Poor predictive value of broad-range PCR for the detection of arthroplasty infection in 92 cases

Background The diagnosis of prosthetic infection remains a challenge, as no test is 100% sensitive and 100% specific Recent advances in molecular biology have enabled the detection of infection in culture negative cases.

Patients and methods We evaluated the effectiveness of polymerase chain reaction (PCR) in detecting infection in failed joint replacements prospectively in 91 consecutive patients (92 prosthetic joints) undergoing revision total hip or knee arthroplasty. Synovial fluid was collected intraoperatively and examined by broad-range PCR assay for detection of bacterial DNA. The clinical diagnosis of infection was based on the results of blood tests, preoperative joint aspiration, culture and histology of multiple intraoperative tissue samples, as well as the surgeon's assessment.

12 joints (13%) were infected, but the PCR was positive in 32 cases. The sensitivity of the technique was 92%, the specificity 74%, the accuracy 76%, the positive predictive value 34%, and the negative predictive value was 98%.

Interpretation The PCR technique cannot be recommended for the routine detection of prosthetic infection. The large number of false positive results may represent sample contamination, or bacterial presence related to low-virulence organisms, low bacterial load, or a strong host immune response.     

Bone Regeneration Based on Tissue Engineering Conceptions — A 21st Century Perspective

The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteoconductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineering and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental “origin” require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts.     

The impact of self-efficacy,alexithymia and multiple traumas on posttraumatic stress disorder and psychiatric co-morbidity following epileptic seizures: A moderated mediation analysis

This study investigated the incidence of posttraumatic stress disorder (PTSD) and psychiatric co-morbidity following epileptic seizure, whether alexithymia mediated the relationship between self-efficacy and psychiatric outcomes, and whether the mediational effect was moderated by the severity of PTSD from other traumas. Seventy-one (M=31, F=40) people with a diagnosis of epilepsy recruited from support groups in the United Kingdom completed the Posttraumatic Stress Diagnostic Scale, the Hospital Anxiety and Depression Scale, the Toronto Alexithymia Scale-20 and the Generalized Self-Efficacy Scale. They were compared with 71 people (M=29, F=42) without epilepsy. For people with epilepsy, 51% and 22% met the diagnostic criteria for post-epileptic seizure PTSD and for PTSD following one other traumatic life event respectively. For the control group, 24% met the diagnostic criteria for PTSD following other traumatic life events. The epilepsy group reported significantly more anxiety and depression than the control. Partial least squares (PLS) analysis showed that self-efficacy was significantly correlated with alexithymia, post-epileptic seizure PTSD and psychiatric co-morbidity. Alexithymia was also significantly correlated with post-epileptic seizure PTSD and psychiatric co-morbidity. Mediation analyses confirmed that alexithymia mediated the path between self-efficacy and post-epileptic seizure PTSD and psychiatric co-morbidity. Moderated mediation also confirmed that self-efficacy and PTSD from one other trauma moderated the effect of alexithymia on outcomes. To conclude, people can develop posttraumatic stress disorder symptoms and psychiatric co-morbidity following epileptic seizure. These psychiatric outcomes are closely linked with their belief in personal competence to deal with stressful situations and regulate their own functioning, to process rather than defend against distressing emotions, and with the degree of PTSD from other traumas.     

Relationships between brain and body temperature,clinical and imaging outcomes after ischemic stroke

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using ¹H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes.     

Neurocognition in the Extended Psychosis Phenotype: Performance of a Community Sample of Adolescents With Psychotic Symptoms on the MATRICS Neurocognitive Battery

Neurocognitive dysfunction is well established in psychosis, but recent work suggests that processing speed deficits might represent a particularly important cognitive deficit. A number of significant confounds, however, such as disease chronicity and antipsychotic medication use, have been shown to affect processing speed, causing debate as to the core cognitive features of psychosis. We adopted a novel strategy of testing neurocognitive performance in the “extended psychosis phenotype,” involving community-based adolescents who are not clinically psychotic but who report psychotic symptoms and who are at increased risk of psychosis in adulthood. This allows investigation of the earliest cognitive factors associated with psychosis risk, while excluding potential confounds such as disease chronicity and antipsychotic use. A population sample of 212 school-going adolescents aged 11–13 years took part in this study. Psychotic symptoms were assessed using the psychosis section of the Schedule for Affective Disorders and Schizophrenia. Neurocognition was assessed using the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) consensus neurocognitive battery. Adolescents with psychotic symptoms performed significantly more poorly on 3 processing speed tasks: Trail Making Test-A (F = 3.3, P < .05), Trail Making Test-B (F = 3.1, P < .05), and digit symbol coding task (F = 7.0, P < .001)—as well as on a nonverbal working memory (spatial span) task (F = 3.2, P < .05). Our findings support the idea that neurocognitive impairment, and processing speed impairment in particular, is a core feature of psychosis risk. This group likely demonstrates some of the earliest cognitive impairments associated with psychosis vulnerability.Key words: epidemiology/adolescents/cognitionKey words: epidemiology, adolescents, cognition     

