Relationship of IQ to verbal learning and memory: test and retest

A Closer Look at Practice Effects in Mild Cognitive Impairment and Alzheimer's Disease

Practice effects have become a potentially important variable regarding the diagnosis, prognosis, and treatment recommendations in mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, the understanding of these short-term changes in test scores remains unclear. The current observational study sought to examine variables that influence the magnitude of short-term practice effects in MCI and AD, including demographic information, cognitive performance, daily functioning, and medical comorbidities. One hundred sixty-six older adults classified as cognitively intact, amnestic MCI, or mild AD were tested twice across 1 week with a brief battery of neuropsychological tests. Correlational and regression analyses examined the relationship of practice effects with demographic and clinical variables. Results indicated that practice effects were minimally related to demographic variables and medical comorbidities, but they were significantly related to cognitive variables, depressive symptoms, and daily functioning. These findings expand our understanding of practice effects in MCI and AD, and they may allow a better appreciation of how they could affect clinical care and research.

Validation of one-year reliable change in the RBANS for community-dwelling older adults with amnestic mild cognitive impairment

Objective: The current study sought to externally validate previously published standardized regression-based (SRB) equations for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Indexes administered twice over a one-year period. Method: Hammers and colleagues' SRB prediction equations were applied to two independent samples of community-dwelling older adults with amnestic Mild Cognitive Impairment (MCI), including those recruited from the community (n = 64) and those recruited from a memory disorders clinic (n = 58). Results: While Observed Baseline and Observed Follow-up performances were generally comparable for both MCI samples over one year, both samples possessed significantly lower Observed One-Year Follow-up scores than were predicted based on Hammers and colleagues' development sample across many RBANS Indexes. Relatedly, both amnestic MCI samples possessed a greater percentage of participants either "declining" or failing to exhibit a long-term practice effect over one year relative to expectation across most Indexes. Further, the clinic-recruited amnestic MCI sample displayed worse baseline performances, smaller long-term practice effects, and greater proportions of individual participants exhibiting a decline across one year relative to the community amnestic MCI sample. Conclusions: These findings validate Hammers and colleagues' SRB prediction equations by (1) indicating their ability to identify clinically meaningful change across RBANS Indexes in independent samples, and (2) discriminating rates of cognitive change among cognitively nuanced samples.

Intimate partner violence during infancy and cognitive outcomes in middle childhood: Results from an Australian community-based mother and child cohort study

The cognitive functioning of children who experience intimate partner violence (IPV) has received less attention than their emotional-behavioral outcomes. Drawing upon data from 615 (48.4% female) 10-year-old Australian-born children and their mothers (9.6% of mothers born in non-English speaking countries) participating in a community-based longitudinal study between 2004 and 2016, this study examined the associations between IPV in infancy and cognition in middle childhood (at age 10). Results showed that IPV in the first 12 months of life was associated with lower general cognitive ability and poorer executive attention but not working memory skills. IPV in middle childhood (in the 10th year postpartum) was not associated with cognition. This study provides evidence for the long-term impact of early life exposure to IPV on children's cognition, and points to the importance of early intervention to optimize development.

A population-based cross-sectional study of cognitive deficits in paranoia

This study sought to investigate the association between paranoia and performance in a range of neurocognitive domains using a large community sample. We conducted a cross-sectional survey of 4507 individuals within the PISMA-ep Study. We used a large community sample selected after multistage sampling using standard stratification techniques. Socio-demographic variables such as age, gender, educational level, urbanicity, and geographical region were recorded. The Spanish version of the Green Paranoid Thought Scale (S-GPTS) was used to assess paranoid thoughts. The Screening for Cognitive Impairment in Psychiatry (SCIP) was used to assess neurocognitive performance both globally and by domains (i.e., immediate and delayed verbal learning, working memory, verbal fluency and processing speed). Individuals with high S-GPTS paranoia scores showed significantly lower performance on global cognitive function and also on immediate (but not delayed) verbal learning, working memory, verbal fluency and processing speed. These results held statistical significance even after controlling for the effects of education and estimated IQ. We propose that cognitive deficits may be mediators of paranoid thinking formation and need to be considered when assessing patients with high levels of paranoia.

Validation of one-week reliable change methods in cognitively intact community-dwelling older adults

OBJECTIVE

Reliable change methods can assist the determination of whether observed changes in performance are meaningful. The current study sought to validate previously published standardized regression-based (SRB) equations for commonly administered cognitive tests using a cognitively intact sample of older adults, and extend findings by including relevant demographic and test-related variables known to predict cognitive performance. Method: This study applied previously published SRB prediction equations to 107 cognitively intact older adults assessed twice over one week. Prediction equations were also updated by pooling the current validation sample with 93 cognitively intact participants from original development sample to create a combined development sample. Results: Significant improvements were seen between observed baseline and follow-up scores on most measures. However, few differences were seen between observed follow-up scores and those predicted from these SRB algorithms, and the level of practice effects observed based on these equations were consistent with expectations. When SRBs were re-calculated from this combined development sample, predicted follow-up scores were mostly comparable with these equations, but standard errors of the estimate were consistently smaller. Conclusions: These results help support the validity of of these SRB equations to predict cognitive performance on these measures when repeated administration is necessary over short intervals. Findings also highlight the utility of expanding SRB models when predicting follow-up performance serially to provide more accurate assessment of reliable change at the level of the individual. As short-term practice effects are shown to predict cognitive performance annually, they possess the potential to inform clinical decision-making about individuals along the Alzheimer's continuum.

