Biomedical subjects

W G van Gorp

Publications and source records attributed to W G van Gorp.

At least 19 recordsLinked to original sources

PubMed2001

Long-term effects of high-dose zidovudine treatment on neuropsychological performance in mildly symptomatic HIV-positive patients: results of a randomized, double-blind, placebo-controlled investigation.

This study examined the treatment outcome of high-dose (1500 mg/day) zidovudine (AZT) on neuropsychological (NP) functioning (Trailmaking Test A & B, WAIS-R Digit Symbol, and Rey Auditory Verbal Learning Test) across a 12-month period in mildly symptomatic HIV-1 seropositive men (n = 46 at entry) enrolled in a randomized, double-blind, placebo-controlled trial (VA Cooperative Studies Program #298). Neither short-term (0-6 months) nor long-term (0-12 months) AZT administration revealed enhancement in NP performance. The results suggest that, although AZT may afford patients prophylactic benefits, protracted high-dose AZT treatment does not improve NP functioning in mildly symptomatic HIV-positive individuals.

Adult↗

PubMed2001

Base rate of a WMS-R malingering index in a sample of non-compensation-seeking men infected with HIV-1.

HIV-1 infected persons who are pursuing disability benefits are increasingly seeking neuropsychological assessment for purposes of corroborating functional impairment. Thus, research on the utility of measures of symptom validity among these patients is needed. Recently, Mittenberg, Azrin, Millsaps, and Heilbronner (1993) proposed a malingering index score for the WechslerMemoryScale-Revised that is derived by subtracting the Attention/Concentration Index (ACI) score from the General Memory Index Score (GMI). This study is a cross-validation of the specificity of the GMI-ACI Malingering Index in a sample of 55 non-compensation-seeking HIV-positive (HIV+) patients. An overall false-positive rate of 7% was observed for the GMI-ACI Malingering Index. However, further analyses showed that GMI-ACI Malingering Index scores were correlated with GMI scores such that false-positive errors were substantially higher (18%) among patients who obtained above-average GMI scores. These findings suggest a cautious approach to application of the GMI-ACI Malingering Index, particularly among patients who obtain above-average GMI scores.

Adult↗

PubMed2001

Post-Daubert admissibility of scientific evidence on malingering of cognitive deficits.

In Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993) the Supreme Court held that evidence must be "reliable" to be admissible and for scientific evidence "evidentiary reliability" is based on scientific validity. This article addresses the question "Do the Rey 15-Item Test ('FIT'), the Test of Memory Malingering ('TOMM'), and the Validity Indicator Profile ('VIP') likely meet the Daubert standard for admissibility of scientific evidence?" Sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively), and base rates of 30 and 15 percent were calculated for each test. Given the existing literature on malingering and the implications of a misclassification of malingering, we discuss the findings for each of the three tests using a PPV > or = 80 percent with a base rate of malingering of < or = 30. Our analyses indicate that the Rey 15-FIT fails to meet this standard of scientific validity. In contrast, the TOMM shows high specificity and PPV, and our findings suggest cautious optimism regarding the VIP. These results are discussed within the context of the courts' guidelines for the Daubert standard.

Cognition Disorders↗

PubMed2000

Responses to perceived unethical practices in clinical neuropsychology: ethical and legal considerations.

Neuropsychologists often review the work of colleagues who have performed a neuropsychological evaluation. At times, these reviews may cause one to believe that a colleague acted in an unethical manner. However, it is often unclear whether the situation warrants contacting the colleague or filing a complaint. This article provides examples of potential unethical practices in neuropsychology, and then reviews the relevant ethical principles and legal precedents concerning the obligations and possible risks of reporting perceived unethical practices of a colleague. The paper concludes with a series of recommendations and options as to when and how one should proceed in such situations.

Confidentiality↗

PubMed2000

Psychiatric comorbidity of methamphetamine dependence in a forensic sample.

The objective of this study was to examine the association between psychiatric symptoms and methamphetamine dependence. A four-hour survey was administered to 1,580 arrestees sampled from the 14 most populous counties in California. The survey included items assessing demographic profile, history of substance dependence, and psychiatric symptomatology. In the 12 months prior to the assessment, methamphetamine-dependent individuals were more likely to report depressive symptoms and suicidal ideation than individuals denying methamphetamine dependence, even after controlling for demographic profile and dependence on other drugs. Methamphetamine-dependent individuals also were more likely to report a need for psychiatric assistance at the time of the interview. These findings suggest that methamphetamine-dependent individuals are at greater risk to experience particular psychiatric symptoms. Further study to determine the etiology of these symptoms is warranted.

