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Barton W Palmer

Publications and source records attributed to Barton W Palmer.

At least 19 recordsLinked to original sources
PubMed2007

Neurocognitive impairment in middle-aged and older adults with bipolar disorder: comparison to schizophrenia and normal comparison subjects.

BACKGROUND: The frequency, pattern, and correlates of neurocognitive impairment in older patients with bipolar disorder have received little study. We examined neurocognitive abilities in middle-aged and older adults with bipolar disorder to groups with schizophrenia or normal subjects, as well as the relation of neurocognition to clinical characteristics. METHOD: We administered a battery of neurocognitive and clinical measures to older (45-85 years) outpatients with bipolar disorder (n=67), schizophrenia (n=150), and normal comparison subjects (n=85). Within the bipolar group, we assessed the association between neurocognitive performance and psychiatric symptoms, quality of life, and medication status. RESULTS: The group with bipolar disorder differed on nearly all neuropsychological tests compared to normal subjects, with medium effect sizes. Bipolar patients as impaired as those with schizophrenia on half of the tests administered, and performed better on the remaining tests, with small effect sizes. Neurocognitive deficits in bipolar disorder group related to lower quality of life, but not to psychiatric symptom severity or duration of illness. LIMITATIONS: Samples were outpatients with mild-moderate symptoms, and findings may not generalize to acutely ill populations. We lacked data on illness history to examine the cumulative impact of psychopathology. CONCLUSIONS: Among clinically stable middle-aged and older outpatients, bipolar disorder was associated with substantial neurocognitive impairment, with a pattern that was somewhat distinct from that found in schizophrenia. Deficits in the bipolar group were not related to severity or duration of psychiatric symptoms, but were related to quality of life. Bipolar disorder often involve disabling and enduring cognitive impairments in older outpatients.

Age Factors↗
PubMed2006

Prevalence and correlates of adequate performance on a measure of abilities related to decisional capacity: differences among three standards for the MacCAT-CR in patients with schizophrenia.

Despite the availability of structured decision-making capacity assessment tools, insufficient guidance exists for applying their results. Investigators often use cutpoints on these instruments to identify potential subjects in need of further assessment or education. Yet, information is lacking regarding the effects of different cutpoints on the proportion and characteristics of individuals categorized as possessing adequate or impaired decisional abilities for consent to research. To demonstrate the potential impact of different standards, we informed 91 individuals, aged 50 or older with a diagnosis of schizophrenia or schizoaffective disorder, about a hypothetical clinical trial, and assessed their decisional abilities with the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR). Three published MacCAT-CR-based standards were applied to participants' scores to examine the rates and correlates of categorical determinations of adequate performance. The three standards ranged in stringency: the most stringent incorporated cutpoints on all three of the major MacCAT-CR subscales (Understanding, Appreciation, and Reasoning); the other two standards required threshold performance only on the Understanding subscale. The most stringent standard resulted in a 57% rate of impaired performance; the intermediate standard, 19%; and the least stringent standard, 8%. Nearly half of the participants (n=45) were classified as having performed adequately by the least stringent standard yet inadequately by the most stringent. The majority of these 45 were impaired on the Appreciation subscale (n=9), Reasoning (n=15), or both (n=18). Cognitive functioning was correlated with performance status for the more stringent standards. These findings underscore the need for refinement of capacity assessment procedures and for improvements in the use of capacity assessment tools for screening purposes and to assist in categorical capacity determinations.

Aged↗
PubMed2006

Verbal fluency impairments among middle-aged and older outpatients with schizophrenia are characterized by deficient switching.

Patients with schizophrenia demonstrate impaired verbal fluency, but no studies have examined the underlying cognitive mechanisms (e.g., clustering and switching) associated with impaired fluency among middle-aged and older, non-institutionalized patients. Using Troyer et al.'s [Troyer, A.K., Moscovitch, M., Winocur, G., 1997. Clustering and switching as two components of verbal fluency: evidence from younger and older healthy adults. Neuropsychology 11 (1), 138-146] conceptual model, we examined clustering and switching on verbal fluency tasks among 163 middle-aged and older outpatients with schizophrenia and 92 age comparable healthy comparison (HC) participants. The patients produced significantly fewer total words than HC participants on both the letter ("F", "A", "S") and Animal fluency conditions. With regard to clustering, patients were similar to HC participants on both FAS and Animal fluency tasks. However, significantly fewer switches between lexical-semantic categories were observed among patients with schizophrenia on both conditions relative to HC participants. A small, but statistically significant association was found between number of switches on the Animal fluency task and severity of negative symptoms. The absence of a difference in mean cluster size between the patient and HC groups suggests intact lexical-semantic stores among middle-aged and older outpatients with schizophrenia. Differences in switching between patients and HC participants may be driven by several cognitive impairments associated with schizophrenia. Further delineation of the cognitive mechanisms of the observed lexical-semantic switching deficits in schizophrenia should be a focus of future research.

