelligence in schizophrenia has not yet been satisfactorily established despite the widespread use of the NART in schizophrenia research.Method. We examined NART stability in a diverse group of 45 schizophrenic patients in a prospective longitudinal study over 6·5–7·5 years.Results. The results showed that NART performance does not decline significantly with increasing duration of schizophrenic illness and that test–retest reliability, even over 6·5–7·5 years, is extremely high.Discussion. Our results provide the necessary evidence that the NART can be used as a stable measure of pre-morbid intelligence in schizophrenia.

Neurocognitive effects of aluminum.

The neurocognitive effects of aluminum (Al) were studied in 35 hemodialysis patients. Higher Al levels were associated with a decline in visual memory. As Al levels increased, patients with lower vocabulary scores (a measure of premorbid intelligence) showed a decline in attention/concentration, frontal lobe functions, and on several neurocognitive measures, while those with higher vocabulary scores revealed no Al-related decline. These results suggest that individuals with lower verbal intelligence may possess less well-developed compensatory strategies to overcome the neurocognitive effects associated with Al. These data also indicate that Al is neurotoxic and, therefore, potential sources of environmental Al should be identified and eliminated.

Estimation of verbal intelligence in an elderly community: An epidemiological study using NART

The National Adult Reading Test (NART) has become widely used by psychologists in clinical practice as part of the assessment of cognitive decline in organic mental disorders. Some normative data have been presented on community samples from a wide range of ages, but little is known of the instrument's performance in true community samples of the elderly. This study presents data on NART from an epidemiological study of dementia and cognitive impairment in elderly women. The contribution of educational level and social class to performance on the scale was examined. NART was found to be strongly related to current level of cognitive function as measured by the Mini Mental State Examination and CAMCOG-the neuropsychological battery of the Cambridge Examination for Mental Disorders in the Elderly. For most subjects in the community the NART was found acceptable as a measure of premorbid intelligence.

Qualitative changes in vocabulary test performance after lobotomy and selective frontal operations

The vocabulary performance of 40 neurotic patients before and after lobotomy and three types of selective frontal operations has been analysed in various ways. After lobotomy there was a significant decrease in quantitative (conventional) scores and a significant lowering of the quality of the word defintions. After the selective operations there was no significant decrease in quantitative scores but a marked lowering of the quality of the word definitions. The findings justify warnings against accepting conventional vocabulary scores as a measure of premorbid intelligence in brain-injured patients. They also support the Yacorzynski hypothesis that the stability of the vocabulary test in some cases of mental impairment is only apparent. The traditional dichotomous scoring of vocabulary tests, being too crude, may conceal important losses in finer word discriminations in such cases. The importance of adequate analysis and quantification of qualitative aspects of test performances in experimental clinical testing is stressed.