The reliability and clinical application of the new indexes for thyroid cartilage position and muscle strength of suprahyoid muscle group

Abstract

Purpose： We have developed four clinical indexes for assessing the secondary factors that impede laryngeal movement in swallowing．This study examined the reliability of the measurement，and its application in the clinical field， especially characteristics with aging and sexuality，and the relationship between these indexes and dysphagia．

Method： One hundred and nine persons participated in this study．We subdivided the subjects into five groups (A：younger healthy group，30；B：elderly group，17；C：chronic CVD without dysphagia，20； D：chronic CVD with dysphagia，32；E：dysphagic inpatient with CVD，10)．The four clinical indexes are as follows： distance from genio to thyroid with neck extension (GT)，distance of thyroid-sternum with neck extension (TS)，calculated ratio of the thyroid cartilage level (T-position ＝ GT/(GT+TS))，and classification of neck flexion holding ability in the supine position (GS grade)．

Results：The reliability of these indexes was 0.84-0.94 with ICC (1，1) and ICC (2，1) in group E．The standard values of these indexes were measured (GT＝6.4 ± 0.9cm， TS ＝ 12.2 ± 1.0cm， T-position： 0.34 ± 0.04 in group A， GT＝6.6 ±1.0cm，TS＝9.5 ± 1.1cm，T-position ＝ 0.41 ± 0.05 in group B)．In comparison among group B，C and D，there was no significant difference between B and C，but there was a significant difference between C and D with TS， T-position，and GS grade．

Conclusion： The results of this study clarified that these indexes are useful for evaluating the secondary factors that impede laryngeal movement in swallowing．