Age Factors↗
PubMed2006

Transient and executive function working memory in schizophrenia.

Transient working memory requires attention and temporary storage of information, whereas executive function working memory requires additional mental manipulation of that information. Working memory impairment is common in schizophrenia patients, but only some studies have found differential impairment in executive function working memory compared to transient working memory. We measured both types of working memory using the Digit Span forward (DF) and backward (DB) tasks in a large sample of schizophrenia patients (n=267) and normal comparison subjects (n=82); in the patients, we also examined associations between performance on the Digit Span tasks and Letter-Number Sequencing (LNS), a putative executive function working memory test. Compared to healthy subjects, the schizophrenia patients showed impairment in the medium effect size range on both DF (d=-0.55) and DB (d=-0.68). DB scores predicted LNS performance, whereas DF scores did not. Worse negative symptoms were associated with worse performance on DF, DB and LNS. These results do not reflect differential executive function working memory dysfunction in schizophrenia, but appear to support transient and executive function working memory as separable constructs.

Adult↗
PubMed2006

Baseline neurocognitive deficits in the CATIE schizophrenia trial.

Neurocognition is moderately to severely impaired in patients with schizophrenia. However, the factor structure of the various neurocognitive deficits, the relationship with symptoms and other variables, and the minimum amount of testing required to determine an adequate composite score has not been determined in typical patients with schizophrenia. An 'all-comer' approach to cognition is needed, as provided by the baseline assessment of an unprecedented number of patients in the CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) schizophrenia trial. From academic sites and treatment providers representative of the community, 1493 patients with chronic schizophrenia were entered into the study, including those with medical comorbidity and substance abuse. Eleven neurocognitive tests were administered, resulting in 24 individual scores reduced to nine neurocognitive outcome measures, five domain scores and a composite score. Despite minimal screening procedures, 91.2% of patients provided meaningful neurocognitive data. Exploratory principal components analysis yielded one factor accounting for 45% of the test variance. Confirmatory factor analysis showed that a single-factor model comprised of five domain scores was the best fit. The correlations among the factors were medium to high, and scores on individual factors were very highly correlated with the single composite score. Neurocognitive deficits were modestly correlated with negative symptom severity (r=0.13-0.27), but correlations with positive symptom severity were near zero (r<0.08). Even in an 'all-comer' clinical trial, neurocognitive deficits can be assessed in the overwhelming majority of patients, and the severity of impairment is similar to meta-analytic estimates. Multiple analyses suggested that a broad cognitive deficit characterizes this sample. These deficits are modestly related to negative symptoms and essentially independent of positive symptom severity.

Adult↗
PubMed2006

An evaluation of longitudinal neurocognitive performance among middle-aged and older schizophrenia patients: use of mixed-model analyses.

The purpose of this study was to evaluate the trajectory of neuropsychological performance among middle-aged and older patients with schizophrenia using hierarchical linear modeling (HLM). Using the Mattis Dementia Rating Scale (DRS), we assessed cognitive performance of 143 schizophrenia outpatients (Mean age=53.1 years, SD=8.8) and 66 healthy comparison subjects (Mean age=61.8 years, SD=8.8). All participants had DRS data from two or more testing sessions with average intervals between sessions being 15 months (range=6-55). Using HLM, we found cognitive performance to be stable over time in both schizophrenia patients and healthy comparison subjects. Age, gender, ethnicity, and education did not affect trajectories. We also analyzed the data using more traditional statistical approaches to longitudinal data and found similar results. In sum, we found cognitive impairment to be stable over time among outpatients with schizophrenia, regardless of the statistical methodology used to analyze longitudinal data.

Adult↗
PubMed2006

Adherence to continuous positive airway pressure treatment in patients with Alzheimer's disease and obstructive sleep apnea.

