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PubMed2005

(Mis)alignments in counseling for Huntington's Disease predictive testing: clients' responses to reflective frames.

As a sequel to an earlier paper (Sarangi et al., 2004. J Genet Couns, 13(2), 135-155) examining genetic counselors' initiation of reflective frames, in this paper we analyze the variable ways in which clients respond to such reflective frames in the clinical setting. Of the six types of reflective questions identified, we focus on two types, which recur throughout the counseling protocol: (i) questions about clients' decisions to have genetic testing and (ii) questions exploring the potential impact of a positive or negative test result. The analytic focus here is on the mismatches surrounding clients' apparent readiness to discuss coping with the onset of disease (risk of disease) when they have been asked to discuss coping with genetic test results (risk of knowing). Our theoretical discussion is centered around the notion of alignment as a framework for locating the convergence and divergence of counselors' and clients' agendas in interaction. Drawing on detailed transcripts of 24 Huntington's Disease counseling consultations in South Wales, we analyze 119 counselor-client question-response sequences using the methodology of discourse analysis. Preliminary coding of clients' responses led us to identify three recurrent themes: (a) gaining knowledge as a basis for future action; (b) needing to know as a subjective necessity; and (c) downplaying what can be known. In a further analysis of extended data extracts, we draw attention to how clients display varying degrees of engagement with regard to the testing process and outcomes along the temporal and social axes. At one extreme, clients may take up the opportunity to engage in self-reflection, and thus endorse the legitimacy of the reflective frame. At the other extreme, clients may implicitly or explicitly challenge the relevance of self-reflection, and hence the usefulness of this counselor-initiated routine. We suggest that clients' varied response behaviors result from the perceived need of some clients to display their 'readiness' for predictive testing-an overarching 'meta-question' posed by the very existence of the counseling protocol.

Attitude to Health↗

PubMed1984

Altered acoustic reflectance on two-dimensional echocardiography as an early predictor of myocardial infarct size.

P6 area of increased acoustic reflectance was readily observed by 2-dimensional echocardiography (2-D echo) in the acutely ischemic canine myocardium. Fifteen mongrel dogs subjected to closed-chest coronary artery occlusion were used to test the hypothesis that these areas of altered acoustic reflectance were predictors of subsequent myocardial infarction (MI). Each dog was studied by 2-D echo in short-axis views of the left ventricle at 4 levels before and after coronary artery occlusion. The dogs were killed after 48 hours and heart sections were stained with triphenyltetrazolium chloride to identify the areas of necrosis. Four sections were then selected, approximating the same location within the left ventricle as the short-axis views taken for 2-D echocardiographic analysis. The in vivo 2-D echocardiographic examination revealed alteration of acoustic reflectance immediately after coronary occlusion, which detected the presence of MI with a sensitivity of 92% and a specificity of 90%. The extent of altered acoustic reflectance seen by echo correlated closely (r = 0.81) with the extent of MI detected by triphenyltetrazolium staining of the excised heart. Altered acoustic reflectance seen by 2-D echo immediately after coronary artery occlusion reflects acute ischemic changes and may be an early predictor of MI size.

Animals↗

PubMed1995

Imaging the dorsal hippocampus: light reflectance relationships to electroencephalographic patterns during sleep.

We assessed the correspondence of 660 nm light reflectance changes from the dorsal hippocampus with slow wave electroencephalographic (EEG) activity during quiet sleep (QS) and rapid eye movement (REM) sleep in four cats. An optic probe, attached to a charge-coupled-device (CCD) video camera, was placed on the dorsal hippocampal surface to collect reflectance images simultaneously with EEG, which was measured by macroelectrodes placed around the probe circumference. Spectral estimates of EEG and light reflectance amplitude indicated that reflectance changes occurred in a similar frequency range as EEG changes. Dividing the image into 10 subregions revealed that reflectance changes at the rhythmical slow wave activity band (RSA, 4-6 Hz) persisted in localized regions during QS and REM sleep, but regional changes showed considerable wave-by-wave independence between areas and from slow wave electrical activity. Peak frequencies for reflectance changes corresponded to fast RSA frequencies observed in the EEG. Optical changes most likely derive from fast-acting physical phenomena, rather than from alterations in blood perfusion, and provide increased spatial resolution over that offered by electrical measurements.

Animals↗

PubMed1995

Mechanics of wave reflections in a coronary bypass loop model: the possibility of partial flow cut-off.

