Biomedical subjects

Elizabeth W Twamley

Publications and source records attributed to Elizabeth W Twamley.

13 recordsLinked to original sources

PubMed2006

Deficits in cue detection and intention retrieval underlie prospective memory impairment in schizophrenia.

Emerging evidence indicates that individuals with schizophrenia (SCZ) may exhibit deficits in prospective memory (ProM), a dissociable and ecologically important aspect of episodic memory entailing the formation, maintenance, and execution of future intentions. The present study aimed to elucidate the component processes of ProM impairment in 41 individuals with SCZ relative to 41 demographically similar healthy comparison (HC) participants. Results revealed that the SCZ group performed worse than HCs on overall ProM, with comparable deficits on time- and event-based ProM trials. In the SCZ cohort, better ProM performance was associated with younger age and less severe negative symptoms. Although a significantly greater number of Task Substitution and Loss of Time errors were evident in the SCZ group as compared to HCs, the most prevalent error type in SCZ was characterized by a complete failure to respond to the ProM cue. Importantly, the SCZ and HC groups did not differ on a post-test multiple-choice recognition trial, suggesting adequate formation and maintenance (i.e., retention) of the ProM cue-intention pairing when self-directed monitoring and retrieval demands were minimized. Findings indicate that SCZ is associated with impairment in the cue detection and self-initiated retrieval components of executing future intentions, which is consistent with a possible prefrontostriatal loop neuropathogenesis. Further studies are needed to explore the neurobiological mechanisms of SCZ-associated ProM impairment and the impact of such deficits on daily functioning (e.g., medication compliance).

Adult↗

PubMed2006

Self-assessment of functional status in schizophrenia.

With new treatments targeting features of schizophrenia associated with functional disability, there is a need to evaluate the validity of ratings of everyday outcomes. It is unknown whether patients can validly self-report on aspects of their functional status, which would be a potentially economical method for obtaining outcome data. In this study, 67 older schizophrenia outpatients provided self-ratings of everyday real-world functioning using the specific levels of functioning scale (SLOF). They were also administered assessments of neuropsychological performance, performance-based measures of functional capacity and social skills, clinical symptoms, and quality of life. Case managers, unaware of other ratings, also generated SLOF ratings. Based on discrepancy scores, participants were categorized as accurate raters (n=24), underestimators (n=16), or overestimators (n=27) of their functional status as compared to case managers' ratings. Patients' self-rated functional status was correlated with their subjective quality of life, but remarkably unassociated with case manager ratings of functional status or their own performance on functional capacity or social skills measures. Case manager ratings, however, were highly correlated with performance on functional capacity and social skills measures. Patients who underestimated their real world performance had better cognitive skills and greater self-rated depression than those who overestimated. Accurate raters demonstrated greater social skills than both overestimators and underestimators, while overestimators were most cognitively and functionally impaired. Accurate ratings of everyday outcomes in schizophrenia may require systematic observation of real world outcomes or performance-based measures, as self-reports were inconsistent with objective information.

Aged↗

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

Neuropsychological and neuroimaging changes in preclinical Alzheimer's disease.

Alzheimer's disease (AD) is a common, devastating form of dementia. With the advent of promising symptomatic treatment, the importance of recognizing AD at its very earliest stages has increased. We review the extant neuropsychological and neuroimaging literature on preclinical AD, focusing on longitudinal studies of initially nondemented individuals and cross-sectional investigations comparing at-risk with normal individuals. We systematically reviewed 91 studies of neuropsychological functioning, structural neuroimaging, or functional neuroimaging in preclinical AD. The neuropsychological studies indicated that preclinical AD might be characterized by subtle deficits in a broad range of neuropsychological domains, particularly in attention, learning and memory, executive functioning, processing speed, and language. Recent findings from neuroimaging research suggest that volume loss and cerebral blood flow or metabolic changes, particularly in the temporal lobe, may be detected before the onset of dementia. There exist several markers of a preclinical period of AD, in which specific cognitive and biochemical changes precede the clinical manifestations. The preclinical indicators of AD reflect early compromise of generalized brain integrity and temporal lobe functioning in particular.

Alzheimer Disease↗

PubMed2006

Work-related abilities in schizophrenia and HIV infection.