OBJECTIVE: This analysis examined whether patients with Alzheimer disease (AD) tolerate continuous positive airway pressure (CPAP). METHOD: Thirty patients with AD were randomized to CPAP or sham CPAP and completed sleep, depression, and quality-of-life questionnaires. Participants could choose to continue treatment after the trial. RESULTS: Patients wore CPAP for 4.8 hours per night. More depressive symptoms were associated with worse adherence (rS=-0.37; N=30, p<0.04). Patients who continued using CPAP had fewer depressive symptoms (t [19]=2.45, p=0.02) and better adherence (t [19]=2.32, p=0.03) during the trial. CONCLUSION: Patients with AD with obstructive sleep apnea can tolerate CPAP. Adherence and long-term use may be more difficult among those patients with more depressive symptoms.

Adult↗
PubMed2006

Continuous positive airway pressure reduces subjective daytime sleepiness in patients with mild to moderate Alzheimer's disease with sleep disordered breathing.

OBJECTIVES: Studies have reported that 33% to 70% of patients with Alzheimer's disease (AD) have sleep-disordered breathing (SDB). Continuous positive airway pressure (CPAP) treatment has been shown to reduce daytime sleepiness and improve health-related quality of life in nondemented older people with SDB. The effect of therapeutic CPAP treatment on daytime sleepiness in patients with mild-moderate AD with SDB was assessed. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Patients' home and the University of California San Diego, General Clinical Research Center, J. Christian Gillin Laboratory of Sleep and Chronobiology. PARTICIPANTS: Thirty-nine community-dwelling elderly patients with mild-moderate probable AD with SDB. INTERVENTION: Patients were randomly assigned to receive 6 weeks of therapeutic CPAP or 3 weeks of sham CPAP followed by 3 weeks of therapeutic CPAP. MEASUREMENTS: Epworth Sleepiness Scale (ESS) was administered at baseline, 3 weeks, and 6 weeks. Changes in daytime sleepiness in subjects who received optimal therapeutic CPAP were compared with changes in the sham CPAP group. RESULTS: Within the therapeutic CPAP group, ESS scores were reduced from 8.89 during baseline to 6.56 after 3 weeks of treatment (P=.04) and to 5.53 after 6 weeks of treatment (P=.004). In the sham CPAP group, there was no significant difference after 3 weeks of sham CPAP but a significant decrease from 7.68 to 6.47 (P=.01) after 3 weeks of therapeutic CPAP. CONCLUSION: These data provide evidence of the effectiveness of CPAP in reducing subjective daytime sleepiness in patients with AD with SDB.

Aged↗
PubMed2006

Assessing decisional capacity for clinical research or treatment: a review of instruments.

OBJECTIVE: The need to evaluate decisional capacity among patients in treatment settings as well as subjects in clinical research settings has increasingly gained attention. Decisional capacity is generally conceptualized to include not only an understanding of disclosed information but also an appreciation of its significance, the ability to use the information in reasoning, and the ability to express a clear choice. The authors critically reviewed existing measures of decisional capacity for research and treatment. METHOD: Electronic medical and legal databases were searched for articles published from 1980 to 2004 describing structured assessments of adults' capacity to consent to clinical treatment or research protocols. The authors identified 23 decisional capacity assessment instruments and evaluated each in terms of format, content, administration features, and psychometric properties. RESULTS: Six instruments focused solely on understanding of disclosed information, and 11 tested for understanding, appreciation, reasoning, and expression of a choice. The instruments varied substantially in format, degree of standardization of disclosures, flexibility of item content, and scoring procedures. Reliability and validity also varied widely. All instruments have limitations, ranging from lack of supporting psychometric data to lack of generalizability across contexts. CONCLUSIONS: Of the instruments reviewed, the MacArthur Competence Assessment Tools for Clinical Research and for Treatment have the most empirical support, although other instruments may be equally or better suited to certain situations. Contextual factors are important but understudied. Capacity assessment tools should undergo further empirically based development and refinement as well as testing with a variety of populations.

Adult↗
PubMed2006

Assessment of therapeutic misconception in older schizophrenia patients with a brief instrument.

