[Studies on bone mineral status with bone quantitative ultrasonography in severely handicapped school children--correlations with gross motor function and dietary status].

OBJECTIVE: Severely handicapped children and adolescents have reduced bone mineral density and high prevalence of pathological fractures. Bone quantitative ultrasonography (QUS) is a radiation-free method for assessing bone density. It is portable and easy to use in subjects with severe bodily deformities. METHODS: We evaluated 166 students (age 6-20 years) at a school for disabled children for bone mineral density using the osteo-sono-assessment index (OSI) calculated by measuring the velocity of ultrasound waves, the speed of sound (SOS) and the transmission index (TI), at the calcaneus. All examinations were performed using an AOS-100 analyzer (ALOKA Ltd., Tokyo, Japan). The Gross Motor Function Classification System (GMFCS) for cerebral palsy was also applied. We assessed OSI for dietary texture modifications and methods of feeding. RESULTS: Those with pathological fractures tended to have lower OSI than other students. Such fractures were individually unrelated to age, sex and GMFCS. OSI was significantly higher at GMFCS level I than level II. OSI in levels I to III was equally significantly higher than that in levels IV and V. As to feeding methods, the tube feeding group tended to have lower OSI than the oral ingestion group. In the oral ingestion group, those receiving a regular diet had significantly higher OSI than the mixed-minced diet group. However, students with a gastrostomy tended to have higher OSI than those receiving gastro-nasal tube feeding. CONCLUSIONS: Gross motor function (applied GMFCS) is a major factor affecting bone mineral density. Tube feeding reduces bone mineral density. However, forced oral intake may also reduce it. In the tube feeding group, a modified diet of appropriate texture delivered via gastrostomy may be the key to improving bone mineral density.