Measurement of the Visual Attention Patterns of People with Aphasia: A Preliminary Investigation of Two Types of Human Engagement in Photographic Images

Exploring high-technology augmentative and alternative communication interfaces: the effect of age and technology experience

PURPOSE

Many people with aphasia have inadequate language skills for functional communication thereby necessitating well-designed augmentative and alternative communication (AAC) interfaces. Using both a grid and a VSD interface with single word hotspots by neurologically healthy adults, across ages and with different technology experiences, this study examines the utility of these interfaces prior to investigating their use with people with aphasia in future studies.

METHOD

Participants include 18 young adults, 24 older adults with technology experience, and 20 older adults with limited technology experience. The older adult groups were matched for mean age and for sex. Participants described pictures with each interface, and performance was measured based on four dependent variables: (a) the total number of correct information units (CIUs), (b) the percentage of CIUs, (c) CIUs per minute, and (d) preferred interface.

RESULTS

There was a significant difference between older adults and the young adult group for the total number of CIUs (p < 0.001) and CIUs per minute (p < 0.001). Despite the changes in technology experience between the two older groups, there was no significant difference in performance. Additionally, there was no significant difference in performance across the two interfaces in any of the groups.

CONCLUSION

Findings suggest age does impact performance on AAC. However, the difference in technology experience in older adult groups did not affect performance. Furthermore, both interfaces used in the current study were equally beneficial when describing pictures by healthy adults. Implications for RehabilitationAugmentative and alternative communication (AAC) systems involve various interface designs. Consequently, the comparative utility of these interfaces must be examined across populations and communicative functions.Advancement in technology has given rise to numerous high-tech AAC interface designs. However, older adults with acquired language difficulties whose technology experience is limited may become reluctant to use high-tech AAC. Hence, the  influence of technology experience on high-tech AAC performance should be investigated.Prior to examining interfaces with individuals with acquired language difficulties, the current study examined the use of a) grid display and b) visual scene display (VSD) with single word hotspots, by healthy adults of different ages and technology experiences.The study revealed that older adults with limited technology experience were equally competent in using high-tech AAC interfaces, as those with technology experience. Hence, an individual's technology experience should not be considered a deterrent to using high-tech AAC interfaces.Additionally, the study found no differences in performance between the two interfaces, making it essential to consider user's personal preference when adopting AAC interface designs.

Examining the Visual Attention Patterns and Identification Accuracy of Adults With Aphasia for Grids and Visual Scene Displays

PURPOSE

We compared the degree of cognitive processing needed by people with aphasia to identify themes depicted in grids and visual scene displays (VSDs). We also compared the accuracy of theme identification for both display types.

METHOD

Eye-tracking technology was employed to measure the visual processing patterns of 21 adults with aphasia when interpreting themes presented through grids and VSDs. Additionally, we assessed theme identification accuracy by having participants select themes from four choices after viewing each display.

RESULTS

Participants more rapidly identified VSDs than grid displays, and VSDs required fewer visual fixations to process than grids. No significant differences were noted between grids and VSDs for theme identification accuracy; however, results indicate a ceiling effect for the variable, as participant accuracy levels were nearly 100% for both display conditions.

CONCLUSIONS

Results from this study add to a growing body of evidence supporting the use of VSDs for adults with aphasia. Both display types were accurately identified; however, VSDs were processed more efficiently than grids indicating that both display types may prove effective for people with aphasia; however, VSDs may require less cognitive effort to effectively use than grid displays.

What's in a Photograph? The Perspectives of Composition Experts on Factors Impacting Visual Scene Display Complexity for Augmentative and Alternative Communication and Strategies for Improving Visual Communication

