Prevalence and Predictors of Physician-Patient Discordance in Prognostic Perceptions in Advanced Cancer.

BACKGROUND: Discordance between physicians' and patients' prognostic perceptions in advanced cancer care threatens informed medical decision-making and end-of-life preparation, yet this phenomenon is poorly understood. We sought to: (1) describe the extent and direction of prognostic discordance, patients' prognostic information preferences in cases of prognostic discordance, and physicians' awareness of prognostic discordance; and (2) examine which patient, physician, and caregiver factors predict prognostic discordance. MATERIALS AND METHODS: Oncologists and advanced cancer patients (median survival ≤12 months; n = 515) from 7 Dutch hospitals completed structured surveys in a cross-sectional study. Prognostic discordance was operationalized by comparing physicians' and patients' perceptions of the likelihood of cure, 2-year mortality risk, and 1-year mortality risk. RESULTS: Prognostic discordance occurred in 20% (likelihood of cure), 24%, and 35% (2-year and 1-year mortality risk) of physician-patient dyads, most often involving patients with more optimistic perceptions than their physician. Among patients demonstrating prognostic discordance, the proportion who preferred not knowing prognosis varied from 7% (likelihood of cure) to 37% (1-year mortality risk), and 45% (2-year mortality risk). Agreement between physician-perceived and observed prognostic discordance or concordance was poor (kappa = 0.186). Prognostic discordance was associated with several patient factors (stronger fighting spirit, self-reported absence of prognostic discussions, an information source other than the healthcare provider), and greater physician-reported uncertainty about prognosis. CONCLUSION: Up to one-third of the patients perceive prognosis discordantly from their physician, among whom a substantial proportion prefers not knowing prognosis. Most physicians lack awareness of prognostic discordance, raising the need to explore patients' prognostic information preferences and perceptions, and to tailor prognostic communication.

Characteristics of patients with advanced cancer preferring not to know prognosis: a multicenter survey study.

BACKGROUND: For some patients with advanced cancer not knowing prognosis is essential. Yet, in an era of informed decision-making, the potential protective function of unawareness is easily overlooked. We aimed to investigate 1) the proportion of advanced cancer patients preferring not to know prognosis; 2) the reasons underlying patients' prognostic information preference; 3) the characteristics associated with patients' prognostic information preference; and 4) the concordance between physicians' perceived and patients' actual prognostic information preference. METHODS: This is a cross-sectional study with structured surveys (PROSPECT). Medical and thoracic oncologists included patients (n = 524), from seven Dutch hospitals, with metastatic/inoperable cancer and an expected median overall survival of ≤ 12 months. For analysis, descriptive statistics and logistic regression models were used. RESULTS: Twenty-five to 31% of patients preferred not to know a general life expectancy estimate or the 5/2/1-year mortality risk. Compared to patients preferring to know prognosis, patients preferring unawareness more often reported optimism, avoidance and inability to comprehend information as reasons for wanting limited information; and less often reported expectations of others, anxiety, autonomy and a sense of control as reasons for wanting complete information. Females (p < .05), patients receiving a further line of systemic treatment (p < .01) and patients with strong fighting spirit (p < .001) were more likely to prefer not to know prognosis. Concordance between physicians' perceived and patients' actual prognostic information preference was poor (kappa = 0.07). CONCLUSIONS: We encourage physicians to explore patients' prognostic information preferences and the underlying reasons explicitly, enabling individually tailored communication. Future studies may investigate changes in patients' prognostic information preferences over time and examine the impact of prognostic disclosure on patients who prefer unawareness.

Three dimensional vestibular ocular reflex testing using a six degrees of freedom motion platform.

