831
COMPARISON OF GASTRIC ALIMETRY® BODY SURFACE GASTRIC MAPPING VERSUS ELECTROGASTROGRAPHY SPECTRAL ANALYSIS
Date
May 8, 2023
Explore related products in the following collection:
Society: AGA
Background
Electrogastrography (EGG) non-invasively evaluates gastric motility but is widely viewed as lacking clinical utility. Gastric Alimetry® is a new diagnostic test that combines high-resolution body surface gastric mapping (BSGM) with validated symptom profiling, with the goal of overcoming numerous technical limitations of the EGG. This study directly compared EGG and BSGM to define performance differences in spectral analysis.
Methods
Comparisons between Gastric Alimetry BSGM and EGG were conducted by protocolized evaluation of 178 subjects (110 controls; 68 nausea and vomiting (NVS) and/or type 1 diabetes (T1D)). Data collection was identical. Comparisons followed standard methodologies for each test, with statistical evaluations for group-level differences, symptom correlations, and patient-level classifications. Four spectral metrics were computed for BSGM tests (Gastric Alimetry Rhythm IndexTM (GA-RI), Principal Gastric Frequency (PGF), BMI-Adjusted Amplitude, and Fed:Fasted Amplitude Ratio)1 and EGG tests (% time normal frequency, dominant frequency, amplitude, and amplitude ratio)2. Patient-level classifications were determined by a blinded consensus panel reference standard3 and automatedly, using published reference values as cutoffs for EGG and BSGM metrics2,4.
Results
Group-level: BSGM showed tighter frequency ranges vs EGG in controls (median 3.04 cpm (IQR 2.90-3.18) vs 2.88 (1.50-3.12); p<0.0001). Both tests detected rhythm instability in NVS (p<0.001) and T1D (p<0.05), but EGG showed opposite frequency effects in T1D (2.50 vs controls 2.88; p=0.28) to BSGM (3.15 vs 3.04; p=0.0004). Symptom correlations: GA-RI correlated with nausea, pain, bloating, and total symptom burden; PGF deviation with excessive fullness, pain, bloating; % time in normal frequency correlated with bloating (p<0.05). Patient-level: EGG sensitivity was 1.0, specificity 0.38; BSGM sensitivity 1.0, specificity 0.96 (Figure 1).
Conclusions and Inferences
EGG detected group-level differences in patients, but lacked symptom correlations and showed poor accuracy at patient-level classification, explaining EGG’s weak clinical utility. BSGM demonstrated substantial performance improvements over EGG across all domains.
References
1. Schamberg G et al.. Neurogastroenterol Motil. Published online November 21, 2022:e14491.
2. Yin J, Chen JDZ. Journal of Neurogastroenterology and Motility. 2013;19(1):5-17.
3. Gharibans AA et al. Sci Transl Med. 2022;14(663):eabq3544.
4. Varghese C et al. Am J Gastroenterol; In Press [doi:10.1101/2022.07.25.22278036]
Figure 1: Individual classifications using rhythmic stability metrics and reference labels. (A) Confusion matrix for GA-RI ≥ 0.25. (B) Confusion matrix for % time normal frequency ≥ 70%. (C) ROC curves with the location on the curve associated (published thresholds indicated by a dot). (D) Quantitative evaluation.
Background
Electrogastrography (EGG) non-invasively evaluates gastric motility but is widely viewed as lacking clinical utility. Gastric Alimetry® is a new diagnostic test that combines high-resolution body surface gastric mapping (BSGM) with validated symptom profiling, with the goal of overcoming numerous technical limitations of the EGG. This study directly compared EGG and BSGM to define performance differences in spectral analysis.
