Biomedical subjects

Gordon J Chelune

Publications and source records attributed to Gordon J Chelune.

18 recordsLinked to original sources

PubMed2006

Development of demographic norms for four new WAIS-III/WMS-III indexes.

Following the publication of the third edition Wechsler scales (i.e., WAIS-III and WMS-III), demographically corrected norms were made available in the form of a computerized scoring program (i.e., WAIS-III/WMS-III/WIAT-II Scoring Assistant). These norms correct for age, gender, ethnicity, and education. Since then, four new indexes have been developed: the WAIS-III General Ability Index, the WMS-III Delayed Memory Index, and the two alternate Immediate and Delayed Memory Indexes. The purpose of this study was to develop demographically corrected norms for the four new indexes using the standardization sample and education oversample from the WAIS-III and WMS-III. These norms were developed using the same methodology as the demographically corrected norms made available in the WAIS-III/WMS-III/WIAT-II Scoring Assistant.

Adolescent↗

PubMed2006

Application of new WAIS-III/WMS-III discrepancy scores for evaluating memory functioning: relationship between intellectual and memory ability.

Analysis of the discrepancy between memory and intellectual ability has received some support as a means for evaluating memory impairment. Recently, comprehensive base rate tables for General Ability Index (GAI) minus memory discrepancy scores (i.e., GAI-memory) were developed using the WAIS-III/WMS-III standardization sample (Lange, Chelune, & Tulsky, in press). The purpose of this study was to evaluate the clinical utility of GAI-memory discrepancy scores to identify memory impairment in 34 patients with Alzheimer's type dementia (DAT) versus a sample of 34 demographically matched healthy participants. On average, patients with DAT obtained significantly lower scores on all WAIS-III and WMS-III indexes and had larger GAI-memory discrepancy scores. Clinical outcome analyses revealed that GAI-memory scores were useful at identifying memory impairment in patients with DAT versus matched healthy participants. However, GAI-memory discrepancy scores failed to provide unique interpretive information beyond that which is gained from the memory indexes alone. Implications and future research directions are discussed.

Aged↗

PubMed2006

Development of WAIS-III General Ability Index Minus WMS-III memory discrepancy scores.

Analysis of the discrepancy between intellectual functioning and memory ability has received some support as a useful means for evaluating memory impairment. In recent additions to Wechlser scale interpretation, the WAIS-III General Ability Index (GAI) and the WMS-III Delayed Memory Index (DMI) were developed. The purpose of this investigation is to develop base rate data for GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores using data from the WAIS-III/WMS-III standardization sample (weighted N = 1250). Base rate tables were developed using the predicted-difference method and two simple-difference methods (i.e., stratified and non-stratified). These tables provide valuable data for clinical reference purposes to determine the frequency of GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores in the WAIS-III/WMS-III standardization sample.

Abstracting and Indexing↗

PubMed2006

Clinical validation of the General Ability Index--Estimate (GAI-E): estimating premorbid GAI.

The clinical utility of the General Ability Index--Estimate (GAI-E; Lange, Schoenberg, Chelune, Scott, & Adams, 2005) for estimating premorbid GAI scores was investigated using the WAIS-III standardization clinical trials sample (The Psychological Corporation, 1997). The GAI-E algorithms combine Vocabulary, Information, Matrix Reasoning, and Picture Completion subtest raw scores with demographic variables to predict GAI. Ten GAI-E algorithms were developed combining demographic variables with single subtest scaled scores and with two subtests. Estimated GAI are presented for participants diagnosed with dementia (n = 50), traumatic brain injury (n = 20), Huntington's disease (n = 15), Korsakoff's disease (n = 12), chronic alcohol abuse (n = 32), temporal lobectomy (n = 17), and schizophrenia (n = 44). In addition, a small sample of participants without dementia and diagnosed with depression (n = 32) was used as a clinical comparison group. The GAI-E algorithms provided estimates of GAI that closely approximated scores expected for a healthy adult population. The greatest differences between estimated GAI and obtained GAI were observed for the single subtest GAI-E algorithms using the Vocabulary, Information, and Matrix Reasoning subtests. Based on these data, recommendations for the use of the GAI-E algorithms are presented.

