Sturman Molly M, Vaillancourt David E, Corcos Daniel M
Department of Movement Sciences (M/C 994 University of Illinois at Chicago, 808 South Wood, 690 CMET, Chicago, IL 60612, USA.
J Neurophysiol. 2005 Jun;93(6):3064-74. doi: 10.1152/jn.01218.2004. Epub 2005 Feb 16.
The purpose of this investigation was to determine the effects of healthy aging on the regularity of physiological tremor under rest and postural conditions. Additionally, we examined the contribution of mechanical reflex factors to age-related changes in postural physiological tremor. Tremor regularity, tremor-electromyographic (EMG) coherence, tremor amplitude, and tremor modal frequency were calculated for 4 age groups (young: 20-30 yr, young-old: 60-69 yr, old: 70-79 yr, and old-old: 80-94 yr) under resting and loaded postural conditions. There were 6 important findings from this study: 1) there were no differences between the young and elderly subjects for any of the dependent variables measured under the rest condition; 2) postural physiological tremor regularity was increased in the elderly; 3) postural physiological tremor-EMG coherence was also increased in the elderly, and there was a strong linear relation between peak tremor-EMG coherence in the 1- to 8-Hz frequency band and regularity of tremor. This relation was primarily driven by the increased magnitude of tremor-EMG coherence at 5.85 and 6.83 Hz; 4) enhanced mechanical reflex properties were not responsible for the increased magnitude of tremor-EMG coherence in the elderly subjects; 5) tremor amplitude was not different between the 4 age groups, but there was a slight decline in tremor modal frequency in the oldest age group in the unloaded condition; and 6) despite the increases in postural physiological tremor regularity and the magnitude of low frequency tremor-EMG coherence with age, there was a clear demarcation between healthy aging and previously published findings related to tremor pathology.
本研究的目的是确定健康衰老对静息和姿势状态下生理震颤规律性的影响。此外，我们还研究了机械反射因素对姿势性生理震颤年龄相关变化的作用。计算了4个年龄组（青年组：20 - 30岁，年轻老年组：60 - 69岁，老年组：70 - 79岁，高龄老年组：80 - 94岁）在静息和负重姿势条件下的震颤规律性、震颤 - 肌电图（EMG）相干性、震颤幅度和震颤模态频率。本研究有6项重要发现：1）在静息状态下测量的任何因变量在青年和老年受试者之间均无差异；2）老年人姿势性生理震颤的规律性增加；3）老年人姿势性生理震颤 - EMG相干性也增加，并且在1至8赫兹频段的震颤 - EMG相干峰值与震颤规律性之间存在很强的线性关系。这种关系主要由5.85和6.83赫兹处震颤 - EMG相干幅度的增加所驱动；4）增强的机械反射特性并非老年人震颤 - EMG相干幅度增加的原因；5）4个年龄组之间的震颤幅度没有差异，但在无负重条件下，最年长年龄组的震颤模态频率略有下降；6）尽管姿势性生理震颤规律性和低频震颤 - EMG相干幅度随年龄增加，但健康衰老与先前发表的与震颤病理学相关的研究结果之间存在明显界限。