Reliable change in cognition over 1 week in community-dwelling older adults: a validation and extension study

OBJECTIVE

Reliable change methods can aid neuropsychologists in understanding if performance differences over time represent clinically meaningful change or reflect benefit from practice. The current study sought to externally validate the previously published standardized regression-based (SRB) prediction equations developed by Duff for commonly administered cognitive measures.

METHOD

This study applied Duff's SRB prediction equations to an independent sample of community-dwelling participants with amnestic mild cognitive impairment (MCI) assessed twice over a 1-week period. A comparison of MCI subgroups (e.g., single v. multi domain) on the amount of change observed over 1 week was also examined.

RESULTS

Using pairwise t-tests, large and statistically significant improvements were observed on most measures across 1 week. However, the observed follow-up scores were consistently below expectation compared with predictions based on Duff's SRB algorithms. In individual analyses, a greater percentage of MCI participants showed smaller-than-expected practice effects based on normal distributions. In secondary analyses, smaller-than-expected practice effects were observed in participants with worse baseline memory impairment and a greater number of impaired cognitive domains, particularly for measures of executive functioning/speeded processing.

CONCLUSIONS

These findings help to further support the validity of Duff's 1-week SRB prediction equations in MCI samples and extend previous research by showing incrementally smaller-than-expected benefit from practice for increasingly impaired amnestic MCI subtypes.

Validating 1-Year Reliable Change Methods

OBJECTIVE

reliable change methods can assist in the determination of whether observed changes in performance are meaningful. The current study sought to validate previously published 1-year standardized regression-based (SRB) equations for commonly administered neuropsychological measures that incorporated baseline performances, demographics, and 1-week practice effects.

METHOD

Duff et al.'s SRB prediction equations were applied to an independent sample of 70 community-dwelling older adults with either normal cognition or mild cognitive impairment, assessed at baseline, at 1 week, and at 1 year.

RESULTS

minimal improvements or declines were seen between observed baseline and observed 1-year follow-up scores, or between observed 1-year and predicted 1-year scores, on most measures. Relatedly, a high degree of predictive accuracy was observed between observed 1-year and predicted 1-year scores across cognitive measures in this repeated battery.

CONCLUSIONS

these results, which validate Duff et al.'s SRB equations, will permit clinicians and researchers to have more confidence when predicting cognitive performance on these measures over 1 year.

Generalizability of reliable change equations for the RBANS over one year in community-dwelling older adults

Objective: Reliable change methods can assist neuropsychologists in determining whether observed changes in a patient's performance are clinically meaningful. The current study sought to validate previously published standardized regression-based (SRB) equations for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Indexes and subtests.Methods: Duff and colleagues's SRB prediction equations, developed from 223 cognitively intact primary care patients, were applied to an independent sample of robustly cognitively intact (n = 129) community-dwelling older adults assessed with the RBANS twice over a one-year period.Results: Results suggest that the cognitively intact participants in the current validation sample possessed significantly better Observed Follow-up scores than was predicted based on Duff's developmental sample across most RBANS Indexes and many RBANS subtests, though significantly lower Observed Follow-up scores were observed for the Visuospatial/Constructional Index than was predicted. As a result of these findings, the current study calculated updated prediction algorithms for the RBANS Index and subtest scores from the sample of 129 cognitively intact participants.Conclusions: Duff's 2004 and 2005 SRB prediction equations for the RBANS Index and subtest scores failed to generalize to a sample of cognitively intact community-dwelling participants recruited from senior living centers and independent assisted living facilities. These updated SRB prediction equations - being developed from a more medically "clean" sample of cognitively intact older adults who remained stable over 12 months - have the potential to provide a more accurate assessment of reliable change in an individual patient.

Risk- and protective factors for memory plasticity in aging

Risk and protective factors for cognitive function in aging may affect how much individuals benefit from their environment or life experiences by preserving or improving cognitive abilities. We investigated the relations between such factors and outcome from episodic-memory training in 136 healthy young and older adults. Tested risk factors included carrying the ɛ4 variant of the apolipoprotein E allele (APOE), age, body mass index, blood pressure, and cholesterol. Protective factors included higher levels of education, intelligence quotient (IQ), physical activity, fatty acids, and vitamin D. Average increases in memory performance were seen after training, with ample variation between individuals. Being young, female, and having higher IQ were positive predictors of memory improvement. No other relationships were observed. Similar benefit was observed across APOE allelic variation. This indicates that beyond IQ, age, and sex, known risk -and protective factors of cognitive function in aging were not significantly related to memory plasticity.