Algorithms↗

PubMed2006

Is depth of anesthesia, as assessed by the Bispectral Index, related to postoperative cognitive dysfunction and recovery?

We randomized 74 patients to either a lower Bispectral Index (BIS) regimen (median BIS, 38.9) or a higher BIS regimen (mean BIS, 50.7) during the surgical procedure. Preoperatively and 4-6 wk after surgery, the patients' cognitive status was assessed with a cognitive test battery consisting of processing speed index, working memory index, and verbal memory index. Processing speed index was 113.7 +/- 1.5 (mean +/- se) in the lower BIS group versus 107.9 +/- 1.4 in the higher BIS group (P = 0.006). No difference was observed in the other two test battery components. Somewhat deeper levels of anesthesia were therefore associated with better cognitive function 4-6 wk postoperatively, particularly with respect to the ability to process information.

Adjuvants, Anesthesia↗

PubMed2005

Development of the WAIS-III general ability index estimate (GAI-E).

The WAIS-III General Ability Index (GAI; Tulsky, Saklofske, Wilkins, & Weiss, 2001) is a recently developed, 6-subtest measure of global intellectual functioning. However, clinical use of the GAI is currently limited by the absence of a method to estimate premorbid functioning as measured by this index. The purpose of this study was to develop regression equations to estimate GAI scores from demographic variables and WAIS-III subtest performance. Participants consisted of those subjects in the WAIS-III standardization sample that has complete demographic data (N=2,401) and were randomly divided into two groups. The first group (n=1,200) was used to develop the formulas (i.e., Development group) and the second (n=1,201) group was used to validate the prediction algorithms (i.e., Validation group). Demographic variables included age, education, ethnicity, gender and region of country. Subtest variables included vocabulary, information, picture completion, and matrix reasoning raw scores. Ten regression algorithms were generated designed to estimate GAI. The GAI-Estimate (GAI-E) algorithms accounted for 58% to 82% of the variance. The standard error of estimate ranged from 6.44 to 9.57. The correlations between actual and estimated GAI ranged from r=.76 to r=.90. These algorithms provided accurate estimates of GAI in the WAIS-III standardization sample. Implications for estimating GAI in patients with known or suspected neurological dysfunction is discussed and future research is proposed.

Abstracting and Indexing↗

PubMed2005

Subjective cognitive complaints relate to mild impairment of cognition in multiple sclerosis.

Cognitive impairment is common in multiple sclerosis (MS), but cannot be reliably predicted by physical impairment. The negative impact of cognitive impairment makes early detection important, but subjective cognitive complaints may be attributed to depression. We examined the relationship between subjectively reported and objectively measured cognitive impairment in MS, adjusting for mood. A neuropsychological battery, the Multiple Sclerosis Functional Composite (MSFC), the Mental Health Inventory (MHI), the Modified Fatigue Impact Scale (MFIS), the Perceived Deficits Questionnaire (PDQ) were administered to 136 patients. Demographically-adjusted cognitive scores were calculated. Subjective impairment was defined as PDQ score >2 standard deviations above that for healthy persons. We modeled the relationship of cognitive scores (independent variables) to being subjectively impaired (dependent variable) using logistic regression. Immediate Memory (IM) and Processing Speed Index (PSI) scores were non-linearly related to subjective impairment Patients were less likely to report subjective impairment if their PSI was normal (OR =0.11; 0.02-0.73) or markedly impaired (OR =0.17; 0.03-0.91), compared to mildly reduced PSI. In young patients decreases in IM were associated with increased subjective impairment (OR = 1.25; 1.07-1.47). Subjectively reported impairment reflects subtle declines in PSI and IM independent of mood, fatigue, and physical impairment Cognitive complaints should not be discounted due to depression.

Adult↗

PubMed2004

WMS-III performance in epilepsy patients following temporal lobectomy.

