A necklace sonar with adjustable scope range for assisting the visually impaired

A sonar based device with tactile feedback was developed to improve the mobility and independence of visually impaired individuals. It features a transceiver/receiver, a potentiometer, a microcontroller, a rechargeable polymer lithium ion battery, and a Nokia Cell phone vibrator. All components are commercially available and housed in a custom acrylic package with 86 mm × 34 mm × 12 mm in dimension, and 120 grms in weight. Additionally, the device features an adjustable detection scheme for user customization of distance range, and a tactile feedback system that avoids interference with auditory sensory information. The device was tested for its navigational efficacy in an artificial indoor environment, and in a live outdoor setting. Ten subjects (9 males and 1 female), with a mean age of 35 years-old (range: 17 to 52) were presented with a series of navigational tasks resulting in considerable reduction of head, shoulder, chest, and arms collisions during their locomotion. We conclude that this device greatly improves the mobility and safety of visually impaired individuals.

Holographic display system for restoration of sight to the blind

OBJECTIVE

We present a holographic near-the-eye display system enabling optical approaches for sight restoration to the blind, such as photovoltaic retinal prosthesis, optogenetic and other photoactivation techniques. We compare it with conventional liquid crystal displays (LCD) or digital light processing (DLP)-based displays in terms of image quality, field of view, optical efficiency and safety.

APPROACH

We detail the optical configuration of the holographic display system and its characterization using a phase-only spatial light modulator.

MAIN RESULTS

We describe approaches to controlling the zero diffraction order and speckle related issues in holographic display systems and assess the image quality of such systems. We show that holographic techniques offer significant advantages in terms of peak irradiance and power efficiency, and enable designs that are inherently safer than LCD or DLP-based systems. We demonstrate the performance of our holographic display system in the assessment of cortical response to alternating gratings projected onto the retinas of rats.

SIGNIFICANCE

We address the issues associated with the design of high brightness, near-the-eye display systems and propose solutions to the efficiency and safety challenges with an optical design which could be miniaturized and mounted onto goggles.

Gross motor skill performance in children with and without visual impairments--research to practice

The aim of this study was to provide an empirical basis for teaching gross motor skills in children with visual impairments. For this purpose, gross motor skill performance of 23, 6-12 year old, boys and girls who are blind (ICD-10 H54.0) and 28 sighted controls with comparable age and gender characteristics was compared on six locomotor and six object control tasks using the Test of Gross Motor Development-Second Edition. Results indicate that children who are blind perform significantly (p<.05) worse in all assessed locomotor and object control skills, whereby running, leaping, kicking and catching are the most affected skills, and corresponding differences are related to most running, leaping, kicking and catching component. Practical implications are provided.

Establishing a conditional signal for assistance in teenagers with blindness

Five teenagers with severe intellectual impairments and no discernible communication skills were enrolled in training to teach a conditional request for assistance using a speech-generating device (SGD). All were either blind or severely visually impaired since birth. All learned to operate an adaptive switch to control sensory outcomes, next showed preferences among sensory outcomes, and then demonstrated the ability to use their switch to signal for assistance with an SGD when the sensory outcome was remotely disabled. During the signaling phase, or subsequent attempts to generalize its use outside the laboratory, three participants began vocalizing. Most notably, they began imitation of the word "song" or the word "help" emitted by the SGD. The potential role of cause-and-effect training with adaptive switches is discussed.

Determinants of inclusive education of 8-12 year-old children with cerebral palsy in 9 European regions

The principle of inclusive education has been increasingly recognised over recent decades and most countries officially support schooling of children with disabilities in mainstream settings. The SPARCLE study offers the opportunity to report on the schooling practices for children with cerebral palsy according to the nature and severity of their impairments and the schooling policy in European regions. The aim of this paper is to describe the type of schooling of children with cerebral palsy in various European regions after controlling for relevant individual factors. Children aged 8-12 years with cerebral palsy from 9 European regions and their families were interviewed. Our findings support the hypothesis that between-region variations in the type of schooling are still significant after adjustment for individual factors; and that motor function and intellectual ability have different effects on inclusion in mainstream school, depending on the region.

Two women with multiple disabilities communicate with distant partners via a special text messaging system

This study extended the research on a special text messaging system, which allows persons with multiple disabilities to (a) write and send messages to distant partners and (b) have messages from those partners read out to them. The study involved two women with multiple disabilities (including blindness or minimal residual vision). The system comprised a net-book computer, a mobile communication modem, and an input microswitch, and relied on special keyboards (not used before) to allow the women to write their messages. One of the keyboards included (a) two rows of 10 and 11 keys, respectively, reporting the 21 basic letters of the Italian alphabet arranged in alphabetical order and marked with Braille labels and (b) a space bar and an enlarged back/erase key. The other keyboard had Braille cues on the initial, central, and final keys of the letter rows. Moreover, most function keys were covered (cut out from the usable space). Both women learned to use the messaging system with the special keyboards successfully (i.e., to write their messages, to send them out, and to listen to incoming messages). These findings are analyzed in relation to preliminary data with the system and the need to adapt the writing technology to the participants' characteristics.

