Continuously varying skin potentials elicited by sinusoidally varying electric shock potentials

An investigation was carried out to determine whether a form of quasi-linear systems analysis can be applied to electrodormal responses to yield new insights into the nature of the response mechanisms and their interrelationships. The response investigated was the electrodermal response (galvanic skin potential, GSP) as elicited by an electric shock stimulus applied to the skin. The response subsequent to this stimulation was examined and its characteristics measured. A series of experimental runs on three Ss was accomplished, using sinusoidal modulation envelopes of frequencies. Results showed that it was possible to drive the GSP and to achieve relatively high coherence between the driving frequency and the response itself. The analysis was limited to Fourier analysis of the response in order to determine the relative energies at the driving frequency and at successive harmonics of that driving frequency, and correlational analysis in order to determine the degree of linear relationship between the driving frequency and the driven response

An investigation of the visual sampling behaviour of human observers

Visual sampling behavior of human observers for aerospace vehicle design application

At least some errors are randomly generated (Freud was wrong)

An experiment was carried out to expose something about human error generating mechanisms. In the context of the experiment, an error was made when a subject pressed the wrong key on a computer keyboard or pressed no key at all in the time allotted. These might be considered, respectively, errors of substitution and errors of omission. Each of seven subjects saw a sequence of three digital numbers, made an easily learned binary judgement about each, and was to press the appropriate one of two keys. Each session consisted of 1,000 presentations of randomly permuted, fixed numbers broken into 10 blocks of 100. One of two keys should have been pressed within one second of the onset of each stimulus. These data were subjected to statistical analyses in order to probe the nature of the error generating mechanisms. Goodness of fit tests for a Poisson distribution for the number of errors per 50 trial interval and for an exponential distribution of the length of the intervals between errors were carried out. There is evidence for an endogenous mechanism that may best be described as a random error generator. Furthermore, an item analysis of the number of errors produced per stimulus suggests the existence of a second mechanism operating on task driven factors producing exogenous errors. Some errors, at least, are the result of constant probability generating mechanisms with error rate idiosyncratically determined for each subject

Human visual sampling processes - A simulation validation study

Pilots and flight simulator used in study of human visual sampling stud

Differential Growth Factor Adsorption to Calvarial Osteoblast-Secreted Extracellular Matrices Instructs Osteoblastic Behavior

Craniosynostosis (CS), the premature ossification of cranial sutures, is attributed to increased osteogenic potential of resident osteoblasts, yet the contribution of the surrounding extracellular matrix (ECM) on osteogenic differentiation is unclear. The osteoblast-secreted ECM provides binding sites for cellular adhesion and regulates the transport and signaling of osteoinductive factors secreted by the underlying dura mater. The binding affinity of each osteoinductive factor for the ECM may amplify or mute its relative effect, thus contributing to the rate of suture fusion. The purpose of this paper was to examine the role of ECM composition derived from calvarial osteoblasts on protein binding and its resultant effect on cell phenotype. We hypothesized that potent osteoinductive proteins present during sutural fusion (e.g., bone morphogenetic protein-2 (BMP-2) and transforming growth factor beta-1 (TGF-β1)) would exhibit distinct differences in binding when exposed to ECMs generated by human calvarial osteoblasts from unaffected control individuals (CI) or CS patients. Decellularized ECMs produced by osteoblasts from CI or CS patients were incubated in the presence of BMP-2 or TGF-β1, and the affinity of each protein was analyzed. The contribution of ECM composition to protein binding was interrogated by enzymatically modulating proteoglycan content within the ECM. BMP-2 had a similar binding affinity for each ECM, while TGF-β1 had a greater affinity for ECMs produced by osteoblasts from CI compared to CS patients. Enzymatic treatment of ECMs reduced protein binding. CS osteoblasts cultured on enzymatically-treated ECMs secreted by osteoblasts from CI patients in the presence of BMP-2 exhibited impaired osteogenic differentiation compared to cells on untreated ECMs. These data demonstrate the importance of protein binding to cell-secreted ECMs and confirm that protein-ECM interactions have an important role in directing osteoblastic differentiation of calvarial osteoblasts

Using nurses and office staff to report prescribing errors in primary care

Objective. To implement a prescribing-error reporting system in primary care offices and analyze the reports. Design. Descriptive analysis of a voluntary prescribing-error-reporting system Setting. Seven primary care offices in Vermont, USA. Participants. One hundred and three prescribers, managers, nurses and office staff. Intervention. Nurses and office staff were asked to report all communications with community pharmacists regarding prescription problems

