Catriona Bennie
Dept of Speech & Hearing Sciences, Queen Margaret University College, Clerwood Terrace, Edinburgh EH12 8TS, UK

Introduction

Clinical observations of a group of high tech Augmentative and Alternative Communication (AAC) aid users suggested that less cognitively able clients were struggling to locate messages on communication aids.

People with significant learning disabilities particularly appeared to be having difficulty navigating semantically organised dynamic systems.

An honours project was undertaken to look into semantic organisation in adults with learning disabilities.

Semantic Organisation

Semantic Organisation describes the way in which individuals mentally store vocabulary by meaning associations.

Current literature suggests there are two ways that concepts can be organised; schematically or taxonomically (Bauer and Mandler 1989; Rosch, Mervis, Gray, Johnson and Boyes-Braem, 1976). For example, given a list of words a child may put these words together: Ball, Slide, Trees, Grass, Wellingtons, Coats.

The child's explanation for putting these words together may be, e.g. "They are all part of going to the play park". This would be described as a schematic organisation as the words are organised in relation to how they occur in one schema or event together.

In contrast, when given these words adults are more likely to group the words taxonomically with hierarchical headings:

Vegetation   Trees and Grass
Children's toys   Ball and Slide
Clothes   Wellingtons and Coats

Schematic organisation patterns are highly individual relating to events that occur in an individual's daily life. Taxonomic organisation is more universal however still influenced by the individual's beliefs and experience.

Studies have identified a developmental shift from a schematic vocabulary organisation pattern to a taxonomic pattern of vocabulary organisation between the ages of 6 and 7. It is also understood that this developmental process is influenced by conversations with adults and formal teaching in relation to the child's own language abilities (Lucariello, 1998; Lucariello & Nelson, 1985; Nelson, 1996; Snow, 1990).

Fallon, Light and Achenbach, (2003) conducted a study in which twenty 4 and 5 year olds were asked to place 42 line drawings together in a way they thought they best fitted together. The 42 line drawings represented 42 different concepts including nouns, verbs, adjectives, pronouns, prepositions, questions and one interjection. Half of the concepts were said to be abstract and the other half were concrete.

After placing the line drawings together the children were asked to describe why they had put the drawings together in the groups they had made.

Vocabulary placements were determined meaningfully placed if the child explained why the line drawing was placed there in relation to the other line drawings in that group.

The research found that of the total number of line drawings placed meaningfully 93% of vocabulary concepts were organised according to schematic organisation.

Only 7% of items were arranged according to a taxonomic structure.

This result supports other studies reporting that children's use of a taxonomic organisational system begins to emerge in the early school years.

Not much is known about the semantic organisation patterns of adults with learning disabilities. Studies focusing on the semantic organisation of learning disabled children found them to be following a delayed but normal developmental sequence (Winters and Brzoska, 1976).

"The way vocabulary is coded into an AAC aid is often determined by what seems logical to the Speech and Language Therapist working with the client." (Blackstone, 1993)

If an adult with a learning disability is using a communication aid set up taxonomically (hierarchically) by another person the adult with the learning disability may find it difficult to learn where the symbols are located as the method of organisation is not the most natural one to them. This may affect the adult's ease of communication and confidence in using the VOCA.

Aims and Hypotheses

• This study aimed to investigate to what extent the semantic organisation of the adults with and without learning disabilities differs.
• To discuss the implications of delayed semantic organisation for adults with learning disabilities who are learning to use AAC.
• To suggest alternative ways of organising vocabulary on a communication aid for an adult with learning disabilities taking into account their abilities, knowledge and future development.

The hypotheses of the project were that:

1. Adults without learning disabilities will organise vocabulary in a mainly taxonomic way, and use schematic organisation for highly familiar groups of words.
2. The semantic organisation patterns of adults with learning disabilities are comparable to those of normally developing children.

Participants and Method

Four adults with learning disabilities took part in the study. All the participants were speaking and had no previous experience of using communication aids. All had mild learning disabilities and three had a diagnosis of ASD. Ten adults without learning disabilities took part in the study. All were English speaking and had been to mainstream schools.

The method developed by Fallon, Light and Achenbach, 2003 was used in this study. Line drawings of 42 vocabulary items were used and each participant was asked to group these vocabulary items together and later give an explanation of why they had grouped these concepts. The rationales that each participant gave for their vocabulary groupings were analysed using a coding scheme developed by Fallon, Light and Achenbach (2003).

The resulting information was further analysed to identify each participant:

• Evidence of Organisational Structure – Identifying for each participant how many of the concepts were meaningfully placed.
• Type of Organisation Used – To find out if the participant used taxonomic or schematic organisation in their grouping of concepts. This was done by analysing the rationales with the help of the coding scheme.
• And the percentage of each participant's abstract and concrete concepts placed meaningfully.

