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To derive scores for mental disorganization and impoverishment from commonly used rating scales, and test the hypothesis that disorganization and impoverishment, along with impaired cognition and role-function reflect a latent variable that is a plausible candidate for the putative core deficit.
For more than 100 years, disorganization and impoverishment of mental activity have been recognised as fundamental symptoms of schizophrenia. These symptoms may reflect a core brain process underlying persisting disability. Delusions and hallucinations have been regarded as accessory features. The psychopathological processes predisposing to persisting disability in schizophrenia are poorly understood. The delineation of a core deficit underlying persisting disability would be potentially of great value in predicting outcome and developing improved treatment.
Patients aged 18–55 years were included if: they satisfied DSM IV criteria for schizophrenia or schizoaffective disorder. Healthy controls were recruited by public advertisement and selected to match the patient group in age and sex. Study sample included 39 participants with schizophrenia, 1 with schizoaffective disorder and 44 matched healthy controls. We derived disorganization and impoverishment scores from three symptom scales: PANSS, SSPI and CASH. We computed composite scores for disorganization and for impoverishment and employed Confirmatory Factor Analysis to test the hypothesis that a single factor accounts for the relationships between disorganization, impoverishment, cognitive impairment and impaired role function. We assessed the relationship between this latent “core deficit” and diminished Post Movement Beta Rebound (PMBR), an electrophysiological measure from Magnetoencephalography (MEG), associated with persisting brain disorders.
Fit indices for the single factor model from CFA indicated a good fit: χ2(2) = 1.817, p = .403; RMSEA <.001 GFI = .979. PMBR was significantly reduced in the schizophrenia group compared to healthy controls, t (68) = 3.55, p < .001. Within the patient group, PMBR was significantly and negatively correlated with the CFA factor scores representing the Core Deficit score, r=−.543, p < .01, indicating that high core deficit scores were associated with reduced PMBR. PMBR was significantly correlated with the composite Disorganization score, r=−.521, p < .001.
Our findings demonstrate that the shared variance between impoverishment (psychomotor poverty); disorganization; cognitive impairment; and impaired role function can be accounted for by a latent variable that can reasonably be described as the core deficit of classical schizophrenia. The demonstration that the severity of the putative core deficit is correlated with the reduction in PMBR provides evidence that the core deficit is associated with an identifiable abnormality of brain dysfunction.
To identify the BOLD (blood oxygenation level dependent) correlates of bursts of beta frequency band electrophysiological activity, and to compare BOLD responses between healthy controls and patients with psychotic illness.
The post movement beta rebound (PMBR) is a transient increase in power in the beta frequency band (13-30 Hz), recorded with methods such as electroencephalography (EEG), following the completion of a movement. PMBR size is reduced in patients with schizophrenia and inversely correlated with severity of illness. PMBR size is inversely correlated with measures of schizotypy in non-clinical groups. Therefore, beta-band activity may reflect a fundamental neural process whose disruption plays an important role in the pathophysiology of schizophrenia. Recent work has found that changes in beta power reflect changes in the probability-of-occurrence of transient bursts of beta-frequency activity. Understanding the generators of beta bursts could help unravel the pathophysiology of psychotic illness and thus identify novel treatment targets.
EEG data were recorded simultaneously with BOLD data measured with 3T functional magnetic resonance imaging (fMRI), whilst participants performed an n-back working memory task. We included seventy-eight participants – 32 patients with schizophrenia, 16 with bipolar disorder and 30 healthy controls. Beta bursts were identified in the EEG data using a thresholding method and burst timings were used as markers in an event-related fMRI design convolved with a conventional haemodynamic response function. A region of interest analysis compared beta-event-related BOLD activity between patients and controls.
Beta bursts phasically activated brain regions implicated in coding task-relevant content (specifically, regions involved in the phonological representation of letter stimuli, as well as areas representing motor responses). Further, bursts were associated with suppression of tonically-active regions. In the EEG, PMBR was greater in controls than patients, and, in patients, PMBR size was positively correlated with Global Assessment of Functioning scores, and negatively correlated with persisting symptoms of disorganisation and performance on a digit symbol substition test. Despite this, patients showed greater, more extensive, burst-related BOLD activation than controls.
