Visual speech aids: a British survey of use and evaluation by speech and language therapists.

One hundred and eighty speech and language therapists throughout the UK completed a postal questionnaire which asked for ratings of visual speech aids (VSAs) on a number of dimensions together with information regarding frequency of use of such aids, comments on the range of applicability of each type of aid and other demographic data relating to the diversity of client groups covered in case loads. The results (using analysis of variance) revealed a main effect of VSA type. There was also a main effect of question type; all VSAs scored poorly on some dimensions as compared with others. Furthermore there was a significant interaction between type of VSA and dimension type. This suggests that VSAs not only tend to be built for particular client groups, but that the makers tend to focus on some specific design criteria to the detriment of others. These results are discussed with respect to the future design of VSAs, and with respect to their testing and future evaluation.