An Event Related Potentials Study of Semantic Coherence Effect during Episodic Encoding in Schizophrenia Patients

The objective of this electrophysiological study was to investigate the processing of semantic coherence during encoding in relation to episodic memory processes promoted at test, in schizophrenia patients, by using the N400 paradigm. Eighteen schizophrenia patients and 15 healthy participants undertook a recognition memory task. The stimuli consisted of pairs of words either semantically related or unrelated to a given category name (context). During encoding, both groups exhibited an N400 external semantic coherence effect. Healthy controls also showed an N400 internal semantic coherence effect, but this effect was not present in patients. At test, related stimuli were accompanied by an FN400 old/new effect in both groups and by a parietal old/new effect in the control group alone. In the patient group, external semantic coherence effect was associated with FN400, while, in the control group, it was correlated to the parietal old/new effect. Our results indicate that schizophrenia patients can process the contextual information at encoding to enhance familiarity process for related stimuli at test. Therefore, cognitive rehabilitation therapies targeting the implementation of semantic encoding strategies can mobilize familiarity which in turn can overcome the recollection deficit, promoting successful episodic memory performance in schizophrenia patients.

Within-session and one-week practice effects on a motor task in amnestic mild cognitive impairment

Practice effects on neuropsychological tests, which are improvements in test scores due to repeated exposure to testing materials, are robust in healthy elders, but muted in older adults with cognitive disorders. Conversely, few studies have investigated practice effects on motor tasks involving procedural memory, particularly across test-retest periods exceeding 24 hours. The current study examined one-week practice effects on a novel upper extremity motor task in 54 older adults with amnestic mild cognitive impairment. Results indicate that these individuals with primary memory deficits did improve on this motor task within a brief training session as well as across one week. These practice effects were unrelated to demographic characteristics or global cognition. One-week practice effects were, however, negatively related to delayed memory function, with larger practice effects being associated with poorer delayed memory and potentially better visuospatial ability. The presence of longer term practice effects on a procedural motor task not only has implications for how longitudinal assessments with similar measures involving implicit memory might be interpreted, but may also inform future rehabilitative strategies for patients with more severe declarative memory deficits.

The effect of premorbid intelligence on neurocognitive and psychosocial functioning in bipolar disorder

BACKGROUND

The aim of this study was to assess if premorbid IQ moderates the association between measures of clinical severity and neurocognitive or psychosocial functioning in euthymic patients with bipolar disorder.

METHODS

One hundred and nineteen outpatients and forty healthy controls were included. The length of illness, number of previous hypo/manic and depressive episodes, episode density, and history of psychosis assessed clinical severity. Performances in verbal memory, attention, and executive functions, as well as level of psychosocial functioning were used as outcomes.

RESULTS

The negative relationship between number of hypo/manic episodes and performance in executive functions decreased as a function of higher values of premorbid IQ. No other influences of premorbid IQ were found in the association between clinical severity measures and neurocognitive and psychosocial functioning.

CONCLUSIONS

Premorbid IQ might moderate the relationship between the number of hypo/manic episodes and executive functioning in bipolar disorder. Possible interpretations of this finding are discussed.

Temporal Stability of the Dutch Version of the Wechsler Memory Scale-Fourth Edition (WMS-IV-NL)

OBJECTIVE

The Wechsler Memory Scale-Fourth Edition (WMS-IV) is one of the most widely used memory batteries. We examined the test-retest reliability, practice effects, and standardized regression-based (SRB) change norms for the Dutch version of the WMS-IV (WMS-IV-NL) after both short and long retest intervals.

METHOD

The WMS-IV-NL was administered twice after either a short (M = 8.48 weeks, SD = 3.40 weeks, range = 3-16) or a long (M = 17.87 months, SD = 3.48, range = 12-24) retest interval in a sample of 234 healthy participants (M = 59.55 years, range = 16-90; 118 completed the Adult Battery; and 116 completed the Older Adult Battery).

RESULTS

The test-retest reliability estimates varied across indexes. They were adequate to good after a short retest interval (ranging from .74 to .86), with the exception of the Visual Working Memory Index (r = .59), yet generally lower after a long retest interval (ranging from .56 to .77). Practice effects were only observed after a short retest interval (overall group mean gains up to 11 points), whereas no significant change in performance was found after a long retest interval. Furthermore, practice effect-adjusted SRB change norms were calculated for all WMS-IV-NL index scores.

CONCLUSIONS

Overall, this study shows that the test-retest reliability of the WMS-IV-NL varied across indexes. Practice effects were observed after a short retest interval, but no evidence was found for practice effects after a long retest interval from one to two years. Finally, the SRB change norms were provided for the WMS-IV-NL.

Practice effects and amyloid deposition: preliminary data on a method for enriching samples in clinical trials

Clinical trials in Alzheimer disease are moving toward prevention studies in prodromal individuals with amyloid burden. However, methods are needed to identify individuals expected to be amyloid positive for these studies to be feasible and cost-effective. The current study sought to determine whether short-term practice effects on cognitive tests can identify those with notable uptake on amyloid imaging. Twenty-five, nondemented older adults (15 cognitively intact, 10 with mild cognitive impairment) underwent amyloid imaging through F-flutemetamol and 2 cognitive testing sessions across 1 week to determine practice effects on a visual memory test. Results indicated that, whereas F-flutemetamol uptake showed little association with baseline performance on a visual memory test (r=-0.04, P=0.85), it was significantly correlated with practice effects across 1 week on that same memory measure (r=-0.45, P=0.02), with greater uptake being associated with lower practice effects. The odds ratio of notable F-flutemetamol uptake was 5 times higher in individuals with low practice effects compared with high practice effects. Although these preliminary results need to be replicated in larger samples, short-term practice effects on cognitive tests may provide an affordable screening method to identify individuals who are amyloid positive, which could enrich samples for preventative clinical trials in Alzheimer disease.