Schizophrenia and human immunodeficiency virus (HIV) infection both are associated with high rates of neurocognitive impairment. These impairments predict unemployment in both disorders, independent of other disease-related factors that may affect employment. In this study, we investigated work-related abilities and previous employment patterns in 27 unemployed patients with schizophrenia, 27 demographically matched unemployed HIV-infected participants, and 27 nonmatched employed HIV seropositive (HIV+) participants. All subjects were administered a computerized and hands-on assessment of vocational abilities and a comprehensive work history interview. Compared with the employed HIV+ group, the two unemployed groups had lower estimates of maximal lifetime job functioning. In terms of current vocational abilities, the employed HIV+ subjects generally performed best, followed by the unemployed HIV+ subjects and the patients with schizophrenia. Although the unemployed schizophrenia subjects had the most decline in vocational abilities (from estimated lifetime maximum level), the patterns of decline were similar in the two unemployed groups and were suggestive of parallel impairments in frontal-subcortical functioning.

Adult↗

PubMed2005

Work rehabilitation for middle-aged and older people with schizophrenia: a comparison of three approaches.

We examined employment outcomes among middle-aged and older clients with schizophrenia in three work rehabilitation programs that varied in their emphasis on conventional vocational rehabilitation (train-then-place) versus supported employment principles (place-then-train). We analyzed retrospective data from 36 veterans receiving VA Wellness and Vocational Enrichment Clinic (WAVE) services and prospective data from a randomized controlled trial of 30 subjects receiving Department of Rehabilitation/Employment Services (DOR) or Individual Placement and Support (IPS). Across interventions, half the subjects obtained volunteer or paid work. IPS participants, those with schizophrenia (versus schizoaffective disorder), and those with more education were more likely to work or volunteer. Rates of volunteer or paid work were 81% in IPS, 44% in WAVE, and 29% in DOR. Rates of competitive/paid work only were highest in IPS (69%), followed by DOR (29%) and WAVE (17%). Middle-aged and older people with schizophrenia-spectrum disorders benefit most from a supported employment approach.

Adult↗

PubMed2004

Neuropsychological function in college students with and without posttraumatic stress disorder.

Previous research on the neuropsychology of posttraumatic stress disorder (PTSD) has identified several neurocognitive deficits that co-occur with the disorder. However, it remains unclear whether these deficits are due to trauma exposure, PTSD symptomatology or psychiatric/substance abuse comorbidity. We examined trauma exposure, PTSD symptoms and neuropsychological performance in 235 undergraduate students, i.e. a non-clinical sample. The sample comprised 146 subjects with trauma exposure (38 with current PTSD and 108 without lifetime PTSD) and 89 no-trauma comparison (NC) subjects who were administered tests of attention, working memory, psychomotor speed, word generation and executive functioning. Relationships of neuropsychological functioning to measures of psychiatric symptoms and substance abuse were examined. Current PTSD (PTSD+), trauma-exposed without PTSD (PTSD-) and NC subjects did not differ significantly on the vast majority of neuropsychological tests. There were very few significant associations between neuropsychological performance and clinical variables, and those that were statistically significant were small in magnitude. The striking lack of differences in neuropsychological performance between the three groups suggests that college students with trauma exposure, regardless of the presence of PTSD symptoms, may be cognitively resilient. Neuropsychological impairment may not be an invariant feature of PTSD, but when it is present, it may be associated with poorer functional outcomes.

Adult↗

PubMed2003

Sexual trauma and pregnancy: a conceptual framework.

In this paper, we propose that a history of sexual traumatization is associated with pregnancy complications and poor pregnancy-related outcomes. We further hypothesize that this relationship is mediated by the sequelae of trauma (psychopathology, health problems, and increased negative health behaviors). We review the literature linking sexual trauma with psychopathology, health, and health behavior and then outline the impact of these variables on pregnancy. Based on this review, we draw conclusions about the potential impact of sexual trauma on pregnancy outcomes. We suggest future directions for this area of research and discuss the clinical implications of this association, including the development of prenatal intervention and prevention programs.

Adult↗

PubMed2003

A review of cognitive training in schizophrenia.

Empirically supported treatments for schizophrenia now include a variety of psychosocial interventions, such as social skills training, vocational rehabilitation, and psychotherapy. As awareness of the functional importance of neurocognitive impairments in schizophrenia has increased, interest in treatments to improve cognition has grown. We review the literature on cognitive training (CT), which has been studied in 17 published randomized, controlled trials to date. The differential effectiveness of noncomputerized and computer-assisted interventions, with and without strategy coaching, and an environmental adaptation intervention, is examined. We conclude that the different types of approaches, whether computer assisted or not, all have effective components that hold promise for improving cognitive performance, symptoms, and everyday functioning. Our recommendations for further research, including the use of functional outcome measures and long-term followup, highlight the importance of improving ecological validity in this area of treatment research.

Activities of Daily Living↗

PubMed2003

Vocational rehabilitation in schizophrenia and other psychotic disorders: a literature review and meta-analysis of randomized controlled trials.

