Silence in Conversations About Advancing Pediatric Cancer

Background and Objectives

Skillful use of silence by clinicians can support patient-centered communication. However, what makes a period of silence feel meaningful is not well understood. This study aimed to characterize profound, skillful silences during difficult conversations between pediatric oncologists, children with advancing cancer, and their families.

Methods

We audio-recorded serial disease reevaluation discussions between pediatric oncologists, patients with high-risk cancer, and their families across 24 months or until death, whichever occurred first. Using an inductive process, we performed content analysis across all dialogue recorded at timepoints of disease progression to examine types of silence.

Results

17 patient-parent dyads with disease progression yielded 141 recorded conversations. Inductive coding yielded a layered typology of silence, including “intentional silence” (≥5 seconds), “profound silence” (≥5 seconds following receipt of difficult information, juxtaposed with statements of shared understanding, emotion, or enlightenment), and “stacked silence” (series of silences juxtaposed within dialogue). Intentional silence lasting ≥5 seconds occurred 238 times in 35/49 “bad news” recordings; nearly half (103/238) of these silences were identified as profound silence, in which silences appeared to create space for processing, allowed for questions to emerge, and synergized with empathic and affirmational statements. In most cases, profound silences involved the juxtaposition, or stacking, of multiple silences close together.

Conclusions

Profound silences occur often during conversations about advancing pediatric cancer and share distinct characteristics. Opportunities exist to teach clinicians to use profound and stacked silences with intention during difficult conversations as a fundamental aspect of communication.

Real-time holographic deconvolution techniques for one-way image transmission through an aberrating medium: characterization, modeling, and measurements

We propose and demonstrate a new photorefractive real-time holographic deconvolution technique for adaptive one-way image transmission through aberrating media by means of four-wave mixing. In contrast with earlier methods, which typically required various codings of the exact phase or two-way image transmission for correcting phase distortion, our technique relies on one-way image transmission through the use of exact phase information. Our technique can simultaneously correct both amplitude and phase distortions. We include several forms of image degradation, various test cases, and experimental results. We characterize the performance as a function of the input beam ratios for four metrics: signal-to-noise ratio, normalized root-mean-square error, edge restoration, and peak-to-total energy ratio. In our characterization we use false-color graphic images to display the best beam-intensity ratio two-dimensional region(s) for each of these metrics. Test cases are simulated at the optimal values of the beam-intensity ratios. We demonstrate our results through both experiment and computer simulation.

Photoconductive optically driven deformable membrane under high-frequency bias: fabrication, characterization, and modeling

The fabrication and characterization of an optically addressable deformable mirror for a spatial light modulator are described. Device operation utilizes an electrostatically driven pixelated aluminized polymeric membrane mirror supported above an optically controlled photoconductive GaAs substrate. A 5 mum thick grid of patterned photoresist supports the 2 mum thick aluminized Mylar membrane. A conductive ZnO layer is placed on the backside of the GaAs wafer. Similar devices were also fabricated with InP. A standard Michelson interferometer is used to measure mirror deformation data as a function of illumination, applied voltage, and frequency. The device operates as an impedance distribution between two cascaded impedances of deformable membrane substrate, substrate, and electrode. An analysis of device's operation under several bias conditions, which relates membrane deformation to operating parameters, is presented.

Optically driven microelectromechanical-system deformable mirror under high-frequency AC bias

A new, optically addressed deformable mirror device is demonstrated. The device consists of a pixellated metalized polymeric membrane mirror supported above an optically addressed photoconductive substrate. A conductive transparent ZnO layer is deposited on the back side of the substrate. A very high-frequency AC bias is applied between the membrane and the back electrode of the device. The membrane is deformed when the back of the device is illuminated because of impedance and bias redistribution between two cascaded impedances. We fabricated, demonstrated, and modeled the operation of this device.

Homodyne and heterodyne imaging through a scattering medium

We introduce a novel two-dimensional (2D) homodyne and heterodyne technique for imaging objects through or embedded in a scattering medium. Our imaging approach is based on heterodyning of light with different Doppler broadenings that is scattered from objects of two different textures or from an opaque object and a textured scattering medium. We report on the initial demonstration of pulling signals out of noise for an object hidden behind a scattering medium. Enhancements of signal-to-noise ratio of the order of 50 have been achieved by use of a 2D holographic phase-sensitive detector. We also discuss the experimental feasibility of this approach for objects embedded in a scattering medium.

