Department of Kinesiology, Mississippi State University, 233 McCarthy Gym, P.O. Box 6186, Mississippi State, MS 39762, USA.
Res Dev Disabil. 2010 May-Jun;31(3):857-63. doi: 10.1016/j.ridd.2010.03.002. Epub 2010 Mar 21.
This study examined whether the autonomic response to passive upright tilt as evidenced by changes in measures of heart rate and blood pressure variability differs between individuals with DS and without DS. Beat-to-beat blood pressure was measured in 26 individuals with Down syndrome (DS) and 11 individuals without DS during 5 min of rest and 5 min of upright tilt. Dependent variables included heart rate, blood pressure, frequency component measures of heart rate and blood pressure variability, and baroreflex sensitivity. The normalized high frequency (HF) power, normalized low frequency (LF) power, and LF/HF of heart rate variability, as well as the LF of blood pressure variability were reduced in persons with DS in response to upright tilt (p<0.05). This was accompanied by smaller change in baroreflex sensitivity (p<0.05) in individuals with DS. Blood pressure responses to upright tilt were also reduced in individuals with DS (p<0.05), but the heart rate response did not differ between groups. Individuals with DS show less vagal withdrawal and sympatho-excitation in response to passive upright tilt. These effects may be partially mediated by smaller change in baroreflex sensitivity in individuals with DS. The results support the hypothesis of altered autonomic modulation in people with DS.
本研究旨在探讨在自主神经反应方面，患有唐氏综合征（Down syndrome，DS）和不患有 DS 的个体之间是否存在差异，其证据是心率和血压变异性测量值的变化。在 5 分钟的休息和 5 分钟的直立倾斜期间，对 26 名患有 DS 的个体和 11 名不患有 DS 的个体进行了逐拍血压测量。依赖变量包括心率、血压、心率和血压变异性的频率分量测量值以及压力反射敏感性。DS 患者对直立倾斜的反应中，心率变异性的归一化高频（HF）功率、归一化低频（LF）功率和 LF/HF 以及血压变异性的 LF 降低（p<0.05）。这伴随着 DS 个体中压力反射敏感性的变化较小（p<0.05）。DS 患者的直立倾斜血压反应也降低（p<0.05），但心率反应在两组之间没有差异。DS 患者在被动直立倾斜时表现出较小的迷走神经撤出和交感神经兴奋。这些影响可能部分由 DS 个体中压力反射敏感性的变化较小介导。研究结果支持 DS 人群自主神经调节改变的假说。
