Decline In Intelligence Quotient Research Articles

Occupational outcome in bipolar disorder is not predicted by premorbid functioning and intelligence

Bipolar disorder (BD), over the long term, can manifest a variety of outcomes depending on a number of different conditions. There is a need for further knowledge regarding preventive factors as well as predictors of the disabling course of the disorder. Studies regarding the impact on functional outcome of premorbid and current general intellectual function [intelligence quotient (IQ)] and premorbid functioning in BD patients are sparse. The present study addressed the role of premorbid functioning [assessed with the Premorbid Adjustment Scale (PAS)], intelligence, course of illness, and sociodemographics on occupational outcome in BD. Bipolar disorder patients were recruited consecutively from psychiatric units (outpatient and inpatient) in four major hospitals in Oslo, Norway [(N = 226: 64.4% bipolar I disorder (BD-I); 30.1% bipolar II disorder (BD-II); 5.5% bipolar disorder not otherwise specified (BD-NOS); 38.6% males]. The associations between current IQ, premorbid IQ [assessed using the National Adult Reading Test (NART)], PAS, clinical and sociodemographic characteristics, and receipt of disability benefit were analysed using descriptive statistics and logistic regression analyses. The number of hospitalizations for depressive episodes and illness duration was associated with a higher risk of receipt of disability benefit. PAS, premorbid and current IQ, as well as decline in IQ, did not explain the higher risk of receipt of disability benefits. Severe clinical course of BD was associated with receipt of disability benefit. Occupational outcome was unrelated to PAS, premorbid and current IQ, as well as decline in IQ. This suggests that the persistence of severe clinical symptoms, rather than global cognitive functioning, determines occupational outcome in BD and emphasizes the protective potential of early and continuous clinical treatment.

Is Obesity Associated With a Decline in Intelligence Quotient During the First Half of the Life Course?

Is Obesity Associated With a Decline in Intelligence Quotient During the First Half of the Life Course?

Factors Influencing Neurocognitive Outcomes in Young Patients With Benign and Low-Grade Brain Tumors Treated With Stereotactic Conformal Radiotherapy

To present the effect of radiotherapy doses to different volumes of normal structures on neurocognitive outcomes in young patients with benign and low-grade brain tumors treated prospectively with stereotactic conformal radiotherapy (SCRT). Twenty-eight patients (median age, 13 years) with residual/progressive brain tumors (10 craniopharyngioma, 8 cerebellar astrocytoma, 6 optic pathway glioma and 4 cerebral low-grade glioma) were treated with SCRT to a dose of 54 Gy in 30 fractions over 6 weeks. Prospective neuropsychological assessments were done at baseline before RT and at subsequent follow-up examinations. The change in intelligence quotient (IQ) scores was correlated with various factors, including dose-volume to normal structures. Although the overall mean full-scale IQ (FSIQ) at baseline before RT remained unchanged at 2-year follow-up after SCRT, one third of patients did show a >10% decline in FSIQ as compared with baseline. Logistic regression analysis demonstrated that patients aged <15 years had a significantly higher chance of developing a >10% drop in FSIQ than older patients (53% vs. 10%, p = 0.03). Dosimetric comparison in patients showing a >10% decline vs. patients showing a <10% decline in IQ revealed that patients receiving >43.2 Gy to >13% of volume of the left temporal lobe were the ones to show a significant drop in FSIQ (p = 0.048). Radiotherapy doses to other normal structures, including supratentorial brain, right temporal lobe, and frontal lobes, did not reveal any significant correlation. Our prospectively collected dosimetric data show younger age and radiotherapy doses to left temporal lobe to be predictors of neurocognitive decline, and may well be used as possible dose constraints for high-precision radiotherapy planning.

