Biomedical subjects

William B Barr

Publications and source records attributed to William B Barr.

21 records · Page 2Linked to original sources

PubMed2002

Neuropsychological testing for assessment of treatment effects: methodologic issues.

Neuropsychological (NP) testing is now recognized as an important method for evaluating treatment effects. However, there are limitations to how these tests are currently used in most drug treatment protocols. Changes in cognition are typically defined in statistical terms, with little knowledge as to whether the observed differences are meaningful in any other sense. Methods for assessing changes in test scores need to account for test-retest reliability, practice effects, regression to the mean, and the impact of initial performance. All of these factors may vary according to the individual characteristics of the subject. This article reviews two methods from the NP literature that have attempted to account for these sources of test-retest bias. The reliable change index provides a confidence interval for predicted change by taking into account the test-retest reliability of the measure. Standardized regression-based measures use a more sophisticated statistical approach that enables them to better account for other potential sources of confound. Use of this methodology has been limited to studies of epilepsy surgery and sports-related concussion. These methods have the potential for enhancing the interpretation of NP test data in drug treatment protocols by providing an empirically based definition of clinically meaningful change.

Journal Article↗

PubMed2002

Neurocognitive correlates of response to treatment in formal thought disorder in patients with first-episode schizophrenia.

OBJECTIVE: To examine the independent contribution of executive versus semantic function to improvement in formal thought disorder after initial stabilization in a first-episode sample. BACKGROUND: Neurocognitive deficits have been suggested to predict treatment response in patients with first-episode schizophrenia. However, studies targeting putative neurocognitive mechanisms to explore improvement in positive psychotic symptoms and especially formal thought disorder are lacking. METHOD: Formal thought disorder symptoms in 81 first-episode patients with schizophrenia or schizoaffective disorder either showed significant improvement (responders > 60% change) or not (nonresponders < 60%) 6 months after initial stabilization of symptoms. These two groups were compared on neuropsychologic (n = 16), clinical (n = 15), and volumetric measures of the frontal and temporal lobes (n = 5) in univariate analyses. The variables that significantly differed between these two groups were used in a forward binary logistic regression analysis. RESULTS: As compared with nonresponders, responders were younger at time of testing, had higher verbal intelligence and reading achievement scores, higher scores on the arithmetic subtest of the Wechsler Adult Intelligence Scale-Revised, and lower number of perseverative responses on the Wisconsin Card Sort Test. Responders also had larger frontal lobe volumes than nonresponders. Only two measures (perseverative responses on the Wisconsin Card Sort Test and age at testing) entered the regression equation. Measures of semantic competency and volumetric measures of the temporal lobes were not associated with formal thought disorder improvement. CONCLUSIONS: Neurocognitive deficits are associated with treatment response in formal thought disorder in first-episode patients with schizophrenia. The improvement in formal thought disorder is more strongly linked to executive than semantic function in this sample, pointing to the salience of frontal systems in treatment response in positive psychotic symptoms.

Adult↗

PubMedDate not supplied

Is neuropsychological testing useful in the management of sport-related concussion?

OBJECTIVE: Neuropsychological (NP) testing has been used for several years as a way of detecting the effects of sport-related concussion in order to aid in return-to-play determinations. In addition to standard pencil-and-paper tests, computerized NP tests are being commercially marketed for this purpose to professional, collegiate, high school, and elementary school programs. However, a number of important questions regarding the clinical validity and utility of these tests remain unanswered, and these questions present serious challenges to the applicability of NP testing for the management of sport-related concussion. Our purpose is to outline the criteria that should be met in order to establish the utility of NP instruments as a tool in the management of sport-related concussion and to review the degree to which existing tests have met these criteria. DATA SOURCES: A comprehensive literature review of MEDLINE and PsychLit from 1990 to 2004, including all prospective, controlled studies of NP testing in sport-related concussion. DATA SYNTHESIS: The effects of concussion on NP test performance are so subtle even during the acute phase of injury (1-3 days postinjury) that they often fail to reach statistical significance in group studies. Thus, this method may lack utility in individual decision making because of a lack of sensitivity. In addition, most of these tests fail to meet other psychometric criteria (eg, adequate reliability) necessary for this purpose. Finally, it is unclear that NP testing can detect impairment in players once concussion-related symptoms (eg, headache) have resolved. Because no current guideline for the management of sport-related concussion allows a symptomatic player to return to sport, the incremental utility of NP testing remains questionable. CONCLUSIONS/RECOMMENDATIONS: Despite the theoretic rationale for the use of NP testing in the management of sport-related concussion, no NP tests have met the necessary criteria to support a clinical application at this time. Additional research is necessary to establish the utility of these tests before they can be considered part of a routine standard of care, and concussion recovery should be monitored via the standard clinical examination and subjective symptom checklists until NP testing or other methods are proven effective for this purpose.

Journal Article↗