Abstract
To evaluate the effects of the palatal lift prosthesis (PLP) for patients with velopharyngeal incompetence resulting from acquired neurogenic disease, velopharyngeal competence, motor speech ability and speech intelligibility were investigated in forty-four patients. The assessment of velopharyngeal competence was carried out using lateral radiographic cephalometric films with a contrast medium, soft blowing time, maximum prolongation time for the consonants /s/ and /∫/. The assessment of motor speech ability was carried out using maximum phonation time for the vowels /a/ and /i/ and oral diadochokinesis. The assessment of speech intelligibility was carried out using speech intelligibility test scores. These examinations were carried out prior to and after construction and placement of the PLP according to each patient's ability and the following results were obtained.
(1) After construction and placement of the PLP, velopharyngeal competence assessed by soft blowing time, blowing ratio, maximum prolongation time for the consonants /s/ and /∫/ improved immediately in many patients. Motor speech ability examined by maximum phonation time for the vowels /i/ and /a/ and oral diadochokinesis also improved in many patients.
(2) Twenty one patients improved soft blowing time remarkably with use of the PLP and ten of these patients (47.6%) demonstrated a 10% increase in speech intelligibility. These patients improved their articulation according to improvement in velopharyngeal competence with use of the PLP.
(3) Three patients in whom residual lumen size without the PLP was decreased after three to twelve months following the insertion of the PLP revealed improvement in ability of motor speech and articulation without the PLP.
