Biomedical subjects

Robin C Hilsabeck

Publications and source records attributed to Robin C Hilsabeck.

13 recordsLinked to original sources

PubMed2006

Information processing following mild head injury.

Research has shown that individuals who have sustained mild head injury demonstrate a slowed speed of processing that is exacerbated by fatigue/stress. We administered the Paced Auditory Serial Addition Test (PASAT) at the beginning and at the end of a 4-h experimental protocol to determine whether fatigue or a stressor would result in poorer scores for individuals who had previously sustained mild head injury. A significant improvement was found between the first and second administration for both head-injured and control subjects, but difference scores revealed a significant between-groups difference for the first of the four trials, with the head-injured participants performing worse than controls. Apparently, head-injured participants were slower to develop, as well as slower to regain, a means of efficiently processing rapidly presented information.

Adolescent↗

PubMed2006

Complex partial seizure symptom endorsement in individuals with a history of head injury.

Research has shown that subjects at risk for cerebral dysfunction endorse more complex partial seizure symptoms than low risk controls. It has been suggested that seizure activity be regarded as occurring on a continuum of neurobehavioral dysfunction, rather than as a discrete syndrome. The present study assessed seizure symptom endorsement in individuals reporting a positive history of head injury. There were three groups of college student participants: head injury with loss of consciousness (LOC; n=31); head injury followed by a dazed period or alteration of consciousness (AOC; n=36); non-injured controls (NHI; n=60). In general, the LOC group reported greater frequency of symptomatology and a greater number of clinically significant symptoms (above the 90th percentile) than the NHI group, and a greater number of clinically significant symptoms than the AOC group. The AOC group did not differ from the NHI group on either variable. These results lend credence to the concept of a continuum representing an epilepsy spectrum disorder.

Adolescent↗

PubMed2005

Detecting simulated memory impairment: further validation of the Word Completion Memory Test (WCMT).

The Word Completion Memory Test (WCMT) was developed to detect sophisticated attempts at simulating memory impairment. The primary purpose of the present study was to provide additional validity and reliability information about the WCMT. Seventy-one participants were recruited for this study: 30 normal volunteers and 11 memory-disordered patients instructed to perform their best, and 30 normal volunteers instructed to fake memory impairment. Normal volunteers were administered five tests of neuropsychological functioning and five tests of simulation to explore the convergent and divergent validity of the WCMT. Two weeks later, these participants completed all 10 measures a second time. Memory-disordered patients were administered the WCMT and two additional simulation measures as part of a comprehensive neuropsychological evaluation. The WCMT successfully discriminated simulators from nonsimulators with an overall classification accuracy of 97% and demonstrated good psychometric properties. In conclusion, the WCMT continues to show promise as a measure of simulated memory impairment.

Adolescent↗

PubMed2005

Neuropsychological aspects of coinfection with HIV and hepatitis C virus.

Infection with hepatitis C virus (HCV) is commonly seen in persons with human immunodeficiency virus (HIV) infection, because the viruses share risk factors for transmission; coinfection is a leading cause of morbidity and mortality among HIV-infected persons. Neuropsychological consequences of HIV infection are well established, and studies of HCV-infected persons have revealed neuropsychiatric dysfunction in this population as well. Investigators now are focusing on neuropsychological sequelae of coinfection with HIV and HCV, and preliminary results suggest that coinfection has a possible deleterious effect on global cognitive functioning consistent with frontal-subcortical dysfunction. Data on neuropsychiatric symptoms in coinfected persons are inconclusive at this time and are complicated by important differences in study populations (e.g., injection drug use and disease severity). This review summarizes what is known about neuropsychological aspects of monoinfection with HIV and HCV, as well as coinfection, discusses implications of these findings, and suggests future directions for this research area.

Cognition↗

PubMed2005

Biopsychosocial predictors of fatigue in chronic hepatitis C.

OBJECTIVE: The objective of this study was to investigate the relationship of biopsychosocial variables to fatigue in patients with chronic hepatitis C (CHC) with the goal of identifying areas of possible intervention. METHOD: Ninety-four patients with CHC not on antiviral therapy completed a demographic questionnaire and measures of fatigue, health-related quality of life, and depression. Fibrosis stage and relevant medical information were obtained from medical records. RESULTS: A stepwise multiple regression analysis revealed that the most significant predictor of fatigue was poor social functioning, followed by poor physical functioning, greater depression, and female gender. Together, these variables accounted for 68% of the total variance in fatigue. DISCUSSION: Study findings suggest that treatment strategies for fatigue in patients with CHC should focus on increasing social functioning in addition to improving physical functioning and decreasing depressive symptoms. Research investigating the effectiveness of interventions targeting social functioning, such as support groups and supportive counseling, is recommended.

Age Factors↗

PubMed2005

Effect of interferon-alpha on cognitive functioning in patients with chronic hepatitis C.