OBJECTIVE: "Therapeutic misconception," or conflation of goals and procedures of clinical research with those of usual clinical care, is an important topic in research ethics because it may impede informed consent. How best to assess therapeutic misconception is unclear. Also unclear is to what degree patients with severe mental illnesses, such as schizophrenia, may manifest these beliefs. METHOD: With a hypothetical, double-blind, placebo-controlled trial as a stimulus, the authors examined the frequency of a key aspect of therapeutic misconception with a true/false scale in 87 middle-age and older patients with schizophrenia or schizoaffective disorder. They also analyzed the demographic, clinical, neurocognitive, and decision-making correlates of therapeutic misconception and examined the psychometric properties of a scale designed to measure therapeutic misconception. RESULTS: Subjects showed variable performance on the therapeutic misconception measure. Nearly one-third answered all questions correctly; two-thirds answered four or more of the six items correctly. Patients with less education or worse cognitive functioning manifested higher levels of therapeutic misconception. Degree of therapeutic misconception was inversely associated with understanding, appreciation, and reasoning scores on the MacArthur Competence Assessment Tool for Clinical Research but was not associated with severity of psychopathology. The scale showed fair internal consistency. CONCLUSIONS: As in studies of other patient populations, patients with schizophrenia show a substantial incidence of beliefs associated with therapeutic misconception. Further work should focus on refining measures of therapeutic misconception, identifying participants or protocols (e.g., higher-risk studies) in which it may warrant greater concern, and developing educational interventions to mitigate it.

Age Factors↗
PubMed2006

The effect of sleep-disordered breathing on stages of sleep in patients with Alzheimer's disease.

Patients with Alzheimer's disease (AD) commonly have poor sleep and a high reported incidence of sleep-disordered breathing (SDB). This study examined how the presence of SDB affected sleep stages in AD patients. Sixty-six volunteers with mild - moderate AD underwent home polysomnography. Results showed that patients with SDB spent less of the night in REM sleep than those with no SDB, but there were no differences in other sleep stages. The findings suggest that the decreased amount of REM sleep may be due to the presence of AD and SDB. Treating these patients' SDB may increase their amount of REM sleep, which may result in improved daytime functioning. Controlled trials of SDB treatment in AD are needed to answer this question.

Aged↗
PubMed2006

Schizophrenia in late life: emerging issues.

Schizophrenia in late life is emerging as a major public health concern worldwide. We discuss several areas of research and clinical care that are particularly pertinent to older persons with schizophrenia, including the public health challenge and the cost of care. We then discuss clinical issues relevant to late-life schizophrenia (course of illness and cognition), medical care and comorbidity in older psychiatric patients (general and illness-related), and treatment concerns related to the use of atypical antipsychotics in older persons with psychosis (efficacy and side effects). Clinical care for this ever-increasing segment of our population requires special consideration of the unique characteristics of older persons with schizophrenia.

Age of Onset↗
PubMed2005

A review of performance-based measures of functional living skills.

There is growing recognition of the need to consider the effect of mental health treatments on functional independence/abilities, in addition to any effects on primary symptoms. A variety of performance-based measures of functional living skills have appeared in the medical literature over the past 25 years in discipline-specific journals, but there has been little attempt to synthesize this information to guide mental health clinicians and researchers in choosing among the available measures. Thus, the goal of the present review was (1) to identify and evaluate the strengths and weaknesses of currently available performance-based assessments of functional living skills for adult populations, and (2) to make specific recommendations regarding use of currently available instruments as well as recommendations for future instrument development. Through a comprehensive search of electronic citation databases for English-language articles on performance-based instruments, as well as via cross-referenced articles in the bibliography of each initially identified article, we identified 94 relevant articles covering 31 instruments, including 20 multi-domain instrument batteries, and 11 additional domain-specific performance-based instruments. Most identified instruments provided evidence of adequate reliability, but empirical data regarding the predictive validity of each scale in terms of actual "real world functioning" was less prevalent. Several good performance-based measures have been developed for individuals with dementia, psychiatric illnesses, and older healthy individuals. Future instrument development may benefit from a focus on brevity, empirical item selection as determined by patients/caregivers, predictive validity with an emphasis on change in functioning over time, and the relationship of performance to levels of competency required for the completion of everyday tasks.

Activities of Daily Living↗
PubMed2005

Meta-consent in research on decisional capacity: a "Catch-22"?

Empirical studies of ethical issues, which have increased in number and scope in recent years, may themselves raise both practical and ethical issues. One example of such an issue is the question of who may be legitimately enrolled in studies of decision-making capacity; must all participants in studies of consent capacity have capacity to consent? This question may pose a "Catch-22": For example, if some of the participants in a study of consent capacity are deemed by a particular standard to be incapable of consent. In weighing the risks and benefits of studies of consent capacity, how should reviewers consider the context of actual versus hypothetical trials for which the participant's consent is being sought? Here, we explore these "meta-consent" issues by describing the dimensions of the issue and potential solutions, centering around the concept of "active assent" (requiring expressed understanding of the purpose of the study and its voluntary nature, as well as expression of a choice to participate).