Effects of Lead on IQ in Children

Lanphear et al. (2005) pooled data from seven prospective studies that had been initiated to test the effect of prenatal and early childhood lead exposure. The primary investigators of these studies had planned the studies so that the sequence of data collection might shed light on the question of early causation. At that time, most of us anticipated a strong association of prenatal exposure and developmental deficit related to rapid prenatal central nervous system (CNS) development (Ernhart 1992). Lanphear et al. (2005) pooled our data to report a significant association of cord blood lead (BPb) and IQ (intelligence quotient) and concluded that prevention of lead exposure must occur before pregnancy or childbirth. Their analysis did not include control of the sociodemographic factors known to confound research on the topic; hence, the conclusion is not justified. In the balance of the report, Lanphear et al. (2005) selected concurrent lead level at 5–6 years of age, as opposed to earlier measures of lead exposure, because it had the highest association with IQ. The closer association for the lead measurement made at or near the time of the IQ test may reflect concomitant factors not well controlled in the analyses. In most studies, parental intelligence and HOME (Home Observation for Measurement of the Environment; a measure of caretaking and parental stimulation) are major predictors of child IQ. These variables are difficult to measure (Kaufman 2001), and undercontrol of confounding is likely. Bias is particularly likely in the data of the Rochester, New York, cohort (Canfield et al. 2003) because the HOME (toddler version) was administered at the age of 2 years, not at 5–6 years of age. Using available covariate data, Lanphear et al. (2005) did report a deficit of approximately 2 IQ points for the BPb range of 10–20 μg/dL. This replicates previous analyses conducted by Pocock et al. (1994). The latter investigators interpreted the association as possibly due to limited control of confounding, selection biases, and/or reverse causality. The most problematic portion of the article by Lanphear et al. (2005) concerns very low lead exposure. The authors selected data for the 244 children who had peak, or maximal, BPb levels < 10 μg/dL. The decline in IQ for this group consisted of 6.2 points for the concurrent BPb range of 1–10 μg/dL (β = −0.80, SE = 0.48, p = 0.09). For a more restricted group of 103 children with peak BPb levels < 7.5 μg/dL, the association was stronger (β = −2.94, SE = 1.14, p = 0.012) although the sample size was further truncated. Lanphear et al. (2005) concluded that “lead exposure in children who have maximal BPb levels < 7.5 μg/dL is associated with intellectual deficits.” There are major problems with this conclusion. First, groups selected on the basis of peak lead level < 10 μg/dL and < 7.5 μg/dL differed significantly from the balance of the sample on factors omitted as non-contributing for the full study. Lanphear et al. (2005) ignored race (U.S. cohorts), maternal age, and maternal use of cigarettes and alcohol during pregnancy in the analyses of these groups. Second, cohort contribution was critical for these groups. Of the 103 children with BPb levels < 7.5 μg/dL (Lanphear et al 2005), 67% were from the Rochester cohort. In addition to the limitation in the HOME data, information regarding this cohort at 3 and 5 years of age reflects peculiar shifts in demographic variables, including race and maternal education (Canfield et al. 2003; Canfield RL, Henderson CR, Lanphear BP, Cory-Schlecta DA, Smith EG, Cox C, unpublished data). This was a prospective study, yet the sample increased from 154 children at 5 years of age to 182 at 6 years of age, and the number with peak lead levels < 10 μg/dL increased from 86 to 103. Canfield et al.’s 6-year data used in the pooled analysis have not been published, and my requests for further information were denied. Finally, there was no significant association of IQ and three of the four indices of lead exposure—early childhood, peak (or maximal), and lifetime average—for the segments of the sample with peak lead levels < 10 μg/dL or < 7.5 μg/dL. Lanphear et al. (2005) omitted these analyses from their article. Lanphear et al. (2005) reached conclusions intended to support policies to further reduce the already low level of childhood lead exposure. Although I contributed data [the Cleveland Study (Ernhart et al. 1989)] and participated in planning and review of analyses, I withdrew from authorship because I could not concur with the manuscript, including the inferences drawn.

Intellectual and Functional Outcome of Children 3 Years Old or Younger Who Have CNS Malignancies

To evaluate the impact of tumor location, clinical parameters, and therapy on neurocognitive, neuroendocrine, and functional outcomes in children < or = 3 years old with intracranial CNS malignancies who survived at least 2 years after diagnosis. Records were retrospectively reviewed for 194 children diagnosed from 1985 to 1999 at St Jude Children's Research Hospital (Memphis, TN). The median age at diagnosis was 1.8 years (range, 0.1 to 3.5 years). Median follow-up was 7.64 years (2.0 to 19.4 years). Tumors were infratentorial (102), diencephalic (53), and hemispheric (39); 47% required ventriculoperitoneal shunts, 36% developed seizure disorders, and 20% developed severe ototoxicity. Therapy included no radiation therapy (RT) in 57 (30%), local RT in 87 (45%), and craniospinal irradiation (CSI) in 49 (25%). Overall survival at 10 years was 78 +/- 4%. In a longitudinal analysis of 126 patients with at least one neurocognitive evaluation (NE), the mean rate of intelligence quotient (IQ) change for patients who received CSI (-1.34 points per year) and local RT (-0.51 points per year) was significantly different from the no RT group (0.91 points per year; P = .005 and P = .036, respectively). Patients with hemispheric tumors had a significantly greater IQ decline (-1.52 points per year) than those with midline tumors (0.59 points per year; P = .038). Among those with NE > or = 5 years after diagnosis, 71.4% of CSI recipients compared with 23% of local RT recipients had IQ less than 70 (P = .021). Patients undergoing CSI were more likely to develop endocrinopathies (P < .0001) and to require special education (P = .0007). In young children with CNS tumors, CSI and hemispheric location are associated with significant declines in IQ scores.