Adolescent↗

PubMed1999

Declarative and procedural memory in bipolar disorder.

BACKGROUND: Memory function is an important but under researched area for neuropsychological investigation in persons with bipolar disorder. Previous studies have reported cognitive deficits on tasks of declarative memory in bipolar patients in the euthymic state. METHODS: This study extended these findings by investigating declarative as well as procedural learning and memory in bipolar patients (with and without alcohol abuse) who were examined in the euthymic state. The California Verbal Learning Test, Star Mirror Tracing Task, Pursuit Rotor Task, American National Adult Reading Test, and the Vocabulary Subtest of the WAIS-R, were administered to bipolar patients and control subjects by researchers who were blind to the subject's group. RESULTS: Bipolar patients performed worse than control subjects on a measure of declarative memory (California Verbal Learning Test) but did not differ from the performance of control subjects on either of the two procedural learning tasks (Pursuit Rotor Task and Star Mirror Task). CONCLUSIONS: These results suggest disturbed function of temporal lobe, but not basal ganglia, structures in persons with bipolar disorder.

Adult↗

PubMed1999

Declarative and procedural memory functioning in abstinent cocaine abusers.

BACKGROUND: We determined the nature and recovery of procedural and declarative memory functioning in a cocaine-abusing cohort in the 45-day period following use. METHODS: Thirty-seven cocaine abusers and 27 control subjects were administered the following memory and mood measures: California Verbal Learning Test, recall of the Rey-Osterrieth Complex Figure Test, Pursuit Rotor Task, and Profile of Mood States at 4 visits (within 72 hours of admission and at 10, 21, and 45 days following abstinence). RESULTS: Analysis of performance on the Rey-Osterrieth Complex Figure Test revealed that both groups improved in their recall over repeated administrations, though the control group recalled significantly more of the information than cocaine subjects during the 45-day interval. Results for the California Verbal Learning Test indicated improved learning for both subject groups over time, but no group x time interaction. On the Pursuit Rotor Task, cocaine abusers improved their performance at a faster rate than controls at visit 1. At day 45 (visit 4), cocaine abusers again showed improvement on the Pursuit Rotor Task, whereas controls demonstrated a relative plateau in rate of learning. CONCLUSIONS: This study documented a lasting detrimental effect on a sensitive nonverbal declarative memory task in cocaine-dependent subjects following abstinence of 45 days. In contrast, abstinence from cocaine during this 45-day period was associated with sustained improvement on a motor learning test in the cocaine abusers relative to controls.

Adult↗

PubMed1999

The relationship between employment and neuropsychological impairment in HIV infection.

The relationship between neurocognitive impairment and employment in a cohort of 130 predominantly symptomatic individuals with HIV-1 infection was examined. Participants were classified as employed (full or part-time for pay) or unemployed (N = 64) and administered a neuropsychological test battery. When covarying for CD4 count, age, and physical limitations, the results revealed that unemployed men performed below that of employed participants on tasks of memory, set shifting-cognitive flexibility, and psychomotor speed. The results are discussed within the context of similar findings in other illnesses.

Adult↗

PubMed1999

Screening for dementia: comparison of three commonly used instruments.

The sensitivity and specificity of three cognitive screening measures - the Mini-Mental State Exam (MMSE), Mattis Dementia Rating Scale (MDRS), and Neurobehavioral Cognitive Status Examination (NCSE) - were compared in a cohort of subjects with dementia as well as normal elderly individuals. Twenty-two patients met criteria for probable Alzheimer' s disease (AD), 19 for vascular dementia (VaD), and 12 were normal control subjects. The use of standard cutpoints resulted in poor to good classification accuracy for the three measures, but measurable improvement in sensitivity was obtained by adjusting the cutpoints for each measure. Discriminatory power was maximized with an MMSE cutpoint of < or = 26, an MDRS cutpoint of < or = 134, and requiring one or more NCSE subtests to be in the impaired range. Use of age and education adjusted norms resulted in good to excellent classification accuracy for the MMSE and MDRS. The NCSE subtest score pattern failed to differentiate between AD and VaD.

Aged↗

PubMed1999

How well do standard clinical neuropsychological tests identify malingering? A preliminary analysis.