Purpose Visual scene displays (VSDs) can support augmentative and alternative communication (AAC) success for children and adults with complex communication needs. Static VSDs incorporate contextual photographs that include meaningful events, places, and people. Although the processing of VSDs has been studied, their power as a medium to effectively convey meaning may benefit from the perspective of individuals who regularly engage in visual storytelling. The aim of this study was to evaluate the perspectives of individuals with expertise in photographic and/or artistic composition regarding factors contributing to VSD complexity and how to limit the time and effort required to apply principles of photographic composition. Method Semistructured interviews were completed with 13 participants with expertise in photographic and/or artistic composition. Results Four main themes were noted, including (a) factors increasing photographic image complexity and decreasing cohesion, (b) how complexity impacts the viewer, (c) composition strategies to decrease photographic image complexity and increase cohesion, and (d) strategies to support the quick application of composition strategies in a just-in-time setting. Findings both support and extend existing research regarding best practice for VSD design. Conclusions Findings provide an initial framework for understanding photographic image complexity and how it differs from drawn AAC symbols. Furthermore, findings outline a toolbox of composition principles that may help limit VSD complexity, along with providing recommendations for AAC development to support the quick application of compositional principles to limit burdens associated with capturing photographic images. Supplemental Material https://doi.org/10.23641/asha.15032700.

Clinical and Research Perspectives on Visual Scene Displays

Purpose The purposes of this study were to measure the perceptions of speech-language pathologists (SLPs) and researchers regarding the design of visual scene displays (VSDs) and to investigate the perceived difficulties of SLPs in regard to the acquisition and programming of VSDs. Method We recruited 270 SLPs and nine researchers who focus on VSDs to complete an online survey. The SLP survey addressed both perception of VSD design and difficulties associated with implementing these images as communication supports in the clinical realm. The researcher group was surveyed solely regarding their opinions associated with VSD design. Results SLPs and researchers both ranked high-context VSDs as more effective at supporting communication than low-context VSDs. In addition, both groups ranked VSDs with task-engaged people as more effective at supporting communication than VSDs with camera-engaged people or no people. SLPs reported difficulties with acquiring high-quality VSDs from online sources as well as difficulties with maintenance and upkeep of VSDs. In addition, a large portion of SLPs reported challenges with representing complex concepts through VSDs. Conclusions Results from this study provide evidence of general agreement between SLPs and researchers regarding perception of VSD design. SLPs continue to report challenges with the acquisition and programming of VSDs. Further research is needed to develop evidence-based guidelines to support clinical endeavors in these areas.

Effectiveness and Utility of Visual Scene Displays as Communication Supports for Adults and Children With Complex Communication Needs: Perspectives of Clinicians and Researchers

Purpose The aims of this research study were to describe the perspectives of clinicians and researchers regarding the effectiveness of visual scene displays (VSDs) as communication supports in order to inform the translation of research to clinical practice. Method An online survey was completed by 298 clinicians and nine VSD researchers. Participants rated the effectiveness of VSDs in supporting a variety of communication functions and their strength of agreement regarding statements of VSD utility. Results Regardless of population served, clinicians and researchers rated VSDs as effective at supporting a range of communication functions. Participants also tended to agree with statements of VSD utility. Conclusions The current study highlights the perceptions of clinicians and researchers regarding the uses and benefits of VSDs for adults and children with complex communication needs and provides an initial measure of the current translation of research to clinical practice. Results indicate that VSDs can be used to support a variety of communication functions and utilities; however, further work is necessary to explore additional communication functions and delineate similarities and differences of VSD uses for differing populations. Supplemental Material https://doi.org/10.23641/asha.14551344.

Visual Attention to Cued Targets in Simulated Aided Augmentative and Alternative Communication Displays for Individuals With Intellectual and Developmental Disabilities

Purpose Many aided augmentative and alternative communication (AAC) systems require the use of an external display that is represented via a visual modality. It is critical to evaluate and understand visual-perceptual processing in individuals with disabilities who could benefit from AAC. One way to evaluate how individuals process visual materials is through research-based automated eye-tracking technologies that obtain a fine-grained stream of data concerning gaze paths of visual attention. Method The current study examined how individuals with autism spectrum disorder (n = 13), Down syndrome (n = 13), intellectual and developmental disabilities (n = 9), or typical development (n = 20) responded to a spoken prompt to find a thumbnail-sized navigation key within a complex AAC display, including a main visual scene display (VSD) and a navigation bar of four thumbnail-sized VSDs. Stimuli were presented on a monitor containing automated eye-tracking research technology that recorded patterns of visual attention. Results Participants across groups spent more time fixating on a target thumbnail VSD navigation image after the presentation of the spoken cue to look at the target, compared to before the presentation of the spoken cue; they also spent more time looking at the target thumbnail VSD than the other thumbnail-sized VSDs in the navigation bar after the cue. Discussion Participants were able to locate the target thumbnail VSDs, even within the context of a visually complex AAC display. Implications for the design of AAC displays and for assessment of comprehension are discussed.