Meaningful Change in Cognition in Multiple Sclerosis: Method Matters

Objective:

To determine if different methods of evaluating cognitive change over time yield measurably different outcomes.

Methods:

Twelve cognitively impaired patients with clinically definite Multiple sclerosis (10 relapsing-remitting, 2 secondary progressive) underwent neuropsychological testing (baseline, 6, 12 months). Data was analysed using: t-tests evaluating group differences on individual tests, group differences in composite scores, reliable change analyses at the level of the individual, and comparisons regarding number of tests failed at each time point.

Results:

Group t-tests on individual tests yielded no change. When tests were grouped according to theoretical constructs, analyses revealed change in processing speed. Reliable change estimates revealed that 16% of the sample deteriorated. When change was measured with respect to the number of domains affected at each time point, 58% of the sample deteriorated on at least one subtest.

Conclusions:

Methodology has a significant impact on interpretation of longitudinal data. In the same group of subjects, traditional group analyses documented no change in individual test scores or change on a single composite score. Analyses of individual results documented change from 16 to 58% of the sample. Advantages and disadvantages of each method were discussed. Findings have implications for interpretation of longitudinal studies.

A preliminary investigation of cognitive function in rheumatoid arthritis patients on long-term methotrexate treatment

Some studies suggest that cognitive function is impaired in rheumatoid arthritis patients. One possible influence may be commonly used rheumatoid arthritis treatment, methotrexate. This study examined cognitive function in long-term methotrexate users with rheumatoid arthritis and, using a 24-hour pre- and post-methotrexate dose administration, investigated whether there may be transient cognitive function changes. Rheumatoid arthritis patients ( n = 35) were assessed immediately before taking methotrexate and 24 hours later. Low and high methotrexate dose groups were then compared. Cognitive performance was unchanged across two assessment points and was within the normal range, although lower in high methotrexate dose group.

Practice effects: a unique cognitive variable

Practice effects are improvements in cognitive test performance due to repeated evaluation with the same or similar test materials. Prior studies have reported that these improvements can vary with age, education/intellect, and disease status. However, additional information is needed about variables that influence practice effects. The current study prospectively quantified short-term practice effects in 268 community-dwelling older adults and compared these practice effects to demographic variables, global cognition, premorbid intellect, depression, and individual cognitive domains. Overall, practice effects were not significantly related to most demographic and clinical characteristics or individual cognitive domains, which was contrary to our hypotheses. However, since practice effects appear to be uninfluenced by many variables that typically affect cognitive scores, they may be a unique and valuable tool that could be applied in a number of diverse patient groups.

Prospective memory in schizophrenia and schizotypy

INTRODUCTION

Most evidence suggests that schizophrenia is associated with pervasive prospective memory (PM) impairment that does not vary as a function of task demands. However, a central tenet of the Multiprocess Framework is that PM involves both automatic and strategic processes, and that their relative prominence varies as a function of PM task characteristics, such as target-cue saliency.

METHODS

Participants with schizophrenia (n = 30), matched controls (n = 29), low schizotypes (n = 35), and high schizotypes (n = 36) were administered a PM measure in which saliency was manipulated. To further clarify the relationship between PM and schizotypy, high and low schizotypies were additionally assessed on Virtual Week, a laboratory measure which has documented sensitivity to schizophrenia-related impairment.

RESULTS

Relative to controls, participants with schizophrenia exhibited PM difficulties, but the magnitude of this deficit did not vary as a function of target-cue saliency. High and low schizotypes did not differ on any PM test parameter.

CONCLUSIONS

These data are consistent with other evidence showing that schizophrenia is characterised by generalised PM impairment. However, the absence of any schizotypy effects on PM does not support the recent suggestion that PM may represent an endophenotype for schizophrenia.

Applying new research criteria for diagnosis of early Alzheimer's disease: sex and intelligence matter

Alzheimer's disease (AD) can be diagnosed according to new research criteria proposed recently (Dubois et al., 2007). Diagnosis is made on grounds of episodic memory deficits and one pathological biomarker: cerebrospinal fluid (CSF) or structural/functional imaging. Goal was to investigate the dependence of episodic memory function on material (verbal, visuospatial), gender and premorbid intellectual ability (IQ). The new research criteria of AD were applied retrospectively using data of 68 patients (Mini-Mental-Status Examination, MMSE ≥ 22) from a university memory clinic. Women with lower IQ performed worse on visuospatial episodic memory than women with higher IQ and men with the same IQ. Thus, women with lower IQ appear to be particularly vulnerable to visuospatial episodic memory deficits despite similar CSF tau values indicating a similar activity of the neurodegenerative process. Gender, premorbid IQ, and visuospatial material need to be considered in the assessment of episodic memory breakdown applying the newly proposed research criteria for the diagnosis of AD.