Neuropsychological research has primarily focused on identification of malingerers through specialized tests designed for this purpose. Little attention has been given to the degree to which traditional clinical measures differentiate between malingerers and non-malingerers. This study examined the neuropsychological performance of 81 subjects who had a history of mild to moderate head injury, some of whom are believed to have been motivated to malinger their test performance. Subjects were classified as malingerers or non-malingerers based on their history as well as their performance on specific neuropsychological malingering tests. Performance on traditional neuropsychological clinical measures was examined for both groups. Results indicated that subjects' pattern of neuropsychological performance was not a reliable indicator of malingering performance, supporting the notion that specialized malingering tests are a critically necessary component to clinical classification of malingering. However, level of performance may provide an indication of malingering, as probable malingerers consistently performed worse on traditional and clinical neuropsychological measures. These findings are discussed in the context of the malingering literature.

Adult↗

PubMed1998

Cognitive impairment in euthymic bipolar patients with and without prior alcohol dependence. A preliminary study.

BACKGROUND: Few studies of the neurocognitive performance of patients with bipolar disorder have been performed while patients are in the euthymic state. METHODS: Twenty-five euthymic bipolar patients (12 with and 13 without a history of alcohol dependence) were compared with 22 normal control subjects on a neuropsychological test battery assessing a range of cognitive domains. The relationship between subjects' neurocognitive performance and the course-of-illness variables (lifetime episodes and duration of mania, depression, or both), as well as current lithium level, was determined. RESULTS: The results indicated differences across the groups, with the bipolar patients with and without alcohol dependence performing more poorly than controls on tests of verbal memory. Furthermore, bipolar subjects with a history of alcohol dependence had additional decrements in executive (i.e., frontal lobe) functions when compared with controls. For subjects in the bipolar group, lifetime months of mania and depression were negatively correlated with performance in verbal memory and several executive function measures. CONCLUSIONS: Our findings support the presence of persistent neurocognitive difficulties in patients with long-standing bipolar disorder who are not in the psychiatrically acute state or who are suffering the effects of alcohol abuse and suggest that there may be an aggregate negative effect of lifetime duration of bipolar illness on memory and frontal or executive systems.

Alcoholism↗

PubMed1998

Pilot neuropsychological findings from a treatment regimen consisting of intensive chemotherapy and bone marrow rescue for young children with newly diagnosed malignant brain tumors.

Ten children (6 girls and 4 boys) who completed a protocol in which their localized brain tumors were successfully treated without cranial irradiation were referred for neuropsychological assessment. At the time of testing, they were disease free without any neuroaxis dissemination or leptomeningeal disease. Tumor types included pineoblastoma, glioblastoma, ependymoma, PNET and medulloblastoma. They had a mean age of 5 years and 8 months (SD = 1.86; range = 2.1-8.9 years) and were an average of 37.8 months post bone marrow transplant (SD = 16.42; range = 14-58 months). Neuropsychological data from this study reveal that the mean scores for this nonradiated group of children were within the average range for the following domains: academic achievement tests of reading, spelling and mathematics, verbal and visual memory, visual-motor integration, social-emotional and behavioral functioning. Furthermore, this group of children were performing within the low average range of overall Intelligence, as well as both verbal IQ/verbal reasoning and performance IQ/abstract visual reasoning. On tasks of fine motor dexterity, this group was within the low average range when using their dominant hand; however, they performed within the borderline range when using their non-dominant hand. Of note, this group of children demonstrated significant deficits within the borderline to impaired ranges on language tasks of expressive picture naming and receptive picture vocabulary.

Achievement↗

PubMed1998

Depression predicts procedural but not episodic memory in HIV-1 infection.

Forty-three homosexual/bisexual males with HIV-1 infection participated in a study that sought to determine: (1) whether increased levels of self-reported depressive symptomatology were associated with poorer performance on episodic or procedural memory tasks, (2) the relative strength of association between the affective/cognitive or somatic symptoms of depression and memory deficits and level of immunosuppression, and (3) whether increased depression or neuropsychological deficits are associated with degree of immunosuppression. Linear regression analyses revealed that increased affective/cognitive symptomatology was correlated with poorer performance on a procedural memory task, but was not correlated with performance on an episodic memory task or degree of immunosuppression. In contrast, somatic symptoms showed the strongest association with level of immunosuppression, but were not correlated with performance on the memory tasks. These findings underscore the complex interplay between neuropsychiatric and neuropsychological symptomatology in HIV-1 infection.

