Studies on the luminance-related characteristics of the transient pattern reversal electroretinogram

The electroretinogram evoked by reversal pattern stimulation (rPERG) is known to contain both pattern contrast and luminance related components. The retinal mechanisms of the transient rPERGs subserving these functional characteristics are the main concern in the present studies. Considerable attention has been paid to the luminance-related characteristics of the response. The transient PERGs were found to consist of two subsequent processes using low frequency attenuation analysis. The processes overlapped and the individual difference in each process timings formed the major cause for the variations of the negative potential waveform of the transient rPERGs. Attention has been paid to those having ‘notch’ type of variation. Under different contrast levels, the amplitudes of the positive and negative potentials were linearly increased with higher contrast level and the negative potential showed a higher sensitivity to contrast changes and higher contrast gain. Under lower contrast levels, the decreased amplitudes made the difference in the timing course of the positive and negative processes evident, interpreting the appearance of the notch in some cases. Visual adaptation conditions for recording the transient rPERG were discussed. Another effort was to study the large variation of the transient rPERGs (especially the positive potential, P50) in the elderly who’s distant and near visual acuity were normal. It was found that reduction of retinal illumination contributed mostly to the P50 amplitude loss and contrast loss mostly to the negative potential (N95) amplitude loss. Senile miosis was thought to have little effect on the reduction of the retinal illumination, while the changes in the optics of the eye was probably the major cause for it, which interpreted the larger individual variation of the P50 amplitude of the elderly PERGs. Convex defocus affected the transient rPERGs more effectively than concave lenses, especially the N95 amplitude in the elderly. The disability of accommodation and the type and the degree of subjects’ ametropia should be taken into consideration when the elderly rPERGs were analysed.

Work disability and depressive disorders:impact on the European population

OBJECTIVE: Our aim was to study the impact of depressive disorders on work disability to discover the determinants of depression for work disability in the European countries. DESIGN: The sample was composed of 31,126 individuals from 29 countries included in the 2002 World Health Survey of the World Health Organization. National representative samples of countries from all regions of Europe and with different levels of economic development and health coverage were selected. RESULTS: Estimates of people not working because of ill health did not differ among European countries in relation to levels of economic development or health coverage. Significant determinants of people with diagnosis of depression not working because of ill health (reference category) versus working were age (odds ratio = 0.97), female sex (odds ratio = 1.71), education (odds ratio = 1.11), marital status (being unmarried indicating less probability), lowest income level, and comorbidity with angina pectoris (odds ratio = 0.51). Moreover, according to previous studies, we found some determinants (comorbidity with other diseases, young age, and unemployment) impacting on health status. CONCLUSIONS: Depression is a substantial cause of work disability and it is a complex phenomenon that involves many variables. Investigation into this relationship should improve, focusing on the role of determinants.

Organizational response to employment under the ADA of workers with psychiatric disabilities: Four case studies

Title 1 of the Americans with Disabilities Act (ADA) requires all employers, public and private, with more than fifteen employees to provide reasonable accommodation to qualified individuals with disabilities if the accommodation would, within limits, allow the individual to perform the essential functions of the job. Seven years after Congress enacted the law and five years after the initial provisions became effective, little information is available about the experience of organizations faced with requests for workplace accommodation.^ The question addressed in this study is: How are organizations responding to the ADA mandate to fit individuals with psychiatric disabilities in the workplace? The data sources are three organizations that allowed access to this sensitive information, and a fourth that had two disability discrimination charges filed against it.^ A brute-force case method approach applied to the four organizations yields the following information: Attorneys are hesitant to allow inquiry into company policy owing to fear of litigation; workers are not disclosing and requesting accommodation; tacit accommodation of long-standing employees appears to be a regular practice; knowledge of the intent of the ADA makes a difference in terms of equality of treatment; and insensitivity to employee privacy results in an adversarial situation.^ Implications are relevant to the need to improve lines of communication between human resource, EEO, supervisory, and legal staff; consequences of failure to address accommodations on an explicit level; need for better understanding of the availability and use of outside resources for achieving accommodation; and improvement of self-advocacy and disclosure by the employees with disabilities. ^

Examining Cognitive Processing in Children with an Arithmetic Disability

Currently there is no consensus as to the specific cognitive impairments that characterize mathematical disabilities (MD) or specific subtypes such as an arithmetic disability (AD). The present study sought to address this concern by examining cognitive processes that might undergird AD in children. The present study utilized archival data to conduct two investigations. The first investigation examined the executive functioning and working memory of children with AD. An age-matched achievement-matched design was employed to explore whether children with AD exhibit developmental lags or deficits in these cognitive domains. While children with AD did not exhibit impairments in verbal working memory or colour word inhibition, they did demonstrate impairments in shifting attention, visual-spatial working memory, and quantity inhibition. As children with AD did not perform more poorly than their younger achievement-matched peers on any of these tasks, impairments in specific areas of executive functioning and working memory appeared to reflect a developmental lag rather than a cognitive deficit. The second study examined the phonological processing performance of children with AD compared to children with comorbid disabilities in arithmetic and word recognition (AD/WRD) and to typically achieving (TA) children. Results indicated that, while children with AD did demonstrate impairments on all isolated naming speed tasks, trail making digits, and memory for digits, they did not demonstrate impairments on measures of phonological awareness, nonword repetition, serial processing speed, or serial naming speed. In contrast, children with AD/WRD demonstrated impairments on measures of phonological awareness, phonological short-term memory, isolated naming speed, serial processing speed, and the alphabet a-z task. Overall, results suggested that phonological processing impairments are more prominent in children with a WRD than children with an AD. Together, these studies further our understanding of the nature of the cognitive processes that underlie AD by focusing upon rarely used methods (i.e., age-matched achievement-matched design) and under-examined cognitive domains (i.e., phonological processing).