Local hemodynamics in a bypass loop model with dimensions typical of those in the human coronary circulation are studied, particularly with regards to the effects of wave reflections. While in a single vessel of such dimensions and a single source of wave reflections the effects would be insignificant, in a bypass loop the combination of a narrowed vessel with a converging junction and several reflection sites may produce wave reflections with significant effects on the pressure and flow distributions within the vessels forming the loop. Calculations to test this possibility were performed, based on D'Alembert's solutions of the wave equation and with a proposed matching scheme to deal with the converging junction. The results indicate that there are very large wave reflection effects at a frequency of 10 Hz, smaller but significant effects at 5 Hz, and some insignificant effects at 1 Hz. The results also indicate that partial flow cut-off may occur within the loop under some singular circumstances, whereby certain harmonic components of the incident wave are totally reflected. In the clinical setting these effects would detract from the efficiency of the bypass as a conduit, to a degree dependent on the degree of occlusion of the bypassed vessel. The choice of a larger diameter for the bypass appears to diminish this dependence and is thus on the whole favorable despite the contribution it makes to impedance mismatch at the junction.

Biomechanical Phenomena↗

PubMed1996

On the wave transmission and reflection properties of stenoses.

This study is concerned with the wave reflection properties of arterial stenoses. Two theoretical models have been developed for deriving the reflection coefficient: a linear model resulting from the linearization of the pressure drop-flow equation and an indirect, quasi-nonlinear model, based on the separation of pressure waves into their forward and backward running components proximal and distal to the stenosis. The linear method gave consistently lower values for the reflection coefficient when compared to the quasi-nonlinear model. In vitro experiments in elastic tubes showed that the reflection coefficient is strongly dependent on stenosis severity, mean flowrate, and the elastic properties of the proximal unobstructed artery. For critical stenoses the reflection coefficient is frequency and pulsatility independent. The results suggest that hemodynamically nonsevere stenoses may cause significant wave reflections.

Algorithms↗

PubMed1996

Concurrent reflectance imaging and microdialysis in the freely behaving cat.

We present a method to perform simultaneous microdialysis with light reflectance imaging of neural activity in a discrete brain region of the freely behaving animal. We applied this method to the dorsal hippocampus of freely behaving cats to (1) measure extracellular glutamate and reflectance variations across a sleep-waking cycle, (2) assess spatially coherent neural activity changes accompanying local perfusion of cocaine and (3) measure local changes in cell volume induced by infusion of hyper- and hypo-osmotic solutions. Higher extracellular glutamate concentrations corresponded to higher imaged neural activity. Sequential images showed that cocaine perfusion elicited a propagating reflectance change as cocaine reached the tissue. Microperfusion of hypo-osmotic solution ( - 100 mOsm), which increases cell volume, decreased reflectance. Microperfusion of hyperosmotic sucrose solutions, which reduce cell volume, increased reflectance in a dose-dependent manner. The data indicate that reflectance imaging can measure changes in cell volume, and could, thus, measure neural activity through activity/cell volume corollaries. Combining microdialysis and optical imaging enables investigation of the neurochemical bases of spontaneous neural activity patterns within discrete brain nuclei.

Animals↗

PubMed1988

Reflected reentry in depolarized foci with variable conduction impairment in 1 day old infarcted canine cardiac tissue.

A recent study in 1 day old infarcted canine cardiac tissue demonstrated that variations in entrance and exit characteristics of depolarized spontaneous foci could profoundly affect their expression, resulting in behaviors such as modulated parasystole and entrainment, second and third degree exit block "autoentrainment" and annihilation (abrupt termination) of spontaneous activity. Foci with exit and entrance delay should also allow the occurrence of reflected reentry. To test this, the left circumflex coronary artery was ligated and, after 1 day, simultaneous microelectrode impalements were made in infarcted and uninfarcted portions of isolated ventricular preparations. Preparations were stimulated from the uninfarcted portions. Reflected reentry was demonstrated in 5 of 11 preparations. It occurred when exit conduction delay resulted in reexcitation of the focus or, alternatively, when entrance conduction delay resulted in reexcitation of extrafocal tissue. Reflection occurred in which the action potentials were reexcited during phase 2 or 3, resulting in prolongation of action potential duration (type I), and in which reexcitation occurred after full or nearly full repolarization, resulting in a closely coupled extrasystole (type II). Electrotonic modulation and reflection could coexist, the type of behavior depending on the phase relation between focal and extra-focal action potentials. An example is illustrated in which type I reflection occurred only when preceding driven activity induced overdrive suppression of exit conduction from the focus. The results suggest that, in infarcted tissue, entrance and exit conduction delays to depolarized foci may form the basis for the occurrence of reflected reentry.

