Mary Lou Jackson

Combining Visual Rehabilitative Training and Noninvasive Brain Stimulation to Enhance Visual Function in Patients With Hemianopia: A Comparative Case Study

To standardize a protocol for promoting visual rehabilitative outcomes in post‐stroke hemianopia by combining occipital cortical transcranial direct current stimulation (tDCS) with Vision Restoration Therapy (VRT).

Temporal profile of functional visual rehabilitative outcomes modulated by transcranial direct current stimulation.

Objectives:  We have previously reported that transcranial direct current stimulation (tDCS) delivered to the occipital cortex enhances visual functional recovery when combined with three months of computer‐based rehabilitative training in patients with hemianopia. The principal objective of this study was to evaluate the temporal sequence of effects of tDCS on visual recovery as they appear over the course of training and across different indicators of visual function.

Vision rehabilitation for Canadians with less than 20/40 acuity: the SmartSight model*

Traditionally, vision rehabilitation was directed towards patients who were blind or had very low vision. There is increasing evidence that less severe vision loss is associated with increased risk of falls, hip fractures, medication errors, poor nutrition, reduced physical activity, social isolation, clinical depression, longer hospitalizations, and mortality. The American Academy of Ophthalmology (AAO) 2003 SmartSight initiative in low vision rehabilitation outlined a model of graduated low vision interventions. This paper is a review of the AAO SmartSight model and how it can apply in the Canadian setting. All patients with visual acuity less than 20/40, a scotoma, field loss, or loss of contrast sensitivity would be offered information about available low vision rehabilitation. Eye physicians would be encouraged to communicate with other health care providers to coordinate existing services and integrate graduated services. Enhanced communication among caregivers about the consequences of vision loss, such as depression, falls, and visual hallucinations, could help ensure that all patients who would benefit receive appropriate vision rehabilitation.

Contrast sensitivity and visual hallucinations in patients referred to a low vision rehabilitation clinic

Aim: To examine the association of reported visual hallucinations and measured visual parameters in adult patients referred for low vision rehabilitation. Methods: All patients (N = 225) referred to a low vision rehabilitation clinic for a calendar year were asked a standardised question about symptoms of formed visual hallucinations. Best corrected visual acuity and contrast sensitivity using the Pelli-Robson chart were measured. We conducted multiple logistic regression analysis of the association between visual hallucinations and visual parameters. Results: Of the total cohort, 78 (35%) reported visual hallucinations. Visual acuity and contrast sensitivity were considered in four quartiles. In multiple logistic regression controlling for contrast sensitivity, age, gender, report of depression and independence, measured acuity in each of the poorer three categories (compared to the best) was not associated with reported hallucinations. Contrast sensitivity in the three poorer quartiles (compared to the best) was strongly associated with the report of hallucinations (OR 4.1, CI 1.1, 15.9; OR 10.5, CI 2.6, 42.1; OR 28.1, CI 5.6, 140.9) after controlling for acuity, age, sex, depression and independence. Conclusions: Lowest contrast sensitivity was the strongest predictor of reported hallucinations after adjusting for visual acuity.

Empirical methodologies in software engineering

The collection and use of evidence in software engineering practice and research are essential elements in the development of the discipline. This paper discusses the need for evidence-based software engineering, the nature of evidence in its various forms and some of the research methodologies used in other disciplines for the collection of evidence, which are also relevant to software engineering. Two frameworks or models are proposed which illustrate the relationships between the methodologies discussed. In particular, the paper highlights the importance and roles of both positivist and interpretivist methods of investigation.

Medicare Coverage for Vision Assistive Equipment

Vision loss that cannot be corrected medically, surgically, or by refractive means is considered low vision. Low vision often results in impairment of daily activities, loss of independence, increased risk of fractures, excess health care expense, and reduced physical functioning, quality of life, and life expectancy. Vision rehabilitation can enable more independent functioning for individuals with low vision. The Centers for Medicare and Medicaid Services recognizes the importance of rehabilitation for achieving medically necessary goals but has denied Medicare coverage for vision assistive equipment that is necessary to complete these goals, although they provide coverage for assistive equipment to provide compensation for other disabilities. We believe that this is discriminatory and does not comport with congressional intent. The Centers for Medicare and Medicaid Services should provide coverage for vision assistive equipment, allowing beneficiaries with vision loss to benefit fully from Medicare-covered rehabilitation to achieve the cost-effective results of these services.

