Schamberg Gabriel, Varghese Chris, Calder Stefan, Waite Stephen, Erickson Jonathan, O'Grady Greg, Gharibans Armen A
Alimetry Ltd, Auckland, New Zealand.
Department of Surgery, The University of Auckland, Auckland, New Zealand.
Neurogastroenterol Motil. 2023 Mar;35(3):e14491. doi: 10.1111/nmo.14491. Epub 2022 Nov 21.
Electrogastrography (EGG) non-invasively evaluates gastric function but has not achieved common clinical adoption due to several technical limitations. Body Surface Gastric Mapping (BSGM) has been introduced to overcome these limitations, but pitfalls in traditional metrics used to analyze spectral data remain unaddressed. This study critically evaluates five traditional EGG metrics and introduces improved BSGM spectral metrics, with validation in a large cohort.
Pitfalls in five EGG metrics were assessed (dominant frequency, percentage time normogastria, amplitude, power ratio, and instability coefficient), leading to four revised BSGM spectral metrics. Traditional and revised metrics were compared to validate performance using a standardized 100-subject database of BSGM tests (30 min baseline; 4-h postprandial) recorded using Gastric Alimetry® (Alimetry).
BMI and amplitude were highly correlated (r = -0.57, p < 0.001). We applied a conservative BMI correction to obtain a BMI-adjusted amplitude metric (r = -0.21, p = 0.037). Instability coefficient was highly correlated with both dominant frequency (r = -0.44, p < 0.001), and percent bradygastria (r = 0.85, p < 0.001), in part due to misclassification of low frequency transients as gastric activity. This was corrected by introducing distinct gastric frequency and stability metrics (Principal Gastric Frequency and Gastric Alimetry Rhythm Index (GA-RI) ) that were uncorrelated (r = 0.14, p = 0.314). Only 28% of subjects showed a maximal averaged amplitude within the first postprandial hour. Calculating Fed:Fasted Amplitude Ratio over a 4-h postprandial window yielded a median increase of 0.31 (IQR 0-0.64) above the traditional ratio.
CONCLUSIONS & INFERENCES: The revised metrics resolve critical pitfalls impairing the performance of traditional EGG, and should be applied in future BSGM spectral analyses.
胃电图（EGG）可对胃功能进行无创评估，但由于一些技术限制，尚未在临床上广泛应用。体表胃电图（BSGM）已被引入以克服这些限制，但用于分析频谱数据的传统指标仍存在缺陷。本研究对五个传统的EGG指标进行了严格评估，并引入了改进的BSGM频谱指标，并在一个大型队列中进行了验证。
评估了五个EGG指标（主频、正常胃电百分比时间、振幅、功率比和不稳定系数）的缺陷，从而得出四个修订后的BSGM频谱指标。使用Gastric Alimetry®（Alimetry）记录的标准化的100名受试者的BSGM测试数据库（30分钟基线；餐后4小时），比较传统指标和修订指标以验证性能。
体重指数（BMI）与振幅高度相关（r = -0.57，p < 0.001）。我们应用了保守的BMI校正来获得BMI校正后的振幅指标（r = -0.21，p = 0.037）。不稳定系数与主频（r = -0.44，p < 0.001）和心动过缓百分比（r = 0.85，p < 0.001）均高度相关，部分原因是低频瞬变被误分类为胃活动。通过引入不相关的独特胃频率和稳定性指标（主要胃频率和胃电图节律指数（GA-RI））（r = 0.14，p = 0.314）对其进行了校正。只有28%的受试者在餐后第一小时内显示出最大平均振幅。在餐后4小时的窗口内计算进食：禁食振幅比，得出的中位数比传统比值增加了0.31（四分位间距0 - 0.64）。
修订后的指标解决了影响传统EGG性能的关键缺陷，应在未来的BSGM频谱分析中应用。
