Biomedical subjects

Rael T Lange

Publications and source records attributed to Rael T Lange.

16 recordsLinked to original sources

PubMed2007

WAIS-III index score profiles in the Canadian standardization sample.

Representative index score profiles were examined in the Canadian standardization sample of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). The identification of profile patterns was based on the methodology proposed by Lange, Iverson, Senior, and Chelune (2002) that aims to maximize the influence of profile shape and minimize the influence of profile magnitude on the cluster solution. A two-step cluster analysis procedure was used (i.e., hierarchical and k-means analyses). Cluster analysis of the four index scores (i.e., Verbal Comprehension [VCI], Perceptual Organization [POI], Working Memory [WMI], Processing Speed [PSI]) identified six profiles in this sample. Profiles were differentiated by pattern of performance and were primarily characterized as (a) high VCI/POI, low WMI/PSI, (b) low VCI/POI, high WMI/PSI, (c) high PSI, (d) low PSI, (e) high VCI/WMI, low POI/PSI, and (f) low VCI, high POI. These profiles are potentially useful for determining whether a patient's WAIS-III performance is unusual in a normal population.

Canada↗

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

Suppressed working memory on the WMS-III as a marker for poor effort.

The purpose of this study was to examine the clinical utility of memory minus Working Memory Index (memory-WMI) discrepancy scores on the WMS-III for detecting poor effort in 145 personal injury litigants (19 poor effort, 126 adequate effort). On average, participants in the poor effort group performed significantly lower on all WMS-III memory indexes and demonstrated larger memory-WMI discrepancy scores compared to participants in the adequate effort group. Discriminant function analyses using memory-WMI discrepancy scores as independent variables revealed poor overall classification rates (60.0% to 63.4%). Based on the prevalence of unusually suppressed attention-concentration ability relative to memory functioning using unidirectional memory-WMI discrepancy scores, high specificity and negative predictive power values were found. However, there was unacceptably low sensitivity and positive predictive power. These results suggest that memory-WMI discrepancy scores on the WMS-III do not provide clinically useful information regarding response set and should be used cautiously as an indicator of poor effort.

Adult↗

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

Expanding the WAIS-III Estimate of Premorbid Ability for Canadians (EPAC).

Since the release of the Canadian WAIS-III normative data in 2001 (Wechsler, 2001), the clinical application of these norms has been limited by the absence of a method to estimate premorbid functioning. However, Lange, Schoenberg, Woodward, and Brickell (2005) recently developed regression algorithms that estimate premorbid FSIQ, VIQ and PIQ scores for use with the Canadian WAIS-III norms. The purpose of this study was to expand work by Lange and colleagues by developing regression algorithms to estimate premorbid GAI (Saklofske et al., 2005), VCI, and POI scores. Participants were the Canadian WAIS-III standardization sample (n = 1,105). The sample was randomly divided into two groups (Development and Validation group). Using the Development group, a total of 14 regression algorithms were generated to estimate GAI, VCI, and POI scores by combining subtest performance (i.e., Vocabulary, Information, Matrix Reasoning, and Picture Completion) with demographic variables (i.e., age, education, ethnicity, region of the country, and gender). The algorithms accounted for a maximum of 77% of the variance in GAI, 78% of the variance in VCI, and 63% of the variance in POI. In the Validation Group, correlations between predicted and obtained scores were high (GAI = .70 to .88; VCI = .87 to .88; POI = .71 to .80). Evaluation of prediction errors revealed that the majority of estimated GAI, VCI, and POI scores fell within a 95% CI band (93.5% to 97.0%) and within 10 points of obtained index scores (72.3% to 85.6%) depending on the subtests used. These algorithms provide a promising means for estimating premorbid GAI, VCI, and POI scores using the Canadian WAIS-III norms.

Adolescent↗

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↗

PubMed2005

WAIS-III General Ability Index in neuropsychiatry and forensic psychiatry inpatient samples.

The purpose of this study is to examine the WAIS-III General Ability Index (GAI) in a sample of 33 neuropsychiatry inpatients and 47 forensic psychiatry inpatients. The GAI is comprised of the six subtests that form the Verbal Comprehension and the Perceptual Organization Indexes. The GAI, although highly correlated with the FSIQ, was on average 5.3 points higher in the neuropsychiatry sample and 4.2 points higher in the forensic psychiatry sample. The GAI was significantly higher than the Working Memory and the Processing Speed Indexes in both groups. The GAI, a composite measure of verbal and nonverbal intellect, appears to be an appropriate measure for use in day-to-day clinical practice in neuropsychology. To facilitate clinical use, statistically reliable difference scores between the GAI and the WMI and PSI, for the 95% confidence interval, are presented.