Prosthetic eye rehabilitation and management of completely blind patients

Facial prostheses aim to restore the appearance, contours, and esthetics of the face while consequently enhancing patients' self-esteem and reintegration into social life. Restoring unilateral missing ocular and orbital tissues is a challenging task that requires great skill from the clinician (anaplastologist) to accurately mimic the opposing natural tissues. Bilateral defects present additional technical and clinical challenges for clinicians and patients alike. This article presents two cases involving restoration of the ocular and orbital components of bilaterally blind patients. The first case comprised the construction of indwelling scleral eye shells for both eyes, while the second comprised left orbital (implant-retained) and right indwelling eye shell prostheses. Custom-made bilaterally indwelling eyes are more esthetically pleasing than stock options and show better fit and comfort following conventional impression techniques. Clinical challenges include impression taking, prosthesis fabrication, identification of the correct orientation into the socket, communication with the patient, and satisfaction of patient expectations. Since both patients were blind, their families played a vital role in describing their prostheses and thus in improving the patients' self-esteem and satisfaction with treatment.

Future trends in global blindness

The objective of this review is to discuss the available data on the prevalence and causes of global blindness, and some of the associated trends and limitations seen. A literature search was conducted using the terms "global AND blindness" and "global AND vision AND impairment", resulting in seven appropriate articles for this review. Since 1990 the estimate of global prevalence of blindness has gradually decreased when considering the best corrected visual acuity definition: 0.71% in 1990, 0.59% in 2002, and 0.55% in 2010, corresponding to a 0.73% reduction per year over the 2002-2010 period. Significant limitations were found in the comparability between the global estimates in prevalence or causes of blindness or visual impairment. These limitations arise from various factors such as uncertainties about the true cause of the impairment, the use of different definitions and methods, and the absence of data from a number of geographical areas, leading to various extrapolation methods, which in turn seriously limit comparability. Seminal to this discussion on limitations in the comparability of studies and data, is that blindness has historically been defined using best corrected visual acuity.

Braille use among Norwegian children from 1967 to 2007: trends in the underlying causes

PURPOSE

The aim of the study was to estimate the occurrence, diagnoses and time trends among Norwegian children that have received education in braille from 1967 to 2007.

METHODS

We used a retrospective population-based study design. The health care system is free for all inhabitants in Norway. We included all children that had received braille education the last four decades. From each student's record, we abstracted year born, country of birth, gender, year diagnosed, diagnosis, classification of visual impairment and type of reading media.

RESULTS

We identified 287 children (137 girls and 150 boys) that had received braille education over the last 40 years. Of these, 262 (91.3%) children were born in Norway, 145 (53.7%) were diagnosed within the first year of life and 59 (20.6%) from age of one to five. The most frequent diagnoses were Retinopathy of Prematurity (ROP), Juvenile Ceroid Lipofuscinoses (JNCL), Lebers Congenital Amaurosis (LCA) and Retinitis Pigmentosa (RP). Among the children, 63% (N = 170) used braille only, 9% (N = 25) braille and print, but priority braille, and 27% (N = 73) braille and print, priority print. The number of children with ROP using braille had a peak in 1977, then the number declined. The number diagnosed with LCA increased from 1987 to 1992. The number of braille users among children diagnosed with JNCL tended to increase substantially after 1992.

CONCLUSION

Braille education seemed to be dependent of trends in diagnoses as well as trends in recommendations from professional educators.

[Research on and design of visual prosthesis based on visual information processing]

Induced by a variety of retinopathy, visual loss has become the most serious form of disability, which influences the quality of human life. With the rapid development and crossing among the information science, microelectronics, material science and biomedical disciplines, the visual prosthesis makes reparation possible for the visual blindness caused by retinitis pigmentosa, age-related macular degeneration, and other eye, retina, optic nerve and visual cortex lesions. With technology innovation, the prosthesis design, manufacturing and surgical technique are no longer the biggest obstacles to the future development of the visual prosthesis, but how to construct effective transmission of information between the brain and the prosthesis. However, due to the complex structure of the human visual system, the visual prosthesis manufacturing and visual information signal mapping are facing some difficulties. Thus, we can only study the representation strategy of image information and micro-electrode array stimulation basing on limited pixels of simulated prosthesis visual information. By studying the visual information processing of the visual prosthesis, we propose a visual prosthesis design which is based on biological, mechanical, and electronic integration.