Personalization of Visual Scene Displays: Preliminary Investigations of Adults with Aphasia, Typical Females across the Age-Span, and Young Adult Males and Females

Visual scene displays (VSDs) are becoming an increasingly popular method of message representation within augmentative and alternative communication (AAC) supports; however, design factors can influence the effectiveness of these images as communication supports. One issue that has come to light in recent years is the fact that selecting personalized VSDs, which depict the person with complex communication needs or an individual with whom they are familiar, are preferred over generic VSDs, which depict unfamiliar individuals. Although personalization is likely an important factor in the usability of VSDs, these images may be difficult for clinicians to obtain. As such, compromises must be identified. The purpose of this study was to explore the effects of controlling personal relevance factors (i.e., age and gender of the people depicted in generic VSDs) on the image preference patterns of adults with and without aphasia. Results from three very preliminary study summaries indicate that gender and age are both mitigating factors in image preference, as males tended to indicate preference for VSDs containing males over those containing females. In addition, females tended to indicate preference for females of a similar age depicted in VSDs.

Preference and visual cognitive processing demands of alphabetic and QWERTY keyboards of individuals with and without brain injury

Following a severe brain injury (BI), some literate individuals who require augmentative and alternative communication (AAC) strategies to support communication may benefit from the use of onscreen keyboards to generate text. A range of layouts are available to these individuals within specialized communication software. However, a paucity of information is available to describe user preferences, user perceptions, as well as the visual-cognitive processing demands of such layouts. Such information is critical to guide clinical decision-making for keyboard selection and to provide patient-centered services. This study: (a) described the preferences and perceptions of two onscreen keyboard layouts (QWERTY and alphabetic) and (b) used eye-tracking analysis to investigate the visual-cognitive processing demands between these onscreen keyboards for individuals with and without BI. Results indicated participants in both groups held a strong preference for QWERTY keyboard interfaces and had extensive prior experience using the QWERTY keyboard layout on mobile devices. Eye-tracking analysis revealed less visual-cognitive processing demands using a QWERTY keyboard layout for both groups but were only statistically significant for those without BI. Results suggest that use of a keyboard layout that aligns with client preferences and prior experiences (i.e., the QWERTY keyboard for these participants) may lead to increased satisfaction with the communication experience and increased communication efficiency.

Speech-Language pathologists' decisions when designing an aided AAC display for a compilation case study of a beginning communicator

PURPOSE

The current study sought to identify decisions speech-language pathologists (SLPs) make and their rationale for those decisions when designing an AAC display for a hypothetical school-aged child who was a beginning communicator. Augmentative and alternative communication (AAC) displays support communicative interactions for children who are unable to use spoken language to meet their communication needs. Children who are at the early stages of learning language, often termed beginning or emerging communicators, may rely heavily on the AAC display to support comprehension and expression. Thus, it is important for speech-language pathologists (SLPs) to design a display that facilitates beginning communicators' communication development.

METHODS

This paper reports on the answers related to a specific case study presented in an online survey completed by 77 SLPs with experience in AAC.

RESULTS

Data illustrated design decisions driven by child-specific characteristics and informed by research regarding type of layout, representation, and the importance of various design features.

CONCLUSIONS

Suggestions for future research are provided, including identifying goals and communicative functions best supported by different types of displays, clinicians' challenges/successes growing a system with the child, and determining the importance of symbol arrangement and organisation in communicative tasks by AAC users.Implications for RehabilitationIdentification of current practices reported by speech-language pathologists given a case study to develop and implement future research.A gap between research and practice suggests the need for better dissemination and application of research supporting the inclusion of people engaged in the event depicted in a visual scene display.Foundations for future research to provide guidance regarding best design of and communication goals supported by visual scene displays and grid-based displays.