Action Potentials↗

PubMed1992

Dynamic optical property changes: implications for reflectance feedback control of photocoagulation.

During laser treatment, coagulation affects the optical properties of the tissue. In particular, the formation of a white lesion significantly increases the scattering coefficient. This change in the optical properties in turn affects the laser light distribution in the tissue. The white lesion formed during photocoagulation of the retina has a dynamic effect upon reflection and fluence rate. This problem has been simulated on a model medium consisting of a thin absorbing layer covered with a 1 cm thick layer of albumin. The albumin layer is subdivided into coagulated (white) and uncoagulated (clear) layers. The optical properties of each layer have been determined and these values have been used to model light distribution in the medium. One-dimensional adding-doubling and three-dimensional Monte Carlo methods have provided light distributions in the medium for varying thicknesses of the coagulated albumin. Computed fluence reaching the absorbing layer decreased in the presence of a 275 microns or thicker coagulated layer. The coagulated layer attenuates light because it is highly scattering; however, this scattering also leads to a sub-surface peak in fluence rate at a level higher than the incident fluence. The latter effect outweighed the former for coagulated layer thicknesses less than 275 microns. Computed reflectance of argon laser light from a semi-infinite coagulated region initially increased linearly as a function of thickness. As the coagulation thickness increased beyond 4-5 optical depths, the reflectance approached a constant value, R infinity, at 9 optical depths (2 mm). Experimentally measured total reflectance is shown to be an inadequate indicator of the thickness of a lesion (finite coagulated volume); however, central reflectance from a lesion measured with a CCD camera confirmed the computed trends. These results provide a theoretical foundation for control of lesion thickness using reflectance images.

Argon↗

PubMed2004

Skin reflectance changes in preterm infants with patent ductus arteriosus.

INTRODUCTION: Patent ductus arteriosus (PDA) is a common complication in preterm infants. While two-dimensional echocardiography is the method of choice for diagnosing a PDA, clinical signs are known to be of limited value. STUDY DESIGN: Haemodynamically significant PDA (hs-PDA) was defined as a ductal left-to-right shunt with elevated left atrial/aortic root ratio ( > 1.6:1), a ductal diameter > 2 mm, retrograde diastolic flow exceeding 30% of the anterograde flow and anterograde peak diastolic flow velocity in left pulmonary artery > 50 cm/s. A hs-PDA may affect the cerebral circulation and skin color is known to be related to local perfusion. In this study, we tested the value of a caudal-to-cephalic skin reflectance differential in detecting preterm infants with hs-PDA. The study was blinded and prospective. SUBJECTS: Fifteen infants with a hs-PDA (M: 8, F: 7; gestational age: 28.0 +/- 2.0 weeks, birth weight: 880 +/- 130 g) and 15 gender- and gestational age-matched infants without a haemodynamically significant PDA (M: 8, F: 7; gestational age: 28.2 +/- 2.3 weeks, birth weight: 885 +/- 135 g) participated to the study. OUTCOME MEASURE: Skin reflectance measurements were performed using a reflectance spectrophotometer (CM-2600d/2500d, Minolta, Osaka, Japan). Sole ("postductal" site) to forehead ("preductal" site) skin reflectance ratio (caudal-to-cephalic ratio). RESULTS: hs-PDA infants showed significantly lower forehead light reflectance values on for the whole visible spectrum (p < or = 0.043) with the exception of 580-590 nm (p = 0.058), whereas no statistically significant differences were observed for the sole skin reflectance between the two groups in the examined visible spectrum. Consequently, hs-PDA infants showed a significantly higher caudal to cephalic ratio in the 410-430 nm (p < or = 0.042), 460-530 nm (p < or = 0.027) and 590-700 nm (p < or = 0.011) wavelength ranges. CONCLUSIONS: These findings may provide a previously unrecognised clinical marker for haemodynamically significant PDA in preterm infants, thus predicting those preterm infants who may require intervention for PDA.

Blood Flow Velocity↗

PubMed2005

Life, illness and death--existential reflections of a Swedish sample of patients who have undergone curative treatment for breast or prostatic cancer.

