BACKGROUND & AIMS:
:Tremendous numbers of heart rate variability studies have aimed to elucidate age-associated alterations of autonomic function in the past decades. However, the studies, far from clarifying ageing mechanisms, fell into confusion by a lack of common scales. The purpose of this study is to show a possibility to establish a comparative scale of autonomic function through a method, tone-entropy (T-E) analysis on heart period variation, whose validity has been already examined on typical physiological cases (Oida et al. in J Appl Physiol 82:1794-1801, 1997; Oida et al. in J Gerontol 54A:M219-M224, 1999a; Oida et al. in Acta Physiol Scand 165:129-134, 1999b; Oida et al. in Acta Physiol Scand 165:421-422, 1999c; Amano et al. in Eur J Appl Physiol 94:602-610, 2005). In this study, 276 subjects from teens to seventies were examined at rest by T-E analysis together with conventional time and frequency domain analyses. The tone (negativity represents vagal predominance) became significantly high [-0.174 +/- 0.026 (teens) to -0.024 +/- 0.004 (seventies), P < 0.05 for one-way ANOVA], and the entropy (total autonomic activity), significantly low [4.40 +/- 0.12 (teens) to 2.90 +/- 0.09 bit (seventies), P < 0.05] with advancing age. The result, plotted in 2-D T-E space, showed that the ageing traced a curvi-linear relation from right-bottom to left-top, and was consistent with previously studied typical physiological cases. The conventional analyses showed almost the same autonomic reduction as T-E did, but failed in detecting delicate alteration of autonomic balance. The results, showing that autonomic activity reduced in both pathways impairing vagal predominance significantly with ageing, suggested a possibility to assess autonomic function in 2-D T-E space in a comparative way.
背景与目标:
: 在过去的几十年中,大量的心率变异性研究旨在阐明与年龄相关的自主神经功能变化。然而,这些研究非但没有阐明衰老机制,反而因缺乏共同的量表而陷入混乱。这项研究的目的是通过一种方法,即心脏周期变化的音调熵 (t-e) 分析,表明建立自主功能的比较量表的可能性,该方法的有效性已经在典型的生理情况下进行了检验 (Oida等。在J Appl Physiol 82:1794-1801中,1997; Oida等人在J Gerontol 54A:M219-M224,1999a; Oida等人在《物理学报》Scand 165:129-134,1999b; Oida等人在《物理学报》Scand 165:421-422,1999c; Amano等人在Eur J Appl Physiol 94:602-610,2005)。在这项研究中,通过t-e分析以及常规的时域和频域分析,对276名青少年至70岁的受试者进行了静息检查。音调 (负性代表迷走神经占优势) 变得显著高 [-0.174 +/- 0.026 (青少年) 至-0.024 +/- 0.004 (七十年代),P <0.05单因素方差分析] 和熵 (总自主活动),随着年龄的增长,显着降低 [4.40/- 0.12 (青少年) 至2.90/- 0.09位 (70岁),P <0.05]。在2-D T-E空间中绘制的结果表明,衰老从右下到左上具有曲线线性关系,并且与先前研究的典型生理情况一致。常规分析显示出与t-e几乎相同的自主神经降低,但未能检测到自主神经平衡的微妙变化。结果表明,随着年龄的增长,两种途径的自主神经活动均降低,从而显着损害了迷走神经的优势,这表明有可能以比较的方式评估2-D t-e空间中的自主神经功能。