Eye Tracking Measures Reveal How Changes in the Design of Displays for Augmentative and Alternative Communication Influence Visual Search in Individuals With Down Syndrome or Autism Spectrum Disorder

Purpose This research note reports on how small changes to the organization of a simulated display for augmentative and alternative communication influence the visual search patterns of individuals with Down syndrome or autism, as measured through eye tracking technologies. Prior research had demonstrated that clustering symbols by their internal color facilitates search and reduces attention to distracters, in children with typical development. This research systematically replicated the procedures with individuals with Down syndrome or autism spectrum disorder. Method Participants engaged in a visual search task on a monitor with embedded automated eye tracking technology. Patterns of gaze during search were measured via this technology. Results Participants were significantly faster to fixate on the target and to select it with the mouse when the like-colored symbols were clustered together. In addition, participants were significantly less likely to fixate on distracters in the clustered condition. No group differences were found. Conclusions Small changes to the organization of the simulated augmentative and alternative communication display resulted in substantial differences in eye gaze and speed to find a target. Of greatest clinical import is the finding that clustering symbols reduced attention to distracters, given that individuals with disabilities may be prone to distraction.

Identification and Expression of Themes Depicted in Visual Scene and Grid Displays by Adults With Traumatic Brain Injury

Purpose The study purpose was to compare the speed and accuracy with which people with traumatic brain injury (TBI) identified themes depicted in visual scene and grid displays. Additionally, we compared the verbal responses associated with the 2 display types to determine whether adults with TBI tended to produce more action or naming messages. Method Thirteen adults with and 13 without TBI viewed grid and visual scene displays matched for content and theme. They then provided verbal responses stating the theme or central idea of each image. Results Although no significant differences were noted between groups for theme identification accuracy, adults with TBI required significantly more time than adults without TBI to process both display types. Both participant groups more rapidly and accurately identified visual scenes than grid displays. Additionally, participants with and without TBI produced more action messages in response to visual scenes and naming messages in response to grid displays. Conclusions This investigation provides preliminary evidence that themes that depicted visual scenes maybe more rapidly and accurately identified than those depicted in grid displays. Additionally, visual scenes may more effectively represent action messages, and grids may more effectively represent naming messages for people with TBI.

Validity of an eyetracking method for capturing auditory-visual cross-format semantic priming

INTRODUCTION

Semantic priming paradigms are important for understanding lexical-semantic processing and the nature of linguistic deficits accompanying language performance in neurologically impaired individuals such as people with aphasia. Reaction-time-(RT)-based traditional semantic priming tasks entail potential confounds, especially problematic when applied to people with aphasia, who may have concomitant neurocognitive challenges that limit task performance. Some of these confounds include requirements of following complex instructions, making metalinguistic judgments, and using speech or limb-based motor actions to indicate overt responses. Eyetracking methods have great potential for avoiding some of these confounds. We tested the validity of an eyetracking method in capturing semantic priming in an auditory-visual cross-format priming paradigm (auditory word prime-visual image target).

METHOD

A total of 72 neurologically unimpaired adults participated in two phases: a stimulus development phase using traditional priming (n = 32) and an experimental eyetracking phase (n = 40). Each phase included two conditions, representing distinct levels of prime-target semantic relatedness: unrelated and related. Mean RT data from the traditional priming (stimuli development) phase guided image selection for the eyetracking experiment. Eyetracking indices of fixation duration and latency of fixation were recorded to capture semantic priming in the eyetracking experiment.

RESULTS

Eye fixation data indicated that images related to auditory primes were attended to earlier and attracted significantly greater visual attention than unrelated images. These results mirrored RT data from the traditional priming method, which showed faster RT latencies and more accurate naming performance for related images than for unrelated images.

CONCLUSIONS

Results support the validity of eyetracking indices of semantic priming and offer a robust testing protocol for future studies in this line of research. Current clinical relevance for people with aphasia is highlighted. Further empirical testing of the psychometric properties of the eyetracking measures in various semantic priming contexts is recommended.

