How a Digital Case Management Platform Affects Community-Based Palliative Care of Sub-Saharan African Cancer Patients: Clinician-Users' Perspectives.

BACKGROUND: Symptom control among cancer patients is a Tanzanian public health priority impacted by limited access to palliative care (PC) specialists and resources. Mobile Palliative Care Link (mPCL), a mobile/web application, aims to extend specialist access via shared care with local health workers (LHWs) with the African Palliative care Outcome Scale (POS) adapted for regular, automated symptom assessment as a core feature. OBJECTIVE: The aim of the study is to assess clinicians' attitudes, beliefs, and perceptions regarding mPCL usability and utility with their patients within a government-supported, urban Tanzanian cancer hospital setting. METHODS: We used a mixed methods approach including surveys, qualitative interviews, and system usage data to assess clinicians' experience with mPCL in a field study where discharged, untreatable cancer patients were randomized to mPCL or phone-contact POS collection. RESULTS: All six specialists and 10 LHWs expressed overall satisfaction with mPCL among 49 intervention arm patients. They perceived mPCL as a way to stay connected with patients and support remote symptom control. Timely access to POS responses and medical records were identified as key benefits. Some differences in perceptions of mPCL use and utility were seen between clinician groups; however, both expressed strong interest in continuing app use, recommending it to colleagues, and extending use throughout Tanzania. Primary use was for clinical status communication and care coordination. Pain and other symptom progression were the most frequently reported reasons for provider-patient interactions accounting for 34% (n = 44) and 12% (n = 15) of reasons, respectively. Usage barriers included time required to create a new clinical record, perceived need for response to non-urgent reminders or alerts, and training. necessary for competent use. System-level implementation barriers included variable patient access to smartphones and SIM cards and unreliable Internet access. CONCLUSION: This work demonstrates broad clinician desire for digital health tools to support remote community-based PC among cancer patients, particularly pain management.

Implementing a digital system for contact tracing and case investigation during COVID-19 pandemic in San Francisco: a qualitative study.

During the COVID-19 pandemic, many health jurisdictions deployed digital informatics systems to support "manual" case investigation and contact tracing (CICT). This case study evaluates the implementation and use of a digital information system through the experiences of CICT workers in the City and County of San Francisco (CCSF). We conducted semi-structured, 90-min interviews with a sample of the CCSF CICT workforce (n = 37). Participants also completed standardized assessments of the digital system using the System Usability Scale (SUS). Qualitative analyses highlighted (1) the importance of digital tools to ensure rapid onboarding and effective data capture in a public health emergency; (2) the use of digital systems to support culturally sensitive care; and (3) the role of digitals tools in building supportive work environments. The mean SUS score was 70/100 (SD = 17), indicating relative ease of use. In summary, the analysis highlights the importance of digital tools to support manual CICT in the COVID-19 response.

mPalliative Care Link: Examination of a Mobile Solution to Palliative Care Coordination Among Tanzanian Patients With Cancer.

PURPOSE: Late-stage cancer patient symptom control is a national priority in Tanzania. Mobile health promises to improve the reach of a limited pool of palliative care specialists through interprofessional, community-based care coordination. This work assessed the effectiveness of a smartphone- or Web-based app, mPalliative Care Link (mPCL), to extend specialist access via shared data and communication with local health workers. Central to mPCL is the African Palliative care Outcome Scale (POS), adapted for automated mobile symptom assessment and response. METHODS: Adult patients with incurable cancer were randomly assigned at hospital discharge to mPCL versus phone-contact POS collection. Sociodemographic, clinical, and POS data were obtained at baseline. Twice-weekly POS responses were collected and managed via mPCL or phone contact with clinician study personnel for up to 4 months, on the basis of study arm assignment. Patient end-of-study care satisfaction was assessed via phone survey. RESULTS: Forty-nine patients per arm participated. Comparison of baseline characteristics showed an insignificant trend toward more women (P = .07) and higher discharge morphine use (P = .09) in the mPCL group compared with phone-contact and significant between-group differences in cancer types (P = .003). Proportions of deaths were near equal between groups (mPCL: 27%; phone-contact: 29%). Overall symptom severity was significantly lower in the phone-contact group (P < .0001), and symptom severity decreased over time in both groups (P = .0001); however, between-group change in overall symptoms over time did not vary significantly (P = .34). Care satisfaction was generally high in both groups. CONCLUSION: Higher symptom severity scores in the mPCL arm likely reflect between-group sociodemographic and clinical differences and clinical support of phone-contact arm participants. Similar rates of care satisfaction in both groups suggest that mPCL may support symptom-focused care coordination in a more efficient and scalable manner than phone contact. A broader study of mPCL's cost efficiency and utility in Tanzania is needed.