Intelligence and medial temporal lobe function in older adults: a functional MR imaging-based investigation

BACKGROUND AND PURPOSE

The influence of general intelligence and formal education on functional MR imaging (fMRI) activation has not been thoroughly studied in older adults. Although these factors could be controlled for through study design, this approach makes sample selection more difficult and reduces power. This study was undertaken to examine our hypothesis that intelligence and education would impact medial temporal lobe (MTL) fMRI responses to an episodic memory task in healthy elderly subjects.

MATERIALS AND METHODS

Thirty-six women and 38 men, 50-83 years of age (mean, 63.4 +/- 7.9 years), completed an auditory paired-associates paradigm in a 1.5T magnet. The amplitude and volume of fMRI activation for both the right and left MTLs and MTL subregions were correlated with the intelligence quotients (IQs) and educational levels by using Pearson correlation coefficient tests and regression analyses.

RESULTS

The participants' mean estimated full scale IQ and verbal IQ scores were 110.4 +/- 7.6 (range, 92-123) and 108.9 +/- 8.7 (range, 88-123), respectively. The years of education showed a mean of 16.1 +/- 3.2 years (range, 8-25 years). The paradigm produced significant activation in the MTL and subregions. However, the volume and amplitude of activation were unrelated to either IQ or years of schooling in men and/or women.

CONCLUSIONS

We found no evidence of an effect of IQ or education on either the volume or amplitude of fMRI activation, suggesting that these factors do not necessarily need to be incorporated into study design or considered when evaluating other group relationships with fMRI.

Role of processing speed and premorbid IQ on visual recognition in patients with schizophrenia

Previous research had shown that processing speed and premorbid IQ are predictors of verbal-memory efficiency in patients with schizophrenia. We investigated whether the same factors are involved in visual memory. A total of 49 patients with schizophrenia and 43 healthy controls were administered a picture recognition task. Half of the pictures were black and white, and half were in color, in order to vary the depth of encoding. Processing speed was measured by three standard tasks, and premorbid IQ was measured by the National Adult Reading Test (NART). Patients were significantly impaired in picture recognition. Regression analyses revealed that NART score was a significant predictor of the recognition of both types of picture in patients. Processing speed was a significant predictor of the recognition of the colored pictures. The effect of diagnosis on the recognition of colored pictures was reduced to nonsignificance when processing speed was entered in the regression. These data suggest that premorbid IQ is involved in visual-recognition efficiency. However, the deficit observed in patients is accounted for by decreased processing speed.

Test-Retest Stability and Practice Effects of the RBANS in a Community Dwelling Elderly Sample

Repeated neuropsychological assessments are common with older adults, and the determination of true neurocognitive change is important for diagnostic assessment. Several statistical formulas are available to assist in this determination, but they rely on access to test-retest stability coefficients and practice effect values. The current study presents data on these psychometric properties of the RBANS in a large community dwelling elderly sample. Across a one-year retest interval, stability coefficients ranged from .58 to .83 for the Index scores, and from .51 to .83 for the subtest scores. Practice effects were largely absent, with most performances slightly decreasing at retest. These psychometric properties are contrasted with those reported in the RBANS manual, and possible reasons for these differences are discussed. A case example is provided that demonstrates the use of the current findings in conjunction with existing change formulas.

Memory, emotional and vocational impairments before and after anterior temporal lobectomy for complex partial seizures

PURPOSE

To assess the pre- and postsurgical frequency of memory, emotional, and vocational impairments in patients who underwent anterior temporal lobectomy (ATL), and to assess the relationship between emotional disturbance and memory abilities after ATL.

METHODS

Retrospective analysis of data was performed on 90 patients with medically intractable complex partial seizures who underwent ATL between 1981 and 2003. Patients were evaluated an average of 5 months before surgery and 11.3 months after surgery.

RESULTS

A moderate to high frequency of memory impairment (44.4%; verbal or nonverbal), emotional disturbance (38.9%) and unemployment (27.8%) existed in the same individuals both before and after surgery. There were small to moderate rates of new onset memory (18.9%), emotional (11.1%), and vocational (7.8%) difficulties after surgery often regardless of seizure control outcome. Patients who underwent left-ATL and had emotional disturbance after surgery had the lowest verbal memory test scores.

CONCLUSIONS

Results highlight the importance of taking into account emotional status when assessing memory abilities after ATL. Results replicate the finding of moderate to high frequencies of memory impairment, emotional disturbance, and unemployment both before and after ATL. Results provide support for the rationale that cognitive, psychiatric and vocational interventions are indicated to mitigate the problems that exist before and persist after ATL.

Gifted students with learning disabilities: who are they?

More than 20 years ago, psychologists first described gifted students with learning disabilities (LD). In the past decade, several sets of identification criteria have been proposed for this population. Many of the suggested assessment practices are unsupported by research in psychoeducational assessment, and some have been directly contradicted by recent research. We argue that an uncritical acceptance of the concept of concomitant giftedness and LD has led to unsound identification procedures and to interventions that are not targeted properly. Specific recommendations for future research and implications for current clinical practice are discussed.

Memory performance in severely depressed patients treated by electroconvulsive therapy

OBJECTIVES

Depression is accompanied by disturbed implicit (unconscious) and explicit (conscious) memory functions. The aim was the assessment of immediate and delayed verbal and visual memory functions, concentration/attention during the course of electroconvulsive therapy (ECT) treatment.

