The effectiveness of a computer-based graphic symbol communication system in individuals with severe aphasia

The purpose of this study was to implement and to evaluate the effectiveness of a computer-based graphic symbol communication system in severely aphasic individuals living primarily in nursing care facilities. Specifically, 6 individuals with chronic severe aphasia received extensive training on a special software program that turns an IBM-compatible computer into an electronic communication device. The Talking Screen pictographic communication software (TSPCS) which runs on a lap-top IBM-compatible computer was used to train participants (Woltosz, 1994). All subjects were initially trained on a set of "core" vocabulary symbols. A total of 42 nouns, 15 verbs, and 4 adjectives were taught to each subject. The "core" vocabulary was collected by evaluating and prioritizing the words from various standard vocabulary lists. In addition to the "core" vocabulary, subjects were taught certain specific symbols. These specific symbols were particular to the individual subjects' lifestyle and experiences. These symbols were selected after formal consultations with the immediate caregivers. Each subject was taught a total of nine specific symbols. In addition to the 'core' and specific symbols, subjects were trained to construct simple syntactic phrases by describing pictures using symbols from the 'Talking Screen" program. A structured treatment protocol was followed. Three different contexts were used to teach symbols to participants. The first context was representational picture (RP) to symbol matching. Here the subject was instructed to match the RP to the symbol on the screen. The second context was Picture Communication Symbol (PCS) to symbol matching. Each subject was instructed to match the PCS symbol to the correct graphic symbol on the screen. The third context presented to each subject was verbal production (VP) to symbol matching. Each subject was asked to match the VP of the symbol by the investigator to the correct symbol on the screen. These three contexts were used to train all the core and specific vocabulary symbols and two and three word phrases.

Multiple baseline across subjects with base-rating different behaviors across different subjects was used to evaluate the efficacy of computer based graphic symbol intervention. The following dependent variables were measured during the process of training: (1) rate of learning of symbols from different grammatical categories; (2) percent correct expressive use of symbols during picture description task; and (3) percent correct identification of symbols during three different contexts.

Based on the results obtained in this present study, it can be concluded that participants in this study have learned graphic symbols to varying degrees of proficiency. The subjects demonstrated the ability to master the mechanics of the computer and access the graphic symbols, learn symbols for nouns, verbs, and other grammatical categories, and comprehend and construct simple syntactic phrases. It was observed that performance varied across the three different training contexts. The VPM context was more difficult for subjects than RPM and PCSM contexts.

These results provide support for a theory of multiple symbolic capacities in individuals with aphasia. The finding that individuals with severe aphasia can learn graphic symbols has significant clinical implications for aphasia rehabilitation. If the main objective in aphasia treatment is to improve the ability of aphasic individuals to convey their thoughts and ideas, aphasiologists need to incorporate AAC systems in the rehabilitation process.