Participant NLD7:
Vocabulary grouped – read, work, talk, run, cry, drink, make, eat, going to
Rationale – "They are all verbs."
Coding – Taxonomic

Participant NLD5:
Vocabulary grouped – coffee, kitchen, hungry, eat, drink, cake, pizza, cup, finish, yummy
Rationale – "These words are all connected with eating."
Coding – Schematic: highly familiar

Participant ALD1:
Vocabulary grouped – father, in, kitchen, more, cake, yummy
Rationale – "Dad is in the kitchen with more cake, he thinks it's yummy."
Coding – Schematic: novel

It can be seen that NLD7's rational explains that the vocabulary was grouped together using taxonomic organisation because to that participant the words are connected by the fact they all come under the hierarchical heading of verbs. NLD5 grouped words together that were connected by the fact that they are regularly used in one scene or schema. Adults with quite developed semantic organisation skills can choose which organisation they prefer to use. Fallon, Light and Achenbach, (2003) describe Schematic: highly familiar as a vocabulary grouping where 'The explanation involves a conventional or predictable schema/script that suggests an event based origin' (Fallon, Light and Achenbach, 2003).

The rational given by ALD1 for the grouping of the words Father, in, Kitchen, more, cake, yummy relates to a very individual event or one that has been made up for the purpose of fitting the words together and so is coded as schematic: novel. Fallon, Light and Achenbach, (2003) describe schematic: novel as a vocabulary grouping where 'The rationale for placement involves an event based schema, however the script is unique or novel, not predictable'.

The graph (Figure 1) shows the type of organisation used by each participant as well as the percentage of concepts placed meaningfully.

Fig 1  Evidence of Organisational Structure and Type of Organisation

Participants ALD1-ALD4 are the participants with learning disabilities and participants NLD1-NLD10 show the results of the participants without learning disabilities. None of the participants without learning disabilities used a schematic: novel organisation to group concepts. The participants without learning disabilities also used more taxonomic organisation than schematic: highly familiar. Of the participants with learning disabilities only one used some taxonomic organisation. Interestingly participant ALD4 spent her primary school years in a Language Unit receiving intensive speech therapy. This relates to the fact that semantic organisation is a developmental process influenced by formal teaching. It is also interesting that NLD7 is by profession a computer programmer who uses hierarchical planning and organisation regularly in day to day life.

The event based schemas produced by the learning disabled participants were all very individual and varied from participant to participant. This highlights the fact that wherever possible the client who is to use an AAC aid should be involved in where and how vocabulary is stored, as vocabulary has different meaning and importance to each individual. The learning disabled participants made extensive use of event based schemas in their arrangement of the vocabulary. Organising vocabulary according to familiar and recurring events could promote greater access and learning of their aid, in turn facilitating effective communication.

It is likely that people who use AAC to communicate will have learnt their own communication aid layout to some extent and will then have developed some areas of semantic organisation through experience with their aid.

It is also possible however that some learning disabled users of AAC may still find the layout of their aid confusing and this may affect how well and how often they use it. It would therefore be beneficial to teach organisation skills when introducing a new communication aid to a learning disabled adult. Taxonomic organisation may be difficult for adult with learning disabilities to learn after years of organising vocabulary in another way. This highlights the fact that children learning to use AAC should be helped in their development of semantic organisation in order to help them develop these skills.

One method of dynamic AAC layout has been suggested by DynaVox Systems Ltd (2003) considering the semantic organisation development of young children through the placement of vocabulary on a dynamic AAC aid. It suggests that a page could be made up according to an event based schema such as 'Eating'. Vocabulary depicting food items could be placed on one side of the page with vocabulary depicting related words such as 'yummy' and 'plate' on the other side. The food items could be labelled as food in order to promote the development of categorisation skills. The words related to Eating schema would still be easily accessible, promoting smooth communication and the development of categorisation (DynaVox Systems Ltd, 2003).

As has been suggested in Light et al (2004), current aided AAC systems need to be redesigned in order to meet the needs of those who require AAC to reduce the cognitive load of learning the system. One new option for design includes embedding vocabulary into a scene on the communication aid (Light et al 2004). Vocabulary can be stored within the scene so that when a part of the scene is pressed this vocabulary would be available to the person who uses AAC. This type of layout would put vocabulary within a context supporting users to learn vocabulary. It reflects the way people learn to organise vocabulary semantically, first in relation to schemes and then in relation to items taxonomically. It is likely that this, 'the integrated contextual scene layout', may also benefit adults with learning disabilities as it was found that some adults with learning disabilities link vocabulary together in relation to different schemas.  §

Acknowledgments

Hons project supervisor: Dr Jim Scobbie
Advisor: Alison MacDonald

References

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