Designing effective AAC displays for individuals with developmental or acquired disabilities: State of the science and future research directions

This paper reviews research on the impact of AAC display variables on visual attention and performance of children with developmental disabilities and adults with acquired conditions, and considers implications for designing effective visual scene displays (VSDs) or grids. When using VSDs with children with developmental disabilities or adults with acquired conditions, research supports the use of personalized photo VSDs that include familiar people engaged in meaningful activities, with navigation bars with thumbnail VSDs, located adjacent to the main VSD. Adults with acquired conditions seem to benefit from the inclusion of text boxes adjacent to the scene. Emerging evidence supports the use of motion to capture visual attention to VSDs (video VSDs) or to specific elements in VSDs. When using grid displays with children with developmental disabilities, research supports the use of spatial cues and clustering based on internal symbol colour to facilitate visual searching and selection. Background colour does not seem to facilitate searching for symbols on smaller displays, and may actually distract children from processing the meaningful components of symbols. Preliminary research suggests that the organization of onscreen keyboards and the number, types, and pairings of symbols in grids may impact performance of adults with acquired conditions. Directions for future research are discussed.

Gaze Toward Naturalistic Social Scenes by Individuals With Intellectual and Developmental Disabilities: Implications for Augmentative and Alternative Communication Designs

PURPOSE

A striking characteristic of the social communication deficits in individuals with autism is atypical patterns of eye contact during social interactions. We used eye-tracking technology to evaluate how the number of human figures depicted and the presence of sharing activity between the human figures in still photographs influenced visual attention by individuals with autism, typical development, or Down syndrome. We sought to examine visual attention to the contents of visual scene displays, a growing form of augmentative and alternative communication support.

METHOD

Eye-tracking technology recorded point-of-gaze while participants viewed 32 photographs in which either 2 or 3 human figures were depicted. Sharing activities between these human figures are either present or absent. The sampling rate was 60 Hz; that is, the technology gathered 60 samples of gaze behavior per second, per participant. Gaze behaviors, including latency to fixate and time spent fixating, were quantified.

RESULTS

The overall gaze behaviors were quite similar across groups, regardless of the social content depicted. However, individuals with autism were significantly slower than the other groups in latency to first view the human figures, especially when there were 3 people depicted in the photographs (as compared with 2 people). When participants' own viewing pace was considered, individuals with autism resembled those with Down syndrome.

CONCLUSION

The current study supports the inclusion of social content with various numbers of human figures and sharing activities between human figures into visual scene displays, regardless of the population served. Study design and reporting practices in eye-tracking literature as it relates to autism and Down syndrome are discussed.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.6066545.

Using Images With Individuals With Aphasia: Current Research and Clinical Trends

PURPOSE

Visuographic supports in the form of images are utilized during assessment and treatment for individuals with aphasia to supplement speech, language, and cognitive losses limiting communication. Clinicians rely on prior experience and intuition to make decisions regarding image-based support design and selection (e.g., augmentative and alternative communication strategies). Researchers have begun to focus on the relationship between the images and the benefits they provide for adults with aphasia.

METHOD

The aim of this review-resulting from a roundtable discussion at the 2016 Clinical Aphasiology Conference-was to disseminate summaries of current and past researches regarding image use by individuals with aphasia and to highlight areas of need within research and practice.

RESULTS

Review of the literature illuminated 4 major themes: (a) image creation, capture, and sharing; (b) image characteristics; (c) image use across linguistic domains and contexts; and (d) implications for clinical and research practices.

CONCLUSIONS

Reviewing current knowledge and practice regarding the use of visual supports for individuals with aphasia is essential to advancing therapeutic practices and providing evidence-based protocols for creating, selecting, and implementing images within augmentative and alternative communication strategies. Several gaps in knowledge were identified as future research needs (e.g., caregiver training and enhanced image feature investigation).