We examined performances on the Wechsler Memory Scale-3rd Edition (WMS-III) among patients who underwent temporal lobectomy for the control of medically intractable epilepsy. There were 51 right (RTL) and 56 left (LTL) temporal lobectomy patients. All patients were left hemisphere speech-dominant. The LTL and RTL patients were comparable in terms of general demographic, epilepsy, and intellectual/attention factors. Multivariate analyses revealed a significant crossover interaction (p <.001), with the RTL group scoring significantly lower on the visual than auditory indexes while the LTL group scored significantly lower on the auditory than visual memory indexes. Within-group pairwise analyses revealed statistically significant auditory versus visual index score comparisons (all p <.001) for both surgical groups. Discriminant analysis (p <.001) identified Verbal Paired Associates I, Faces I, and Family Pictures II to significantly discriminate RTL and LTL patients, with an overall correct classification rate of 81.3%. Our findings suggest that the WMS-III is sensitive to modality-specific memory performance associated with unilateral temporal lobectomy.

Adult↗

PubMed2004

Increasing the reliability of ipsative interpretations in neuropsychology: a comparison of reliable components analysis and other factor analytic methods.

Ipsative approaches to neuropsychological assessment typically involve interpreting difference scores between individual test scores. The utility of these methods is limited by the reliability of neuropsychological difference scores and the number of comparisons between scores. The present study evaluated the utility of difference scores using factor analytic methods, including reliable components analysis (RCA), equally weighted composites and individual neuropsychological measures. Data from 1,364 individuals referred for neuropsychological assessment were factor analyzed and the resulting solutions were used to compute composite scores. Reliabilities and confidence intervals were derived for each method. Results indicated that RCA outperformed other factor analytic methods, but produced a slightly different factor structure. Difference scores derived using orthogonal solutions were slightly more reliable than oblique methods, and both were more reliable than those from equally weighted composites and individual measures. Confidence intervals for difference scores were considerably smaller for factor methods relative to those for individual test comparisons, due to the greater reliability of factor based difference scores and the smaller number of comparisons required. These findings suggest that difference scores derived from orthogonal factor solutions, particularly RCA solutions, may improve reliability for clinical assessment purposes.

Adolescent↗

PubMed2004

Education-stratified base-rate information on discrepancy scores within and between the Wechsler Adult Intelligence Scale--Third Edition and the Wechsler Memory Scale--Third Edition.

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997a) and the Wechsler Memory Scale--Third Edition (WMS-III; D. Wechsler, 1997b) are 2 of the most frequently used measures in psychology and neuropsychology. To facilitate the diagnostic use of these measures in the clinical decision-making process, this article provides information on education-stratified, directional prevalence rates (i.e., base rates) of discrepancy scores between the major index scores for the WAIS-III, the WMS-III, and between the WAIS-III and WMS-III. To illustrate how such base-rate data can be clinically used, this article reviews the relative risk (i.e., odds ratio) of empirically defined "rare" cognitive deficits in 2 of the clinical samples presented in the WAIS-III--WMS-III Technical Manual (The Psychological Corporation, 1997).

Educational Status↗

PubMed2004

Development of a new Delayed Memory Index for the WMS-III.

This paper presents the Delayed Memory Index (DMI) as an alternative to the General Memory Index (GMI) of the Weschler Memory Scale-Third Edition (WMS-III). The WMS-III Immediate Memory Index (IMI) and the GMI are not parallel in structure, making a direct comparison between these index scores (i.e., immediate vs. delayed memory variables) difficult. The IMI is composed of the sum of scaled scores of four subtests (Logical Memory I, Verbal Paired Associates I, Faces I, and Family Pictures I) while the GMI is composed of the sum of scaled scores of five subtests (Logical Memory II, Verbal Paired Associates II, Faces II, Family Pictures II and Auditory Recognition Delayed). Inclusion of Auditory Recognition Delayed in the GMI is also problematic as it is highly skewed and limited by extreme ceiling effects (see Tulsky, Chiaravalloti, Palmer, & Chelune, 2003). To remedy these problems, we present a new index score that does not include auditory recognition, the Delayed Memory Index. Normative tables for the new Delayed Memory Index based on the inclusion of the Faces subtest, or alternatively the Visual Reproduction subtest, are presented, and initial estimates of their psychometric properties are described.