Association of vision loss in glaucoma and age-related macular degeneration with IADL disability

PURPOSE

To determine if glaucoma and/or age-related macular degeneration (AMD) are associated with disability in instrumental activities of daily living (IADLs).

METHODS

Glaucoma subjects (n = 84) with bilateral visual field (VF) loss and AMD subjects (n = 47) with bilateral or severe unilateral visual acuity (VA) loss were compared with 60 subjects with normal vision (controls). Subjects completed a standard IADL disability questionnaire, with disability defined as an inability to perform one or more IADLs unassisted.

RESULTS

Disability in one or more IADLs was present in 18.3% of controls as compared with 25.0% of glaucoma subjects (P = 0.34) and 44.7% of AMD subjects (P = 0.003). The specific IADL disabilities occurring more frequently in both AMD and glaucoma subjects were preparing meals, grocery shopping, and out-of-home travelling (P < 0.05 for both). In multivariate logistic regression models run adjusting for age, sex, mental status, comorbidity, and years of education, AMD (odds ratio [OR] = 3.4, P = 0.02) but not glaucoma (OR = 1.4, P = 0.45) was associated with IADL disability. However, among glaucoma and control patients, the odds of IADL disability increased 1.6-fold with every 5 dB of VF loss in the better-seeing eye (P = 0.001). Additionally, severe glaucoma subjects (better-eye MD worse than -13.5 dB) had higher odds of IADL disability (OR = 4.2, P = 0.02). Among AMD and control subjects, every Early Treatment of Diabetic Retinopathy Study line of worse acuity was associated with a greater likelihood of IADL disability (OR = 1.3).

CONCLUSIONS

VA loss in AMD and severe VF loss in glaucoma are associated with self-reported difficulties with IADLs. These limitations become more likely with increasing magnitude of VA or VF loss.

Causes of visual impairment in Thai diabetic patients in the visual rehabilitation clinic

BACKGROUND

Visual disability from diabetic retinopathy is one of many public health problems. Knowing the causes of blindness and low vision in diabetic patients will help in policy planning in order to reduce diabetic complications and prevent blindness.

OBJECTIVE

To study the causes of visual impairment, blindness and related factors in diabetic patients who registered at the visual rehabilitation clinic, Siriraj Hospital, Mahidol University, Bangkok.

MATERIAL AND METHOD

A retrospective study of 133 diabetic patients who registered at the visual rehabilitation clinic between January 2007 and December 2010 was conducted. The patients were divided into 2 groups: a low vision group (VA in the better eye < 6/18-3/60) and a blindness group (VA in the better eye < 3/60--No light perception). The history of diabetic mellitus, associated systemic diseases, laboratory investigations, ocular changes and treatment were recorded. The causes of visual impairment and blindness were collected and analyzed.

RESULTS

Of a total of 133 diabetic patients, 93 cases (69.9%) were in a low vision group and 40 cases (30.1%) were in a blindness group. The causes of visual impairment were proliferative diabetic retinopathy (84.6%), retinal detachment (37.2%), macular edema and scar (25.9%), optic atrophy (143%), neovascular glaucoma (11.7%) and vitreous hemorrhage (4.9%). Tractional retinal detachment (p-value < 0.001) and optic atrophy (p-value = 0.021) were the associated factors causing blindness in visual disability patients with statistical significance. Optic atrophy (38 eyes) occurred post vitrectomy in 19 eyes.

CONCLUSION

Visual disability in diabetic patients is caused by the complications of diabetic retinopathy and its management. The prevention of disease progression, especially macular edema and proliferative diabetic retinopathy, will decrease the rate of visual impairment and blindness.

Retinal implants: emergence of a multidisciplinary field

PURPOSE OF REVIEW

This review summarizes the current status of retinal prostheses, recent accomplishments, and major remaining research, engineering, and rehabilitation challenges.

RECENT FINDINGS

Retinal research, materials and biocompatibility studies, and clinical trials in patients blind from retinitis pigmentosa are representative of an emerging field with considerable promise and sobering challenges. A summary of progress in dozens of laboratories, companies, and clinics around the world is presented through a synopsis of relevant studies, not only to summarize the progress but also to convey the remarkable increase in interest, effort, and outside funding this field has enjoyed.

SUMMARY

At present, clinical applications of retinal implant technology are dominated by one or two groups/companies, but the field is wide open for others to take the lead through novel approaches in technology, tissue interfacing, information transfer paradigms, and rehabilitation. Where the field will go in the next few years is almost anybody's guess, but that it will move forward is a certainty.