The effect of human engagement depicted in contextual photographs on the visual attention patterns of adults with traumatic brain injury

Photographs are a frequently employed tool for the rehabilitation of adults with traumatic brain injury (TBI). Speech-language pathologists (SLPs) working with these individuals must select photos that are easily identifiable and meaningful to their clients. In this investigation, we examined the visual attention response to camera- (i.e., depicted human figure looking toward camera) and task-engaged (i.e., depicted human figure looking at and touching an object) contextual photographs for a group of adults with TBI and a group of adults without neurological conditions. Eye-tracking technology served to accurately and objectively measure visual fixations. Although differences were hypothesized given the cognitive deficits associated with TBI, study results revealed little difference in the visual fixation patterns of adults with and without TBI. Specifically, both groups of participants tended to fixate rapidly on the depicted human figure and fixate more on objects in which a human figure was task-engaged than when a human figure was camera-engaged. These results indicate that strategic placement of human figures in a contextual photograph may modify the way in which individuals with TBI visually attend to and interpret photographs. In addition, task-engagement appears to have a guiding effect on visual attention that may be of benefit to SLPs hoping to select more effective contextual photographs for their clients with TBI. Finally, the limited differences in visual attention patterns between individuals with TBI and their age and gender matched peers without neurological impairments indicates that these two groups find similar photograph regions to be worthy of visual fixation.

LEARNING OUTCOMES

Readers will gain knowledge regarding the photograph selection process for individuals with TBI. In addition, readers will be able to identify camera- and task-engaged photographs and to explain why task-engagement may be a beneficial component of contextual photographs.

More Than the Verbal Stimulus Matters: Visual Attention in Language Assessment for People With Aphasia Using Multiple-Choice Image Displays

PURPOSE

Language comprehension in people with aphasia (PWA) is frequently evaluated using multiple-choice displays: PWA are asked to choose the image that best corresponds to the verbal stimulus in a display. When a nontarget image is selected, comprehension failure is assumed. However, stimulus-driven factors unrelated to linguistic comprehension may influence performance. In this study we explore the influence of physical image characteristics of multiple-choice image displays on visual attention allocation by PWA.

METHOD

Eye fixations of 41 PWA were recorded while they viewed 40 multiple-choice image sets presented with and without verbal stimuli. Within each display, 3 images (majority images) were the same and 1 (singleton image) differed in terms of 1 image characteristic. The mean proportion of fixation duration (PFD) allocated across majority images was compared against the PFD allocated to singleton images.

RESULTS

PWA allocated significantly greater PFD to the singleton than to the majority images in both nonverbal and verbal conditions. Those with greater severity of comprehension deficits allocated greater PFD to nontarget singleton images in the verbal condition.

CONCLUSION

When using tasks that rely on multiple-choice displays and verbal stimuli, one cannot assume that verbal stimuli will override the effect of visual-stimulus characteristics.

Effect of Message Type on the Visual Attention of Adults With Traumatic Brain Injury

PURPOSE

The purpose of this investigation was to measure the effect of message type (i.e., action, naming) on the visual attention patterns of individuals with and without traumatic brain injury (TBI) when viewing grids composed of 3 types of images (i.e., icons, decontextualized photographs, and contextualized photographs).

METHOD

Fourteen adults with TBI and 14 without TBI-assigned either to an action or naming message condition-viewed grids composed of 3 different image types. Participants' task was to select/sustain visual fixation on the image they felt best represented a stated message (i.e., action or naming).

RESULTS

With final fixation location serving as a proxy for selection, participants in the naming message condition selected decontextualized photographs significantly more often than the other 2 image types. Participants in the action message condition selected contextualized photographs significantly more frequently than the other 2 image types. Minimal differences were noted between participant groups.

CONCLUSIONS

This investigation provides preliminary evidence of the relationship between image and message type. Clinicians involved in the selection of images used for message representation should consider the message being represented when designing supports for people with TBI. Further research is necessary to fully understand the relationship between images and message type.

A Comparison of the Visual Attention Patterns of People With Aphasia and Adults Without Neurological Conditions for Camera-Engaged and Task-Engaged Visual Scenes

PURPOSE

The purpose of the study was to compare the visual attention patterns of adults with aphasia and adults without neurological conditions when viewing visual scenes with 2 types of engagement.