Abstracting and Indexing↗

PubMed2004

Is speed of processing or working memory the primary information processing deficit in multiple sclerosis?

OBJECTIVE: To examine whether processing speed or working memory is the primary information processing deficit in persons with MS. DESIGN: Case-control study. SETTING: Hospital-based specialty clinic. PARTICIPANTS: 215 adults with clinically definite MS. MAIN OUTCOME MEASURE: Mean demographically corrected T-scores, prevalence rates of impairment and relative risk of impaired Processing Speed and Working Memory Index Scores from the WAIS-WMS III. RESULTS: Deficits in Processing Speed were much more common than Working Memory in all comparisons. This was observed for both relapsing remitting (RRMS) and secondary progressive MS (SPMS) subjects, but accentuated in the latter group. CONCLUSIONS: Results strongly suggest that the primary information processing deficit in persons with MS is in speed of processing.

Adult↗

PubMed2003

Reexamining the effects of epilepsy surgery on IQ in children: use of regression-based change scores.

Prior studies have found no adverse effects of pediatric epilepsy surgery on IQ. However, empirical techniques such as regression models, designed to account for confounding factors such as practice effects and test-retest reliability and able to provide a standardized method for evaluating outcome, have not been used in studying change after pediatric epilepsy. The goal of this study was to demonstrate the regression technique while empirically measuring the effect of epilepsy surgery on IQ in a group of pediatric patients. Predictors of retest IQ (e.g., baseline IQ, retest interval, demographics, epilepsy severity) were evaluated in a control group with intractable seizures (N = 23) assessed twice with the WISC-III. The resulting equation was used to evaluate IQ changes in a second group of children who underwent epilepsy surgery (N = 22). In controls, baseline IQ was a strong predictor of retest IQ. Number of AEDs was inversely related to retest IQ. Based on the control regression, four children (18%) in the surgical sample obtained significantly higher than expected postsurgical IQ scores and one child (5%) obtained a lower than expected IQ score. This study demonstrates that regression-based techniques yield informative estimates on outcome and may be an improvement over prior methods of measuring change after pediatric epilepsy surgery.

Adolescent↗

PubMed2003

Confirmatory factor analysis of the WMS-III in patients with temporal lobe epilepsy.

Five competing models specifying the factor structure underlying the Wechsler Memory Scale-Third Edition (D. Wechsler, 1997b) primary subtest scores were evaluated in a sample of patients with intractable temporal lobe epilepsy (N = 254). Models specifying separate immediate and delayed constructs resulted in inadmissible parameter estimates and model specification error. There were negligible goodness-of-fit differences between a 3-factor model of working memory, auditory memory, and visual memory and a nested--more parsimonious--2-factor model of working memory and general memory. The results suggest that specifying a separate visual memory factor provides little advantage for this sample--an unexpected finding in a population with lateralized dysfunction, for which one might have predicted separate auditory and visual memory dimensions.

Adult↗

PubMed2003

Verbal and nonverbal fluency performance before and after seizure surgery.

The utility of verbal (FAS) and nonverbal (Ruff Figural Fluency Test: RFFT) fluency tests for detecting deficits associated with focal seizures and surgical interventions was examined. The patients were 174 adults with intractable epilepsy who underwent epilepsy surgery: 152 temporal lobectomies and 22 frontal lobectomies. The results of the study suggest that the RFFT is somewhat superior to FAS in its ability to discriminate between frontal and temporal seizure foci, and is a useful component of preoperative neuropsychological batteries. Conversely, FAS appears more useful in detecting changes in neurocognitive outcome related to side of surgery. Controlling for postsurgical seizure outcome did not change the results, although continued seizures did have a deleterious effect on both FAS and RFFT, regardless of site of surgery.