METHODS

Twenty severely depressed, drug-treatment resistant, elderly patients were assessed with the Wechsler Memory Scale-Revised (WMS-R) before and at the end of the ECT series.

RESULTS

Patients revealed deficits in acquisition (immediate verbal and visual memory), attention/concentration, and retrieval of information (delayed memory) before ECT. After ECT, significant improvements were observed in immediate memory but not in delayed memory. Although higher total stimulation levels (millicoulombs) (P = 0.015) were associated with improvements in immediate visual memory, we found that longer duration of convulsions (P = 0.016) as well as lower levels of stimulation at last ECT (P = 0.036) were associated with improvements in immediate verbal memory. Moreover, we found that stimulation energy (millicoulombs) in total and at last ECT was the best predictor among several clinical and ECT parameters of improved visual memory and concentration and decreased verbal and general memory.

CONCLUSIONS

Prefrontal cortex-related memory processes, especially immediate memory encoding, improved after ECT, whereas long-term memory remained impaired, indicating that severely depressed patients remain cognitively inferior to normal subjects despite clinically successful treatment. This study may yield a better understanding of the time course of memory alterations in severely depressed patients receiving ECT. Improvement of immediate memory may be essential for establishing normal daily activities of life in the recovery phase of depression.

Estrogen therapy selectively enhances prefrontal cognitive processes: a randomized, double-blind, placebo-controlled study with functional magnetic resonance imaging in perimenopausal and recently postmenopausal women

OBJECTIVE

Estrogen therapy (ET) seems to differentially effect cognitive processes in younger versus older postmenopausal women, suggesting a window of opportunity when ET is most beneficial. Cognitive improvement in younger postmenopausal women has been attributed to ET's influence on hot flushes and sleep, but empiric examination of the mediating role of menopause symptoms versus direct effects of ET on the brain is limited.

DESIGN

In a double-blind trial, 52 women were randomly assigned to estradiol 0.05 mg/day (n = 26) or placebo transdermal patches (n = 26) for 12 weeks. Women completed tests of memory, learning, and executive functioning, and hot flush and sleep assessments at baseline and study end. A subset of women (five ET treated, six placebo treated) also underwent blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies.

RESULTS

Nondepressed perimenopausal and postmenopausal women were studied. The majority had hot flushes and sleep impairment. Compared with placebo, ET selectively reduced errors of perseveration during verbal recall (P = 0.03), a frontal system-mediated function, but did not influence other cognitive processes. Women with baseline hot flushes had greater cognitive benefit with ET (P < 0.05). Cognitive benefit was not associated with sleep problems or its improvement. Measures of fMRI BOLD activation during tests of verbal and spatial working memory showed significant increases in frontal system activity with ET (P < 0.001).

CONCLUSIONS

Estrogen therapy selectively improves executive functioning as demonstrated by reduced perseverative errors and prefrontal cortex activation during verbal recall tasks. Cognitive improvement with ET is associated with hot flushes, but not with sleep, suggesting that ET has a direct central nervous system effect, rather than an indirect effect mediated through improvement of sleep.

Acute neurobehavioral effects of exposure to static magnetic fields: Analyses of exposure–response relations

PURPOSE

To assess exposure-response relations between exposure to magnetic fields and neurobehavioral effects.

MATERIALS AND METHODS

Twenty company volunteers completed a neurobehavioral test battery after they moved their heads with the magnetic field absent, and while they moved their heads in the inhomogenous stray fields of 1.5 and 3.0 T MRI magnets.

RESULTS

The value of the stray fields at the position of the head of the volunteer was estimated to be 0.6 T and 1.0 T on the 1.5 T and 3.0 T systems, respectively. Exposure-response relations were found for visual (-2.1%/100 mT) and auditory (-1.0%/100 mT) working memory, eye-hand coordination speed (-1.0%/100 mT), and visual tracking tasks (-3.1%/100 mT). Eye-hand precision, scanning speed, and visual contrast sensitivity were apparently not influenced by the magnetic field strength.

CONCLUSION

Additional research should focus on the potential side effects of interventional MR procedures because of the exposure to strong magnetic fields of these systems.

The California Verbal Learning Test-Children's Version: relation to factor indices of the Wechsler Intelligence Scale for Children-Third Edition

The California Verbal Learning Test-Children's Version (CVLT-C) provides clinicians with a method of assessing various aspects of children's verbal memory and has been found to be sensitive to memory deficits resulting from a variety of neurological conditions. Intuitively, the CVLT-C would be expected to be highly related to a child's verbal cognitive abilities; however, with only a few exceptions, the relationship of this test to various domains of cognitive function has not been broadly studied empirically. To examine this issue, we evaluated the amount of unique variance in CVLT-C scores that could be predicted by the Verbal Comprehension, Perceptual Organization, Freedom from Distractibility, and Processing Speed indices of the Wechsler Intelligence Scale for Children, Third Edition (WISC-III) beyond that accounted for by age and gender in a sample of 62 children referred to an outpatient psychiatry clinic for neuropsychological evaluation. While the Processing Speed Index predicted a significant amount of variance for both short and long delay free and cued recall, the Verbal Comprehension Index was a poor predictor of CVLT-C performance on all outcome variables, accounting for only 1.5 to 4.5% additional variance above age and gender. These findings indicate that while the CVLT-C may be relatively independent of influences of verbal intelligence and abstract verbal reasoning, general speed and efficiency of processing play an important role in successful encoding for later retrieval on the CVLT-C.