Speckle velocimetry by means of holographic time-integrative correlation

We develop the theory of the speckle velocimeter that is based on use of a photorefractive real-time hologram in four-wave mixing as a time-integrative correlator. The theory of the speckle velocimeter has been developed for the time correlation between the far-field spectrum of light scattered from the diffuser and the reference wave that is Doppler shifted. Our theoretical derivation shows that it is possible to extract the velocity with minor processing of the output correlation.

Synthetic aperture radar image correlation by use of preprocessing for enhancement of scattering centers

We demonstrate that a significant improvement can be obtained in the recognition of complicated synthetic aperture radar images taken from the Moving and Stationary Target Acquisitions and Recognition database. These images typically have a low number of scattering centers and high noise. We first preprocess the images and the templates formed from them so that their scattering centers are enhanced. Our technique can produce high-quality performance in several correlation criteria. For realistic automatic target recognition systems, our approach should make it easy to implement optical recognition systems with binarized data for many different types of correlation filter and should have a great effect on feeding data-compressed (binarized) information into either digital or optical processors.

Phase-restricted heterogeneous correlation

We introduce a new phase-restricted algorithm for producing a heterogeneous correlation filter that permits new in-class members to be added without changing the phase of the filter. This heterogeneous correlation filter uses amplitude modulation both to enhance in-class cross correlations and to suppress selected out-of-class correlations. This new algorithm should substantially improve the performance of existing class-associative correlators and improve their operation.

Wiener-like correlation filters

We introduce a new, to our knowledge, design for a Wiener-like correlation filter, which consists of cascading a phase-only filter (POF) with a photorefractive Wiener-like filter. Its performance is compared with that of the POF and the Wiener correlation filter (WCF). Correlation results show that for intermediate and higher levels of noise this correlation filter has a peak-to-noise ratio that is larger than that of either the POF or the WCF while still preserving a correlation peak that is almost as high as that of the POF.

Analysis of spatial light modulator contrast ratios and optical correlation

We have performed a general analysis of optical correlators with spatal light modulators (SLM's) whose primary defect is a finite contrast ratio (CR). Our mathematical analysis identifies three noise terms that appear in addition to the correlation term. The filter SLM contains either a phase-only filter (POF) or a binary-phase-only filter (BPOF). Insertion of a dc block at the center of the filter SLM decreases the noise background in the correlator plane; this dc block is larger than that required for the same level of performance in a correlator whose SLM's have transmissive (or reflective) dead zones. With a noise-free input and the dc block, our computer simulations that show the peak intensity falling off as the CR decreases are in quantitative agreement with the correlation term of the mathematical model. For a cluttered, disjoint noise input this agreement is only qualitative, and at low CR's the dc block is definitely required for the BPOF correlator if the secondary peaks in the output are to be brought below the correlation peak.

Nearly optimal correlations for shift-invariant associative memories

The optical implementation of the Hopfield algorithm in shift-invariant holographic associative memories is based on the use of correlators with matched filters. However, it is well known that such correlators have poor discrimination. We propose nearly optimal correlation designs for associative memories based on correlation filters that have maximum discrimination ability. These new designs avoid large cross-correlation-peak terms caused by a mismatch between partial input and the fully stored information in the filter. These solutions rely on whitened spectra of the stored and the recalled information.Computer simulations are made of eight different combinations.

Photorefractive two-beam coupling optimal thresholding filter for additive signal-dependent noise reduction

Computer simulations of photorefractive thresholding filters for the reduction of artifact or dust noise demonstrate an increase in signal-to-noise ratio (SNR) of 70% to 95%, respectively, of that provided by the Wiener filter for inputs with a SNR of approximately 3. These simple, nearly optimal filters use a spectral thresholding profile that is proportional to the envelope of the noise spectrum. Alternative nonlinear filters with either 1/ν or constant thresholding profiles increase the SNR almost as much as the noise-envelope thresholding filter.

Photorefractive phase-conjugate technique for measuring surface granularity

A self-aligned photorefractive autocorrelator is implemented for the real-time use of second-order statistics for texture analysis. We demonstrate the measurement of the length scale of the granularity of a rough surface.

