The use of strategies to increase speech intelligibility in cerebral palsy: an experimental evaluation

The effects of strategies on the intelligibility of cerebral-palsied speech were experimentally evaluated. Listeners were asked to identify words in sentences spoken by subjects whose dysarthria was rated to be either moderate or severe. Results indicated that strategies increased intelligibility and that different strategies were appropriate at different levels of severity. Use of initial letter cueing achieved the greatest gains for the more severely impaired speakers but, for the less severely impaired, the gains achieved by providing visual cues were the same as those achieved by letter cueing and could not be improved upon by repetition. Listeners' experience of dysarthric speech and the redundancy of the test sentences were also manipulated. Previous experience did not influence recognition and redundancy only appeared to have an influence at higher levels of intelligibility. The role of strategies in improving intelligibility is discussed. The results suggest that many speakers will be unable to use simple strategies to improve intelligibility to levels that may be needed for adequate information transfer.