Treatment with interferon-alpha (IFN-alpha) has been shown to adversely affect cognitive functioning in patients with a variety of medical disorders, but information about the effects of IFN-alpha on cognitive functioning in patients with chronic hepatitis C (CHC) is limited. The purpose of this study was to examine the effects of IFN-alpha on neuropsychological test performance in CHC patients. Participants were 30 patients with CHC, 11 who underwent IFN-alpha therapy and 19 who did not. All participants were tested at baseline (i.e., pretreatment) and approximately 6 months later with the Symbol Digit Modalities Test and Trail Making Test. Results revealed that the treatment group performed significantly worse than untreated CHC patients on Part B of the Trail Making Test after approximately 6 months of treatment. No significant group differences were found on Part A of the Trail Making Test or Symbol Digit Modalities Test. Findings suggest that CHC patients undergoing treatment with IFN-alpha may experience reduced abilities to benefit from practice but suffer no decrements in performance after 6 months of treatment. Additional research is needed to replicate these findings and to explore risk factors for susceptibility to IFN-alpha-induced effects.

Antiviral Agents↗

PubMed2005

Neuropsychological test performance in patients co-infected with hepatitis C virus and HIV.

OBJECTIVE: To determine the effect of co-infection on neuropsychological performance in relatively healthy hepatitis C virus (HCV)-alone patients when compared with HCV/HIV-co-infected patients. DESIGN: To test whether the burden of co-infection with HCV and HIV on the central nervous system results in increased cognitive deficits, we tested 47 HCV-alone and 29 HCV/HIV-co-infected patients on a neuropsychological screening battery of tests of attention, concentration and psychomotor speed. METHODS: The neuropsychological test performance of HCV-alone and HCV/HIV-co-infected patients was compared with normative samples. The test performance between HCV-alone and HCV/HIV-co-infected patients was also assessed. Patients with chronic liver disease were divided on the basis of disease severity as determined by fibrosis stage, according to the METAVIR system. Neuropsychological test performance was correlated with fibrosis stage. RESULTS: As previously reported, HCV patients independent of co-infection status demonstrated deficits on neuropsychological measures of attention, concentration and psychomotor speed. No significant differences were found between patients with HCV-alone and HCV/HIV-co-infected patients on the neuropsychological measures. There was a relationship between neuropsychological test performance and fibrosis stage. CONCLUSION: Relatively healthy patients with HCV (either alone or when co-infected with HIV) may have deficits in the domains of attention, concentration and psychomotor speed. In this study no significant differences were found between patients with HCV alone and HCV/HIV-co-infected patients on neuropsychological measures, but as previously demonstrated, greater fibrosis was associated with poorer performance.

Adult↗

PubMed2004

Neuropsychological and emotional changes during simulated microgravity: effects of triiodothyronine alendronate, and testosterone.

INTRODUCTION: We present the results of a two-experiment study designed to evaluate the neurocognitive and psychological effects of six-degree head-down bedrest and pharmacologic interventions (3,5,3'-triiodothyronine; T3) implemented to enhance the muscle and bone atrophy associated with simulated microgravity. Subsequently, the effects of countermeasures (alendronate and testosterone) administered to retard or reverse these T3 plus bedrest enhanced atrophic changes, were evaluated. Each participant was tested weekly for 5 weeks during Bedrest or non-bedrest (Up) conditions with the Neurobehavioral Evaluation System 2 (NES2), the Symptom Check List 90 Revised (SCL-90-R), and the Coping Responses Inventory (CRI). Resultant data were subjected to repeated measures, between groups analysis of variance testing for all 82 neurocognitive and psychological test measures. RESULTS: In Experiment 1, participants in the Placebo-Bedrest condition performed better on several neurocognitive measures compared to participants in the T3-Up condition. However, participants in the Placebo-Bedrest condition also reported more confusion. In Experiment 2 (countermeasure trials), superior coordination was observed for participants in the Testosterone-T3 condition over those in the Alendronate-T3 condition, but just the opposite for reaction time. Also, testosterone and to a lesser degree, alendronate, were associated with less self-reported emotional distress than T3 plus bedrest alone. CONCLUSION: Triiodothyronine, alendronate, and testosterone each influence participant response to simulated microgravity. Between group differences for significant findings were substantial and averaged 1.62 standard deviations. Although the observed neurocognitive effects likely pose no immediate danger for research participants, the significantly greater level of self-reported psychological symptoms by T3-Placebo and Placebo-Bedrest treated participants is of clinical importance.

Adult↗

PubMed2003

Cognitive functioning and psychiatric symptomatology in patients with chronic hepatitis C.

Hepatitis C virus (HCV) infection is a major public-health-care problem, with over 170 million infected worldwide. Patients with chronic HCV infection often complain of various cognitive problems as well as symptoms of depression, anxiety, and fatigue. Relatively little is known, however, about the specific cognitive deficits that are common among HCV patients, and the influence of psychiatric symptomatology on cognitive functioning. In the current study of 21 chronically infected HCV patients, we assessed subjective cognitive dysfunction, depression, anxiety, and fatigue and compared these symptom areas to cognitive tests assessing visuoconstruction, learning, memory, visual attention, psychomotor speed, and mental flexibility. Results revealed that cognitive impairment ranged from 9% of patients on a visuoconstruction task to 38% of patients on a measure of complex attention, visual scanning and tracking, and psychomotor speed, and greater HCV disease severity as indicated by liver fibrosis was associated with greater cognitive dysfunction. Objective cognitive impairment was not related to subjective cognitive complaints or psychiatric symptomatology. These findings suggest that a significant portion of patients with chronic HCV experience cognitive difficulties that may interfere with activities of daily living and quality of life. Future research using cognitive measures with HCV-infected patients may assist researchers in identifying if there is a direct effect of HCV infection on the brain and which patients may be more likely to progress to cirrhosis and hepatic encephalopathy.

