Bioastronautics Laboratory, Smead Aerospace Engineering Sciences Department, University of Colorado-Boulder, 3775 Discovery Dr, Boulder, CO, 80309, USA.
Exp Brain Res. 2020 Jun;238(6):1499-1509. doi: 10.1007/s00221-020-05830-x. Epub 2020 May 22.
Vestibular perceptual thresholds measure vestibular sensory and perceptual noise by quantifying how small of a passive self-motion an individual is able to reliably perceive. Vestibular thresholds have clinical and operational relevance, as they are elevated in vestibular migraine patients, and even healthy individuals with higher (i.e., worse) thresholds have degraded balance. Vestibular thresholds have been quantified across a range of frequencies (motion durations) for rotations and translations, with differences identified for different motion directions (e.g., up/down thresholds are higher than those for left/right motions). While roll tilt thresholds have been well quantified, pitch tilt thresholds have not. Here we aim to quantify pitch tilt thresholds across a range of frequencies and test whether they are higher than in those for roll tilt. In ten normal subjects, we found pitch tilt thresholds at 0.15, 0.2, 0.5, and 1 Hz averaged 1.66, 1.61, 0.99, 0.51 degrees, respectively. Using a general linear model, we found subjects' pitch tilt thresholds were slightly, but significantly, higher than their roll tilt thresholds across all frequencies tested. These differences were approximately 10% at 0.15, 0.2, and 1 Hz and 3% at 0.5 Hz. Pitch tilt thresholds exhibited a similar frequency response as in roll tilt (decreasing a higher frequencies). They also had substantial inter-individual variability, which correlated across pitch tilt frequencies and between pitch and roll tilt thresholds. We discuss why pitch tilt thresholds might be higher, including the pitched-up orientation of the utricular plane of the otoliths, compared to previous studies, and discuss functional implications.
前庭感知阈值通过量化个体能够可靠感知的微小被动自运动来测量前庭感觉和感知噪声。前庭阈值具有临床和操作相关性，因为在偏头痛患者中会升高，即使是具有较高（即较差）阈值的健康个体，其平衡也会受到损害。前庭阈值已经在旋转和平移的一系列频率（运动持续时间）上进行了量化，并确定了不同运动方向的差异（例如，上下阈值高于左右运动）。虽然滚转倾斜阈值已经得到了很好的量化，但俯仰倾斜阈值却没有。在这里，我们旨在量化一系列频率的俯仰倾斜阈值，并测试它们是否高于滚转倾斜阈值。在 10 名正常受试者中，我们发现 0.15、0.2、0.5 和 1 Hz 时的俯仰倾斜阈值平均值分别为 1.66、1.61、0.99 和 0.51 度。使用一般线性模型，我们发现受试者的俯仰倾斜阈值在所有测试频率下均略高于其滚转倾斜阈值，但具有统计学意义。在 0.15、0.2 和 1 Hz 时，这些差异约为 10%，在 0.5 Hz 时约为 3%。俯仰倾斜阈值的频率响应与滚转倾斜相似（在较高频率下降低）。它们还具有很大的个体间可变性，这种可变性在俯仰倾斜频率之间以及俯仰和滚转倾斜阈值之间相关。我们讨论了为什么俯仰倾斜阈值可能更高，包括与之前的研究相比，耳石的椭圆囊平面的向上倾斜的方向，并讨论了其功能意义。