Adolescent↗

PubMed2005

Development of the WAIS-III estimate of premorbid ability for Canadians (EPAC).

This study developed regression algorithms for estimating IQ scores using the Canadian WAIS-III norms. Participants were the Canadian WAIS-III standardization sample (n = 1,105). The sample was randomly divided into two groups (Development and Validation groups). The Development group was used to generate 12 regression algorithms for FSIQ and three algorithms each for VIQ and PIQ. Algorithms combined demographic variables with WAIS-III subtest raw scores. The algorithms accounted for 48-78% of the variance in FSIQ, 70-71% in VIQ, and 45-55% in PIQ. In the Validation group, the majority of the sample had predicted IQs that fell within a 95% CI band (FSIQ=92-94%; VIQ=93-95%; PIQ=94-94%). These algorithms yielded reasonably accurate estimates of FSIQ, VIQ, and PIQ in this healthy adult population. It is anticipated that these algorithms will be useful as a means for estimating premorbid IQ scores in a clinical population. However, prior to clinical use, these algorithms must be validated for this purpose.

Adolescent↗

PubMed2005

Effects of mild traumatic brain injury cannot be differentiated from substance abuse.

PRIMARY OBJECTIVE: Patients involved in litigation relating to mild traumatic brain injury (MTBI) typically undergo a forensic neuropsychological evaluation. However, if cognitive problems are identified, it is difficult to know whether these are related to the MTBI or other factors such as pre- and/or post-injury substance abuse. The purpose of this study was to compare the neuropsychological test performances of 73 patients with acute, uncomplicated MTBIs to a sample of 73 patients from an inpatient substance abuse programme. METHODS AND PROCEDURES: Patients were perfectly matched on age, education and gender. Ten cognitive measures were used that included the Trail Making Test (TMT) and selected sub-tests from the Wechsler Memory Scale-Revised. MAIN OUTCOMES AND RESULTS: Patients with MTBI demonstrated poorer performances on Digits Backwards (p < 0.028) and TMTA (p < 0.032). There were no significant differences between the two groups on the remaining cognitive measures. The clinical usefulness of these measures to differentiate between the groups, using discriminant function analysis, was very poor. CONCLUSIONS: Patients with uncomplicated MTBIs could not be reliably differentiated from patients with substance abuse problems on these measures of concentration, memory and processing speed.

Adolescent↗

PubMed2005

Ecological validity of the WMS-III rarely missed index in personal injury litigation.

The purpose of this study was to evaluate the clinical utility of the Rarely Missed Index (RMI) to detect cognitive exaggeration in 78 nonlitigant patients (i.e., Mixed Clinical group) and 158 personal injury litigants (i.e., 20 Suspected Exaggerators, 12 Borderline Exaggerators, 126 Genuine Responders). The base rate for probable malingered neurocognitive dysfunction in the litigant sample was 12.7%. The false positive error rate of the RMI in the Genuine Responder and Mixed Clinical group ranged from 5.4% to 8.6%. Positive RMI scores were found in 25% and 41.7% of the Suspected Exaggerator and Borderline Exaggerator groups respectively. The clinical utility of the RMI to identify Suspected Exaggerators versus individuals in the Genuine Responder and Mixed Clinical groups revealed low sensitivity (sensitivity = .25), very high specificity (range = .91 to .95), moderate positive predictive power (range = .50 to .71), and moderate to high negative predictive power (range = .68 to .83). These results do not support the use of the RMI as a reliable predictor of cognitive exaggeration.

Adult↗

PubMed2005

Interpreting the trail making test following traumatic brain injury: comparison of traditional time scores and derived indices.

The purpose of this study was to examine the clinical application of traditional time scores and various derived indices from the Trail Making Test (TMT) in a sample of 571 patients with acute traumatic brain injury (TBI). Participants were classified into four injury severity groups. A clear linear relation between injury severity and TMT performance was demonstrated, with the more severely brain injured patients performing more poorly on most measures. Hierarchical logistic regression analysis of TMT time scores across binary extreme groups based on injury severity resulted in high classification rates for patients with very mild TBI (93.0% correctly classified) and low classification rates for patients with moderate to severe TBI (50.0% correctly classified). However, TMT derived indices did not provide a unique contribution to test interpretation beyond what is already available from Part A and B separately.

