Stensdotter Ann-Katrin, Meisingset Ingebrigt, Pedersen Morten Dinhoff, Vasseljen Ottar, Stavdahl Øyvind
Department of Neuromedicine and Movement Science, The Norwegian University of Science and Technology, NTNU, Trondheim, Norway.
Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, The Norwegian University of Science and Technology, NTNU, Trondheim, Norway.
Physiol Rep. 2019 Mar;7(5):e14013. doi: 10.14814/phy2.14013.
Motor control impairments are reported in patients with nonspecific neck pain but the particular deficits in underlying regulatory systems are not known. Head steadiness is controlled both by voluntary and reflex systems that are predominantly effective within different frequency intervals. The aim of the present study was to investigate within which frequency range(s) potential motor control deficits may reside. The ability to keep the head stationary in space in response to unpredictable perturbations was tested in 71 patients with nonspecific neck pain and 17 healthy controls. Participants were exposed to pseudorandom horizontal rotations across 10 superimposed frequencies (0.185-4.115 Hz) by means of an actuated chair in three conditions; with a visual reference, and without vision with, and without a cognitive task. Below 1 Hz, patients kept the head less stable in space compared to healthy controls. Between 1 and 2 Hz, the head was stabilized on the trunk in both groups. Patients kept the head more stable relative to the trunk than relative to space compared to healthy controls. This was interpreted as higher general neck muscle co-activation in patients, which may be explained by altered voluntary control, or/and upregulated gamma motor neuron activity which increases the contribution of reflex-mediated muscle activation. Alternatively, increased muscle activity is secondary to vestibular deficits.
非特异性颈部疼痛患者存在运动控制障碍，但潜在调节系统中的具体缺陷尚不清楚。头部稳定性由主要在不同频率区间发挥作用的自主系统和反射系统共同控制。本研究的目的是调查潜在的运动控制缺陷可能存在于哪个频率范围内。对71例非特异性颈部疼痛患者和17名健康对照者进行了测试，以评估他们在面对不可预测的扰动时将头部保持在空间静止的能力。参与者在三种情况下通过驱动椅接受跨越10个叠加频率（0.185 - 4.115赫兹）的伪随机水平旋转；有视觉参考、无视觉且有认知任务、无视觉且无认知任务。在1赫兹以下，与健康对照者相比，患者在空间中保持头部的稳定性较差。在1至2赫兹之间，两组患者的头部在躯干上均保持稳定。与健康对照者相比，患者相对于躯干保持头部稳定的程度高于相对于空间的程度。这被解释为患者颈部肌肉的总体共同激活程度更高，这可能是由于自主控制改变，或/和γ运动神经元活动上调，从而增加了反射介导的肌肉激活的贡献。或者，肌肉活动增加是前庭缺陷的继发结果。