A Mobile App to Improve Symptom Control and Information Exchange Among Specialists and Local Health Workers Treating Tanzanian Cancer Patients: Human-Centered Design Approach.

BACKGROUND: Improving access to end-of-life symptom control interventions among cancer patients is a public health priority in Tanzania, and innovative community-based solutions are needed. Mobile health technology holds promise; however, existing resources are limited, and outpatient access to palliative care specialists is poor. A mobile platform that extends palliative care specialist access via shared care with community-based local health workers (LHWs) and provides remote support for pain and other symptom management can address this care gap. OBJECTIVE: The aim of this study is to design and develop mobile-Palliative Care Link (mPCL), a web and mobile app to support outpatient symptom assessment and care coordination and control, with a focus on pain. METHODS: A human-centered iterative design framework was used to develop the mPCL prototype for use by Tanzanian palliative care specialists (physicians and nurses trained in palliative care), poor-prognosis cancer patients and their lay caregivers (patients and caregivers), and LHWs. Central to mPCL is the validated African Palliative Care Outcome Scale (POS), which was adapted for automated, twice-weekly collection of quality of life-focused patient and caregiver responses and timely review, reaction, and tracking by specialists and LHWs. Prototype usability testing sessions were conducted in person with 21 key informants representing target end users. Sessions consisted of direct observations and qualitative and quantitative feedback on app ease of use and recommendations for improvement. Results were applied to optimize the prototype for subsequent real-world testing. Early pilot testing was conducted by deploying the app among 10 patients and caregivers, randomized to mPCL use versus phone-contact POS collection, and then gathering specialist and study team feedback to further optimize the prototype for a broader randomized field study to examine the app's effectiveness in symptom control among cancer patients. RESULTS: mPCL functionalities include the ability to create and update a synoptic clinical record, regular real-time symptom assessment, patient or caregiver and care team communication and care coordination, symptom-focused educational resources, and ready access to emergency phone contact with a care team member. Results from the usability and pilot testing demonstrated that all users were able to successfully navigate the app, and feedback suggests that mPCL has clinical utility. User-informed recommendations included further improvement in app navigation, simplification of patient and caregiver components and language, and delineation of user roles. CONCLUSIONS: We designed, built, and tested a usable, functional mobile app prototype that supports outpatient palliative care for Tanzanian patients with cancer. mPCL is expressly designed to facilitate coordinated care via customized interfaces supporting core users-patients or caregivers, LHWs, and members of the palliative care team-and their respective roles. Future work is needed to demonstrate the effectiveness and sustainability of mPCL to remotely support the symptom control needs of Tanzanian cancer patients, particularly in harder-to-reach areas.

The feasibility of text reminders to improve medication adherence in adolescents with asthma.