Adult↗

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↗

PubMed2004

Psychometric properties and factor structure of the Neuropsychiatric Inventory Nursing Home version in an elderly neuropsychiatric population.

BACKGROUND: The Neuropsychiatric Inventory (NPI) is an interview-based instrument designed to elicit information from an informal caregiver to evaluate behavioral disturbances in persons with dementia. Minor modifications of this instrument have produced the Neuropsychiatric Inventory-Nursing Home version (NPI-NH), a version specifically designed for interviewing professional care facility staff. The purpose of this investigation is to further understand the psychometric properties of the NPI-NH by examining its reliability, validity, and factor structure in an elderly neuropsychiatric population. METHOD: Participants were 204 elderly inpatients from a large provincial neuropsychiatric hospital in British Columbia, Canada. Data were collected as part of a patient needs assessment project. RESULTS: The internal consistency reliability of the NPI-NH was alpha=0.67. An exploratory principal axis analysis with varimax rotation revealed five factors that accounted for 63.2% of the variance. These factors reflect aspects of psychiatric disturbance associated with: (a) Agitation; (b) Mood; (c) Psychosis; (d) Sleep/Motor Activity; and (e) Elevated Behavior. Convergent and discriminant validity of the five factors by correlating them with other behavioral measures was considered satisfactory. CONCLUSIONS: These results provide support for the clinical use of the NPI-NH as a screen for neuropsychiatric symptoms in an elderly neuropsychiatric population. However, additional research is encouraged to further evaluate the clinical utility of the NPI-NH in nursing home and inpatient geriatric settings.

Adult↗

PubMed2003

Examination of "postconcussion-like" symptoms in a healthy sample.

The post-concussion syndrome (PCS) is relatively common following mild traumatic brain injury (MTBI). However, the factors that cause and maintain this syndrome continue to be debated. The purpose of this investigation was to examine the prevalence of postconcussion-like symptoms in a sample of healthy individuals. Participants (N = 104) completed the British Columbia Postconcussion Symptom Inventory-Short Form (BC-PSI-Sf), a test designed to measure both the frequency and intensity of ICD-10 criteria for PCS, and the Beck Depression Inventory (2nd ed.). Specific endorsement rates of postconcussion-like symptoms ranged from 35.9% to 75.7% for any experience of the symptoms in the past 2 weeks, and from 2.9% to 15.5% for the experience of more severe symptoms. Symptoms reported on the BC-PSI-Sf also showed a moderately high correlation with self-reported depressive symptoms [r (102) =.76, p <.01]. This study illustrates that the presence of postconcussion-like symptoms: (a). are not unique to mild head injury and are commonly found in healthy individuals, and (b). are highly correlated with depressive symptoms.

Adolescent↗

PubMed2002

Detecting exaggeration and malingering with the trail making test.

The purpose of this study was to examine whether unusual performance on the Trail Making Test could be indicative of deliberate exaggeration. Participants were 571 patients seen as part of a hospital trauma service who had acute traumatic brain injuries, and 228 patients involved in head injury litigation. As expected, the hospital patients with more severe traumatic brain injuries performed more poorly than the patients with less severe brain injuries on Trails A and Trails B. Cutoff score tables were developed for the patients with acute traumatic brain injuries for the total sample and by injury severity groups. Scores falling at or below the 5th percentile were considered suspicious for possible exaggeration. The performances of the head injury litigants who exaggerated on at least one well-validated symptom validity test were compared to these cutoffs. Very high positive predictive values for individuals with very mild head injuries on Trails A and B were identified (i.e., both 100%); lower positive predictive values were obtained for individuals with more severe head injuries (55.6-60%). The negative predictive values were only moderate (range=66.4-78.2%), and the sensitivity was very low (range = 7.1-18.5%) for all groups. Scores that fall in the range of possible biased responding should be considered "red flags" for the clinician because they likely do not make biological or psychometric sense. However, the sensitivity of the test for deliberate exaggeration is very low, so clinicians who rely on this test in isolation to identify deliberately poor performance will fail to identify the vast majority of cases.

Adult↗