要 目的：应用比率低频振幅（fALFF）探讨持续性姿势-感知性头晕（PPPD）患者静息态脑自发活动的改 变。方法：纳入12例PPPD患者，所有患者均进行详细的病史采集，进行外周前庭功能检查排除外周前庭病 变，进行常规头颅MRI检查排除局灶性病变及其他神经科疾病；进行内科检查排除其他与慢性头晕相关的内 科疾病。对确诊的PPPD患者进一步进行fMRI检查，计算fALFF，探讨PPPD患者静息态脑自发功能活动的 改变。结果：与健康受试者相比，PPPD患者右侧楔叶（X=15，Y=－69，Z=6，k=82，P<0.001, FWE校正）fALFF 值显著降低。进一步的相关分析表明，楔叶fALFF与DHI（r=－0.67，P=0.02）、DHI-F（r=－0.71，P=0.01）呈负 相关。结论：PPPD患者楔叶功能活动紊乱，可能与患者的持续性头晕不稳及复杂视觉刺激导致症状加重有 关。

Abstract Objective: To analyze the changes in spontaneous brain activity in persistent postural-perceptual dizziness (PPPD) patients during resting state by using the fractional amplitude of low frequency fluctuation (fALFF). Methods: Twelve PPPD patients were enrolled and assigned to the PPPD group. Patients were tested to exclude peripheral vestibular lesions, focal lesions, other neurological diseases, and other diseases associated with chronic dizziness. At the same time, 12 age- and gender-matched healthy subjects were recruited as the control group. A detailed medical history was collected from all subjects. Functional MRI (fMRI) was conducted and the fALFF calculated to explore the changes in spontaneous functional brain activity in resting state PPPD patients. Results: Compared with that of healthy subjects, the fALFF value in the right cuneus was significantly lower in PPPD patients (X=15, Y=－69, Z=6, k=82, P<0.001, FWE corrected). Further correlation analysis revealed that the changes of fALFF were negatively correlated with DHI (r=－0.67, P=0.02) and DHI-F (r=－0.71, P=0.01) scores. Conclusion: In patients with PPPD, the spontaneous functional activity of the cuneus was disordered, which may lead to persistent dizziness and instability and the worsening of symptoms from complex visual stimuli.