Is filtering difficulty the basis of attentional deficits in schizophrenia?

The distractibility that schizophrenia patients display may be the result of a deficiency in filtering out irrelevant information. The aim of the current study was to assess whether patients with schizophrenia exhibit greater difficulty when task-irrelevant features change compared to healthy participants. Thirteen medicated outpatients with a diagnosis of schizophrenia and thirteen age- and parental education-matched controls performed a target selection task in which the task-relevant letter or the task-irrelevant features of color, and/or location repeated or switched. Participants were required to respond by pressing the appropriate key associated with the target letter. These patients with schizophrenia were slower when the task-relevant target letter switched than when it repeated. In contrast, schizophrenia patients performed similarly to controls when task-irrelevant information changed. Thus, we found no evidence that patients with schizophrenia were impaired in inhibiting irrelevant perceptual features. In contrast, changes in task-relevant features were problematic for patients relative to control participants. These results suggest that medicated outpatients who are mild to moderately symptomatic do not exhibit global impairments of feature processing. Instead, impairments are restricted to situations when task-relevant features vary. The current findings also suggest that when a course of action is not implied by an irrelevant feature, outpatients' behavior is not modulated by extraneous visual information any more than in healthy controls.     

Suicide in people with epilepsy: How great is the risk?

Purpose:   Suicide is more common in populations with epilepsy, but estimates vary concerning the magnitude of the risk. We aimed to estimate the risk using meta-analysis.
Methods:   A literature search identified 74 articles (76 cohorts of people with epilepsy) in whom the number of deaths by suicide in people with epilepsy and the number of person–years at risk could be estimated. Standardized mortality ratios (SMRs) with 95% confidence intervals (CIs) were calculated for each cohort, for groups of cohorts, and for the total population.
Results:   The overall SMR was 3.3 (95% CI 2.8–3.7) based on 190 observed deaths by suicide compared with 58.4 expected. The SMR was significantly increased in people with incident or newly diagnosed epilepsy in the community (SMR 2.1), in populations with mixed prevalence and incidence cases (SMR 3.6), in those with prevalent epilepsy (SMR 4.8), in people in institutions (SMR 4.6), in people seen in tertiary care clinics (SMR 2.28), in people with temporal lobe epilepsy (SMR 6.6), in those following temporal lobe excision (SMR 13.9), and following other forms of epilepsy surgery (SMR 6.4). The SMR was significantly low overall in two community-based studies of people with epilepsy and developmental disability.
Discussion:   We confirm that the risk of suicide is increased in most populations of people with epilepsy. Psychiatric comorbidity has been demonstrated to be a risk factor for suicide in the general population and in people with epilepsy, and such comorbidity should thus be identified and treated.     

Do people with a first episode of psychosis differ in personality profiles?

Studies on personality profiles in psychosis typically report certain personality traits as linked to the disorder. OBJECTIVES: To determine if individuals with a first episode of psychosis: 1) differ from a non-clinical group on the five factor model of personality; 2) all present with similar personality profiles; 3) hold stable personality traits over time. METHOD: 79 individuals with a first episode of psychosis were recruited. RESULTS: The first episodes significantly differed from the control group on all five personality dimensions. Results also revealed three personality profiles, one linked to psychotic symptoms. Moreover, personality traits of the first episodes showed stability over time.     

Predictors of onset of psychosis in patients with Parkinson's disease: Who gets it early?

IntroductionPsychosis is one of the common non-motor symptoms of PD, which substantially worsens the quality of life. Hence, it is important to identify factors that are associated with early onset of psychosis in PD. In order to identify those factors, the current study aims to compare various demographic and clinical features of PD patients with early and late onset psychosis.MethodologyIn this prospective case-control study, 51 consecutive patients with PD having psychosis (PDP) were recruited. Median of the latency of onset of psychotic symptoms from the onset of motor symptoms was calculated (5.5 years) and after doing a median split, the cohort of PDP was divided into early onset PDP (EOP, n = 25) and late onset PDP (LOP, n = 26). Both the groups were compared for several demographic and clinical characteristics.ResultsCompared to those with LOP, patients with EOP had poor scores on frontal assessment battery (13.8 ± 2.0 vs 15.3 ± 1.8, p = 0.007), more frequently had Rapid Eye movement sleep Behavior Disorder (RBD) (80% vs 46.2%, p = 0.02), Postural Instability with Gait Difficulty (PIGD) phenotype (72% vs 26.9%, p = 0.002), and excessive daytime sleepiness (Epworth Sleepiness Scale: 8.04 ± 3.7 vs 3.9 ± 3.1). Patients with LOP were older (63.4 ± 7.0 years vs 56.5 ± 8.1 years, p = 0.002) and had higher Levodopa equivalent dose/day (LEDD: 819.1 ± 365.8 vs 608.5 ± 356.3, p = 0.04) compared to those with EOP.ConclusionPresence of RBD, excessive daytime sleepiness, frontal lobe dysfunction, and PIGD phenotype of PD may be associated with early onset of psychosis in PD. Higher LEDD may not trigger early occurrence of psychosis in PD.     

Cognitive improvement after treatment with second-generation antipsychotic medications in first-episode schizophrenia: is it a practice effect?

