The Effects of Source Credibility in the Presence or Absence of Prior Attitudes: Implications for the Design of Persuasive Communication Campaigns.

Most theories of persuasion predict that limited ability and motivation to think about communications should increase the impact of source credibility on persuasion. Furthermore, this effect is assumed to occur, regardless of whether or not the recipients have prior attitudes. In this study, the effects of source credibility, ability, and motivation (knowledge, message repetition, relevance) on persuasion were examined meta-analytically across both attitude formation and change conditions. Findings revealed that the Source Credibility × Ability/Motivation interaction emerged only when participants lacked prior attitudes and were unable to form a new attitude based on the message content. In such settings, the effects of source credibility decayed rapidly. The implications of these findings for applied communication campaigns are discussed.

A longitudinal study of awareness of deficit after moderate to severe traumatic brain injury.

Lack of awareness of deficits is a common problem after traumatic brain injury (TBI), and is associated with worse functional outcome and poor compliance with rehabilitation. Little is known, however, about the course of awareness of deficits after TBI. Using a longitudinal design, we examined changes in self-awareness between the subacute stage (about 45 days after injury) and one-year follow-up in a sample of 123 individuals with moderate to severe TBI. Awareness of deficits was operationalised as the discrepancy between patient and family ratings on the Awareness Questionnaire (AQ) and Patient Competency Rating Scale (PCRS). Compared to baseline, awareness was improved at one year, as evidenced by smaller discrepancy scores and stronger correlations between participant and family ratings. Changes in awareness were most pronounced for the behavioural/affective domain and least pronounced for the motor/sensory domain, which showed best agreement at baseline. Even at one year, participants rated themselves as higher functioning than did their relatives. Awareness at baseline and, for the AQ, time to follow commands, significantly predicted awareness at one year. These results suggest that awareness of deficits improves between the subacute and post-acute stages after TBI, and highlight the need for effective interventions for persons with impaired awareness and for flexible timing of rehabilitation efforts.

Effects of methylphenidate on working memory in traumatic brain injury: a preliminary FMRI investigation.

As part of a preliminary investigation on the effects of methylphenidate on brain activation during a working memory (WM) task in patients with traumatic brain injury (TBI), patients with TBI received 15 mg of methylphenidate (N = 4) or placebo (N = 5) twice a day for one month in a double-blind, placebo-controlled design. Brain activation was assessed at pre-treatment and on the final treatment day using functional magnetic resonance imaging (fMRI) with an N-back task using faces as stimuli. In a whole brain voxel-wise analysis, methylphenidate, compared to placebo, produced a decrease in brain activation for the 2-load minus 0-load contrast in the anterior cingulate, thalamus, cuneus and cerebellum, regions associated with WM performance. Further, an a priori region of interest analysis with small volume correction found reduced activation in the anterior cingulate. Although based on a small sample size, these preliminary findings suggest methylphenidate may increase processing efficiency associated with cognitive control during WM tasks in patients with TBI.

Anxiety in dementia: a critical review.

Until recently, little attention has been paid to anxiety symptoms in dementia. However, anxiety is common in this population, and associated with poor outcome and quality of life. The current review examines the existing literature around three major themes: the definition of anxiety in dementia, the properties of available instruments for assessment, and the clinical characteristics of anxiety in this population. Defining anxiety in individuals with dementia is complicated by the overlap between symptoms of anxiety, depression and dementia, and by the influence of the source of information. Several instruments are available to assess anxiety in this population, including general neuropsychiatric instruments and two scales designed specifically for this purpose. The reliability of these instruments is acceptable, but their validity has not been sufficiently examined, and they may discriminate poorly between anxiety and depression. Anxiety may be higher in vascular dementia than in Alzheimer's Disease, and it decreases in the severe stages of dementia. It is associated with poor quality of life and behavioral disturbances, even after controlling for depression. Little is known, however, about its social and environmental correlates. Limitations of the existing literature and key directions for future research are discussed.

Factor structure and diagnostic efficiency of the BDI-II in treatment-seeking substance users.

