Brain mapping in a patient with congenital blindness – A case for multimodal approaches

Recent advances in basic neuroscience research across a wide range of methodologies have contributed significantly to our understanding of human cortical electrophysiology and functional brain imaging. Translation of this research into clinical neurosurgery has opened doors for advanced mapping of functionality that previously was prohibitively difficult, if not impossible. Here we present the case of a unique individual with congenital blindness and medically refractory epilepsy who underwent neurosurgical treatment of her seizures. Pre-operative evaluation presented the challenge of accurately and robustly mapping the cerebral cortex for an individual with a high probability of significant cortical re-organization. Additionally, a blind individual has unique priorities in one's ability to read Braille by touch and sense the environment primarily by sound than the non-vision impaired person. For these reasons we employed additional measures to map sensory, motor, speech, language, and auditory perception by employing a number of cortical electrophysiologic mapping and functional magnetic resonance imaging methods. Our data show promising results in the application of these adjunctive methods in the pre-operative mapping of otherwise difficult to localize, and highly variable, functional cortical areas

Neuroplasticity Associated with Tactile Language Communication in a Deaf-Blind Subject

A long-standing debate in cognitive neuroscience pertains to the innate nature of language development and the underlying factors that determine this faculty. We explored the neural correlates associated with language processing in a unique individual who is early blind, congenitally deaf, and possesses a high level of language function. Using functional magnetic resonance imaging (fMRI), we compared the neural networks associated with the tactile reading of words presented in Braille, Print on Palm (POP), and a haptic form of American Sign Language (haptic ASL or hASL). With all three modes of tactile communication, indentifying words was associated with robust activation within occipital cortical regions as well as posterior superior temporal and inferior frontal language areas (lateralized within the left hemisphere). In a normally sighted and hearing interpreter, identifying words through hASL was associated with left-lateralized activation of inferior frontal language areas however robust occipital cortex activation was not observed. Diffusion tensor imaging -based tractography revealed differences consistent with enhanced occipital-temporal connectivity in the deaf-blind subject. Our results demonstrate that in the case of early onset of both visual and auditory deprivation, tactile-based communication is associated with an extensive cortical network implicating occipital as well as posterior superior temporal and frontal associated language areas. The cortical areas activated in this deaf-blind subject are consistent with characteristic cortical regions previously implicated with language. Finally, the resilience of language function within the context of early and combined visual and auditory deprivation may be related to enhanced connectivity between relevant cortical areas

Using sensory substitution devices for a letter recognition task

Les êtres humains exploitent de manière optimale leur sens de la vision dans le but d’interagir avec leur environnement. Ceux souffrant de cécité présentent évidemment un handicap, ainsi de nombreux scientifiques, tel que le Dr. Paul Bach-y-Rita, ont mis au point des appareils de substitution sensorielle ayant comme objectif l’amélioration de l’autonomie des personnes aveugles. Ce projet a impliqué huit sujets atteints d’une cécité congénitale et de huit sujets aux yeux bandés servant de contrôles dans une expérience d’entraînement de trois jours consécutifs sur une tâche de reconnaissance de caractère. Cette expérience a employé les plus récents appareils de substitution sensorielle, tel que le Tongue Display Unit (où une image est convertie en un patron de stimulation tactile sur la langue) et le vOICe (où l’image est cette fois convertie en sons). Nous avons mesuré les temps de réaction comme moyen d’évaluer la performance à la tâche de reconnaissance de lettre. Les lettres apparaissent sur un écran se situant devant les participants et une caméra, posée sur des lunettes, capture la scène et la convertit en sensations tactiles sur la langue, en sons ou les deux simultanément. Chaque sujet aveugle était comparé à un sujet aux yeux bandés de même âge et d’habilité musicale similaire. Les paires de participants ont été répartis dans trois groupes d’entrainements: un groupe audio (seulement le vOICe), un groupe tactile (seulement le TDU) et un groupe audio-tactile (vOICe + TDU simultanément). Nous avons découvert que les sujets atteints d’une cécité congénitale surpassaient les contrôles voyants dans le groupe audio seulement. Nous demeurons optimistes, vu les dernières technologies disponibles aujourd’hui, que les prochaines percées scientifiques fourniront aux aveugles un meilleur sens d’autonomie.Humans use their sense of vision in order to interact with their environment in an optimal manner. Those who suffer from blindness are therefore at a disadvantage, and so, scientists, such as Dr. Paul Bach-y-Rita have created sensory substitution devices (SSDs) with the purpose of providing the blind population with more independence. This project recruited eight congenitally blind (CB) and eight blindfolded sighted control (SC) subjects to engage in a training experiment on a letter recognition task on three consecutive days. The experiment made use of state-of-the-art sensory substitution devices, such as the tongue display unit (TDU) (where a visual scene is transformed into a pattern of tactile stimulations on the tongue), and the vOICe (where visual information is transformed into sounds). We measured performance on the letter recognition task using reaction times. The letters would appear on a screen in front of the participants and a camera, mounted onto glasses, would capture the scene and convert it into tactile sensations on the tongue, sounds, or both. Congenitally blind subjects and the blindfolded sighted controls were matched for age and musical experience. The pairs were then assigned to three different training conditions; an audio group (vOICe only), a tactile group (TDU only), and an audio-tactile group (vOICe + TDU simultaneously). We found that the congenitally blind subjects significantly outperformed the sighted controls in the audio group only. We remain optimistic in the breadth of new technologies available for the blind, as well as the potential breakthroughs that will, one day, provide blind individuals with an increased sense of autonomy