OBJECTIVE: Personal health applications have the potential to help patients with chronic disease by improving medication adherence, self-efficacy, and quality of life. The goal of this study was to assess the impact of MyMediHealth (MMH) - a website and a short messaging service (SMS)-based reminder system - on medication adherence and perceived self-efficacy in adolescents with asthma. METHODS: We conducted a block-randomized controlled study in academic pediatric outpatient settings. There were 98 adolescents enrolled. Subjects who were randomized to use MMH were asked to create a medication schedule and receive SMS reminders at designated medication administration times for 3 weeks. Control subjects received action lists as a part of their usual care. Primary outcome measures included MMH usage patterns and self-reports of system usability, medication adherence, asthma control, self-efficacy, and quality of life. RESULTS: Eighty-nine subjects completed the study, of whom 46 were randomized to the intervention arm. Compared to controls, we found improvements in self-reported medication adherence (P = .011), quality of life (P = .037), and self-efficacy (P = .016). Subjects reported high satisfaction with MMH; however, the level of system usage varied widely, with lower use among African American patients. CONCLUSIONS: MMH was associated with improved medication adherence, perceived quality of life, and self-efficacy.Trial Registration This project was registered under http://clinicaltrials.gov/ identifier NCT01730235.

Disparities in the use of a mHealth medication adherence promotion intervention for low-income adults with type 2 diabetes.

OBJECTIVE: Mobile health (mHealth) interventions may improve diabetes outcomes, but require engagement. Little is known about what factors impede engagement, so the authors examined the relationship between patient factors and engagement in an mHealth medication adherence promotion intervention for low-income adults with type 2 diabetes (T2DM). MATERIALS AND METHODS: Eighty patients with T2DM participated in a 3-month mHealth intervention called MEssaging for Diabetes that leveraged a mobile communications platform. Participants received daily text messages addressing and assessing medication adherence, and weekly interactive automated calls with adherence feedback and questions for problem solving. Longitudinal repeated measures analyses assessed the relationship between participants' baseline characteristics and the probability of engaging with texts and calls. RESULTS: On average, participants responded to 84.0% of texts and participated in 57.1% of calls. Compared to Whites, non-Whites had a 63% decreased relative odds (adjusted odds ratio [AOR] = 0.37, 95% confidence interval [CI], 0.19-0.73) of participating in calls. In addition, lower health literacy was associated with a decreased odds of participating in calls (AOR = 0.67, 95% CI, 0.46-0.99, P = .04), whereas older age (Pnonlinear = .01) and more depressive symptoms (AOR = 0.62, 95% CI, 0.38-1.02, P = .059) trended toward a decreased odds of responding to texts. CONCLUSIONS: Racial/ethnic minorities, older adults, and persons with lower health literacy or more depressive symptoms appeared to be the least engaged in a mHealth intervention. To facilitate equitable intervention impact, future research should identify and address factors interfering with mHealth engagement.

A novel approach to supporting relationship-centered care through electronic health record ergonomic training in preclerkship medical education.

PROBLEM: How can physicians incorporate the electronic health record (EHR) into clinical practice in a relationship-enhancing fashion ("EHR ergonomics")? APPROACH: Three convenience samples of 40 second-year medical students with varying levels of EHR ergonomic training were compared in the 2012 spring semester. All participants first received basic EHR training and completed a presurvey. Two study groups were then instructed to use the EHR during the standardized patient (SP) encounter in each of four regularly scheduled Doctoring (clinical skills) course sessions. One group received additional ergonomic training in each session. Ergonomic assessment data were collected from students, faculty, and SPs in each session. A postsurvey was administered to all students, and data were compared across all three groups to assess the impact of EHR use and ergonomic training. OUTCOMES: There was a significant positive effect of EHR ergonomics skills training on students' relationship-centered EHR use (P<.005). Students who received training reported that they were able to use the EHR to engage with patients more effectively, better articulate the benefits of using the EHR, better address patient concerns, more appropriately position the EHR device, and more effectively integrate the EHR into patient encounters. Additionally, students' self-assessments were strongly corroborated by SP and faculty assessments. A minimum of three ergonomic training sessions were needed to see an overall improvement in EHR use. NEXT STEPS: In addition to replication of these results, further effectiveness studies of this educational intervention need to be carried out in GME, practice, and other environments.