Screening instruments are needed to rapidly and efficiently identify depression in drug and alcohol users. The Beck Depression Inventory-Second Edition (BDI-II) has excellent validity in psychiatric, normative and primary care samples, but its diagnostic efficiency has not been examined in substance users. Using a large sample of treatment-seeking substance users and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) to establish diagnosis, we examined the factor structure of the BDI-II and its ability to detect clinical depression, defined as the presence of a Major Depressive Disorder (MDD) or substance-induced depression. A three-factor structure provided the best fit, and the diagnostic efficiency of the BDI-II was moderate, and independent of gender and substance of abuse. Subscores had lower diagnostic efficiency than the BDI-II total score. A range of possible cutoff scores with corresponding sensitivity, specificity, positive predictive power and negative predictive power is provided to aid clinicians and researchers in choosing the optimal parameters for their screening needs.

Impact of acceptance and commitment therapy versus education on stigma toward people with psychological disorders.

Acceptance and commitment therapy (ACT) has previously been shown to alter stigmatizing attitudes and to be relatively useful for psychologically inflexible participants. The present study is the first to bring those two findings together by comparing ACT to an education intervention for reducing stigma toward people with psychological disorders, and examining whether results differ for psychologically inflexible versus flexible individuals. A sample of college students (N =95) was randomly assigned to a 2(1)2h ACT or educational workshop. Measures were taken before and after the workshop and at a 1-month follow-up. ACT reduced mental health stigma significantly regardless of participants' pre-treatment levels of psychological flexibility, but education reduced stigma only among participants who were relatively flexible and non-avoidant to begin with. Acceptance could be an important avenue of exploration for stigma researchers.

Abnormal affective startle modulation in individuals with psychogenic [corrected] movement disorder.

Despite recent advances, psychogenic movement disorder (PMD) remains a poorly understood phenomenon. Emotional functioning and responsiveness to stress are believed to play a role in the development of psychogenic symptoms, but empirical studies examining emotional responsiveness in PMD and other conversion disorders are lacking. We investigated modulation of the startle eyeblink reflex by affective pictures in 12 patients with PMD and 12 age- and education-matched control participants. Participants viewed positive, neutral, and negative pictures, while eyeblink responses to white noise bursts were recorded. Control participants showed the expected pattern of startle modulation, with significant potentiation by negative pictures and slight (nonsignificant) inhibition by positive pictures. In the PMD group, however, both positive and negative pictures yielded significantly greater startle responses than neutral pictures. Depression and anxiety symptomatology did not correlate with startle modulation, and the two groups did not differ in self-reported emotional reactions to the pictures. Our findings suggest that individuals with PMD show aversive physiological reactions to positive as well as negative stimuli. Abnormal affective startle modulation may be used to help distinguish between malingering and PMD. Future studies using larger samples are needed to better understand the role of emotions in conversion disorder.

Cognitive control in closed head injury: context maintenance dysfunction or prepotent response inhibition deficit?

The authors contrasted 2 potential explanations for the cognitive control deficits observed in closed head injury (CHI): a prepotent response inhibition deficit or a deficit in context maintenance, defined as the guidance of appropriate responding by task-relevant information. Healthy and CHI participants performed the traditional card Stroop task and a single-trial Stroop task sensitive to context maintenance deficits. As predicted by a context maintenance deficit, moderate to severe CHI participants showed higher error rates in the single-trial Stroop task only, and only when task instructions had to be maintained over a long delay. Moreover, context maintenance impairment and generalized slowing were both related to reports of daily functioning in CHI participants. Thus, context maintenance could be a useful framework for characterizing cognitive control deficits in CHI.

Parametric manipulation of working memory load in traumatic brain injury: behavioral and neural correlates.

Traumatic brain injury (TBI) is often associated with enduring impairments in high-level cognitive functioning, including working memory (WM). We examined WM function in predominantly chronic patients with mild, moderate and severe TBI and healthy comparison subjects behaviorally and, in a small subset of moderate-to-severe TBI patients, with event-related functional magnetic resonance imaging (fMRI), using a visual n-back task that parametrically varied WM load. TBI patients showed severity-dependent and load-related WM deficits in performance accuracy, but not reaction time. Performance of mild TBI patients did not differ from controls; patients with moderate and severe TBI were impaired, relative to controls and mild TBI patients, but only at higher WM-load levels. fMRI results show that TBI patients exhibit altered patterns of activation in a number of WM-related brain regions, including the dorsolateral prefrontal cortex and Broca's area. Examination of the pattern of behavioral responding and the temporal course of activations suggests that WM deficits in moderate-to-severe TBI are due to associative or strategic aspects of WM, and not impairments in active maintenance of stimulus representations. Overall, results demonstrate that individuals with moderate-to-severe TBI exhibit WM deficits that are associated with dysfunction within a distributed network of brain regions that support verbally mediated WM.