Mayo's Older Americans Normative Studies: Age- and IQ-Adjusted Norms for the Auditory Verbal Learning Test and the Visual Spatial Learning Test

Although normative data sets for standardized neuropsychometric instruments frequently feature adjustments for subject variables, there are reasons to believe that improvements in interpretive accuracy that result from such adjustments are less than optimal. In particular, years of education may be less closely associated with test performances than is overall intellectual functioning. In this last of four reanalyses of results from the Mayo Clinic's Older Americans Normative Studies (MOANS) databases, age-adjusted scores for the Rey Auditory Verbal Learning Test and the Visual Spatial Learning Test were found to be more strongly related to Mayo age-adjusted WAIS-R Full Scale IQ scores (rs=.150 to .395) than to education (rs=.060 to .236) for healthy older examinees between 56 and 99 years of age. Although AVLT-FSIQ correlations were greatest at moderate levels of intelligence, VSLT-FSIQ correlations consistently increased in strength as intelligence increased (cf. Dodrill, 19971999). Based on these results, we present tables of age- and IQ-adjusted percentile equivalents of Mayo age-adjusted AVLT index scores and MOANS age-adjusted AVLT and VSLT scaled scores for ten age ranges and either seven (AVLT) or five (VSLT) IQ ranges.

Mayo's Older Americans Normative Studies: Age- and IQ-Adjusted Norms for the Boston Naming Test, the MAE Token Test, and the Judgment of Line Orientation Test

Although many extant normative data sets for standardized neuropsychometric instruments feature adjustments for subject variables, there are reasons to believe that improvements in interpretive accuracy that result from such adjustments are less than optimal. In particular, several theoretical considerations suggest that years of formal education may be less closely related to test performances than is general intellectual functioning. In this first of four reanalyses of results from the Mayo Clinic's Older Americans Normative Studies (MOANS) databases, age-adjusted scores on the Boston Naming Test, the MAE Token Test, and the Judgment of Line Orientation Test were indeed found to be more strongly associated with Mayo Age-adjusted WAIS-R Full Scale IQ scores (rs=.608, .473, and .502, respectively) than with education (rs=.310, .306, and .236, respectively) for healthy older examinees (56-99 years). Consistent with the remarks of Dodrill (19971999), these correlations generally decreased at higher levels of intelligence. The magnitude and pattern of such declines varied across the three tests, however, suggesting that IQ-test score associations must be empirically determined rather than assumed to be linear. Tables of Age- and IQ-Adjusted percentile equivalents of MOANS Age-adjusted BNT, Token Test, and JLO scaled scores are presented for eleven age ranges and seven IQ ranges. The article concludes with a discussion of factors that may underlie observed relations among age, intelligence, and neuropsychometric test performances.

Effects of using same- versus alternate-form memory tests during short-interval repeated assessments in multiple sclerosis

Repeated neuropsychological testing gives rise to practice effects in that patients become familiar with test material as well as test-taking procedures. Using alternate forms prevents the learning of specific test stimuli, potentially mitigating practice effects. However, changing forms could diminish test-retest reliability coefficients. Our objective was to examine test-retest effects in multiple sclerosis (MS) patients randomly assigned to same- (SF) or alternate-form (AF) conditions. Thirty-four MS patients underwent neuropsychological evaluation. The battery included the California Verbal Learning Test II (CVLT-II) and the Brief Visuospatial Memory Test-Revised (BVMT-R), memory tests recommended by a recently convened consensus panel. Patients were randomly assigned to SF or AF groups and then tested at baseline and follow-up examination 1 week later. Analysis of variance tests (ANOVAs) revealed significant group x time interactions, with SF patients showing greater gain than AF patients. SF practice effects were often large, compromising test validity. Reliability coefficients were either equivalent or higher in the AF group, a finding attributed to ceiling effects and reduced variance in the SF group at retest. The generalizability of the findings may be limited to short test-retest intervals and the MS population. Nevertheless, I conclude that the use of CVLT-II and BVMT-R alternate forms likely helps preserve test validity without compromising test-retest reliability.

Ineffectiveness of an Italian NART-equivalent for the estimation of verbal learning ability in normal elderly

Comparison between current and premorbid memory ability may be of help when trying to make a timely diagnosis of cognitive decline in questionable dementia. In the present study, we evaluated the possibility of estimating episodic verbal memory scores at the Rey Auditory Verbal Learning Test (RAVLT) from an irregular words reading task held to resist to deterioration, that is the Italian analogue of the NART, the TIB (Test d'Intelligenza Breve--brief intelligence test). A regression analysis was performed in a large sample of healthy elderly, using RAVLT scores as dependent variable and TIB score, MMSE score, age and education as predictors. We failed to find a relationship between the two tests that was strong enough for a reliable estimation of memory ability.

