School of Optometry, University of California, Berkeley, Berkeley, CA, USA.
Soroka University Hospital and Faculty of Health Sciences, Ben‑Gurion University of the Negev, Be'er Sheva, Israel.
Exp Brain Res. 2022 Jan;240(1):199-206. doi: 10.1007/s00221-021-06247-w. Epub 2021 Oct 23.
Most prior studies of the subjective visual vertical (SVV) focus on inaccuracy of subjects' SVV responses with the head in an upright position. Here we investigated SVV imprecision during lateral head tilt in patients with chronic dizziness compared to healthy controls. Forty-five dizzy patients and 45 healthy controls underwent SVV testing wearing virtual reality (VR) goggles, sitting upright (0°) and during head tilt in the roll plane (± 30°). Ten trials were completed in each of three static head positions. The SVV inaccuracy and SVV imprecision were analyzed and compared between groups, along with systematic errors during head tilt, i.e., A-effect and E-effect (E-effect is a typical SVV response during head tilts of ± 30°). The SVV imprecision was found to be affected by head position (upright/right head tilt/left head tilt, p < 0.001) and underlying dizziness (dizzy patients/healthy controls, p = 0.005). The SVV imprecision during left head tilt was greater in dizzy patients compared to healthy controls (p = 0.04). With right head tilt, there was a trend towards greater SVV imprecision in dizzy patients (p = 0.08). Dizzy patients were more likely to have bilateral (6.7%) or unilateral (22.2%) A-effect during lateral head tilt than healthy controls (bilateral (0%) or unilateral (6.7%) A-effect, p < 0.01). Greater SVV imprecision in chronically dizzy patients during head tilts may be attributable to increased noise of vestibular sensory afferents or disturbances of multisensory integration. Our findings suggest that SVV imprecision may be a useful clinical parameter of underlying dizziness measurable with bedside SVV testing in VR.
大多数先前关于主观垂直视觉（SVV）的研究都集中在头部处于直立位置时受试者 SVV 反应的不准确性上。在这里，我们研究了与健康对照组相比，慢性头晕患者在头向侧倾斜时 SVV 的不精确性。45 名头晕患者和 45 名健康对照者佩戴虚拟现实（VR）护目镜，分别在直立位（0°）和头在额状面倾斜（±30°）时进行 SVV 测试。每个静态头部位置完成了十次试验。分析并比较了组间的 SVV 不准确性和 SVV 不精确性，以及头倾斜时的系统误差，即 A 效应和 E 效应（E 效应是头倾斜至±30°时典型的 SVV 反应）。发现 SVV 不精确性受头部位置（直立/右倾/左倾，p<0.001）和潜在头晕（头晕患者/健康对照，p=0.005）的影响。与健康对照组相比，头晕患者在左倾头位时 SVV 不精确性更大（p=0.04）。在右倾头位时，头晕患者的 SVV 不精确性有增加的趋势（p=0.08）。与健康对照组（双侧（0%）或单侧（6.7%）A 效应）相比，头晕患者在头向侧倾斜时更有可能出现双侧（6.7%）或单侧（22.2%）A 效应（双侧（0%）或单侧（6.7%）A 效应，p<0.01）。慢性头晕患者在头倾斜时 SVV 不精确性增加可能归因于前庭感觉传入的噪声增加或多感觉整合的干扰。我们的研究结果表明，SVV 不精确性可能是一种有用的临床参数，可通过 VR 中的床边 SVV 测试测量潜在的头晕。