Factors related to braille acquisition among adult and senior learners : establishing evidence-based practice

Les difficultés de lecture sont les raisons les plus fréquentes pour lesquelles des personnes sont orientées vers un service de réadaptation visuelle. Bien qu’il existe une base historique solide à propos de l’enseignement du braille chez les enfants aveugles, il existe très peu de données probantes concernant l’apprentissage du braille chez les personnes en âge de travailler et les personnes âgées. De surcroît, bien qu’il soit clair que le vieillissement est associé à un déclin des capacités tactiles, motrices et cognitives, on sait peu de choses sur la manière dont ces variables peuvent influencer les résultats de la lecture du braille. Pour examiner cette problématique, une étude en quatre phases a été conceptualisée. Dans la première phase, une étude de la portée a été menée afin de synthétiser les connaissances existantes concernant la relation entre le déclin des capacités lié au vieillissement et la performance de la lecture en braille. La seconde a voulu étudier les obstacles et les facilitateurs rencontrés par les adultes qui suivent une formation en braille. La troisième a exploré les variables qui sont en corrélation avec la performance de lecture en braille à l’âge adulte. Enfin, la dernière phase a voulu se pencher sur l’influence du support de lecture sur la performance de lecture des adultes ayant une sensibilité tactile réduite. Les preuves antérieures concernant le braille et le vieillissement restent rares. Il existe une variété de facteurs personnels, sociaux et institutionnels qui façonnent le processus d’apprentissage du braille chez les adultes, incluant la stigmatisation envers le braille et le vieillissement perçue par certains praticiens, des services inadéquats et des difficultés à l’accès aux équipements brailles. Des données soulignent la nécessité de commencer l’apprentissage du braille le plus tôt possible, d’évaluer des mesures objectives de l’acuité tactile tout en considérant le rôle de la fonction du toucher, de fournir une formation accrue en matière de perception tactile et d’envisager une plus grande intégration d’appareils braille. Les résultats font également ressortir la nécessité d’augmenter le financement et les services ; de définir des critères d’éligibilité qui tiennent compte des réalités uniques des clients âgés et l’accès au braille ; et d’étudier plus avant le rôle de la stigmatisation vis-à-vis du braille et du vieillissement. En somme, tous ces éléments réunis peuvent influencer à la fois les décisions cliniques et les résultats d’apprentissage.Reading difficulties are the most common reasons for referral to vision rehabilitation. Though there is a strong historical basis for the provision of braille instruction among blind children, there is little evidence-based research on the needs of working-age and older adults. Aging is associated with declines in tactile, motor and cognitive capacities. Moreover, learning in adulthood is distinct from childhood learning, owing to differences in cortical plasticity and development. Little is known about how these variables may influence braille reading outcomes, but such knowledge is needed to inform the design of evidence-based strategies. For example, low-cost braille devices incorporate dots of greater height and density, but the extent to which such approaches may enhance reading performance for older adults with reduced tactile sensitivity remains unexplored. These questions are especially imperative as the prevalence of age-related vision loss continues to increase. A four-phase study was devised to synthesize prior evidence on the interrelationship between factors known to decline with age and braille reading performance; to investigate the barriers and facilitators encountered by working-age and older adults who pursue braille training; to identify variables that correlate with braille reading performance in adulthood; and to explore the influence of reading medium on the reading performance of adults with reduced tactile sensitivity. This thesis confirms that prior evidence on braille and aging remains scant, heightening the imperative for further research in this domain. Moreover, there are a variety of personal, social and institutional factors which shape the adult braille learning process, including perceived stigma towards braille and aging among some practitioners, inadequate services and access to braille devices. Braille learning age, frequency of usage, and measures of active tactile acuity emerged as significant correlates of braille reading speed. Preliminary evidence suggests that using braille displays with greater dot height enhances performance for those with reduced tactile sensitivity, while also enabling immediate access to relevant reading content. Collectively, these findings point to the need for rehabilitation practitioners to introduce braille as early as possible, evaluate objective measures of tactile acuity while also considering the role of functional touch, provide increased training in tactile perception, and consider a wider integration of braille devices. Findings also highlight the need for increased funding and services, eligibility criteria which takes into account the unique realities of older braille clients, and the need to further explore the role of stigma towards braille and aging which may influence both clinical decisions and learning outcomes