Adult↗

PubMed2003

Utility of the trail making test in the assessment of malingering in a sample of mild traumatic brain injury litigants.

The Trail Making Test (TMT) is one of the most commonly administered tests in neuropsychological assessments. It has been shown to be a valid indicator of brain damage due to traumatic brain injury (TBI), as well as a number of other neuropathological conditions. TMT error and ratio scores have been suggested as possible markers of malingering. The present study examined the utility of various TMT scores as malingering measures in 94 TBI litigants. Litigants were divided into those suspected of (n = 27) and those not suspected of malingering (n = 67) based on scores obtained on the Test of Memory Malingering and/or the Rey 15-Item Test. TMT errors did not discriminate between suspected and nonsuspected malingerers; however, the overall level of performance on the TMT was suppressed in suspected malingerers. The TMT ratio score was significantly lower in litigants suspected of malingering, although the clinical utility of this ratio is minimal. Results of the present study suggest using caution when interpreting TMT scores as markers of malingering in TBI litigants.

Adult↗

PubMed2003

The Recognition Memory Test Examination of ethnic differences and norm validity.

The possibility of racial bias in neuropsychological test materials has received increasing attention in recent years. The purpose of the present study was to investigate whether an own-race recognition bias would provide an advantage for Caucasian participants over African American participants on the Faces subtest of the Recognition Memory Test (RMT). Thirty Caucasian and 30 African American undergraduates completed the RMT, Shipley Institute of Living Scale (SILS), and Symbol Digit Modalities Test (SDMT). No significant group difference was found on RMT Faces. However, mean RMT Faces scores for both groups were below the 10th percentile in spite of average scores on the SDMT and SILS. A second study was conducted to further examine the validity of the RMT norms for this age range (i.e., 18-24) and to provide 2-week test-retest reliabilities. The mean RMT Faces subtest score was 39.78 (10th percentile), and 28% of the sample scored at or below the fifth percentile. Test-retest reliabilities were.63 and.64 for RMT Words and Faces, respectively. Results of these studies suggest that re-examination of the current norms for RMT Faces is warranted for adults aged.

Adolescent↗

PubMed2003

Partial cross-validation of the Wechsler Memory Scale-Revised (WMS-R) General Memory-Attention/Concentration Malingering Index in a nonlitigating sample.

The Wechsler Memory Scale-Revised (WMS-R) malingering indices proposed by Mittenberg, Azrin, Millsaps, and Heilbronner [Psychol Assess 5 (1993) 34.] were partially cross-validated in a sample of 200 nonlitigants. Nine diagnostic categories were examined, including participants with traumatic brain injury (TBI), brain tumor, stroke/vascular, senile dementia of the Alzheimer's type (SDAT), epilepsy, depression/anxiety, medical problems, and no diagnosis. Results showed that the discriminant function using WMS-R subtests misclassified only 6.5% of the sample as malingering, with significantly higher misclassification rates of SDAT and stroke/vascular groups. The General Memory Index-Attention/Concentration Index (GMI-ACI) difference score misclassified only 8.5% of the sample as malingering when a difference score of greater than 25 points was used as the cutoff criterion. No diagnostic group was significantly more likely to be misclassified. Results support the utility of the GMI-ACI difference score, as well as the WMS-R subtest discriminant function score, in detecting malingering.

Adult↗

PubMed2002

Neuropsychological impairment in patients with chronic hepatitis C.

Hepatitis C is the most common cause of chronic liver disease in the United States and it significantly reduces quality of life. The role of cognitive deficits contributing to the morbidity of this disease has not been well characterized. The purpose of this study was to examine cognitive functioning in patients with chronic hepatitis C and to investigate relationships among parameters of disease severity and performance on neuropsychological tests. Sixty-six patients with chronic hepatitis C and 14 patients with other chronic liver diseases were administered a brief battery of neuropsychological tests assessing attention, visuoconstructional ability, learning, memory, and psychomotor speed. Cognitive impairment in patients with chronic hepatitis C ranged from 0% on a visuoconstructional task to 82% on a measure of sustained attention and concentration. Test scores of patients with chronic hepatitis C did not differ from those of patients with other chronic liver diseases. Hence, patients with and without chronic hepatitis C experience cognitive deficits, especially in tasks requiring attention and psychomotor speed. In addition, there was a significant relationship between fibrosis stage and test performance, with greater fibrosis associated with poorer performance. However, both patients with and without cirrhosis exhibited cognitive dysfunction. In conclusion, these findings suggest that progressive hepatic injury may result in cognitive problems even before the development of cirrhosis. Future studies need to determine the effect of this decrease in cognitive function on quality of life.

Adult↗