Relationship between Both IQ and Mini-Mental State Examination and the Regional Cerebral Glucose Metabolism in Clinically Diagnosed Alzheimer’s Disease: A PET Study

In order to clarify the hypofunction in which brain areas demonstrate a decline in Intelligence Quotient (IQ), we examined correlations between the IQ and Mini-Mental State Examination (MMSE) and regional cerebral metabolic rate of glucose (rCMRglc) measured using positron emission tomography (PET) in 26 patients with clinically diagnosed Alzheimer’s disease (AD). The MMSE scores and full-scale IQ (FSIQ) showed significant correlations with the rCMRglc in the temporal and parietal lobes on both sides and in the left frontal lobe, which were significantly reduced in comparison to those in the normal controls. A multiple regression analysis showed only the MMSE score to predict verbal IQ (VIQ), performance IQ (PIQ) and FSIQ. VIQ was also predicted by the rCMRglc in the left parietal lobe, while PIQ was predicted by the age at onset. The results suggested MMSE to be an index of dementia severity reflected by general intelligence as shown by IQ in AD, and a reduction in the VIQ can thus be used as an index of the left parietal dysfunction, which is not expressed by MMSE.

Familial schizophrenia shows no gender difference in age of onset

Schizophrenia patients are typically found to have low IQ both pre- and post-onset, in comparison to the general population. However, a subgroup of patients displays above average IQ pre-onset. The nature of these patients’ illness and its relationship to typical schizophrenia is not well understood. The current study sought to investigate the symptom profile of high-IQ schizophrenia patients.We identified 29 schizophrenia patients of exceptionally high pre-morbid intelligence (mean estimated pre-morbid intelligence quotient (IQ) of 120), of whom around half also showed minimal decline (less than 10 IQ points) from their estimated pre-morbid IQ. We compared their symptom scores (SAPS, SANS, OPCRIT, MADRS, GAF, SAI-E) with a comparison group of schizophrenia patients of typical IQ using multinomial logistic regression.The patients with very high pre-morbid IQ had significantly lower scores on negative and disorganised symptoms than typical patients (RRR = 0.019; 95% CI = 0.001, 0.675, P = 0.030), and showed better global functioning and insight (RRR = 1.082; 95% CI = 1.020, 1.148; P = 0.009). Those with a minimal post-onset IQ decline also showed higher levels of manic symptoms (RRR = 8.213; 95% CI = 1.042, 64.750, P = 0.046).These findings provide evidence for the existence of a high-IQ variant of schizophrenia that is associated with markedly fewer negative symptoms than typical schizophrenia, and lends support to the idea of a psychosis spectrum or continuum over boundaried diagnostic categories.

Neuropsychological Outcome and Social Recovery of Head-injured Patients

The Wechsler Adult Intelligence Scale and Yatabe-Guilford personality test were administered to 123 patients hospitalized for head injury who had made a relatively good recovery. Intelligence quotient (IQ) was correlated with clinical condition based on the Glasgow Coma Scale and duration of coma. More severely injured patients tended to show a greater decline in IQ. The type of lesion, as described by computed tomography, was also an important factor in predicting the outcome of intellectual function. The mean IQ of patients with diffuse injury, such as diffuse axonal injury and diffuse brain swelling, and intracerebral hematoma, was significantly lower than that of the control subjects, especially performance IQ (PIQ). Several patients demonstrated improved IQ level during the initial year. In particular, PIQ improved more than verbal IQ. The difference between the IQ of patients achieving social recovery and not was significant (p < 0.001). Causes of difficulty in returning to previous work were decreased IQ and personality change, such as lack of cooperativeness. Neuropsychological evaluation is important in predicting social recovery and selecting necessary neuropsychological rehabilitation.

Prospective intellectual testing in children with brain tumors.

Sixteen children with brain tumors received prospective intellectual evaluations with a follow-up of 2 to 5 years. All patients were treated with surgery and radiation and 5 received chemotherapy. Most of the children remained within the normal range of intelligence, but intelligence quotient (IQ) scores declined over time. Learning disabilities were present in 15 of 16 children after radiation, and 11 required special educational services. Risk factors associated with decline in IQ appear to be young age at time of radiation and adjuvant chemotherapy.