Neural network for Braille reading and the speech-reading convergence in the blind: Similarities and differences to visual reading

All writing systems represent units of spoken language. Studies on the neural correlates of reading in different languages show that this skill relies on access to brain areas dedicated to speech processing. Speech-reading convergence onto a common perisylvian network is therefore considered universal among different writing systems. Using fMRI, we test whether this holds true also for tactile Braille reading in the blind. The neural networks for Braille and visual reading overlapped in the left ventral occipitotemporal (vOT) cortex. Even though we showed similar perisylvian specialization for speech in both groups, blind subjects did not engage this speech system for reading. In contrast to the sighted, speech-reading convergence in the blind was absent in the perisylvian network. Instead, the blind engaged vOT not only in reading but also in speech processing. The involvement of the vOT in speech processing and its engagement in reading in the blind suggests that vOT is included in a modality independent language network in the blind, also evidenced by functional connectivity results. The analysis of individual speech-reading convergence suggests that there may be segregated neuronal populations in the vOT for speech processing and reading in the blind

Teachers\u27 Perceptions About Addressing Literacy for Students With Vision Impairment

Regular education teachers are sometimes at a disadvantage when required to instruct learners with a visual impairment or other special needs in the classroom. A problem exists with reduced support and training for regular education teachers responsible for meeting literacy needs of students with visual impairment. The purpose of this qualitative interpretive case study was to explore regular education instructors\u27 perceptions of their self-efficacy and ability to modify literature for learners with visual impairment. The research questions targeted this purpose, specifically in the areas of training opportunities and technology use. The social cognitive theory, a model emphasizing learning occurring through social contexts and observations, was used as the conceptual framework for this study. Data were collected from 1-on-1 interviews with 10 volunteer regular education teachers teaching students at the elementary level. The resulting data were analyzed via color-coding transcripts, NVivo running word-frequency queries, and manual review of each transcript. The results revealed the participants did not have training, awareness for the literacy needs of students with visual impairment, or knowledge of the different types of technology used to access and create literacy materials. Although they lacked training and current knowledge of providing literacy instruction, the participants expressed confidence in their ability to research, collaborate, and gain the knowledge needed to effectively do so. The implications for positive social change include implementation of training and/or an education cycle for more efficient instruction when serving a student with visual impairment in the local school district. Efficient instruction can facilitate an improvement in the academic performance of students with visual impairment

Drawing enhances cross-modal memory plasticity in the human brain: a case study in a totally blind adult

In a memory-guided drawing task under blindfolded conditions, we have recently used functional Magnetic Resonance Imaging (fMRI) to demonstrate that the primary visual cortex (V1) may operate as the visuo-spatial buffer, or “sketchpad,” for working memory. The results implied, however, a modality-independent or amodal form of its operation. In the present study, to validate the role of V1 in non-visual memory, we eliminated not only the visual input but all levels of visual processing by replicating the paradigm in a congenitally blind individual. Our novel Cognitive-Kinesthetic method was used to train this totally blind subject to draw complex images guided solely by tactile memory. Control tasks of tactile exploration and memorization of the image to be drawn, and memory-free scribbling were also included. FMRI was run before training and after training. Remarkably, V1 of this congenitally blind individual, which before training exhibited noisy, immature, and non-specific responses, after training produced full-fledged response time-courses specific to the tactile-memory drawing task. The results reveal the operation of a rapid training-based plasticity mechanism that recruits the resources of V1 in the process of learning to draw. The learning paradigm allowed us to investigate for the first time the evolution of plastic re-assignment in V1 in a congenitally blind subject. These findings are consistent with a non-visual memory involvement of V1, and specifically imply that the observed cortical reorganization can be empowered by the process of learning to draw