Base rates of longitudinal RBANS discrepancies at one- and two-year intervals in community-dwelling older adults

Identification of clinically significant change in performance over time on neurocognitive tests is an important aspect of neuropsychological evaluation; however, scant published empirical data exists to guide the clinician in determining the significance of psychometric change across clinically relevant retest intervals. The present study presents base rate data of RBANS score discrepancies in a user-friendly manner based on the performances of a large sample (n=283) of community-dwelling older adults. Data for 1- and 2-year retest intervals are presented in a tabular form that can be used as a convenient reference. Base rates of discrepancy scores were calculated and organized into three groups (i.e., below average, average, and above average) with respect to the participants' OKLAHOMA age- and education-corrected RBANS Total Scale score (Duff, Patton, Schoenberg, Mold, Scott, & Adams, 2003) at initial assessment, in an effort to reduce the influence of regression to the mean and practice effects that is associated with varying levels of cognitive ability. (e.g., Rapport, Axelrod, Theisen, Brines, Kalechstein, & Ricker, 1997; Rapport, Brines, Axelrod, & Theisen, 1997). These data may be helpful in clinical practice by assisting the clinician in determining the clinical significance of score changes.

Item recognition is less impaired than recall and associative recognition in a patient with selective hippocampal damage

This article explores the recall, item recognition, and associative recognition memory of patient B.E., whose pattern of retrograde amnesia was reported by Kapur and Brooks (1999; Hippocampus 9:1-8). Structural magnetic resonance imaging (MRI) has shown that B.E. has bilateral damage restricted to the hippocampus. The structural damage he had sustained was accompanied by bilateral hypoperfusion of the temporal lobe, revealed by positron emission tomography (PET), and which single photon emission computed tomography (SPECT) suggested was greater in the left than the right temporal lobe. B.E. showed a global anterograde amnesia for verbal material, but he displayed some sparing of nonverbal item recognition relative to nonverbal recall and associative recognition. His performance on an item recognition task that used the remember/know procedure and another that involved repetition of the test phase, to reduce the difference between the familiarity of the targets and foils, suggested that his relatively spared nonverbal item recognition may have been mainly supported by familiarity. This finding is consistent with the view that the anterior temporal lobe, including the perirhinal cortex, can support familiarity-based memory judgments (Brown and Bashir, 2002; Philos Trans R Soc Lond B 357:1083-1095). B.E.'s data also highlight the importance of functional as well as structural scan information for interpreting the pattern of memory deficits shown by patients with selective hippocampal structural lesions.

Predicting change with the RBANS in a community dwelling elderly sample

Repeated neuropsychological assessments are common with older adults, and the determination of clinically significant change across time is an important issue. Regression-based prediction formulas have been utilized with other patient and healthy control samples to predict follow-up test performance based on initial performance and demographic variables. Comparisons between predicted and observed follow-up performances can assist clinicians in determining the significance of change in the individual patient. In the current study, multiple regression-based prediction equations for the 5 Indexes and Total Score of the RBANS were developed for a sample of 223 community dwelling older adults. These algorithms were then validated on a separate elderly sample (N = 222). Minimal differences were present between observed and predicted follow-up scores in the validation sample, suggesting that the prediction formulas are clinically useful for practitioners who assess older adults. A case example is presented that illustrates how the algorithms can be used clinically.

Verbal declarative memory dysfunction in schizophrenia: from clinical assessment to genetics and brain mechanisms

The recent literature on the neuropsychology of schizophrenia has emphasized memory deficits as a key area of impairment. Abnormalities in the medial temporal lobe, a brain region crucial for long-term memory formation, have also consistently been reported. We conducted a comprehensive review of verbal declarative memory (VDM) in schizophrenia with the aim of systematically addressing the nature of this impairment. We conclude that verbal declarative memory is significantly impaired in schizophrenia and is largely accounted for by deficits in the encoding stage. Subtle impairments in increased rates of forgetting are present, but are mild compared with those in amnestic disorders. Impairment in other cognitive domains studied thus far (e.g., attention), medication effects, or fluctuations in symptoms do not completely account for the deficit. VDM is among the most impaired neurocognitive domains in schizophrenia (along with attention and executive functions). Milder encoding deficits are present in high-risk subjects and non-psychotic relatives of individuals with schizophrenia suggesting that components of the deficit are associated with a genetic vulnerability to the illness, and are independent of the frank psychotic illness. Furthermore, VDM is observed in individuals experiencing their first-psychotic episode and it remains fairly consistent over time. Preliminary imaging studies and other work suggest abnormalities in prefrontal-hippocampal processing networks. Future work should emphasize delineating specific information processing components contributing to the deficit. This would allow imaging studies to determine which brain regions contribute to specific information processing deficits in schizophrenia.

Retaking ability tests in a selection setting: implications for practice effects, training performance, and turnover

This field study investigated the effect of retaking identical selection tests on subsequent test scores of 4,726 candidates for law enforcement positions. For both cognitive ability and oral communication ability selection tests, candidates produced significant score increases between the 1st and 2nd and the 2nd and 3rd test administrations. Furthermore, the repeat testing relationships with posthire training performance and turnover were examined in a sample of 1,515 candidates eventually selected into the organization. As predicted from persistence and continuance commitment rationales, the number of tests necessary to gain entry into the organization was positively associated with training performance and negatively associated with turnover probability.