學前兒童至老年階段言語功能指標數值的變化

Changes in Indicator Values of Speech Function Across Lifespan

本研究探討華語說話者由兒童至老年的四項言語功能指標數值的變化，包括最長發聲時長（MPT）、發聲基頻（F0）、口腔輪替運動（DDK）速率以及自發性言語速率，跨年齡層的比較這些言語功能指標數值的差異。研究採橫斷法設計，年齡範圍由4歲至83歲，取樣八個年齡組群，分4歲組、5歲組、6歲組、7歲組、9歲組、12歲組、成人組、老年組，共8組，一組有40至60位不等的參與者，各組男女人數約各半，全部參與者共350位。分析結果顯示由兒童至成人隨著年齡的增長，這些言語功能指標數值呈增進趨勢，但由成人至老年，言語功能指標數值則呈衰退趨勢。在MPT方面，除了老年組外，隨著年齡增加，MPT隨之增長，由四歲組平均5秒開始逐漸增加，增長至成人最長，成年男性平均21秒。老年組則MPT減少，平均15秒。在F0方面，在學齡前階段無性別差異，而由9歲開始出現顯著的性別差異，女性F0顯著地高於男性。由兒童至成人，男女性皆隨著年齡的增長F0下降，但由成人至老人的F0變化趨勢是女性長者持續下降，而男性長者的F0則略升高。DDK的速率隨著兒童年齡的增長而變快，由四歲（平均3.25音節／秒）至成人達最高（平均5.28音節／秒），老年組DDK速率（平均4.70音節／秒）則顯著低於成人組。自發言語速率和DDK速率隨年齡變化的趨勢相近似，亦隨著兒童年齡增長而變快，由四歲（平均2.35音節／秒），至成人達最高（平均4.37音節／秒）。自發言語速率與各項DDK速率呈中度正相關，顯現兩者間在構音動作控制的關連性。四個言語功能指標數值隨著年齡而變化的趨勢顯示言語功能在發聲呼吸效能、聲帶質量、構音動作速度與協調性的變化，由兒童期至成人階段大致呈現增長趨勢，由成年至老年言語功能則呈衰退趨勢。

This study investigated the differences on the indicator values related with four speech functions among eight age groups of Mandarin speakers, and explored the changes in speech functions across lifespan. This cross-sectional study explored the changes in speech functions with age. The following four functional indicators of speech were measured: maximum phonation time (MPT), fundamental frequency (F0), oral diadochokinetic (DDK) rates, and spontaneous speech rates. The study recruited 350 participants, comprising of eight age groups, including 4-, 5-, 6-, 7-, 9-, 12-year-old children, young adults and older adults. The participant age ranged from 4 to 83 years. The results demonstrated that MPT increased with age—from an average of 5 seconds in 4-year-old children to an average of 21 seconds in adult male group. The MPTs of the older adults were shorter, at an average of approximately 15 seconds. The F0 values of preschool and 7-year-old children demonstrated no significant gender difference; however, gender difference appeared in 9-year-old children. The results showed that the F0s of adult females were significantly higher than those of adult males. For both genders, the F0s decreased with age, except for the older adults. The F0s of older women continued to decline, whereas those of older males increased slightly. The DDK rates increased with age, with a mean of 3.25 syllable/s, and it was fastest among all groups (mean: 5.28 syllable/s); however, the DDK rates in older adults tended to decrease (mean: 4.70 syllable/s). Although the spontaneous speech rates were slightly slower than the DDK rates, the tendency of changing with age was common for both indicators. The speech rates were moderately correlated with the DDK rates, suggesting that both of them may share the same articulatory motor control mechanism. The change of these indicators suggests that speech function generally improves with age, in terms of phonatory-respiratory efficacy, mass of vocal folds, articulatory agility, and coordination; however, the speech functions were observed to decline for older adults.