Characterization of field loss based on microperimetry is predictive of face recognition difficulties.

PURPOSE To determine how visual field loss as assessed by microperimetry is correlated with deficits in face recognition. METHODS Twelve patients (age range, 26-70 years) with impaired visual sensitivity in the central visual field caused by a variety of pathologies and 12 normally sighted controls (control subject [CS] group; age range, 20-68 years) performed a face recognition task for blurred and unblurred faces. For patients, we assessed central visual field loss using microperimetry, fixation stability, Pelli-Robson contrast sensitivity, and letter acuity. RESULTS Patients were divided into two groups by microperimetry: a low vision (LV) group (n = 8) had impaired sensitivity at the anatomical fovea and/or poor fixation stability, whereas a low vision that excluded the fovea (LV:F) group (n = 4) was characterized by at least some residual foveal sensitivity but insensitivity in other retinal regions. The LV group performed worse than the other groups at all blur levels, whereas the performance of the LV:F group was not credibly different from that of the CS group. The performance of the CS and LV:F groups deteriorated as blur increased, whereas the LV group showed consistently poor performance regardless of blur. Visual acuity and fixation stability were correlated with face recognition performance. CONCLUSIONS Persons diagnosed as having disease affecting the central visual field can recognize faces as well as persons with no visual disease provided that they have residual sensitivity in the anatomical fovea and show stable fixation patterns. Performance in this task is limited by the upper resolution of nonfoveal vision or image blur, whichever is worse.

Charles Bonnet Syndrome and glaucoma.

Dear Editor: Approximately one third of patients referred for vision rehabilitation report experiencing recurrent visual hallucinations, the Charles Bonnet Syndrome (CBS). Four elements are required to define CBS; formed visual hallucinations, insight into the unreal nature of the positive phenomena when it is explained to the patient, some degree of vision loss, and no other psychiatric or neurological diagnosis to explain the hallucinations. Most CBS subjects studied have had a diagnosis of age-related macular degeneration. Glaucoma is a leading cause of irreversible visual impairment and blindness in the developed world, however, little is known about the prevalence of CBS in these patients. A previous study found a 12.3% prevalence of CBS in patients with glaucoma, but excluded patients with greater than 20/80 acuity and included subjects with glaucoma and other ocular disease. A case series reported CBS in 4 patients with glaucoma who had visual acuity better than 6/12. We undertook this study to evaluate the prevalence of CBS in patients with glaucoma referred for vision rehabilitation. We retrospectively reviewed the patients seen at the Massachusetts Eye and Ear Infirmary Vision Rehabilitation Clinic from March 2007 to August 2008. Each patient was asked a leading question to elicit the symptom of hallucinations. “Many patients who come to this Clinic tell us that they see things they know are not there. Some see patterns or shapes. Others see images of people or animals. Have you ever experienced this?” Our analysis considered 3 groups, the total cohort referred to vision rehabilitation, those with a diagnosis of glaucoma and other ocular diagnoses, and those with only a diagnosis of glaucoma. Charles Bonnet Syndrome cases were matched with controls without hallucinations of similar glaucoma status, age, acuity, and contrast sensitivity. Each variable was investigated by matching on the other variables with a one-to-many strategy in which controls were uniquely chosen randomly among eligible pairings. In our cohort of 698 patients, 23% (161/698) reported recurrent visual hallucinations. Twenty percent (141/689) of the overall group had a diagnosis of glaucoma and of these, 127 had other coexisting ophthalmic diagnosis. Twenty-one percent of those with any diagnosis of glaucoma (29/141) had hallucinations, while 29% percent of those with only a diagnosis of glaucoma (4/14) reported hallucinations (Figure 1 and Table 1, available at http://aaojournal.org). There was no significant difference between the report of hallucinations in the patients with glaucoma compared with those without glaucoma (P 0.497). There also was no significant difference between the report of hallucinations in those who only had a diagnosis of glaucoma compared with those with any other diagnosis (Fisher exact test P 0.41) (Table 2, available at http://aaojournal.org). One glaucoma patient with hallucinations had acuity of 0/25. Although visual field data was not available for all ubjects, patients who experienced CBS all had either seere field loss represented by a mean defect greater than -12 Severe Defect by Hodapp-Parrish-Anderson Glaucoma Seerity criteria), or narrative report on the medical record of advanced glaucoma.’ We have previously shown that reuced contrast sensitivity is a risk factor for CBS. This ame association is found in this vision rehabilitation cohort lthough not in the smaller subset of glaucoma-only subects. Age was a significant risk factor for CBS in glaucoma ubjects (T-test P 0.001) (Table 3, available at http:// aojournal.org). Further study with larger samples of glauoma patients would be required to draw conclusions about he level of visual field loss or contrast sensitivity loss at hich patients become at risk of experiencing hallucinaions. Although patients report a negative reaction to the onset f the hallucinations, most do not report hallucinations due o concern that their mental competence may be questioned. hose who do report their hallucinations are often met with uizzical looks, as not all physicians appreciate the nature of he syndrome. Many patients express relief and gratitude hen reassured that the hallucinations are not a symptom of ental incompetence, but rather a symptom of vision loss. ur findings indicate that patients with glaucoma referred or vision rehabilitation have the same chance of reporting BS than patients with other diagnoses. Physicians might nquire about CBS in patients with severe visual field loss in rder to provide assurance to glaucoma patients who may xperience this peculiar symptom. MARY LOU JACKSON, MD BRIAN DROHAN, PHD Boston, Massachusetts