Palliative Medicine:Scoping the level and extent of service provision to people with intellectual disability at end of life Poster Presentation

Background: Concerns exist about the end of life care
that people with intellectual disabilities receive. This population
are seldom referred to palliative care services and
inadequate data sets exist about their place of death.
Aim: To scope the extent of service provision to people
with intellectual disabilities at the end of life by specialist
palliative care and intellectual disability services in one
region of the United Kingdom.
Methods: As part of a larger doctoral study a regional survey
took place of a total sample (n=66) of specialist palliative
care and intellectual disability services using a postal
questionnaire containing forty items. The questionnaire
was informed by the literature and consultation with an
expert reference group. Data were analysed using SPSS to
obtain descriptive statistics.
Results: A total response rate from services of 71.2%
(n=47) was generated. Findings showed a range of experience
among services in providing end of life care to people
with intellectual disabilities in the previous five years, but
general hospitals were reported the most common place of
death. A lack of accessible information on end of life care
for people with learning disabilities was apparent. A few
services (n=14) had a policy to support this population to
make decisions about their care or had used adapted Breaking
Bad News guidelines (n=5) to meet their additional
needs. Both services recognised the value of partnership
working in assessing and meeting the holistic needs of
people with intellectual disabilities at end of life.
Conclusions: A range of experience in caring for people
with intellectual disabilities was present across services,
but more emphasis is required on adapting communication
for this population to facilitate them to participate in their
care. These findings could have international significance
given that studies in other countries have highlighted a
need to widen access to palliative care for this group of
people.

The Broader Impact of Disability Research: Aligning Public Policy with the Experiences of People with Disabilities and Healthcare Providers

Thesis (Ph.D.)--University of Washington, 2016-07

Assessment of visual function in children with multiple disabilities: two case studies of children with cerebral palsy

Purpose: a) multiply handicapped children have a high incidence of disorders affecting the visual system; b) assessment and management of visual disorders in this group of children presents a complex challenge; c) this study describes the results of visual function assessment in two children with neurological disability over a one-year period.

Promoting oral health in adults with learning disability

Introduction: It is complex to define learning disabilities, there is no single universal definition used; there are different interpretations and definitions used for learning disabilities in different countries and communities. Primarily, the term “learning disability” sometimes used as “learning difficulties” is a term widely used in UK. There are various types and degree of severity of learning disabilities depending upon the extent of disorder. Though different definitions used all over the world, its types and classification coupled with their health and oral health needs are discussed in this review. Objectives:  To review the background literature on definitions of learning disabilities and health needs of this population.  To review literature on individual clinical preventive intervention to determine the effectiveness in promoting oral health amongst adults in learning disabilities.  To review literature in relation to community based preventive dental measures.  To determine the interventions in this areas are appropriate to support policy and practice and if these interventions establish good evidence to suggest that the oral health needs of adults with learning disabilities are met or not.  To make recommendations in implementing future preventive oral health interventions for adults with learning disabilities. Methodology: It was develop a comprehensive narrative synthesis of previously published literature from different sources and summarizes the whole research in a particular area identifying gap of knowledge. It provides a broad perspective of a subject and supports continuing education. It also is directed to inform policy and further research. It is a qualitative type of research with a broad question and critical analysis of literature published in books, article and journals. The research question evaluated on PICOS criteria is: Effectiveness of preventive dental interventions in adults with learning disabilities. The research question clearly defines the PICOS i.e. participants, interventions, comparison, outcome and study design. The Cochrane database of systematic reviews (CDSR), Database of Abstracts of Reviews of effects (DARE) through York University and National institute of Health and Clinical Excellence (NICE) was searched to identify need of this review. There was no literature review found on the preventive dental interventions found hence, justifying this review. The guidance used in this review is from York University and methods opted for search of literature is based on the following: Type of participants, interventions, outcome measure, studies and search. The review of literature; author search; systematic and narrative reviews, through the following electronic databases via UFP library services: Pub-Med, Medline, EMBASE, CINHAL, Google scholar; Science Direct; Social and Medicine. A comprehensive search of all available literature from 1990-2015, including systematic reviews, policy documents and some guideline documents was done. Internet resource used to access; Department of Health, World Health Organization, Disability World, Disability Rights Commission, the Stationery office, MENCAP, Australian Learning Disability Association. The literature search was carried out with single word, combined words and phrases, authors' names and the title of literature search. Results: It is primarily looking at the oral health interventions available for adults with learning disabilities in clinical settings and the community measures observed over a period of 25 years 1990-2015. There were 7of the clinical intervention studies and one community based intervention study was added in this review. Conclusion: There is a gap of knowledge identified in not having ample research in the area of preventive dental interventions in adults with learning or intellectual disabilities and there is a need of more research, studies need to be of a better quality and a special consideration is required in the community settings where maintenance of oral hygiene for this vulnerable group of society is hugely dependent on their caregivers. Though, the policy and guideline directs on the preventive dental interventions of adults with LD there still a gap evident in understanding and implication of the guidance in practice by the dental and care support team. Understanding learning disabilities and to identify their behavior, compliance and oral health needs is paramount for all professionals working with or for them at each level.