Phase-coding technique for one-way image transmission through aberrating media

We propose and demonstrate one-way image transmission through an aberrating medium. In contrast to previous techniques, which usually use exact phase compensation for correcting phase distortion, our technique uses the phase- or amplitude-coded form of the exact phase. This technique allows us to utilize a wide variety of spatial light modulators for image correction in one-way image transmission through aberrating media.

General treatment of spatial light modulator dead-zone effects on optical correlation. II. Mathematical analysis

We present a general analytical treatment of optical correlation in correlators that use pixellated spatial light modulators with transmissive (or reflective) dead zones in both the input and filter planes. The active areas of the pixels modulate the light intensity while the dead zones transmit (or reflect) all of the light. Our model can predict the changes in the correlation peak and the signal-to-noise ratio with changes in dead zones, calculated in Part I [Appl. Opt. 32, 6527(1993)] from computer simulations. This model is also a general one: It applies to correlators in which one spatial light modulator contaions only opaque dead zones while the other contains only transmissive dead zones; it also applies to the case in which any one spatial light modulator contains both opaque and transmissive dead zones.

General treatment of spatial light modulator dead-zone effects on optical correlation. I. Computer simulations

In Part I we present an approximate mathematical analysis and exact computer simulations for optical correlation in correlators having pixellated spatial light modulators with transmissive (or reflective) dead zones in both the input and filter planes. We show that the correlation amplitude consists of four terms: a true correlation plus three different types of noise terms originating from the transmissive dead zones in both spatial light modulators; we describe the role that each of these terms plays in the correlation process. We calculate peak intensity, signal-to-noise ratio, and energy throughput efficiency as a function of dead-zone area in both spatial light modulators using either phase-only or matched filters. We utilize a dc block in the filter plane for noise reduction. We also use a filter reference image smaller than the input spatial light modulator size to reduce false correlation peaks. We discuss the effects of fabricating a filter from a filter reference image whose center has been offset rom optic axis. In Part II [Appl. Opt. 32,6536 (1993)] we present a general analytical treatment of our model that can justify the simulation results of Part I. This analysis is applicable even to mixed cases of opaque and transmissive dead zones.

Effects of spatial light modulator opaque dead zones on optical correlation

Each pixel of a spatial light modulator (SLM) consists of a phase- or amplitude-modulating area (the active zone) within an inactive area (the dead zone). Here we study optical correlators that contain input and filter SLM's whose dead zones are opaque. Computer simulations and analytical calculations are carried out for these correlators when a phase-only, a binary phase-only, or a classical matched filter is written on the filter SLM. The correlation signal-to-noise ratio for a particular filter is independent of a dead zone since its energy throughput is proportional to its peak correlation intensity.

Characterization of adenosine A1-receptor binding sites in bovine retinal membranes

Using retinas prepared from freshly dissected bovine eyes, we have characterized the binding of the A1-selective agonist, [3H]PIA (N6-R-[3H](2-phenylisopropyl)adenosine). Specific binding was linear over a range of membrane protein concentrations from 0.10 to 1.0 mg, and accounted for an average of 80-90% of the total binding. At room temperature (24 degrees C), binding reached equilibrium at 60 min, and was reversible upon addition of an excess of cold ligand. Saturation analysis and Scatchard transformation revealed two apparent populations of receptor binding sites. The higher affinity site exhibited a Kd of 0.134 +/- 0.007 nM and Bmax of 26.18 +/- 3.06 fmol-1 mg protein. The lower affinity site exhibited a Kd of 21.83 +/- 4.39 nM and Bmax of 53.94 +/- 15.80 fmol mg-1 protein. Kinetic analysis of association and dissociation rates, performed at a low concentration of [3H]PIA, yielded a calculated affinity constant for the high affinity site of 0.2 nM, in agreement with saturation studies. Competition experiments with a number of purine nucleoside agonists and antagonists were performed, using radioligand concentrations of 1 nM or less to examine binding at the high affinity site, and revealed a rank order of potency consistent with the reported pharmacology of A1 receptors. We have also assayed for adenylate cyclase activity in this same preparation and determined that PIA inhibited forskolin-activated adenylate cyclase in a dose-dependent manner. Maximum inhibition (40%) was observed with 1 nM PIA, while 10 microM 8-cyclopentyl-1,3-dipropylxanthine, an A1 selective antagonist, completely inhibited this modulation by PIA.