Methods
Comparisons between Gastric Alimetry BSGM and EGG were conducted by protocolized evaluation of 178 subjects (110 controls; 68 nausea and vomiting (NVS) and/or type 1 diabetes (T1D)). Data collection was identical. Comparisons followed standard methodologies for each test, with statistical evaluations for group-level differences, symptom correlations, and patient-level classifications. Four spectral metrics were computed for BSGM tests (Gastric Alimetry Rhythm IndexTM (GA-RI), Principal Gastric Frequency (PGF), BMI-Adjusted Amplitude, and Fed:Fasted Amplitude Ratio)1 and EGG tests (% time normal frequency, dominant frequency, amplitude, and amplitude ratio)2. Patient-level classifications were determined by a blinded consensus panel reference standard3 and automatedly, using published reference values as cutoffs for EGG and BSGM metrics2,4.
Results
Group-level: BSGM showed tighter frequency ranges vs EGG in controls (median 3.04 cpm (IQR 2.90-3.18) vs 2.88 (1.50-3.12); p<0.0001). Both tests detected rhythm instability in NVS (p<0.001) and T1D (p<0.05), but EGG showed opposite frequency effects in T1D (2.50 vs controls 2.88; p=0.28) to BSGM (3.15 vs 3.04; p=0.0004). Symptom correlations: GA-RI correlated with nausea, pain, bloating, and total symptom burden; PGF deviation with excessive fullness, pain, bloating; % time in normal frequency correlated with bloating (p<0.05). Patient-level: EGG sensitivity was 1.0, specificity 0.38; BSGM sensitivity 1.0, specificity 0.96 (Figure 1).
Conclusions and Inferences
EGG detected group-level differences in patients, but lacked symptom correlations and showed poor accuracy at patient-level classification, explaining EGG’s weak clinical utility. BSGM demonstrated substantial performance improvements over EGG across all domains.
References
1. Schamberg G et al.. Neurogastroenterol Motil. Published online November 21, 2022:e14491.
2. Yin J, Chen JDZ. Journal of Neurogastroenterology and Motility. 2013;19(1):5-17.
3. Gharibans AA et al. Sci Transl Med. 2022;14(663):eabq3544.
4. Varghese C et al. Am J Gastroenterol; In Press [doi:10.1101/2022.07.25.22278036]
Figure 1: Individual classifications using rhythmic stability metrics and reference labels. (A) Confusion matrix for GA-RI ≥ 0.25. (B) Confusion matrix for % time normal frequency ≥ 70%. (C) ROC curves with the location on the curve associated (published thresholds indicated by a dot). (D) Quantitative evaluation.
Individual classifications using rhythmic stability metrics and reference labels. (A) Confusion matrix for GA-RI ≥ 0.25. (B) Confusion matrix for % time normal frequency ≥ 70%. (C) ROC curves with the location on the curve associated (published thresholds indicated by a dot). (D) Quantitative evaluation.
Tracks
Related Products
SPECIFIC PATIENT PHENOTYPING IN GASTRODUODENAL DISORDERS USING GASTRIC ALIMETRY® WITH COMPARISON TO GASTRIC EMPTYING SCINTIGRAPHY
INTRODUCTION: Patients with upper gastrointestinal (UGI) symptoms of abdominal pain, nausea, vomiting, and bloating often complain within the postprandial period…
TRANSLATION OF BODY SURFACE GASTRIC MAPPING TO PEDIATRIC POPULATIONS: FEASIBILITY AND INITIAL RESULTS
INTRODUCTION: Chronic nausea and abdominal pain are debilitating symptoms that often co-exist in children with functional abdominal pain disorders (FAPD). Standard medical therapy (SMT) includes the off-label medications, cyproheptadine and amitriptyline…
NON-INVASIVE MAPPING OF POST-PANCREATICODUODENECTOMY GASTRIC FUNCTION USING GASTRIC ALIMETRY®
Laparoscopic fundoplication in patients with a history of lung transplant has an average length of stay (LOS) of 3 days with a 30-day readmission rate of 25%, which is significantly worse compared to the non-lung transplant population…
NON-INVASIVE THORACOABDOMINAL MAPPING OF POST-ESOPHAGECTOMY GASTRIC CONDUIT FUNCTION USING GASTRIC ALIMETRY®
The aim of this study was to assess the association between interval between nCRT and