Although most individuals with schizophrenia are unemployed, plentiful evidence suggests that work rehabilitation is effective for this population. Yet, there have been only 11 published randomized controlled trials of work rehabilitation interventions for people with severe mental illness. We review these 11 studies, 9 of which were trials examining Individual Placement and Support (IPS) or supported employment (SE) interventions. Outcomes strongly favored the experimental groups in terms of the percentage of participants who worked at any point during the studies (weighted mean effect size = 0.66). In the 5 investigations comparing IPS/SE to conventional vocational rehabilitation services, 51% of the participants receiving IPS/SE worked competitively, versus 18% of those in the comparison groups (weighted mean effect size = 0.79). This effect size may be a useful benchmark for future trials. Further investigations should examine individual differences as predictors of response, to identify modifiable versus nonmodifiable factors that yield better outcomes.

Adult↗

PubMed2003

Are late-onset schizophrenia spectrum disorders neurodegenerative conditions? Annual rates of change on two dementia measures.

Some investigators assert that emergence of schizophrenia spectrum disorders in mid- to late life (LOSD, i.e., onset after age 45) reflects neurodegenerative processes. The authors examined 1- and 2-year changes among 37 outpatients with LOSDs on the Mini-Mental State Examination (MMSE) and Mattis Dementia Rating Scale, compared with 69 patients having earlier-onset schizophrenia spectrum disorders (EOSD), 67 having Alzheimer's disease (AD) with psychosis, 72 having AD with baseline MMSE scores >/=24, and 56 normal comparison subjects (NCs). Cognitive changes among LOSD patients were similar to those in EOSD patients and NCs, whereas the AD groups had greater declines. Results support viewing LOSDs as static encephalopathies.

Age Factors↗

PubMed2002

Neuropsychological function in female victims of intimate partner violence with and without posttraumatic stress disorder.

BACKGROUND: Various aspects of neuropsychologic function have been reported to be abnormal in patients with posttraumatic stress disorder (PTSD); however, the majority of these data come from studies of seriously ill, treatment-seeking samples with substantial substance use comorbidity. Few studies have included similarly trauma-exposed subjects without PTSD, and fewer still have focused on women. METHODS: Thirty-nine female victims of intimate partner violence (IPV; 22 without lifetime PTSD and 17 with current PTSD), and 22 nonvictimized comparison (NC) subjects were administered tests of attention, working memory, visuoconstruction, language ability, learning and memory, and executive functioning. RESULTS: The IPV and NC subjects did not demonstrate statistically significant differences on most neuropsychologic tests, with the exception of those in the realm of working memory, visuoconstruction, and executive functioning. The IPV subjects, regardless of PTSD status, had poorer performance on tasks of speeded, sustained auditory attention and working memory (Paced Auditory Serial Addition Test) and response inhibition (Stroop). The IPV subjects with PTSD performed worse than NCs on a set-shifting task (Trail Making Test, Part B). No consistent relationships were noted between neuropsychologic functioning and severity of childhood abuse or domestic violence experiences. CONCLUSIONS: Cognitive deficits in IPV subjects were confined to measures of working memory, visuoconstruction, and executive function; were subtle; and were not uniformly worse among those with current PTSD. This pattern, however, is consistent with frontal-subcortical dysfunction in traumatized women. The clinical significance of these findings deserves further study.

Adult↗

PubMed2002

Generalized cognitive impairments, ability to perform everyday tasks, and level of independence in community living situations of older patients with psychosis.

OBJECTIVE: This study examined the relationship between performance of instrumental activities of daily living, as measured with the University of California, San Diego, Performance-Based Skills Assessment (UPSA), and measures of cognitive functioning and independence in the community living situation of older outpatients with psychotic disorders. METHOD: One hundred eleven middle-aged and elderly outpatients with primary psychotic disorders were administered the UPSA, the Mattis Dementia Rating Scale, and standardized measures of psychopathology. Independence in the community living situation was rated on a scale from 1 to 5, with 5 representing the highest level of independence, such as living alone in an apartment or house. Ability in seven domains of neuropsychological functioning was assessed in 67 participants. RESULTS: Total scores on the University of California, San Diego, Performance-Based Skills Assessment were significantly correlated with total and subscale scores on the Mattis Dementia Rating Scale, level of independence in the community living situation, and scores on the neuropsychological measures in the subset of patients who underwent neuropsychological testing. Lower scores on the Mattis Dementia Rating Scale memory subscale and more severe negative symptoms were significantly associated with worse performance on the skills assessment. Performance on the skills assessment contributed uniquely to prediction of independence in the community living situation. CONCLUSIONS: Generalized cognitive abilities are associated with everyday functioning capacity in older patients with psychosis. Reduction of cognitive deficits and negative symptoms may improve patients' ability to function independently in the community.

Activities of Daily Living↗