Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States; Daroff-Dell'Osso Ocular Motor Laboratory, Louis Stokes VA Medical Center, Cleveland, OH, United States.
Department of Otolaryngology, Harvard Medical School, Boston, MA, United States; Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States.
Prog Brain Res. 2019;248:249-267. doi: 10.1016/bs.pbr.2019.04.019. Epub 2019 May 24.
It has been well-established that both vestibular function and balance degrade with age and that balance degradation contributes to falls. While multiple causes contribute to balance declines, there have been few empirical investigations of the specific sensory contributors to balance that mediate (i.e., explain a significant fraction of) the effect of age on balance.
To determine if vestibular function significantly mediates the effect of age on balance, and to quantify the fraction of any such statistically significant age-effect on balance using previously published vestibular threshold and balance data.
Balance was quantified as complete/incomplete on a standard Romberg 4-condition foam balance test. Vestibular thresholds were determined using standard methods with motion provided by a Moog 6DOF motion platform. Standard mediation analyses were performed to determine if any of the five vestibular thresholds measured (0.2Hz roll tilt and 1Hz roll tilt, yaw rotation, y-translation, and z-translation) significantly mediated the previously reported age-effect on balance.
0.2Hz roll tilt thresholds were found to significantly mediate the relationship between age and balance, whether we considered all subjects or just the subjects above the age of 40 (above which vestibular thresholds increase with age). Depending on the exact age cut-off implemented between 37 and 42 years of age, 0.2Hz roll tilt thresholds explained (mediated) between 33% and 55% of the total age-effect on balance.
Vestibular function may mediate approximately 50% of the widely-reported age-effect on balance. If confirmed by future studies, this may provide an opportunity to improve balance (and presumably reduce fall risk) via specific therapies tailored to improve vestibular function.
众所周知，前庭功能和平衡能力会随着年龄的增长而下降，而平衡能力的下降会导致跌倒。虽然有多种原因导致平衡下降，但很少有实证研究专门探讨导致平衡能力下降的特定感觉因素，这些因素可以解释年龄对平衡能力的影响。
确定前庭功能是否显著中介年龄对平衡的影响，并利用先前发表的前庭阈值和平衡数据来量化年龄对平衡的任何显著影响的分数。
使用标准 Romberg 4 条件泡沫平衡测试来量化平衡，标准为完整/不完整。前庭阈值是使用标准方法确定的，运动由 Moog 6DOF 运动平台提供。进行了标准的中介分析，以确定测量的五个前庭阈值（0.2Hz 滚转倾斜和 1Hz 滚转倾斜、偏航旋转、y 平移和 z 平移）中是否有任何一个显著中介了先前报告的年龄对平衡的影响。
发现 0.2Hz 滚转倾斜阈值显著中介了年龄和平衡之间的关系，无论我们考虑所有受试者还是仅考虑年龄在 40 岁以上的受试者（40 岁以上，前庭阈值随年龄增长而增加）。根据在 37 至 42 岁之间实施的确切年龄截止，0.2Hz 滚转倾斜阈值解释了（中介了）平衡总年龄效应的 33%至 55%。
前庭功能可能介导了广泛报道的年龄对平衡的影响的约 50%。如果未来的研究得到证实，这可能为通过专门针对改善前庭功能的特定疗法来改善平衡（并可能降低跌倒风险）提供机会。
