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Case Study S036
2016 Release

Shafiq 2016: Automatic STI Identification

Ghufran Shafiq et al.
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Quick Conclusion: S036 (Shafiq 2016) is a foundational paper for OpenSCG’s automated processing pipeline. By moving beyond lab-only supine measurements to seated trials and achieving millisecond-level precision, it validates the core algorithms needed for practical, non-invasive STI monitoring.


📊 Key Accuracy Metrics

MetricResult
AO Detection ErrorWithin ±2 ms for most cycles
AC Detection LoA (Supine)16.1 ms
AC Detection LoA (Seated)42.9 ms
Outliers (AO, Supine)0.37%


🔍 Study Analysis

Objective & Population

Technical Development & Validation Study. Cohort: 7 healthy subjects (Age 28.7 ± 1.89) (N=7).

What it Supports

The study supports the use of sliding-template ensemble averaging to automatically identify systolic time intervals (STI) from SCG signals. It demonstrates that automated annotation is robust even in seated positions, which are more realistic for everyday wearable use than the traditional supine position.

What it Does Not Support

The study does not provide high-level clinical validation across a large or pathological population. It also does not prove reliability during active movement, but rather in a relatively static seated position.


🛠 Technical Context

Featured Illustration

Figure 2.  Experimental Setup - postures and data acquisition. Accelerometer placed at lower sternum was  considered for this study.

Figure 2.  Experimental Setup - postures and data acquisition. Accelerometer placed at lower sternum was considered for this study.

Study Snapshot

Metadata Summary

Target Population

7 healthy subjects (Age 28.7 ± 1.89)

N

Sample Size

7 Subjects

Validated Metric

Within ±2 ms for most cycles

Critical Appraisal
supporting

Demonstrated the feasibility of sliding-template automation for STI extraction in both supine and seated positions.