UNLABELLED: The vestibular organ is a sensor that measures angular and linear accelerations with six degrees of freedom (6DF). Complete or partial defects in the vestibular organ results in mild to severe equilibrium problems, such as vertigo, dizziness, oscillopsia, gait unsteadiness nausea and/or vomiting. A good and frequently used measure to quantify gaze stabilization is the gain, which is defined as the magnitude of compensatory eye movements with respect to imposed head movements. To test vestibular function more fully one has to realize that 3D VOR ideally generates compensatory ocular rotations not only with a magnitude (gain) equal and opposite to the head rotation but also about an axis that is co-linear with the head rotation axis (alignment). Abnormal vestibular function thus results in changes in gain and changes in alignment of the 3D VOR response. Here we describe a method to measure 3D VOR using whole body rotation on a 6DF motion platform. Although the method also allows testing translation VOR responses (1), we limit ourselves to a discussion of the method to measure 3D angular VOR. In addition, we restrict ourselves here to description of data collected in healthy subjects in response to angular sinusoidal and impulse stimulation. Subjects are sitting upright and receive whole-body small amplitude sinusoidal and constant acceleration impulses. Sinusoidal stimuli (f = 1 Hz, A = 4°) were delivered about the vertical axis and about axes in the horizontal plane varying between roll and pitch at increments of 22.5° in azimuth. Impulses were delivered in yaw, roll and pitch and in the vertical canal planes. Eye movements were measured using the scleral search coil technique (2). Search coil signals were sampled at a frequency of 1 kHz. The input-output ratio (gain) and misalignment (co-linearity) of the 3D VOR were calculated from the eye coil signals (3). Gain and co-linearity of 3D VOR depended on the orientation of the stimulus axis. Systematic deviations were found in particular during horizontal axis stimulation. In the light the eye rotation axis was properly aligned with the stimulus axis at orientations 0° and 90° azimuth, but gradually deviated more and more towards 45° azimuth. The systematic deviations in misalignment for intermediate axes can be explained by a low gain for torsion (X-axis or roll-axis rotation) and a high gain for vertical eye movements (Y-axis or pitch-axis rotation (see Figure 2). Because intermediate axis stimulation leads a compensatory response based on vector summation of the individual eye rotation components, the net response axis will deviate because the gain for X- and Y-axis are different. In darkness the gain of all eye rotation components had lower values. The result was that the misalignment in darkness and for impulses had different peaks and troughs than in the light: its minimum value was reached for pitch axis stimulation and its maximum for roll axis stimulation. CASE PRESENTATION: Nine subjects participated in the experiment. All subjects gave their informed consent. The experimental procedure was approved by the Medical Ethics Committee of Erasmus University Medical Center and adhered to the Declaration of Helsinki for research involving human subjects. Six subjects served as controls. Three subjects had a unilateral vestibular impairment due to a vestibular schwannoma. The age of control subjects (six males and three females) ranged from 22 to 55 years. None of the controls had visual or vestibular complaints due to neurological, cardio vascular and ophthalmic disorders. The age of the patients with schwannoma varied between 44 and 64 years (two males and one female). All schwannoma subjects were under medical surveillance and/or had received treatment by a multidisciplinary team consisting of an othorhinolaryngologist and a neurosurgeon of the Erasmus University Medical Center. Tested patients all had a right side vestibular schwannoma and underwent a wait and watch policy (Table 1; subjects N1-N3) after being diagnosed with vestibular schwannoma. Their tumors had been stabile for over 8-10 years on magnetic resonance imaging.

Version-vergence interactions during memory-guided binocular gaze shifts.