Adolescent↗

PubMed2003

Validity and reliability of the MSQLI in cognitively impaired patients with multiple sclerosis.

Multiple sclerosis (MS) has important effects on quality of life but it is unknown how cognitive impairment affects the ability to assess or report this. Our objective was to determine whether cognitive impairment negatively affects the construct validity and the reliability of the Multiple Sclerosis Quality of Life Inventory (MSQLI). A neuropsychological test battery and the Multiple Sclerosis Functional Composite (MSFC) were administered to a sample of 136 patients referred for cognitive testing by their neurologists. Age, sex, education and ethnicity-adjusted T scores were calculated for each cognitive variable. Cognitive impairment was defined as any T score less than the fifth percentile. The MSQLI was administered prior to neuropsychological testing and readministered one to four weeks later: Correlations between the MSFC and the SF-36 were determined and compared between the cognitively impaired and unimpaired groups as the main test of construct validity. Test-retest and internal consistency reliability of each of the scales were compared for the impaired and unimpaired groups. Seventy-six (56%) patients were cognitively impaired. Construct validity and internal consistency reliability did not differ between the cognitively impaired and unimpaired groups. Test retest reliability was lower for the bladder and vision scales in the impaired group, but remained acceptable for the bladder scale (r > 0.7). Cognitive impairment, a common MS manifestation, does not appear to reduce the reliability or validity of the MSQLI as a patient self-report measure of health status and quality of life.

Adult↗

PubMed2002

Making neuropsychological outcomes research consumer friendly: a commentary on Keith et al. (2002).

J. R. Keith et al. (2002) examined the effects of cardiopulmonary bypass surgery on cognition and suggest that the use of parametric, inferential statistics may have advantages over incidence reports. This commentary addresses several issues that arise when conducting outcomes studies within the context of evidence-based medicine. "Consumer friendly" research within the context of evidence-based medicine must carefully attend to the selection of appropriate and relevant reference groups and recognize that clinicians practice and record outcomes as individual rather than as group events. Traditional null hypothesis significance testing and inferential statistics are useful in establishing the reliability of group differences but do not provide the statistical indexes and base-rate information that clinicians can easily use in their treatment of individual patients. Data analysis and presentation of results using methods from clinical epidemiology can make neuropsychological outcomes research consumer friendly and help bridge the all too frequent schism between academic research and clinical practice.

Cognition Disorders↗

PubMed2002

Minimal neuropsychological assessment of MS patients: a consensus approach.

Cognitive impairment is common in multiple sclerosis (MS), yet patients seen in MS clinics and neurologic practices are not routinely assessed neuropsychologically. In part, poor utilization of NP services may be attributed to a lack of consensus among neuropsychologists regarding the optimal approach for evaluating MS patients. An expert panel composed of neuropsychologists and psychologists from the United States, Canada, United Kingdom, and Australia was convened by the Consortium of MS Centers (CMSC) in April, 2001. Our objectives were to: (a) propose a minimal neuropsychological (NP) examination for clinical monitoring of MS patients and research, and (b) identify strategies for improving NP assessment of MS patients in the future. The panel reviewed pertinent literature on MS-related cognitive dysfunction, considered psychometric factors relevant to NP assessment, defined the purpose and optimal characteristics of a minimal NP examination in MS, and rated the psychometric and practical properties of 36 candidate NP measures based on available literature. A 90-minute NP battery, the Minimal Assessment of Cognitive Function in MS (MACFIMS), emerged from this discussion. The MACFIMS is composed of seven neuropsychological tests, covering five cognitive domains commonly impaired in MS (processing speed/working memory, learning and memory, executive function, visual-spatial processing, and word retrieval). It is supplemented by a measure of estimated premorbid cognitive ability. Recommendations for assessing other factors that may potentially confound interpretation of NP data (e.g., visual/sensory/motor impairment, fatigue, and depression) are offered, as well as strategies for improving NP assessment of MS patients in the future.

Cognition Disorders↗