Assessment and therapy of clients with a history of VPI using electropalatography

Abstract

ABSTRACT It is of both theoretical and practical importance to study the dynamics of ***articulatory movements which occur in individuals with speech disorders associated with a history of velopharyngeal insufficiency (VPI). Theoretically it is of interest to understand how children develop speech in exceptional circumstances, i.e. with an abnormal vocal tract. In practice it is important to investigate the nature of abnormal speech behaviour, in order to diagnose accurately and subsequently treat any articulation disorders which may be present. One safe and convenient method for this purpose is the technique of electropalatography (EPG). EPG provides direct information relating to one important aspect of speech production, namely spatio‐temporal details of the tongue's contact with the hard palate during connected speech. EPG has a further advantage in that it can provide clients with real‐time visual feedback of tongue movement, and this can be utilised in articulation therapy.A recent project, funded by the British Medical Research Council, investigated the value of EPG as a diagnostic and therapy procedure in a group of 20 school age children with persisting speech difficulties. This paper reports the results from six children, all of whom had a history of VPI. In terms of diagnosis, a number of distinct EPG error patterns emerged which could be considered to be unique to this group. Some of the EPG patterns could be anticipated on the basis of auditory perceptual judgements. For example, there was minimal tongue‐palate contact for sounds which were heard as pharyngeal. Further, sounds which were heard by listeners as having a retracted place of articulation had EPG patterns which were located at an abnormally posterior region of the palate. However, some of the EPG patterns were not predicted on the basis of auditory judgements. For example, EPG revealed the presence of double articulations involving simultaneous velar contact for labial and alveolar targets. Such patterns were considered to be of clinical significance since their presence provided a possible explanation for previous lack of progress in therapy.The children were given a course of therapy using EPG for visual feedback of the tongue contact pattern. Post‐therapy EPG recordings showed evidence that the children were able to use the visual information which EPG provided to change their articulation patterns so that they more closely resembled those of a normal speaker. The children varied in the extent to which they were able to transfer skills acquired with visual feedback into automatic speech.The results from these children provide evidence that EPG can be considered to be a useful additional procedure for use with individuals with intractable speech disorders associated with a history of VPI. It is viewed as a means of providing the therapist with important diagnostic information undetected from an auditory‐based evaluation and also giving clients access to visual information about articulation which they cannot obtain through other forms of therapy.