Palatal plate therapy in children with Down syndrome : a longitudinal study of effects on oral motor function

Abstract

The aim of this thesis was to investigate the effect of palatal plate therapy on the oral motor function children with Down syndrome (DS) during 4 years by comparing the baseline values of the treatment group with those of a control group (CG). The effects of palatal plate therapy on speech production errors and communicative preference after 4 years of treatment were also studied and articulation was analyzed. The habitual orofacial dysfunction of children with DS as a group was described in relation to their oral structures. In a final study the effects of growth hormone (GH) therapy on craniofiacial development and dental maturity in children with DS who had not been given GH.

Twenty-nine children with DS, mean age 10.7±6 months, were randomized into two groups, the palatal plate group (PPG, n=14), and the CG (n =15). and were evaluated using video registration of their oral motor function during 1 year and again oiler 4 years of treatment. Twenty of the children (PPG, n=9; CG, n= 11) were evaluated longitudinally during 4 years of palatal plate therapy. All children were enrolled in and had followed the same oral motor and sensory stimulation programs. After 1 year the mean duration of the variable "Closed mouth" was significantly longer (P<0.001) and the mean duration of the variable "inactive protrusion of the tongue" was significantly shorter (P<0.001) in the PPG than in the CG. Summary variables describing active and inactive orofacial muscle function were developed.

After 4 years of treatment, the summary variables describing active orofacial muscle function were f ound to constitute 81.0±11.0% of the registered video time in the PPG (n=9), compared to 68.2±22.5% in the CG (n=11). Statistically significant differences were found between the groups in the summary variables describing inactive oral muscle function (P<0.01).The measures used to evaluate the groups oiler 4 years of treatment were a clinical extra- and intraoral examination, an articulation assessment, a test of communicative preferences (spoken or manual sign language), and a parental questionnaire. Results from the clinical examination revealed significant differences between the groups in the summary variables for "visible tongue" (P<0.01) and the summary variables for "lip rounding score" (P<0.01). Facial expression was assessed on a visual analog scale. The PPG scored 75.6±13.3 compared to 51.8±25.7 in the CG (P<0.05). Six children in the PPG and 7 in the CG had enlarged tonsils, defined as an inter-tonsillary reduction of more than 50%.

Results from the parents's questionnaire showed that snoring at night occurred significantly inure often in the CG than in the PPG (P<0.05). The study indicates that palatal plate therapy has had effects on the orofacial muscles and the habital position of the tongue as well as on facial expression and mouth closure, particularly during the first year of therapy. One provable effect on articulation was also found. However, considering our experience with these children, we would recommend palatal plate therapy only to hypotonous DS children, who have no major medical disorders, and who have sufficient support from their parents and from speech and language pathologists. Furthermore, in parallel with the treatment routine, controls of the air-way passages should be made to ensure that they are unobstructed.

A group of 10 children with DS underwent GH therapy for 3 years, and 3 years after the therapy was terminated craniofacial growth and dental maturity were evaluated. The results were compared with those 16 age-marched children with DS who had not undergone GH therapy. There were no significant differences in craniofacial development between the two groups. The mean chronological age was the same as the dental age for children in the GH group. There were no significant differences between chronological age and dental age in the group who had not undergone GH therapy. In children over 8 years of age (n=7), the dental age was consistently below the chronological age.