Features of online health communities for adolescents with type 1 diabetes.

The aim of this exploratory study was to examine diabetes online health communities (OHCs) available to adolescents with type 1 diabetes (T1D). We sought to identify and classify site features and relate them to evidence-based processes for improving self-management. We reviewed 18 OHCs and identified the following five feature categories: social learning and networking, information, guidance, engagement, and personal health data sharing. While features that have been associated with improved self-management were present, such as social learning, results suggest that more guidance or structure would be helpful to ensure that those processes were focused on promoting positive beliefs and behaviors. Enhancing guidance-related features and structure to existing OHCs could provide greater opportunity for effective diabetes self-management support. To support clinical recommendations, more research is needed to quantitatively relate features and participation in OHCs to patient outcomes.

An assessment of pharmacists' readiness for paperless labeling: a national survey.

OBJECTIVE: To assess the state of readiness for the adoption of paperless labeling among a nationally representative sample of pharmacies, including chain pharmacies, independent retail pharmacies, hospitals, and other rural or urban dispensing sites. METHODS: Both quantitative and qualitative analyses were used to analyze responses to a cross-sectional survey disseminated to American Pharmacists Association pharmacists nationwide. The survey assessed factors related to pharmacists' attitudinal readiness (ie, perceptions of impact) and pharmacies' structural readiness (eg, availability of electronic resources, internet access) for the paperless labeling initiative. RESULTS: We received a total of 436 survey responses (6% response rate) from pharmacists representing 44 US states and territories. Across the spectrum of settings we studied, pharmacists had work access to computers, printers, fax machines and access to the internet or intranet. Approximately 79% of respondents believed that the initiative would improve the adequacy of drug information available in their work site and 95% believed it would either not change (33%) or would improve (62%) communication to patients. Overall, respondents' comments supported advancing the initiative; however, some comments revealed reservations regarding corporate or pharmacy buy-in, success of implementation, and ease of adoption. CONCLUSIONS: This is the first nationwide study to report about pharmacists' perspectives on paperless labeling. In general, pharmacists believe they are ready and that their pharmacies are well equipped for the transition to paperless labeling. Further exploration of perspectives from product label manufacturers and corporate pharmacy offices is needed to understand fully what will be necessary to complete this transition.

Assessing adolescent asthma symptoms and adherence using mobile phones.

BACKGROUND: Self-report is the most common method of measuring medication adherence but is influenced by recall error and response bias, and it typically does not provide insight into the causes of poor adherence. Ecological momentary assessment (EMA) of health behaviors using mobile phones offers a promising alternative to assessing adherence and collecting related data that can be clinically useful for adherence problem solving. OBJECTIVE: To determine the feasibility of using EMA via mobile phones to assess adolescent asthma medication adherence and identify contextual characteristics of adherence decision making. METHODS: We utilized a descriptive and correlational study design to explore a mobile method of symptom and adherence assessment using an interactive voice response system. Adolescents aged 12-18 years with a diagnosis of asthma and prescribed inhalers were recruited from an academic medical center. A survey including barriers to mobile phone use, the Illness Management Survey, and the Pediatric Asthma Quality of Life Questionnaire were administered at baseline. Quantitative and qualitative assessment of asthma symptoms and adherence were conducted with daily calls to mobile phones for 1 month. The Asthma Control Test (ACT) was administered at 2 study time points: baseline and 1 month after baseline. RESULTS: The sample consisted of 53 adolescents who were primarily African American (34/53, 64%) and female (31/53, 58%) with incomes US$40K/year or lower (29/53, 55%). The majority of adolescents (37/53, 70%) reported that they carried their phones with them everywhere, but only 47% (25/53) were able to use their mobile phone at school. Adolescents responded to an average of 20.1 (SD 8.1) of the 30 daily calls received (67%). Response frequency declined during the last week of the month (b=-0.29, P<.001) and was related to EMA-reported levels of rescue inhaler adherence (r= 0.33, P=.035). Using EMA, adolescents reported an average of 0.63 (SD 1.2) asthma symptoms per day and used a rescue inhaler an average of 70% of the time (SD 35%) when they experienced symptoms. About half (26/49, 53%) of the instances of nonadherence took place in the presence of friends. The EMA-measured adherence to rescue inhaler use correlated appropriately with asthma control as measured by the ACT (r=-0.33, P=.034). CONCLUSIONS: Mobile phones provided a feasible method to assess asthma symptoms and adherence in adolescents. The EMA method was consistent with the ACT, a widely established measure of asthma control, and results provided valuable insights regarding the context of adherence decision making that could be used clinically for problem solving or as feedback to adolescents in a mobile or Web-based support system.

