Members of the Barnsley AT Team met recently to spend some time looking at the evidence behind several different vocabulary/language packages for communication aids. This is a key and frequent discussion within the team and we organised a session to help develop our thinking on this. It also links with the forthcoming research project we will be involved with funded by the National Institute for Health Research and in collaboration with Manchester Metropolitan University (more on this later!).
Vocabulary packages can broadly be grouped into: taxonomic (categories), schematic (activities), alphabetic, iconic encoding, visual scene displays and idiosyncratic (personalised). Some systems might use several of these methods to organise vocabulary. For this session we chose to looked at the evidence around Visual Scene Displays (VSDs) and considered the following literature (some published in peer reviewed journals, some ‘grey’ literature):
- Drager, Light et al (2003) The Performance of Typically Developing 2½ Year Olds on Dynamic Display AAC Technologies with Different System Layouts and Language Organizations
- Drager & Light (2010) Designing effective visual scene displays for young children.
This work suggest that visual scene displays may:
- be most beneficial for young children and people with significant cognitive or linguistic difficulties (e.g. Learning Disability, Aphasia, Brain Injury);
- provide a high level of contextual support;
- enable communication partners to engage and support the person with communication needs by providing a framework and context from which they can scaffold a conversation;
- support real life events and experiences as they happen, by providing a supportive narrative;
- be highly personalised/replicate real life experiences;
- provide language in context;
- shift the focus away from expressing wants and needs and towards social interaction and exchange of ideas and information;
- reduce cognitive demands by reducing visual processing;
- access linguistic concepts via episodic memory not semantic memory;
- exploit human capacity for rapid visual processing of visual scenes.
The above studies also discuss the limitations of VSDs suggesting that:
- Children with motor difficulties may find it harder to access hotspots on a VSD than symbol grids.
- VSDs may be more visually complex than evenly spaced symbols in a grid.
- VSDs are labour intensive to produce and maintain.
- Jackson, Wahlquist and Marquis (2011), found children performed better with a grid layout and made more mis-hits with VSDs.
We also looked at the paper: “Critical Review: Which Design Overlay is Better Suited for Early Assisted AAC Intervention in Preschoolers: Visual Scene Displays or Traditional Grid Layouts? ” Kaempffer (2013).
Kaempffer reviewed the literature on VSDs and found results of studies looking at VSDs to be inconclusive and limited. Kaempffer was also critical of methodology and statistical analysis used in studies into VSDs. Only one study has included children with communication needs and some studies have suggested grid layouts may be more appropriate.
Our team concluded that VSDs should still be considered as part of the AAC assessment process. However although the literature suggests that emergent AAC users and adults with cognitive impairments may benefit from VSDs, from this session we could not see strong evidence to suggest particular groups of individuals or situations in which VSDs may be most useful.
A number of software packages are available that support VSDs, these include:
- Tobii-DynaVox Compass, Sono Primo
- MultiChat 15/Touch Chat HD app
- Therapy Box Chatable & Scene and Heard
Have you used VSDs with a communciation aid user, have we missed some important literature? We would love to hear about your experience!
Drager, K., Light, J., Speltz, J., Fallon, K., Jeffries, L. (2003). The Performance of Typically Developing 2½ Year Olds on Dynamic Display AAC Technologies with Different System Layouts and Language Organizations. Journal of Speech, Language, and Hearing Research, 46(2), 298-312.
Jackson, C., Wahlquist, J., Marquis, C. (2011). Visual Supports for Shared Reading with Young Children: the Effect of Static Overlay Design. Augmentative and Alternative Communication, 27 (2), 91-102.
Kaempffer, A (2013) Critical Review: Which Design Overlay is Better Suited for Early Assisted AAC Intervention in Preschoolers: Visual Scene Displays or Traditional Grid Layouts? Poster presentation at University of Ontario. Unpublished/peer reviewed, but available as PDF.
Light, J., Drager, K., & Wilkinson, K. (2010, November). Designing effective visual scene displays for young children. ASHA Conference. Lecture conducted from Philadelphia, PA.. Conference presentation avaliable as a PDF.