Cognitive remediation in ADHD: Effects of periodic non-contingent alerts on sustained attention to response

Few studies have attempted direct cognitive remediation of attention deficits in attention-deficit hyperactivity disorder (ADHD). The present study investigated the efficacy of periodic non-informative alerting cues for improving sustaining attention in ADHD. This technique is known to improve sustained attention in right frontal injury patients and may be effective in ADHD, given that this disorder has also been linked with right frontal dysfunction. Fifteen children with ADHD and 15 matched controls completed four blocks of a modified version of the Sustained Attention to Response Task (SART). Eight random non-contingent alerts were introduced on two of these blocks as a cue for participants to adopt a more supervisory stance to their performance. While the alerting cues did not alter the total number of commission errors committed by ADHD children over a task block, they did produce a significant short-term reduction in commission errors in the period immediately following an alerting cue. Our data demonstrate that sustained attention performance can be enhanced in children with ADHD using a simple cognitive training strategy. Methods from the field of cognitive rehabilitation may be viably applied to the remediation of attention deficits in ADHD.     

Making errorless learning more active: Self-generation in an error free learning context is superior to standard errorless learning of face–name associations in people with Alzheimer's disease

Errorless learning (EL) principles have been shown to enable people with memory impairments to acquire various types of information (Grandmaison & Simard, 2003; Wilson, 2005). However, the effects of EL, based on simple repetition only, tend to be limited with regards to their size and longevity. The present study investigated whether EL could be improved by actively engaging people with Alzheimer's disease in the learning process. Patients learned the names of famous faces over 10 training sessions, treated either with a non-learning control, a simple repetition EL procedure, or an EL condition in which responses had to be self-generated. Cued recall rates after the final training session were significantly greater for the names treated with the self-generated EL technique compared to the control and the repetition EL conditions. In addition, there was evidence that patients with less severe general cognitive impairment benefit more from active generation than more severely impaired patients. The implications of this research for individualised memory rehabilitation programmes are discussed.     

Cognitive behaviour therapy for post-traumatic stress symptoms in the context of hydrocephalus: A single case

There is limited information about anxiety disorders occurring in the context of the challenging condition of hydrocephalus. This paper describes the treatment, via trauma-focused cognitive behaviour therapy (TFCBT), of post-traumatic stress symptoms arising on account of hydrocephalus in a 23-year-old man. Specific components of the intervention included exposure, cognitive disputation, and relaxation training. The 20-session intervention appeared effective with decreases in anxiety (on the Hospital Anxiety and Depression Scale) and event impact (on the Impact of Events Scale) from clinical to sub-clinical levels. The main contributor to change appeared to be the exposure element of the treatment. The benefits of the intervention were maintained at one-, three-, and six-month follow-up.     

Everyday memory measures in multiple sclerosis: a systematic review

ABSTRACT

Everyday memory is one of the most affected cognitive functions in multiple sclerosis (MS). Assessing everyday memory problems is crucial for monitoring the impact of memory deficits on individuals’ day-to-day lives and evaluating the effectiveness of interventions that aim to improve cognitive functions. The aim of this systematic review was to identify the research literature on everyday memory measures used with people with MS, describe the types of measures used, and summarise their psychometric properties. Empirical studies of cognitive function in MS using standardised everyday memory measures were included. Online databases (MEDLINE, PsycINFO, PsycARTICLES, Embase) and Google Scholar were searched. Forty-four studies met the inclusion criteria. A total of 12 measures were identified, with varied uses and administration methods. The majority of papers did not report any psychometric properties for MS populations. The few papers that did, reported that the measures have good reliability and appear to have good face, concurrent, and ecological validity, but these need to be evaluated further. This review presents researchers and clinicians with an overview of the various everyday memory measures used in studies with people with MS, to help them choose the appropriate measure for their evaluations.