Assessing the reliability of an automated dose-rounding algorithm.

OBJECTIVE: Pediatric dose rounding is a unique and complex process whose complexity is rarely supported by e-prescribing systems, though amenable to automation and deployment from a central service provider. The goal of this project was to validate an automated dose-rounding algorithm for pediatric dose rounding. METHODS: We developed a dose-rounding algorithm, STEPSTools, based on expert consensus about the rounding process and knowledge about the therapeutic/toxic window for each medication. We then used a 60% subsample of electronically-generated prescriptions from one academic medical center to further refine the web services. Once all issues were resolved, we used the remaining 40% of the prescriptions as a test sample and assessed the degree of concordance between automatically calculated optimal doses and the doses in the test sample. Cases with discrepant doses were compiled in a survey and assessed by pediatricians from two academic centers. The response rate for the survey was 25%. RESULTS: Seventy-nine test cases were tested for concordance. For 20 cases, STEPSTools was unable to provide a recommended dose. The dose recommendation provided by STEPSTools was identical to that of the test prescription for 31 cases. For 14 out of the 24 discrepant cases included in the survey, respondents significantly preferred STEPSTools recommendations (p<0.05, binomial test). Overall, when combined with the data from all test cases, STEPSTools either matched or exceeded the performance of the test cases in 45/59 (76%) of the cases. The majority of other cases were challenged by the need to provide an extremely small dose. We estimated that with the addition of two dose-selection rules, STEPSTools would achieve an overall performance of 82% or higher. CONCLUSIONS: Results of this pilot study suggest that automated dose rounding is a feasible mechanism for providing guidance to e-prescribing systems. These results also demonstrate the need for validating decision-support systems to support targeted and iterative improvement in performance.

Adapting comparative effectiveness research summaries for delivery to patients and providers through a patient portal.

Despite increases in the scientific evidence for a variety of medical treatments, a gap remains in the adoption of best medical practices. This manuscript describes a process for adapting published summary guides from comparative effectiveness research to render them concise, targeted to audience, and easily actionable; and a strategy for disseminating such evidence to patients and their physicians through a web-based portal and linked electronic health record. This project adapted summary guides about oral medications for adults with type 2 diabetes to a fifth-grade literacy level and modified the resulting materials based on evaluations with the Suitability Assessment of Materials instrument. Focus groups and individual interviews with patients, diabetes providers, and health literacy experts were employed to evaluate and enhance the adapted summary guide. We present the lessons learned as general guidelines for the creation of concise, targeted, and actionable evidence and its delivery to both patients and providers through increasingly prevalent health information technologies.

User perspectives on the usability of a regional health information exchange.