Noise reduction using adaptive spatial filtering in photorefractive two-beam coupling

We present an optical signal-processing technique for additive noise reduction that uses the noisy signal and a Gaussian reference beam to produce an adaptive Wiener filter. We experimentally demonstrate an improvement from 1 to 8 in the signal-to-noise ratio by using nonlinear gain in two-beam coupling in barium titanate to transmit 50% of the signal and 6% of the noise.

Investigation of E1 Strength in Coulomb Excitation of Light Nuclei

Contributions to the predominantly E2 Coulomb excitation of the first excited states of 6U, 7U, lOB, 11 B, 12C and 170 due to virtual E1 transitions through intermediate states are calculated using for all states shell model wavefunctions of the lowest admissible configurations, obtained with a realistic Hamiltonian. When harmonic oscillator single-particle wavefunctions are used, the contributions can be calculated rigorously but are generally less than the experimental values. Increases due to use of Woods-Saxon wavefunctions are estimated in a semi-quantitative way. For 170, the additional increase due to admixtures from higher configurations in the wavefunctions is also considered.

Experimental Investigation and R-matrix Analysis of Low-lying Levels in 5He and 5Li

The ~cle-unstable nuclei SHe and Su have been studied via the 4He<,U,6U)SHe and 4He( Li,6He)SU stripping reactions at beam energies of 50 MeV and the 6U(12C, 13N)SHe and 6Li(13C, 14C)SU pickup reactions at 90 MeV. The experimental data clearly demonstrate a dependence of the lineshapes on the method of production of the mass-5 nuclei (in this case pickup or stripping). The observed lineshapes were analysed using the R-matrix formalism in a two-level approximation for each r value, with parameter values deduced from fits to the available 4He + nucleon scattering data. A best channel radius of 5�5 � 1� 0 fm was determined from the stripping data, and the corresponding set of R-matrix parameters also provided a satisfactory description of the pickup data. This channel radius is significantly larger than that employed in most previous analyses. Properties of the lowest ~ - and ! - sta~s of SHe and sU, observed via direct reactions, ate deduced from the parameter values. These properties are compared with results from earlier experimental analyses and the inferred properties of positive-parity states are compared with the results of recent shell-model calculations.

Behavioral performance of rats following neonatal hypoxia-ischemia

The behavioral performance of rats subjected in the neonatal period to hypoxia-ischemia at either 37 degrees C or 21 degrees C was compared to that of sham-ligated animals. Performance on complex motor tests was significantly delayed only in the hypoxic-ischemic 37 degrees C rats. However, cognitive testing disclosed significant delay of spatial learning in animals subjected to hypoxia-ischemia at 21 degrees C and those with gross infarction at 37 degrees C. There was enhanced avoidance learning in the animals with gross infarction in the hypoxia-ischemia 37 degrees C group. Hypoxic-ischemic damage in the neonatal rat at 37 degrees C results in transient delay of complex motor skills, but longer lasting cognitive changes. Hypoxia-ischemia during hypothermia produces no motor deficits, although there may be similar alterations in learning.

States of 5He and 5Li

A recent shell model calculation has predicted a low-lying! + level in 5He, in apparent conflict with experimental results. We have confirmed the prediction with an alternative shell model interaction chosen specifically to fit properties of light nuclei. The level is expected to be very broad so that it would not be easily seen in reactions. It should contribute significantly to n-a phase shifts, but did not appear in previous analyses because of the small value of about 3 fm chosen for the channel radius a. A ! + level at the expected energy of about 7 MeV is obtained for a ::::: 5�1 fm. Broad ~ + and ~ + levels are then found at about 14 MeV in agreement with the shell model calculations. Properties of the low-lying ~ - and! - levels in 5He and 5Li are discussed, but the measured values now available do not favour a particular value of the channel radius.

