Frequency of Use of Vocabulary for Individuals Using Dynamic Display Systems
ABSTRACT
The goal of this pilot study was to identify the frequency of use of core and extended vocabulary for individuals who use two levels of a semantic organization scheme on dynamic display augmentative and alternative communication (AAC) systems. Language Activity Monitoring (LAM) was used to collect language samples for a total of nine participants with complex communication needs (CCN). LAM data was analyzed to determine the overall pattern of vocabulary use. Results indicated that Group 1 (multi-level display) used core words 44% of the time compared to Group 2 (fixed-level display) who utilized core words 70% of the time. Results of this pilot study provide quantitative performance data to support evidence-based practitioners.
KEYWORDS
Core, Extended, Vocabulary, Language Activity Monitoring, evidence-based practice
BACKGROUND
Historically, AAC vocabulary selection has been based upon the frequency of word usage of able-bodied individuals using natural speech (1). Studies that have investigated vocabulary usage of naturally speaking children include (2), and adults, (3). Currently, only two studies have verified similarities in vocabulary frequency of use between individuals who rely on AAC and speaking individuals (4; 5). Continued research is necessary to determine actual vocabulary usage related specifically to core and extended vocabulary by individuals who rely on AAC and how this may be related to how vocabulary can be accessed on high performance AAC systems. Core vocabulary is made up of a small group of common words that are used across all communication environments (e.g., the, an) (6). Extended (fringe) vocabulary makes up all those remaining words that are specific to each communication context (e.g., computer, keyboard) (7).
Today there is no empirical data that reports how specific semantic organization schemes may affect the type of vocabulary accessed, e.g., the three language representation methods (LRMs) including single meaning pictures, alphabet-based methods, and semantic compaction as well as core and extended vocabulary. Dynamic display devices are gaining steadily in popularity despite a lack of a research-base regarding their performance. Two types of display schemes on dynamic high performance AAC systems that can be compared are: 1) multi-level (dynamic active hierarchy) and 2) fixed-level (all symbols appearing on one page/one location). The type of semantic organization may significantly influence what vocabulary is accessed. For example, on a fixed-level display, all symbols appear on one page meaning only one hit may be necessary to access a word. In contrast, on a multi-level system vocabulary is mostly accessed through screen changes meaning several keystrokes may be necessary to access a word. For example, on a fixed display the core word “the” would require one keystroke, but may require two to three on a multi-level organization scheme. This may influence the type of vocabulary a user accesses.
RESEARCH QUESTION
The objective of this pilot study was to determine the frequency of use of vocabulary for individuals who rely on high performance dynamic display AAC systems. The goal of the study was to analyze the specific vocabulary being accessed as well as to determine how use of core and extended vocabulary by individuals using multi-level and fixed-level semantic organization schemes on a dynamic display system compares with established evidence for core and extended vocabulary use. The research designs and methods of this study support an evidence-based approach to collection of performance data that will have utility for future research and current AAC clinical practice.
METHOD
Participants
The participants of the study were nine individuals (five male and four female) between the ages of 5 years and 44 years (Median age = 12 years). All participants had AAC dynamic display systems manufactured by the Prentke Romich Company configured to support the identified semantic organization schemes. The participants were divided into two groups: Group 1 consisted of six participants (N=6) who used a multi-level scheme. Group 2 consisted of three participants (N=3) who used a fixed-level scheme. Participating site practitioners assigned the group considered most appropriate for the individual using the AAC system based on an appraisal of their AAC system and experience. Experience with a multi-level scheme ranged from five months to five years and on the fixed level from one month to six months. Since this was a pilot study attempting to identify the feasibility of answering the research questions, inclusion criteria were not restricted and matching of groups was not attempted.
Procedures
All language samples were collected using Language Activity Monitoring for this study. Language samples were collected by four practitioners who were working with individuals using the multi-level or fixed-level semantic organization on dynamic display systems. Language sample procedures were provided to each practitioner and were based on procedures designed as part of the SBIR Phase I research on the Language Activity Monitor (LAM) (8).
The primary researcher and one research assistant from Edinboro University of Pennsylvania transcribed the language samples directly from the LAM logfiles. The research assistant transcribed all the language samples and inter-judge reliability was obtained by the primary researcher transcribing randomly selected language samples. The logfiles were edited, coded, and analyzed using PeRT (9) and the Systematic Analysis of Language Transcripts (SALT Ó for Research version 6.1) (10). A composite transcript of the total number of words for all participants and for each of the two groups was generated for vocabulary analysis.
RESULTS
Vocabulary data was collected from 29 LAM logfiles for Group 1 and 46 logfiles for Group 2 and analyzed via composite word lists. Transcripts collected from Group 1 generated a composite transcript with 3164 word samples. Group 2 produced 5430 word samples. The total composite transcript for both groups of participants produced 8594 word samples for analysis. All composite word lists illustrated word frequency of use. Table 1 shows the top 25 words with the frequency of occurrence for Groups 1 and 2 along with the combined word list and frequencies of occurrence for both groups.