OBJECTIVE: We assessed the usability of a health information exchange (HIE) in a densely populated metropolitan region. This grant-funded HIE had been deployed rapidly to address the imminent needs of the patient population and the need to draw wider participation from regional entities. DESIGN: We conducted a cross-sectional survey of individuals given access to the HIE at participating organizations and examined some of the usability and usage factors related to the technology acceptance model. MEASUREMENTS: We probed user perceptions using the Questionnaire for User Interaction Satisfaction, an author-generated Trust scale, and user characteristic questions (eg, age, weekly system usage time). RESULTS: Overall, users viewed the system favorably (ratings for all usability items were greater than neutral (one-sample Wilcoxon test, p<0.0014, Bonferroni-corrected for 35 tests). System usage was regressed on usability, trust, and demographic and user characteristic factors. Three usability factors were positively predictive of system usage: overall reactions (p<0 0.01), learning (p<0.05), and system functionality (p<0.01). Although trust is an important component in collaborative relationships, we did not find that user trust of other participating healthcare entities was significantly predictive of usage. An analysis of respondents' comments revealed ways to improve the HIE. CONCLUSION: We used a rapid deployment model to develop an HIE and found that perceptions of system usability were positive. We also found that system usage was predicted well by some aspects of usability. Results from this study suggest that a rapid development approach may serve as a viable model for developing usable HIEs serving communities with limited resources.

Showing Your Work: Impact of annotating electronic prescriptions with decision support results.

e-Prescribing systems with decision support do not routinely communicate an adequate amount of information regarding the prescribers' decision to pharmacists. To address this communication gap in the e-prescribing process, we implemented a system called Show Your Work (SYW) that appends alerts and override comments to e-prescriptions generated by an e-prescribing system. To assess the quantitative impact of this system, we conducted a randomized, double-blinded, controlled study to assess pharmacy callback rates and types, and to uncover any unintended consequences of the annotations. Each day, SYW output across the enterprise was turned "on" or "off" randomly for all e-prescriptions. A convenience sample of three pharmacies, blinded to SYW status, submitted callback logs each day. These logs were used to calculate the rate of and reason for callbacks. At the conclusion of the study, we surveyed the 50 most frequently used pharmacies in our area to assess the impact of SYW on satisfaction and communication. A total of 202 callbacks had occurred yielding a callback rate of 45 callbacks/1000 prescriptions for SYW "on" days and 40 callbacks/1000 prescriptions for "off" days (p=0.4). We received 38 surveys (76% response rate) with 33 respondents commenting about SYW. Most respondents agreed (69%) that SYW favorably impacted callbacks--especially with pediatric prescriptions (82%). Comments suggested that SYW increased callbacks where necessary and decreased them in other situations, but did not contribute to unnecessary callbacks. These findings support the continued and potentially expanded use of SYW by e-prescribing systems to enhance communication with pharmacists.

The role of visuohaptic experience in visually perceived depth.

Berkeley suggested that "touch educates vision," that is, haptic input may be used to calibrate visual cues to improve visual estimation of properties of the world. Here, we test whether haptic input may be used to "miseducate" vision, causing observers to rely more heavily on misleading visual cues. Human subjects compared the depth of two cylindrical bumps illuminated by light sources located at different positions relative to the surface. As in previous work using judgments of surface roughness, we find that observers judge bumps to have greater depth when the light source is located eccentric to the surface normal (i.e., when shadows are more salient). Following several sessions of visual judgments of depth, subjects then underwent visuohaptic training in which haptic feedback was artificially correlated with the "pseudocue" of shadow size and artificially decorrelated with disparity and texture. Although there were large individual differences, almost all observers demonstrated integration of haptic cues during visuohaptic training. For some observers, subsequent visual judgments of bump depth were unaffected by the training. However, for 5 of 12 observers, training significantly increased the weight given to pseudocues, causing subsequent visual estimates of shape to be less veridical. We conclude that haptic information can be used to reweight visual cues, putting more weight on misleading pseudocues, even when more trustworthy visual cues are available in the scene.

Conjoint measurement of gloss and surface texture.