Biomedical Research↗
PubMed2005

Magnitude of impairment in decisional capacity in people with schizophrenia compared to normal subjects: an overview.

The capacity of individuals with schizophrenia to make decisions related to research participation or clinical treatment has received increasing empirical attention. A number of studies have compared patients with schizophrenia to nonpsychiatric comparison subjects (NPCs) on structured measures of decision-making capacity. In this review, we evaluated the magnitude of the difference between schizophrenia and NPC groups reported across these studies, as well as the influence of sample characteristics on observed effect sizes. We also computed the effect sizes of group differences in psychopathology and cognitive deficits. Twelve studies met the search criteria; a majority of them reported data using the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR) or for Treatment (MacCAT-T). The mean effect size (evaluated in terms of Cohen's d) for group differences on the Understanding subscale of the MacCAT instruments was 0.88 (SD = 0.40); it was twice as high among inpatient samples as among outpatients. Similar differences were observed in terms of Appreciation and Reasoning subscales, but the effect sizes for Expression of Choice were small (mean d = 0.29, SD = 0.24). Notably, these observed effect sizes were generally smaller than those for differences between schizophrenia and NPC groups in psychopathology (mean d = 2.06, SD = 1.03) and cognition (mean d = 1.01, SD = 0.61). The published studies demonstrate a substantial heterogeneity in decision-making capacity among people with schizophrenia, as well as among NPCs, suggesting that the presence of schizophrenia does not necessarily mean the patient has impairment in capacity.

Adolescent↗
PubMed2005

Relationship of individual cognitive abilities to specific components of decisional capacity among middle-aged and older patients with schizophrenia.

Prior empirical studies suggest that cognitive impairment is the strongest predictor of capacity to consent to research among persons with schizophrenia. Yet, despite the frequency and importance of cognitive deficits and impaired decisional capacity in schizophrenia, the scope of neuropsychological testing in most published reports in this area has been relatively narrow. In the present study of 70 people with schizophrenia aged 40 to 70 years we evaluated decisional capacity with the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR). Participants were also evaluated with standardized rating scales of psychopathology and level of insight and with a comprehensive neuropsychological test battery that permitted evaluation of 7 specific cognitive abilities. Results showed that the strongest correlates of capacity (particularly, understanding and appreciation of disclosed information) were cognitive test scores, but there was little evidence of differential relationships between individual cognitive abilities and specific dimensions of capacity. Understanding was also correlated with severity of negative symptoms and of general psychopathology, but not with age, education, severity of positive or depressive symptoms, or level of insight. Understanding improved over successive presentations of consent-relevant information. The results suggest that age and diagnosis should not be viewed as determinants of decisional capacity; investigators should be alert to the presence of cognitive deficits, as well as negative symptoms. Also, an interactive dialogue between patient and investigator with repeated presentation of information is likely to aid understanding of disclosed information among patients with schizophrenia.

Adult↗
PubMed2005

Understanding of placebo controls among older people with schizophrenia.

Research protocols frequently necessitate procedures or design elements that differ from those used in routine clinical care. An example is the inclusion of a placebo arm in many randomized clinical trials. Because there are risks to taking a placebo when one has a chronic disorder such as schizophrenia, ascertaining how well people with severe mental illness understand placebos is an important task for empirical research ethics. We investigated whether schizophrenia patients' understanding of placebo controls could be improved with a brief educational intervention. We randomized 49 middle-aged and older patients with schizophrenia or schizoaffective disorder to receive either (1) a routine explanation of placebos in the context of consent for a hypothetical double-blind placebo-controlled clinical trial, or (2) the consent for the hypothetical trial plus a brief educational module explaining placebos in more depth. Understanding of placebos was assessed with a 12-item questionnaire, and we examined demographic, clinical, neurocognitive, and decision-making correlates of understanding of placebos. Those participants who received the intervention obtained higher scores on the placebo post-test compared to those who received the standard information alone. Performance on the placebo post-test was positively correlated with measures of decisional capacity and neurocognitive abilities and negatively correlated with severity of negative symptoms, but it showed no relationship with positive or general symptoms. Some participants interpreted the common phrase "sugar pill" as relating somehow to diabetes. We conclude that the level of understanding of important research design-related information is not static but may be influenced by how investigators approach the consent process.

Aged↗