The effects of sodium bicarbonate on brain blood flow, brain water content, and blood-brain barrier in the neonatal dog

To explore the relationship between cerebral hemorrhage in the newborn and administration of sodium bicarbonate, we gave a standard dose of sodium bicarbonate (5 mEq/kg) to neonatal dogs and then assessed changes in cerebral blood flow, brain water content, and the blood-brain barrier. This dose of sodium bicarbonate produced no increase in blood pressure or cerebral blood flow and no alteration in blood-brain barrier. However, infusion of sodium bicarbonate did cause hyperosmolality and hypernatremia and a significant decrease in brain water content. Cerebral hemorrhage in the neonate associated with infusions of sodium bicarbonate may be related to shifts in brain water rather than to changes in blood pressure or cerebral blood flow.

Relationship between covert and overt speech measures immediately before and immediately after stuttering treatment

Overt and covert assessments of monologue and conversational speech were compared in 22 male adult stutterers immediately prior to the commencement of intensive treatment, and in 15 male adult stutterers immediately after completion of intensive treatment. There were no overall differences between covert and overt speech measures taken immediately before treatment. Immediately after intensive treatment, stuttering frequency (%SS) was significantly higher in covert evaluation than in overt evaluation, though the magnitude of the difference was small. There were no consistent covert-overt differences in speech rate (SPM). These results suggest that overt speech samples constitute a valid source of information about stutterers' 'real life' speech immediately before treatment but are less valid immediately after treatment.

Token reinforcement during the instatement and shaping of fluency in the treatment of stuttering

The value of token reinforcement in the instatement and shaping of fluency was examined in an intensive treatment program for adult stutterers. Experiment 1 examined the effect of removing the tangible back-up reinforcers for the token system and found that clients' performance in the program was equally good with or without these back-up reinforcers, suggesting that a strict token economy may not be crucial to rapid progress through treatment. Experiment 2 compared contingent and noncontingent taken reinforcement, while controlling for some variables that may have confounded the results of earlier research, and found no difference in clients' performance. Experiment 3 examined the effect of the entire removal of token reinforcement. Performance was found to be no worse under a "no tokens" system than under a system of tokens with back-up reinforcers. It is argued that in a highly structured treatment program where many other reinforcers are operating, token reinforcement may be largely redundant. Clinical and theoretical implications of the findings are discussed.

Traits attributed to stuttering and normally fluent males

To determine if a stereotype of the "typical stutterer" exists and to identify possible differences in that sterotype due to exposure to stuttering, seven groups of subjects having a wide range of possible exposure to stutterers rated four hypothetical concepts (typical eight-year-old male, typical eight-year-old male stutterer, typical adult male, and typical adult male stutterer) on 25 scales arranged in a semantic differential format. These bipolar scales were derived from words previously judged by speech clinicians as descriptive of stutterers and antonyms of those words. It was concluded that a strong stereotype of a stutterer's personal characteristics exists, that the stereotype is predominantly unfavorable, that the stereotype is essentially unaffected by amount of exposure to actual stutterers, and that the traits attributed to boys and men who stutter are similar. Some implications of the study are discussed.

Social position and speaking competence of stuttering and normally fluent boys

To assess the relation of social position to speaking competence and to determine the stuttering child’s awareness of peer evaluation, ratings of social position and speaking competence were obtained from 24 stuttering boys (12 mild and 12 moderate or severe) in each the third and sixth grade and from 562 of their normally fluent male classmates. Peer ratings, self-estimates of ratings, and reasons for certain ratings also were obtained. No significant differences between groups of stuttering boys were found. Upon comparison with fluent boys, stuttering boys both expected to be and were rated significantly poorer as speakers than were the normally fluent. No significant differences were found, however, between stuttering and fluent boys on social position measures, suggesting that whether or not an elementary-school-age boy stuttered was of minor importance in determining his social role among his peers.

Speech clinicians' conceptions of boys and men who stutter

Speech clinicians were asked to write adjectives they felt best described the adult male stutterer. Their responses were compared with the same information obtained about elementary school-aged boys who stutter. Many of the same adjectives were listed for both boys and men, indicating a fairly well established stereotype of a “stutterer,” regardless of age. Furthermore, most of these adjectives were judged to be undesirable personality characteristics for males. When the adjectives were grouped together into broad behavior categories, approximately 75% of the clinicians listed adjectives that grouped within the category of “nervous or fearful,” and 64% listed those that were included in the category of “shy and insecure.” Interestingly, only 31% of the clinicians listed adjectives that reflected “abnormalities in speech.” These data have importance for the clinician who sits for the first time across the clinical desk and begins to work with a stutterer.