Recent advances in optical technology have emerged for measuring blood flow in the extremities using speckleplethysmography (SPG), which may address needs in vascular medicine and other fields. SPG has demonstrated a highly linear response with flow rate, but the susceptibility to differences in skin tone is unclear. Two validation studies using skin-simulating phantoms and a simple clinical protocol were conducted to determine the impact of absorbing skin layers on SPG measurements. Benchtop results demonstrated that the coefficient of determination between known flow rate and SPG was highly linear (R² = 0.990) and was unaffected by the addition of skin-phantom layers with variable absorption (R² = 0.996-0.999). Additionally, no significant trend was found between the fit residuals of SPG and flow rate with increasing skin-phantom absorption (R²=0.025, p = 0.29). In clinical testing, no significant difference was found using both a 4-way ANOVA between demographic classifications (F = 0.89, p = 0.45), and a 2-way ANOVA test between lower- and higher-melanin subclassifications (F = 0.4, p = 0.52).

中文翻译：

---

皮肤光吸收对散斑肌电图（SPG）信号的影响

光学技术的最新进展已经出现，可以使用散斑描记术（SPG）测量四肢的血流，这可能可以满足血管医学和其他领域的需求。SPG已显示出与流量的高度线性响应，但对肤色差异的敏感性尚不清楚。进行了两项使用模拟皮肤的幻象和简单的临床方案进行的验证研究，以确定吸收皮肤层对SPG测量的影响。台式结果表明，已知流速和SPG之间的测定系数呈高度线性（R ² = 0.990），并且不受添加可变吸收的皮肤幻影层的影响（R ²= 0.996-0.999）。另外，随着皮肤幻象吸收的增加，在SPG的拟合残差和流速之间未发现明显趋势（R ² = 0.025，p = 0.29）。在临床测试中，使用人口统计学分类之间的4向ANOVA（F = 0.89，p = 0.45）和较低和较高黑色素子分类之间的2向ANOVA测试（F = 0.4，p = 0.52）。