Our findings are consistent with a recent model in which beta bursts serve to reactivate latently-maintained, task-relevant, sensorimotor information. The increased BOLD response associated with bursts in patients, despite reduced PMBR, could reflect inefficiency of burst-mediated cortical synchrony, or it may suggest that the sensorimotor information reactivated by beta bursts is less precisely specified in psychosis. We propose that dysfunction of the mechanisms by which beta bursts reactivate task-relevant content can manifest as disorganisation and working memory deficits, and may contribute to persisting symptoms and impairment in psychosis.
The Tailored Activity Program (TAP) is an evidence-based occupational therapist-led intervention for people living with dementia and their care partners at home, developed in the USA. This study sought to understand its acceptability to people living with dementia, their care partners, and health professionals, and factors that might influence willingness to participate prior to its implementation in Australia.
This study used qualitative descriptive methods. Semi-structured interviews were conducted with people living with dementia in the community (n = 4), their care partners (n = 13), and health professionals (n = 12). People living with dementia were asked about health professionals coming to their home to help them engage in activities they enjoy, whereas care partners’ and health professionals’ perspectives of TAP were sought, after it was described to them. Interviews were conducted face-to-face or via telephone. All interviews were recorded and transcribed. Framework analysis was used to identify key themes.
Analysis identified four key themes labelled: (i) TAP sounds like a good idea; (ii) the importance of enjoyable activities; (iii) benefits for care partners; and (iv) weighing things up. Findings suggest the broad, conditional acceptability of TAP from care partners and health professionals, who also recognised challenges to its use. People living with dementia expressed willingness to receive help to continue engaging in enjoyable activities, if offered.
While TAP appeared generally acceptable, a number of barriers were identified that must be considered prior to, and during its implementation. This study may inform implementation of non-pharmacological interventions more broadly.
Driving and stopping driving present challenging issues for older people living with memory problems and the family members supporting them. Changes to driving status impact the individual stopping driving and their family members. CarFreeMe is an existing, effective driving cessation program for older people that may be applicable to older people living with dementia. The purpose of this study was to adapt the program and explore feasibility and key stakeholder perspectives.
The Medical Research Council guidelines for conducting research into complex interventions guided the development, acceptability and feasibility piloting. A multidisciplinary approach was taken, and key stakeholders were involved throughout the process. This included an adaptation process, followed by expert reference group feedback and case series pilot study.
The background research indicated that some key changes were required to meet the needs of people living with dementia. Aspects of the content, language, format and activities were adapted and an additional module was created for family members – whose involvement was identified as important. A more personalized, flexible approach was recommended. The expert reference group [psychologists (n = 2), occupational therapists (n = 3) and dementia behavior consultants (n = 2)] indicated the program was appropriate and needed, and made recommendations for feasibility. Pilot testing with three families indicated acceptability.
A driving cessation program adapted for use with people living with dementia and their families required some changes to meet the needs and situations based on feedback from key stakeholders. Future studies will evaluate implementation outcomes across a range of settings.
We investigated whether adults with attention-deficit/hyperactivity disorder (ADHD) show pseudoneglect—preferential allocation of attention to the left visual field (LVF) and a resulting slowing of mean reaction times (MRTs) in the right visual field (RVF), characteristic of neurotypical (NT) individuals —and whether lateralization of attention is modulated by presentation speed and incentives.
Fast Task, a four-choice reaction-time task where stimuli were presented in LVF or RVF, was used to investigate differences in MRT and reaction time variability (RTV) in adults with ADHD (n = 43) and NT adults (n = 46) between a slow/no-incentive and fast/incentive condition. In the lateralization analyses, pseudoneglect was assessed based on MRT, which was calculated separately for the LVF and RVF for each condition and each study participant.
Adults with ADHD had overall slower MRT and increased RTV relative to NT. MRT and RTV improved under the fast/incentive condition. Both groups showed RVF-slowing with no between-group or between-conditions differences in RVF-slowing.
Adults with ADHD exhibited pseudoneglect, a NT pattern of lateralization of attention, which was not attenuated by presentation speed and incentives.
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