Adult↗

PubMed1998

Chronic Neuropsychological sequelae in a case of severe lithium intoxication.

OBJECTIVE: This case provides data from serial assessments using a comprehensive neuropsychological test battery to assess the effects of severe toxicity on cognitive functioning, the pattern of deficits, and the regions of the brain that appear to be involved. BACKGROUND: Lithium carbonate has made a significant contribution to the treatment of bipolar disorder, and considerable investigation has been conducted on both temporary and long-term side effects on the central nervous system. The effects of acute lithium intoxication on the central nervous system have been extensively documented. METHOD: We studied a severe case of acute lithium intoxication and associated neuropsychological sequelae. The patient was evaluated twice with a comprehensive battery of neuropsychological tests within 2 years of the lithium intoxication. RESULTS: Comprehensive neuropsychological evaluations indicated persistent cognitive sequelae, including impaired memory, attention, executive control functions, and visuospatial deficits. CONCLUSIONS: The cognitive sequelae noted in the case of lithium toxicity are consistent with a subcortical dementia and the findings of other authors. Findings should be explored further in more rigorous clinical studies.

Cognition↗

PubMed1997

Subjective complaints versus actual cognitive deficits in predominantly symptomatic HIV-1 seropositive individuals.

The relationship of self-reported cognitive, motor, and affective complaints to actual neuropsychological functioning was explored in a cohort of predominantly symptomatic HIV-1 seropositive individuals. Ninety-two symptomatic HIV-1 infected subjects were questioned about complaints common in HIV infection and were assessed with a comprehensive neuropsychological test battery. No relationship was found between subjective complaints and cognitive functioning, yet a significant relationship was found between self-reported difficulties and formal measures of affect and mood. Failure to show a relationship between self-reported cognitive status and actual neuropsychological functioning in this cohort suggests that complaints of cognitive decline may be attributable to emotional factors.

Adult↗

PubMed1997

EEG power correlates with subcortical metabolic activity in AIDS.

The authors studied the relationship between brain metabolic activity and quantitative electroencephalographic power in AIDS. Basal ganglia and thalamic metabolic activity, measured with positron emission tomography, correlated positively with EEG power in the 6-10-Hz band across most head regions. Metabolic activity of anatomically defined cortical regions did not correlate with EEG power recorded over each region. These results support previously reported associations between abnormalities in subcortical metabolic activity and EEG activity. The lack of correlation between cortical metabolic activity and EEG activity suggests that previously observed abnormalities in EEG activity are primarily subcortical in origin.

Acquired Immunodeficiency Syndrome↗

PubMed1996

Actual versus self-reported cognitive dysfunction in HIV-1 infection: memory-metamemory dissociations.

The relationship between subjective awareness and objective neuropsychological status in HIV-1 infection remains unclear. Forty-six HIV-1 seropositive males were administered a battery of neuropsychological measures assessing episodic memory, metacognition, and depression. Results of ANOVA revealed a dissociation between subjects' self-complaint of neuropsychological impairment and objective performance, with subjects who denied cognitive impairment performing worse on memory testing. Three subgroups were identified: A group whose self-reported cognitive impairment exceeded deficits demonstrated on memory testing (37% of subjects); a group who denied impairment but evidenced deficits on memory testing (26% of subjects); and a group whose self-appraisal was consistent with performance (37% of subjects). These data suggest that self-report of cognitive dysfunction among HIV-1 infected subjects is frequently at variance with objective neuropsychological testing and that diminished awareness of decline among medically symptomatic HIV-1 infected subjects can be identified.

Acquired Immunodeficiency Syndrome↗

PubMed1995

Cerebral metabolic change in patients with AIDS: report of a six-month follow-up using positron-emission tomography.

The authors examined change in cerebral metabolic function over time by using PET in HIV-infected individuals diagnosed with AIDS. Ten subjects with AIDS received [18F]2-fluoro-2-deoxy-D-glucose PET scans and completed a comprehensive neuropsychological battery. The scan and test battery were repeated after 6 months. Over time, the subjects showed increased relative basal ganglia metabolism as well as increased parietal lobe metabolism. There were no statistically significant changes in neuropsychological performance. These results suggest that PET may be more sensitive than traditional neuropsychological evaluation to subtle central nervous system changes in AIDS.

AIDS Dementia Complex↗