The aim of this study is to describe cancer patients' existential reflections and how these reflections were met by the nursing staff. A qualitative method of data collection was used. Ten patients with breast- or prostate cancer who had completed curative treatment were interviewed. The results showed that the cancer diagnosis resulted in existential reflections in some of the patients. These reflections concerned the meaning of life, God/a higher power, health, work, relations and sexuality. Reflections on the cancer consisted in beliefs about the causes of cancer, treatment and cancer and sexuality. It could also be seen that loss of important life values, such as health and sexuality could lead to loss of meaning of life. Explicit reflections on sexuality were only made by two of the men in the study. The patients reported a need of existential support as well as obstacles for giving such support. Obstacles could be lack of time and lack of continuity, as well as lack of knowledge resulting in an inability to identify existential issues. Some of the patients had wanted existential support from nurses, while others received the support they needed from family and friends.

Adaptation, Psychological↗

PubMed2006

Enhanced external counterpulsation treatment improves arterial wall properties and wave reflection characteristics in patients with refractory angina.

OBJECTIVES: To determine if arterial properties and wave reflection characteristics are favorably altered after enhanced external counterpulsation (EECP) treatment in patients with refractory angina. BACKGROUND: Early return of reflected waves from the lower body, resulting from increased arterial stiffness, augments central aortic pressure and increases left ventricular (LV) afterload and myocardial oxygen demand. EECP acutely enhances coronary perfusion (supply) and reduces LV afterload (demand). However, the mechanisms responsible for the sustained beneficial effects of EECP treatment are unclear. METHODS: Radial artery pressure waveforms were recorded by applanation tonometry and central aortic pressure waveforms generated using a mathematical transfer function in 20 patients with stable refractory angina. Data were collected before and after 34 1-h EECP sessions. Augmentation index (AI(a)) and timing of the reflected pressure wave were calculated from the aortic waveform. RESULTS: EECP treatment caused a decline in AI(a) and an increase in reflected wave travel time. These modifications in wave reflection characteristics caused a decrease in aortic systolic pressure and wasted LV pressure energy. The average number of angina episodes and Canadian Cardiovascular Society (CCS) class, both decreased in concordance with the physiologic changes due to EECP treatment. CONCLUSIONS: EECP treatment reduces arterial stiffness and improves wave reflection characteristics in patients with refractory angina. These changes decrease LV afterload and myocardial oxygen demand and reduce the number of angina episodes, therefore enabling patients to participate in continuous exercise programs which in turn may provide long-term benefits and sustained improved quality of life.

Aged↗

PubMed2004

So how do you feel about that? Assessing reflective practice.

Despite a lack of evidence base, reflective practice remains a central feature of education for many professional groups. In addition, current trends in learning, teaching and assessing require a robust alignment between learning outcomes and assessed course work [Active Learning Higher Educat. 2 (2002) 145)]. Varied definitions of what it means to be a 'reflective practitioner' and limited research make it difficult to know how and what to assess [Reflective Practice in Nursing, Blackwell Science]. Assessment of reflective practice frequently requires students to recount narratives about their practice and both formative feedback and assessment criteria make it clear that such narratives must demonstrate the students' application of appropriate and safe professional practice. This paper suggests that only three 'stories' are legitimate and identifies these as 'valedictory' 'condemnatory' and 'redemptive' This conclusion drawn is that the imperative to do well academically discourages students from engaging in honest and open reflection. This being the case, it may be argued that the assessment of reflective practice is a potential barrier to the personal growth and integrity that programmes are trying to nurture.

Clinical Competence↗

PubMed2005

Self-referential reflective activity and its relationship with rest: a PET study.

This study used positron emission tomography (PET) to identify the brain substrate of self-referential reflective activity and to investigate its relationship with brain areas that are active during the resting state. Thirteen healthy volunteers performed reflective tasks pertaining to three different matters (the self, another person, and social issues) while they were scanned. Rest scans were also acquired, in which subjects were asked to simply relax and not think in a systematic way. The mental activity experienced during each scan was assessed with rating scales. The results showed that, although self-referential thoughts were most frequent during the self-referential task, some self-referential reflective activity also occurred during rest. Compared to rest, performing the reflective tasks was associated with increased blood flow in the dorsomedial prefrontal cortex, the left anterior middle temporal gyrus, the temporal pole bilaterally, and the right cerebellum; there was a decrease of blood flow in right prefrontal regions and in medial and right lateral parietal regions. In addition, the ventromedial prefrontal cortex (VMPFC) (1) was more active during the self-referential reflective task than during the other two reflective tasks, (2) showed common activation during rest and the self-referential task, and (3) showed a correlation between cerebral metabolism and the amount of self-referential processing. It is suggested that the VMPFC is crucial for representing knowledge pertaining to the self and that this is an important function of the resting state.

Adult↗

PubMed1990

Hazards of laser beam reflections in eyes containing gas.