Feasibility of a Web-Based Survey of Hallucinations and Assessment of Visual Function in Patients With Parkinson’s Disease

Background Patients with Parkinson’s disease (PD) experience visual hallucinations, which may be related to decreased contrast sensitivity (ie, the ability to discern shades of grey). Objective The objective of this study was to investigate if an online research platform can be used to survey patients with Parkinson’s disease regarding visual hallucinations, and also be used to assess visual contrast perception. Methods From the online patient community, PatientsLikeMe, 964 members were invited via email to participate in this study. Participants completed a modified version of the University of Miami Parkinson’s disease hallucinations questionnaire and an online vision test. Results The study was completed by 27.9% (269/964) of those who were invited: 56.9% of this group had PD (153/269) and 43.1% (116/269) were non-Parkinson’s controls. Hallucinations were reported by 18.3% (28/153) of the Parkinson’s group. Although 10 subjects (9%) in the control group reported experiencing hallucinations, only 2 of them actually described formed hallucinations. Participants with Parkinson’s disease with a mean of 1.75 (SD 0.35) and the control group with a mean of 1.85 (SD 0.36) showed relatively good contrast perception as measured with the online letter test (P=.07). People who reported hallucinations showed contrast sensitivity levels that did not differ from levels shown by people without hallucinations (P=.96), although there was a trend towards lower contrast sensitivity in hallucinators. Conclusions Although more Parkinsons responders reported visual hallucinations, a significant number of non-Parkinsons control group responders also reported visual hallucinations. The online survey method may have failed to distinguish between formed hallucinations, which are typical in Parkinsons disease, and non-formed hallucinations that have less diagnostic specificity. Multiple questions outlining the nature of the hallucinations are required. In a clinical interview, the specific nature of the hallucination would be further refined to rule out a vague description that does not indicate a true, formed visual hallucination. Contrary to previous literature, both groups showed relatively good contrast sensitivity, perhaps representing a ceiling effect or limitations of online testing conditions that are difficult to standardize. Steps can be taken in future trials to further standardize online visual function testing, to refine control group parameters and to take steps to rule out confounding variables such as comorbid disease that could be associated with hallucinations. Contacting subjects via an online health social network is a novel, cost-effective method of conducting vision research that allows large numbers of individuals to be contacted quickly, and refinement of questionnaires and visual function testing may allow more robust findings in future research.

Yersinia pestis Survival and Replication in Potential Ameba Reservoir

Plague ecology is characterized by sporadic epizootics, then periods of dormancy. Building evidence suggests environmentally ubiquitous amebae act as feral macrophages and hosts to many intracellular pathogens. We conducted environmental genetic surveys and laboratory co-culture infection experiments to assess whether plague bacteria were resistant to digestion by 5 environmental ameba species. First, we demonstrated that Yersinia pestis is resistant or transiently resistant to various ameba species. Second, we showed that Y. pestis survives and replicates intracellularly within Dictyostelium discoideum amebae for ˃48 hours postinfection, whereas control bacteria were destroyed in <1 hour. Finally, we found that Y. pestis resides within ameba structures synonymous with those found in infected human macrophages, for which Y. pestis is a competent pathogen. Evidence supporting amebae as potential plague reservoirs stresses the importance of recognizing pathogen-harboring amebae as threats to public health, agriculture, conservation, and biodefense.