The image of a material's surface varies not only with viewing and illumination conditions, but also with the material's surface properties, including its 3-D texture and specularity. Previous studies on the visual perception of surface material have typically focused on single material properties, ignoring possible interactions. In this study, we used a conjoint-measurement design to determine how observers represent perceived 3-D texture ("bumpiness") and specularity ("glossiness") and modeled how each of these two surface-material properties affects perception of the other. Observers made judgments of bumpiness and glossiness of surfaces that varied in both surface texture and specularity. We quantified how changes in each surface-material property affected judgments of the other and found that a simple additive model captured visual perception of texture and specularity and their interaction. Conjoint measurement is potentially a powerful tool for analyzing perception of surface material in realistic environments.

The effect of viewpoint on perceived visual roughness.

In previous work, we examined how the apparent roughness of a textured surface changed with direction of illumination. We found that observers exhibited systematic failures of roughness constancy across illumination conditions for triangular-faceted surfaces where physical roughness was defined as the variance of facet heights. These failures could be due, in part, to cues in the scene that confound changes in surface roughness with changes in illumination. These cues include the following: (1) the proportion of the surface in shadow, (2) mean luminance of the nonshadowed portion, (3) the standard deviation of the luminance of the nonshadowed portion, and (4) texture contrast. If the visual system relied on such "pseudocues" to roughness, then it would systematically misestimate surface roughness with changes in illumination much as our observers did despite the availability of depth cues such as binocular disparity. Here, we investigate observers' judgments of roughness when illumination direction and surface orientation are fixed and the observers' viewpoint with respect to the surface changes. We find a similar pattern of results. Observers exhibited patterned failures of roughness constancy with change in viewpoint, and an appreciable part of their failures could be accounted for by the same pseudocues. While the human visual system exhibits some degree of roughness constancy, our results lead to the conclusion that it does not always select the correct cues for a given visual task.

How attention enhances spatial resolution: evidence from selective adaptation to spatial frequency.

In this study, we investigated how spatial resolution and covert attention affect performance in a texture segmentation task in which performance peaks at midperiphery and drops at peripheral and central retinal locations. The central impairment is called the central performance drop (CPD; Kehrer, 1989). It has been established that attending to the target location improves performance in the periphery where resolution is too low for the task, but impairs it at central locations where resolution is too high. This is called the central attention impairment (CAI; Yeshurun & Carrasco, 1998, 2000). We employed a cuing procedure in conjunction with selective adaptation to explore (1) whether the CPD is due to the inhibition of low spatial frequency responses by high spatial frequency responses in central locations, and (2) whether the CAI is due to attention's shifting sensitivity to higher spatial frequencies. We found that adaptation to low spatial frequencies does not change performance in this texture segmentation task. However, adaptation to high spatial frequencies diminishes the CPD and eliminates the CAI. These results indicate that the CPD is primarily due to the dominance of high spatial frequency responses and that covert attention enhances spatial resolution by shifting sensitivity to higher spatial frequencies.

How direction of illumination affects visually perceived surface roughness.

We examined visual estimation of surface roughness using random, computer-generated, three-dimensional (3D) surfaces rendered under a mixture of diffuse lighting and a punctate source. The angle between the tangent to the plane containing the surface texture and the direction to the punctate source was varied from 50 to 70 deg across lighting conditions. Observers were presented with pairs of surfaces under different lighting conditions and indicated which 3D surface appeared rougher. Surfaces were viewed either in isolation or in scenes with added objects whose shading, cast shadows, and specular highlights provided information about the spatial distribution of illumination. All observers perceived surfaces to be markedly rougher with decreasing illuminant angle. Performance in scenes with added objects was no closer to constant than that in scenes without added objects. We identified four novel cues that are valid cues to roughness under any single lighting condition but that are not invariant under changes in lighting condition. We modeled observers' deviations from roughness constancy as a weighted linear combination of these "pseudocues" and found that they account for a substantial amount of observers' systematic deviations from roughness constancy with changes in lighting condition.