Biomedical subjects

Kevin Duff

Publications and source records attributed to Kevin Duff.

25 records · Page 2Linked to original sources

PubMed2004

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.

Aged↗

PubMed2004

Differential estimation of verbal intelligence and performance intelligence scores from combined performance and demographic variables: the OPIE-3 verbal and performance algorithms.

Data from the WAIS-III standardization sample (The Psychological Corporation, 1997) was used to generate VIQ and PIQ estimation formulae using demographic variables and current WAIS-III subtest performances. The sample (n = 2450) was randomly divided into two groups; the first was used to develop formulas and the second to validate the regression equations. Age, education, ethnicity, gender, region of the country as well as Vocabulary, Matrix Reasoning, and Picture Completion subtests raw scores were used as predictor variables. Prediction formulas were generated using a single verbal and two performance subtest algorithms. The VIQ OPIE-3 model combined Vocabulary raw scores with demographic variables. The PIQ estimation algorithm used Matrix Reasoning and Picture Completion raw scores with demographic variables. The formulas for estimating premorbid VIQ and PIQ were highly significant and accurate in estimation. Differences in estimated VIQ and PIQ scores were evaluated and the OPIE-3 algorithms were found to accurately predict VIQ and PIQ differences within the WAIS-III standardization sample.

Algorithms↗

PubMed2003

An evaluation of the clinical utility of the OPIE-3 as an estimate of premorbid WAIS-III FSIQ.

The clinical utility of the Oklahoma Premorbid Intelligence Estimate--3 (OPIE-3; Schoenberg, Scott, Duff, & Adams, 2002) in estimating premorbid FSIQ was investigated with the WAIS-III standardization sample. The OPIE-3 algorithms combine Vocabulary, Information, Matrix Reasoning, and Picture Completion subtest raw scores with demographic variables to predict FSIQ. Estimated WAIS-III FSIQ scores are presented for patients' diagnosed with dementia, traumatic brain injury, Huntington's disease, Korsakoff's disease, chronic alcohol use, temporal lobectomy, and schizophrenia. A group of patients with depression was employed as a clinical control group. The OPIE-3V and OPIE-3MR algorithms performed well, with the average predicted FSIQ of the combined clinical sample approximating the mean FSIQ of healthy adults. The OPIE-3(Best), which is a procedure that employs either the OPIE-3V, OPIE-3MR, or OPIE-3(2ST) algorithms in a best performance method, is presented. Recommendations in the application of the OPIE-3 are made and future research is proposed.

Brain Diseases↗

PubMed2003

Age- and education-corrected independent normative data for the RBANS in a community dwelling elderly sample.

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS, Randolph, 1998) is likely to become a popular screening instrument for measuring cognitive functioning, particularly in elderly patients. As such, the present study attempted to extend the original normative data by reporting on RBANS performances in a group of 718 community dwelling older adults. Participants were recruited from an outpatient primary care setting, and were assessed for demographic, medical status, functional status, and quality of life information. Utilizing four empirically supported overlapping midpoint age ranges, individual subtest raw scores were converted to age-corrected scaled scores based on their position within a cumulative frequency distribution. These age-corrected scaled scores were also converted into education-corrected scaled scores using the same methodology across four education levels. Independent Index and Total scores were also calculated based on the data from this large elderly sample. These data may considerably advance the clinical utility of the RBANS by allowing clinicians to interpret individual subtests and make direct comparisons between subtests. Practitioners and researchers who elect to use the current normative data are encouraged to consider the similarities and differences between the present sample and their individual patients or research participants.

Aged↗

PubMed2003

Performance of cognitively normal African Americans on the RBANS in community dwelling older adults.

Recent research suggests that cognitively normal African Americans are more likely to be misdiagnosed as impaired compared to Caucasians due to lower neuropsychological test scores (e.g., Manly et al., 1998). Given this, the present study sought to determine whether such racial discrepancies exist on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Performances of 50 cognitively normal older African Americans on the RBANS were compared to those of 50 Caucasians matched on age, education, and gender. The African Americans scored significantly lower on 10 of 12 subtests, 3 of 5 Index scores, and the Total Scale score. Results underscored the utility of demographically appropriate norms when serving minority clients. Given that there remains a paucity of normative data for minority groups, RBANS normative data for older African Americans are provided. Although preliminary, it is hoped that data presented will offer the practitioner assistance with clinical diagnosis and decision-making in a manner that will help minimize diagnostic errors.

Black or African American↗

PubMed2002

Estimation of WAIS-III intelligence from combined performance and demographic variables: development of the OPIE-3.

Data from the WAIS-III standardization sample (The Psychological Corporation, 1997) was used to generate several FSIQ estimation formulas that used demographic variables and current WAIS-III subtest performance. The standardization sample (N=2,450) was randomly divided into two groups, the first was used to develop the formulas and the second group was used to validate the prediction equations. Age, education, ethnicity, gender, region of the country as well as Vocabulary, Information, Matrix Reasoning, and Picture Completion subtests raw scores were used as predictor variables. Regression formulas were generated using four subtest, two subtest, single verbal, two performance subtest, and single performance algorithms. The four-subtest model combined Information, Vocabulary, Matrix Reasoning, and Picture Completion raw scores with demographic variables. The two-subtest algorithm used Vocabulary and Matrix Reasoning raw scores with demographic variables. Formulas to estimate FSIQ using only verbal or performance subtests were developed for use with lateralized populations. The formulas for estimating premorbid FSIQ were highly significant and accurate in predicting FSIQ scores of participants in the WAIS-III normative sample.

Demography↗

PubMed2002

The Pocket Smell Test: successfully discriminating probable Alzheimer's dementia from vascular dementia and major depression.

The present study extended previous work on olfactory dysfunction (odor identification deficits) by using the Pocket Smell Test (PST) to discriminate between groups of patients with Alzheimer's disease (AD), vascular dementia (VaD), and major depression (MD). Sixty patients meeting the DSM-IV criteria for either AD, VaD, or MD (20 per group) underwent assessment with the PST, a three-item screening measure of odor identification, and the Mini-Mental State Examination (MMSE). Patients with AD scored significantly lower than patients with either VaD or MD on the PST, even after controlling for MMSE scores. A PST score of > or =1 (i.e., 1 or 0 correct) discriminated between patients with and without AD with a classification accuracy of 95% (sensitivity 100%, specificity 92.5%). Olfactory assessment may be of diagnostic utility in the differential diagnosis of AD versus VaD versus MD in elderly patients.

Aged↗