Three patients suffered photic or thermal laser injuries at unintended sites because of reflection from gas-fluid interfaces in eyes containing gas. Fresnel's equations predict the amount of light transmitted or reflected at optical interfaces. Application of Fresnel's equations demonstrate that significant laser reflection occurs at gas-fluid or fluid-gas interfaces, especially at high angles of incidence. Photocoagulation across gas-fluid or fluid-gas interfaces should be avoided to reduce the risk of unintended damage from reflected light. If photocoagulation must be performed across an interface, the surgeon should minimize the angle of incidence of the treatment laser beam, use a divergent beam, and consider the location and intensity of the reflected beam. Because of the higher phototoxicity of blue light, photocoagulation with blue-green lasers across gas-fluid or fluid-gas interfaces is undesirable. Proper polarization of the treatment laser beam may significantly reduce laser reflectance.

Aged↗

PubMed2001

The role of internal reflection in transskull phase distortion.

Phase distortion due to reflection in transcranial ultrasound propagation is investigated. Understanding of these phase-dependent properties is motivated by efforts to construct a reliable prediction model for noninvasive ultrasound therapy in the brain. The present study measures the phase of an ultrasound wave after propagation through an ex vivo human skull and considers the dependence of this phase on reflections between the transducer and the skull surface in addition to reflections within the skull. Experiments are performed using a human calvarium fragment placed between an underwater ultrasonic transducer and a polyvinylidene difluoride hydrophone. Data are presented indicating the ultrasound phase dependence as a function of burst length and the distance of the transducer element from the skull at a driving frequency of 0.5 MHz. Experimental results are compared with predictions obtained from a propagation model which considers transmission at the skull interfaces as well as multiple reflections within the skull. It is concluded that by using short ultrasound bursts a distance may be indicated that beyond which the contributions of transducer reflections on the phase of the propagating wave may be neglected. Additionally, a comparison of the measurements with simulated data supports the contention that for reasonably small incident angles, reflection within the skull causes minimal phase shift.

Brain↗

PubMed1999

Three-dimensional shape and two-dimensional surface reflectance contributions to face recognition: an application of three-dimensional morphing.

We measured the three-dimensional shape and two-dimensional surface reflectance contributions to human recognition of faces across viewpoint. We first divided laser scans of human heads into their two- and three-dimensional components. Next, we created shape-normalized faces by morphing the two-dimensional surface reflectance maps of each face onto the average three-dimensional head shape and reflectance-normalized faces by morphing the average two-dimensional surface reflectance map onto each three-dimensional head shape. Observers learned frontal images of the original, shape-normalized, or reflectance-normalized faces, and were asked to recognize the faces from viewpoint changes of 0, 30 and 60 degrees. Both the three-dimensional shape and two-dimensional surface reflectance information contributed substantially to human recognition performance, thus constraining theories of face representation to include both types of information.

Discrimination Learning↗

PubMed1995

Developing and maintaining reflection in clinical journals.

There is a pressing need in today's world for nurses who are willing and able to transform health care. Teaching strategies that foster reflection are in order. The use of dialogue journals has been widely reported in the nursing literature as an effective strategy for assisting students to reflect about learning experiences in the clinical area. Despite the promise that journal writing will enhance students' ability to reflect on their clinical learning experiences, not all students respond positively to journal writing as a learning tool. The paper is a discussion of some of the common difficulties that arise in the use of clinical journals as a reflective strategy in nursing education. Common problems in the use of clinical journals include procrastination; superficial, nonreflective entries; waning enthusiasm about the activity; and unwillingness or inability to reflect. The possible etiologies for these problems will be explored. Specifically, the paper will focus on ways to prevent or minimize these concerns by maintaining and enhancing the factors required for students to reflect in clinical journals.

Autobiographies as Topic↗

PubMed1996

Student reflective groups at a Scottish College of Nursing.

In this paper student views on reflective groups, set up as an important element of the new Project 2000 course in a Scottish College of Nursing, are reported. A random sample of 19 students were interviewed. While the reflective groups were very popular with students because they provided support, there was little evidence of a linkage between theory and practice. It was clear that the ambitious objective of stimulating reflection-on-action was not attained. Practice certainly was discussed, but it tended to be dominated by dramatic and emotionally charged aspects of care rather than the more frequent routine concerns. There were, however, indications that the original aim of the reflective groups could be achieved if tutors could establish a common understanding of the purpose of the groups and of reflection, and if the practices on which students reflected consisted less of single day visits where the students saw themselves as nonparticipant outsiders.

Education, Nursing, Baccalaureate↗