PURPOSE: Visual orientation toward remembered or visible visual targets requires binocular gaze shifts that are accurate in direction (version) and ocular distance (vergence). We determined the accuracy of combined version and vergence movements and the contribution of the abducting and adducting eye during gaze shifts toward memorized and visual targets in three-dimensional space. METHODS: Subjects fixated either a "far" (94 cm) or "near" (31 cm) fixation light-emitting diode (LED) placed in front of the left eye. Next, in the memory-guided experiment, a target LED was lit for 80 ms (13 cm to the left or right and at 45 cm viewing distance). Subjects were instructed to make a saccade to the (remembered) target LED location. In the visually guided experiment, the target LED remained illuminated during the task. In both conditions, gaze shifts consisted of version and vergence movements. RESULTS: Visually guided gaze shifts had both a fast intrasaccadic and a slow postsaccadic vergence component and were most accurate. During memory-guided gaze shifts, the abducting eye was more accurate than the adducting eye. Distance correction was achieved by slow postsaccadic vergence of the adducting eye. Memory-guided gaze shifts that required convergence lacked an intrasaccadic vergence component and were less accurate compared to memory-guided gaze shifts that required divergence. CONCLUSIONS: Visually guided binocular gaze shifts are faster and more accurate than memory-guided binocular gaze shifts. During memory-guided gaze shifts, the abducting eye has a leading role, and an intrasaccadic vergence enhancement during convergence is reduced.

Binocular eye movement control and motion perception: what is being tracked?

PURPOSE: We investigated under what conditions humans can make independent slow phase eye movements. The ability to make independent movements of the two eyes generally is attributed to few specialized lateral eyed animal species, for example chameleons. In our study, we showed that humans also can move the eyes in different directions. To maintain binocular retinal correspondence independent slow phase movements of each eye are produced. METHODS: We used the scleral search coil method to measure binocular eye movements in response to dichoptically viewed visual stimuli oscillating in orthogonal direction. RESULTS: Correlated stimuli led to orthogonal slow eye movements, while the binocularly perceived motion was the vector sum of the motion presented to each eye. The importance of binocular fusion on independency of the movements of the two eyes was investigated with anti-correlated stimuli. The perceived global motion pattern of anti-correlated dichoptic stimuli was perceived as an oblique oscillatory motion, as well as resulted in a conjugate oblique motion of the eyes. CONCLUSIONS: We propose that the ability to make independent slow phase eye movements in humans is used to maintain binocular retinal correspondence. Eye-of-origin and binocular information are used during the processing of binocular visual information, and it is decided at an early stage whether binocular or monocular motion information and independent slow phase eye movements of each eye are produced during binocular tracking.

Peaks and troughs of three-dimensional vestibulo-ocular reflex in humans.

The three-dimensional vestibulo-ocular reflex (3D VOR) ideally generates compensatory ocular rotations not only with a magnitude equal and opposite to the head rotation but also about an axis that is collinear with the head rotation axis. Vestibulo-ocular responses only partially fulfill this ideal behavior. Because animal studies have shown that vestibular stimulation about particular axes may lead to suboptimal compensatory responses, we investigated in healthy subjects the peaks and troughs in 3D VOR stabilization in terms of gain and alignment of the 3D vestibulo-ocular response. Six healthy upright sitting subjects underwent whole body small amplitude sinusoidal and constant acceleration transients delivered by a six-degree-of-freedom motion platform. Subjects were oscillated about the vertical axis and about axes in the horizontal plane varying between roll and pitch at increments of 22.5 degrees in azimuth. Transients were delivered in yaw, roll, and pitch and in the vertical canal planes. Eye movements were recorded in with 3D search coils. Eye coil signals were converted to rotation vectors, from which we calculated gain and misalignment. During horizontal axis stimulation, systematic deviations were found. In the light, misalignment of the 3D VOR had a maximum misalignment at about 45 degrees . These deviations in misalignment can be explained by vector summation of the eye rotation components with a low gain for torsion and high gain for vertical. In the dark and in response to transients, gain of all components had lower values. Misalignment in darkness and for transients had different peaks and troughs than in the light: its minimum was during pitch axis stimulation and its maximum during roll axis stimulation. We show that the relatively large misalignment for roll in darkness is due to a horizontal eye movement component that is only present in darkness. In combination with the relatively low torsion gain, this horizontal component has a relative large effect on the alignment of the eye rotation axis with respect to the head rotation axis.