CONTEXT: Cognitive impairment in schizophrenia is frequent, involves multiple domains, and is enduring. Numerous recent clinical trials have suggested that second-generation antipsychotic medications significantly enhance cognition in schizophrenia. However, none of these studies included healthy controls undergoing repeated testing to assess the possibility that improvements might reflect simple practice effects. OBJECTIVE: To report the results on cognition of a randomized comparison of 2 widely prescribed second-generation antipsychotic medications, olanzapine and risperidone, in patients with first-episode schizophrenia and a healthy control group. DESIGN: Randomized clinical trial. SETTING: Hospital-based research units. Patients A total of 104 participants with first-episode schizophrenia and 84 healthy controls. MAIN OUTCOME MEASURES: Cognitive assessment of all study participants occurred at baseline, 6 weeks later, and 16 weeks later. Neurocognitive tests included measures of working memory and attention, speed, motor function, episodic memory, and executive function. RESULTS: No differential drug effects were observed. Of 16 cognitive measures, 9 demonstrated improvement over time and only 2 demonstrated greater rates of change than those observed in the healthy control group undergoing repeated assessment. The composite effect size for cognitive change was 0.33 in the healthy control group (attributed to practice) and 0.36 in the patients with first-episode schizophrenia. Improvements in cognition in the first-episode schizophrenia group could not be accounted for by medication dose, demographic variables, or intellectual level. CONCLUSIONS: The cognitive improvements observed in the trial were consistent in magnitude with practice effects observed in healthy controls, suggesting that some of the improvements in cognition in the first-episode schizophrenia group may have been due to practice effects (ie, exposure, familiarity, and/or procedural learning). Our results also indicated that differential medication effects on cognition were small. We believe that these findings have important implications for drug discovery and the design of registration trials that attempt to demonstrate cognitive enhancement.     

Does assessment make a difference for people with dementia? The effectiveness of the Aged Care Assessment Teams in Australia

The needs of individuals with dementia and other psychiatric problems of old age have received increased attention in Australia over the last decade. This paper reports on the role of Aged Care Assessment Teams (ACATs) in managing these clients, and the extent to which they are differentiated from other clients in the assessment process and outcomes recommended. Data on some 26,500 clients seen by ACATs in Victoria in the second half of 1999 are analysed to show (1) the relationship between a diagnosis of dementia and reporting of disability in orientation, (2) characteristics of clients with and without a diagnosis of dementia and (3) outcomes for groups of clients defined on the basis of a diagnosis of dementia and disability in orientation.     

Time course of EEG slow-wave activity in pre-school children with sleep disordered breathing: A possible mechanism for daytime deficits?

BackgroundDaytime deficits in children with sleep disordered breathing (SDB) are theorized to result from hypoxic insult to the developing brain or fragmented sleep. Yet, these do not explain why deficits occur in primary snorers (PS). The time course of slow wave EEG activity (SWA), a proxy of homeostatic regulation and cortical maturation, may provide insight.MethodsClinical and control subjects (N = 175: mean age 4.3 ± 0.9 y: 61% male) participated in overnight polysomnography (PSG). Standard sleep scoring and power spectral analyses were conducted on EEG (C4/A1; 0.5–<3.9 Hz). Univariate ANOVA’s evaluated group differences in sleep stages and respiratory parameters. Repeated-measures ANCOVA evaluated group differences in the time course of SWA.ResultsFour groups were classified: controls (OAHI ? 1 event/h; no clinical history); PS (OAHI ? 1 event/h; clinical history); mild OSA (OAHI=1–5 events/h); and moderate to severe OSA (MS OSA: OAHI > 5 events/h). Group differences were found in the percentage of time spent in NREM Stages 1 and 4 (p < 0.001) and in the time course of SWA. PS and Mild OSA children had higher SWA in the first NREM period than controls (p < 0.05). All SDB groups had higher SWA in the fourth NREM period (p < 0.01).ConclusionsThese results suggest enhanced sleep pressure but impaired restorative sleep function in pre-school children with SDB, providing new insights into the possible mechanism for daytime deficits observed in all severities of SDB.     

Event-based prospective memory deficits in individuals with high depressive symptomatology: Problems controlling attentional resources?

Depression has been found to be related to neurocognitive deficits in areas important to successful prospective memory (PM) performance, including executive function, attention, and retrospective memory. However, research specific to depression and PM has produced a mixed pattern of results. The current study further examined the task conditions in which event-based PM deficits may emerge in individuals with high depressive symptomatology (HDS) relative to individuals with low depressive symptomatology (LDS) and the capacity of HDS individuals to allocate attentional resources to event-based PM tasks. Sixty-four participants (32 HDS, 32 LDS) were required to make a PM response when target words were presented during an ongoing lexical decision task. When the importance of the ongoing task was emphasized, response time costs to the ongoing task, and PM accuracy, did not differ between the HDS and LDS groups. This finding is consistent with previous research demonstrating that event-based PM task accuracy is not always impaired by depression, even when the PM task is resource demanding. When the importance of the PM task was emphasized, costs to the ongoing task further increased for both groups, indicating an increased allocation of attentional resources to the PM task. Crucially, while a corresponding improvement in PM accuracy was observed in the LDS group when the importance of the PM task was emphasized, this was not true for the HDS group. The lack of improved PM accuracy in the HDS group compared with the LDS group despite evidence of increased cognitive resources allocated to PM tasks may have been due to inefficiency in the application of the allocated attention, a dimension likely related to executive function difficulties in depression. Qualitatively different resource allocation patterns may underlie PM monitoring in HDS versus LDS individuals.