Technology-based programs to promote walking fluency or improve foot-ground contact during walking: two case studies of adults with multiple disabilities

These two case studies assessed technology-based programs for promoting walking fluency and improving foot-ground contact during walking with a man and a woman with multiple disabilities, respectively. The man showed breaks during walking and the woman presented with toe walking. The technology used in the studies included a microprocessor with specific software, an MP3 with the recordings of preferred stimulus items, and optic sensors. Both studies were carried out according to an ABAB design. In Study I, the optic sensors were activated when the man crossed small marks distributed along the travel routes. At each sensor's activation, the man received a brief period of preferred stimulation. In Study II, the woman received preferred stimulation when the sensors at the toe and the heel of her shoes were activated in close time proximity. The man walked virtually without breaks and improved his mood (with an increase in indices of happiness) during the intervention phases of the study. The woman largely increased her percentages of steps with adequate foot-ground contact, which reached a mean of about 80 during the second intervention phase. The results were discussed in terms of rehabilitation implications and technology demands.

Development of independent locomotion in children with a severe visual impairment

Locomotion of children and adults with a visual impairment (ages 1-44, n = 28) was compared to that of age-related individuals with normal vision (n = 60). Participants walked barefoot at preferred speed while their gait was recorded by a Vicon(®) system. Walking speed, heading angle, step frequency, stride length, step width, stance phase duration and double support time were determined. Differences between groups, relationships with age and possible interaction effects were investigated. With increasing age overall improvements in gait parameters are observed. Differences between groups were a slower walking speed, a shorter stride length, a prolonged duration of stance and of double support in the individuals with a visual impairment. These may be considered either as adaptations to balance problems or as strategies to allow to foot to probe the ground.

A verbal-instruction system to help persons with multiple disabilities perform complex food- and drink-preparation tasks independently

In a recent single-case study, we showed that a new verbal-instruction system, ensuring the automatic presentation of step instructions, was beneficial for promoting the task performance of a woman with multiple disabilities (including blindness). The present study was aimed at replicating and extending the aforementioned investigation with three adults with multiple disabilities. During Part I of the study, the new instruction system was compared with a system requiring the participants to seek instructions on their own. Two tasks were used, one per system. During Part II of the study, the new system was applied with two additional tasks. The results of Part I showed that (a) the participants had a better performance (i.e., in terms of correct steps or task execution time) on the task carried out with the new system than on the task carried out with the comparison/control system, and (b) the performance of this latter task improved rapidly when the new system was used with it. The results of Part II showed satisfactory performance with each of the two tasks carried out directly with the new system. The implications of these data were discussed.

A technology-aided stimulus choice program for two adults with multiple disabilities: choice responses and mood

This study was aimed at replicating and extending early research on technology-aided stimulus choice with two adults with multiple disabilities. The technology-aided program involved (a) a computer-aided system presenting the participants samples of different environmental stimuli and (b) a microswitch device allowing them to choose among those samples and to access the related stimuli for preset periods of time. The system also allowed the participants opportunities to request the continuation/repetition of any stimulus. The program was successful in promoting the participants' selection of preferred stimuli and their requests for continuation/repetition of those stimuli. Data also showed that the intervention sessions largely improved the participants' mood (i.e., increased their indices of happiness). Theoretical and practical relevance of the findings were discussed.

Two adults with multiple disabilities use a computer-aided telephone system to make phone calls independently

This study extended the assessment of a newly developed computer-aided telephone system with two participants (adults) who presented with blindness or severe visual impairment and motor or motor and intellectual disabilities. For each participant, the study was carried out according to an ABAB design, in which the A represented baseline phases and the B represented intervention phases, during which the special telephone system was available. The system involved among others a net-book computer provided with specific software, a global system for mobile communication modem, and a microswitch. Both participants learned to use the system very rapidly and managed to make phone calls independently to a variety of partners such as family members, friends and staff personnel. The results were discussed in terms of the technology under investigation (its advantages, drawbacks, and need of improvement) and the social-communication impact it can make for persons with multiple disabilities.

Effects of video-feedback interaction training for professional caregivers of children and adults with visual and intellectual disabilities

BACKGROUND

Individuals in group homes may experience poor quality of social interaction with their professional caregivers, limiting their quality of life. The video-based Contact programme may help caregivers to improve their interaction with clients.

METHOD

Seventy-two caregivers of 12 individuals with visual and intellectual disabilities received a training programme and four individual video-feedback sessions. Quality of interaction was independently measured in an AB-design across subjects with two baseline and three intervention observations, using a time sampling coding system for interactive behaviour as well as a rating for affective mutuality.

RESULTS

From baseline to intervention, significant increases were found for the frequency with which caregivers confirmed the signals of clients, for the proportion of initiatives taken by clients that were responded to by the caregivers, and the affective mutuality as a quality of the interaction. No significant increase in client responsiveness was observed. Caregivers evaluated the intervention as useful and feasible.

CONCLUSIONS

The start of the Contact programme coincided with improved quality of interaction between professional caregivers and clients with visual and intellectual disabilities in group homes. Further research is necessary regarding the generalisability, long-term effects and effects on quality of life.