The pathophysiology of CADASIL: studies in a Scottish cohort

Since identification that mutations in NOTCH3 are responsible for cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) in the early 1990s, there has been extensive characterisation of the clinical and radiological features of the disease. However therapeutic interventions remain elusive, partly due to a limited understanding of the vascular pathophysiology and how it leads to the development of strokes, cognitive decline and disability. The apparent rarity and heterogenous natural history of CADASIL potentially make conducting any longitudinal or therapeutic trials difficult. The role of disease biomarkers is therefore of some interest. This thesis focuses on vascular function in CADASIL and how it may relate to clinical and radiological markers of disease. Establishing the prevalence of CADASIL in the West of Scotland was important to assess the impact of the disease, and how feasible a trial would be. A mutation prevalence of 10.7 per 100,000 was demonstrated, suggesting significant under diagnosis of the disease across much of Scotland. Cerebral hypoperfusion is thought to be important in CADASIL, and it has been shown that vascular abnormalities precede the development of brain pathology in mouse models. Investigation of vascular function in patients, both in the brain and systemically, requires less invasive measures. Arterial spin labelling magnetic resonance imaging (MRI) and transcranial Doppler ultrasound (TCD) can both be used to obtain non-invasive and quantifiable indices of vascular function. Monitoring patients with MRI whilst they receive different concentrations of inspired oxygen and carbon dioxide can provide information on brain function, and I reviewed the practicalities of this technique in order to guide the design of the studies in this thesis. 22 CADASIL patients were recruited to a longitudinal study. Testing included peripheral vascular assessment, assessment of disability, neurological dysfunction, mood and cognition. A CO2 reactivity challenge during both TCD and arterial spin labelling MRI, and detailed MRI sequences were obtained. I was able to demonstrate that vasoreactivity was associated with the number of lacunes and brain atrophy, as were carotid intima-media thickness, vessel stiffness, and age. Patients with greater disability, higher depressive symptoms and poorer processing speed showed a tendency to worse cerebral vasoreactivity but numbers were small. This observation suggests vasoreactivity may have potential as a therapeutic target, or a biomarker. I then wished to establish if arterial spin labelling MRI was useful for assessing change in cerebral blood flow in CADASIL patients. Cortical grey matter showed the highest blood flow, mean (SD), 55 (10) ml/100g/min and blood flow was significantly lower within hyperintensities (19 (4) ml/100g/min; p <0.001). Over one year, blood flow in both grey matter (mean -7 (10) %; p = 0.028) and deep white matter (-8 (13) %; p = 0.036) declined significantly. Cerebrovascular reactivity did not change over one year. I then investigated whether baseline vascular markers were able to predict change in radiological or neuropsychological measures of disease. Changes in brain volume, lacunes, microbleeds and normalised subcortical hyperintensity volume (increase of 0.8%) were shown over one year. Baseline vascular parameters were not able to predict these changes, or those in neuropsychological testing. NOTCH3 is found throughout the body and a systemic vasculopathy has been seen particularly affecting resistance vessels. Gluteal biopsies were obtained from 20 CADASIL patients, and ex vivo myography investigated the response to vasoactive agents. Evidence of impairment in both vasodilation and vasoconstriction was shown. The addition of antioxidants improved endothelium-dependent relaxation, indicating a role for oxidative stress in CADASIL pathology. Myography measures were not related to in vivo measures in the sub-group of patients who had taken part in both studies. The small vessels affected in CADASIL are unable to be imaged by conventional MR imaging so I aimed to establish which vessels might be responsible for lacunes with use of a microangiographic template overlaid onto brain images registered to a standard brain template. This showed most lacunes are small and associated with tertiary arterioles. On the basis of this thesis, it is concluded that vascular dysfunction plays an important role in the pathophysiology of CADASIL, and further assessment of vascular measures in longitudinal studies is needed. Arterial spin labelling MRI should be used as it is a reliable, non-invasive modality that can measure change over one year. Furthermore conventional cardiovascular risk factor prevention should be undertaken in CADASIL patients to delay the deleterious effects of the disease.