International practice variation in perioperative laboratory testing in glioblastoma patients-a retrospective cohort study

Purpose: Although standard-of-care has been defined for the treatment of glioblastoma patients, substantial practice variation exists in the day-to-day clinical management. This study aims to compare the use of laboratory tests in the perioperative care of glioblastoma patients between two tertiary academic centers—Brigham and Women’s Hospital (BWH), Boston, USA, and University Medical Center Utrecht (UMCU), Utrecht, the Netherlands. Methods: All glioblastoma patients treated according to standard-of-care between 2005 and 2013 were included. We compared the number of blood drawings and laboratory tests performed during the 70-day perioperative period using a Poisson regression model, as well as the estimated laboratory costs per patient. Additionally, we compared the likelihood of an abnormal test result using a generalized linear mixed effects model. Results: After correction for age, sex, IDH1 status, postoperative KPS score, length of stay, and survival status, the number of blood drawings and laboratory tests during the perioperative period were 3.7-fold (p < 0.001) and 4.7-fold (p < 0.001) higher, respectively, in BWH compared to UMCU patients. The estimated median laboratory costs per patient were 82 euros in UMCU and 256 euros in BWH. Furthermore, the likelihood of an abnormal test result was lower in BWH (odds ratio [OR] 0.75, p < 0.001), except when the prior test result was abnormal as well (OR 2.09, p < 0.001). Conclusions: Our results suggest a substantially lower clinical threshold for ordering laboratory tests in BWH compared to UMCU. Further investigating the clinical consequences of laboratory testing could identify over and underuse, decrease healthcare costs, and reduce unnecessary discomfort that patients are exposed to

Mindfulness-based stress reduction for people with multiple sclerosis ? a feasibility randomised controlled trial

Background: Multiple sclerosis (MS) is a stressful condition. Mental health comorbidity is common. Stress can increase the risk of depression, reduce quality of life (QOL), and possibly exacerbate disease activity in MS. Mindfulness-Based Stress Reduction (MBSR) may help, but has been little studied in MS, particularly among more disabled individuals. Methods: The objective of this study was to test the feasibility and likely effectiveness of a standard MBSR course for people with MS. Participant eligibility included: age &#62; 18, any type of MS, an Expanded Disability Status Scale (EDSS) &#60;/= 7.0. Participants received either MBSR or wait-list control. Outcome measures were collected at baseline, post-intervention, and three-months later. Primary outcomes were perceived stress and QOL. Secondary outcomes were common MS symptoms, mindfulness, and self-compassion. Results: Fifty participants were recruited and randomised (25 per group). Trial retention and outcome measure completion rates were 90% at post-intervention, and 88% at 3 months. Sixty percent of participants completed the course. Immediately post-MBSR, perceived stress improved with a large effect size (ES 0.93; p &#60; 0.01), compared to very small beneficial effects on QOL (ES 0.17; p = 0.48). Depression (ES 1.35; p &#60; 0.05), positive affect (ES 0.87; p = 0.13), anxiety (ES 0.85; p = 0.05), and self-compassion (ES 0.80; p &#60; 0.01) also improved with large effect sizes. At three-months post-MBSR (study endpoint) improvements in perceived stress were diminished to a small effect size (ES 0.26; p = 0.39), were negligible for QOL (ES 0.08; p = 0.71), but were large for mindfulness (ES 1.13; p &#60; 0.001), positive affect (ES 0.90; p = 0.54), self-compassion (ES 0.83; p &#60; 0.05), anxiety (ES 0.82; p = 0.15), and prospective memory (ES 0.81; p &#60; 0.05). Conclusions: Recruitment, retention, and data collection demonstrate that a RCT of MBSR is feasible for people with MS. Trends towards improved outcomes suggest that a larger definitive RCT may be warranted. However, optimisation changes may be required to render more stable the beneficial treatment effects on stress and depression. Trial registration: ClinicalTrials.gov Identifier NCT02136485; trial registered 1st May 2014

On the complexity of medical devices and systems

How does one design something that is complex? Or something that is simple? Why should one try to reduce or increase complexity? What is complexity? There are a large number of different uses of the word, including many in mathematics and physics. Most of these are not useful in attempting to fit the word to the problems of the design of systems and devices for medicine. In this paper the concept has been defined to apply to health care, which has led to some conclusions about the future development of medical systems and devices