Composite Word List |
Freq |
Unity Enhanced |
Freq |
Unity One-hit |
Freq |
|---|---|---|---|---|---|
I |
621 |
personal_name |
369 |
I |
467 |
personal_name |
441 |
I |
154 |
want |
196 |
want |
286 |
want |
90 |
red |
151 |
red |
161 |
to |
53 |
color |
141 |
color |
144 |
mom |
51 |
eat |
125 |
do |
134 |
grandma |
34 |
say |
124 |
feel |
129 |
baby |
33 |
do |
122 |
say |
128 |
cartoon |
32 |
help |
121 |
go |
127 |
is |
31 |
feel |
115 |
eat |
127 |
telephone |
30 |
drink |
108 |
my |
125 |
sunday |
29 |
go |
105 |
help |
124 |
my |
27 |
what |
100 |
you |
113 |
you |
25 |
happy |
99 |
to |
112 |
no |
25 |
my |
98 |
work |
111 |
work |
24 |
more |
96 |
what |
111 |
teacher |
24 |
like |
95 |
drink |
110 |
day |
23 |
you |
88 |
please |
109 |
two_thousand_three |
22 |
work |
87 |
like |
108 |
please |
22 |
please |
87 |
happy |
104 |
go |
22 |
sleep |
82 |
mom |
103 |
at |
22 |
paper |
73 |
more |
99 |
am |
20 |
stop |
72 |
sleep |
85 |
saturday |
17 |
need |
72 |
need |
85 |
yes |
16 |
personal_name |
70 |
and |
82 |
with |
16 |
good_bye |
70 |
DISCUSSION
 |
The results of this study suggest a pattern of how vocabulary is accessed on the two semantic organization levels. Analysis of vocabulary access for Group 1 indicated a high usage of single meaning pictures as well as a limited MLU which resulted in a high frequency use of nouns (extended vocabulary) in the top 25 word list. Analysis of the vocabulary list for Group 2 indicated that the use of core vocabulary was significantly higher than that of Group 1. Group 2 participants used core vocabulary 70% of the time in communication in contrast to Group 1 participants who used core words only 44% of the time.
The limitations of this pilot study regarding inclusion criteria and lack of random assignment to groups weaken the significance of the results. The heterogeneity of the participants shows the difficulty in collecting, and reporting results on AAC system performance by individuals with CCN. Never the less, the emerging patterns of vocabulary access show significant contrasts in use of core and extended vocabulary between the two groups. Consequently, practitioners should consider conscientiously how the semantic organization scheme may be influencing communication competence.
REFERENCES
- Yorkston, K., Dowden, P., Honsinger, M., Marriner, N. & Smith, K (1988). A comparison of standard and user vocabulary lists. Augmentative and Alternative Communication, 2 , 189-210.
- Beukelman, D., Jones, R. & Rowan, M (1989). Frequency of word usage by nondisabled peers in intergrated preschool classrooms. Augmentative and Alternative Communication, 5, 243-248.
- Balandin, S., & Iacono, T. (1999). Crews, wusses and whoppas: The core and fringe vocabulary of Australian mealtime conversations. Augmentative and Alternative Communication, 15, 95-109.
- Beukelman, D., & Yorkston, K. (1984). Computer enhancement of message formulation for communication augmentation system users. Seminars in Speech and Langauge, 5 , 1-10.
- Hill, K. (2001). The development of a model for automated performance measurement and the establishment of performance indices for augmented communicators under two sampling conditions. Unpublished doctoral dissertation, University of Pittsburgh.
- Banajee, M., DiCarlo, C., Stricklin, S. (2003). Core vocabulary determination for toddlers. Augmentative and Alternative Communication, 19 (2), 67-73.
- Yorkston, K., Honsinger, M., Dowden, P., & Marriner, N. (1988). Vocabulary selection: A case report. Augmentative and Alternative Communication, 5 (2), 101-108.
- Hill, K. & Romich, B (2001) A summary measure clinical report for characterizing AAC performance. Proceedings of the RESNA 2000 Annual Conference . Reno, NV.
- Hill, K. and Romich, B. (2003). PeRT: Performance Report Tool. [Computer software]. Edinboro, PA: AAC Institute.
- Miller, J. F. & Chapman, R.S. (1983). Systematic analysis of language transcripts (SALT). San Diego, College Hill Press.
Author Contact Information:
Emily Spurk, BA,
Edinboro University
EMAIL: Ylimesp@yahoo.com
Katya Hill, Ph.D., CCC-SLP,
Center for Assistive Technology,
Education and Research,
Edinboro University of Pennsylvania,
Edinboro, PA 16444
EMAIL: Khill@edinboro.edu