METHOD

Eye-tracking technology was used to measure the visual attention patterns of 10 adults with aphasia and 10 adults without neurological conditions. Participants viewed camera-engaged (i.e., human figure facing camera) and task-engaged (i.e., human figure looking at and touching an object) visual scenes.

RESULTS

Participants with aphasia responded to engagement cues by focusing on objects of interest more for task-engaged scenes than camera-engaged scenes; however, the difference in their responses to these scenes were not as pronounced as those observed in adults without neurological conditions. In addition, people with aphasia spent more time looking at background areas of interest and less time looking at person areas of interest for camera-engaged scenes than did control participants.

CONCLUSIONS

Results indicate people with aphasia visually attend to scenes differently than adults without neurological conditions. As a consequence, augmentative and alternative communication (AAC) facilitators may have different visual attention behaviors than the people with aphasia for whom they are constructing or selecting visual scenes. Further examination of the visual attention of people with aphasia may help optimize visual scene selection.

Huffman and linear scanning methods with statistical language models

Current scanning access methods for text generation in AAC devices are limited to relatively few options, most notably row/column variations within a matrix. We present Huffman scanning, a new method for applying statistical language models to binary-switch, static-grid typing AAC interfaces, and compare it to other scanning options under a variety of conditions. We present results for 16 adults without disabilities and one 36-year-old man with locked-in syndrome who presents with complex communication needs and uses AAC scanning devices for writing. Huffman scanning with a statistical language model yielded significant typing speedups for the 16 participants without disabilities versus any of the other methods tested, including two row/column scanning methods. A similar pattern of results was found with the individual with locked-in syndrome. Interestingly, faster typing speeds were obtained with Huffman scanning using a more leisurely scan rate than relatively fast individually calibrated scan rates. Overall, the results reported here demonstrate great promise for the usability of Huffman scanning as a faster alternative to row/column scanning.

N400 brain responses to spoken phrases paired with photographs of scenes: implications for visual scene displays in AAC systems

Augmentative and alternative communication (AAC) systems are often implemented for individuals whose speech cannot meet their full communication needs. One type of aided display is called a Visual Scene Display (VSD). VSDs consist of integrated scenes (such as photographs) in which language concepts are embedded. Often, the representations of concepts on VSDs are perceptually similar to their referents. Given this physical resemblance, one may ask how well VSDs support development of symbolic functioning. We used brain imaging techniques to examine whether matches and mismatches between the content of spoken messages and photographic images of scenes evoke neural activity similar to activity that occurs to spoken or written words. Electroencephalography (EEG) was recorded from 15 college students who were shown photographs paired with spoken phrases that were either matched or mismatched to the concepts embedded within each photograph. Of interest was the N400 component, a negative deflecting wave 400 ms post-stimulus that is considered to be an index of semantic functioning. An N400 response in the mismatched condition (but not the matched) would replicate brain responses to traditional linguistic symbols. An N400 was found, exclusively in the mismatched condition, suggesting that mismatches between spoken messages and VSD-type representations set the stage for the N400 in ways similar to traditional linguistic symbols.

Eye tracking research to answer questions about augmentative and alternative communication assessment and intervention

Recently, eye tracking technologies (i.e., technologies that automatically track the point of an individual's gaze while that person views or interacts with a visual image) have become available for research purposes. Based on the sampling of the orientation of the individual's eyes, researchers can quantify which locations within the visual image were fixated (viewed), for how long, and how many times. These automated eye tracking research technologies open up a wealth of avenues for investigating how individuals with developmental or acquired communication disabilities may respond to aided augmentative and alternative communication (AAC) systems. In this paper, we introduce basic terminology and explore some of the special challenges of conducting eye tracking research with populations with disabilities who might use AAC, including challenges of inferring attention from the presence of fixation and challenges related to calibration that may result from participant characteristics, behavioral idiosyncracies, and/or the number of calibration points. We also examine how the technology can be applied to ask well-structured experimental questions that have direct clinical relevance, with a focus on the unique contributions that eye tracking research can provide by (a) allowing evaluation of skills in individuals who are difficult to assess via traditional methods, and (b) facilitating access to information on underlying visual cognitive processes that is not accessible via traditional behavioral measures.