Serial amplitude-integrated electroencephalography trajectories and brain-injury-associated functional immaturity in extremely preterm infants.
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- # Serial aEEG maturation trajectories and discrimination of brain injury in extremely preterm infants
- Single-centre retrospective longitudinal cohort study of **extremely preterm infants (gestational age <28 weeks)** with serial bedside amplitude-integrated EEG (aEEG) Burdjalov scoring at postmenstrual age (PMA) 26, 28, 30, 32, 34, and 36 weeks. The analysis compares maturation trajectories and discrimination between the **reference / no major brain injury** group and the **brain injury** group.
- This repository provides a reproducible statistical analysis Jupyter notebook, a publication-style figure script, and exported tables (CSV) and figures (PNG/PDF).
- ---
- ## Study overview
- | Item | Description |
- |------|-------------|
- | Design | Single-centre, retrospective, longitudinal repeated measures |
- | Participants | 156 extremely preterm infants (GA <28 weeks) |
- | Longitudinal records | **723** aEEG assessments (after cleaning; 731 non-missing records before removal of 8 exact duplicates) |
- | Groups | Reference / no major brain injury **n = 109**; Brain injury **n = 47** |
- | Time points | PMA 26, 28, 30, 32, 34, 36 weeks (≥3 time points per infant) |
- | Primary marker | Burdjalov total score and four subscores (continuity, sleep–wake cycling, lower-border amplitude, bandwidth) |
- | Primary outcome | Imaging-defined brain injury |
- ### Research questions
- 1. How do Burdjalov total and subdomain scores change across PMA 26–36 weeks?
- 2. Do maturation trajectories differ between the brain injury and reference groups (main effect and PMA × group interaction)?
- 3. At which PMA window does the total score best discriminate brain injury (ROC/AUC)?
- 4. Which subscores show persistent between-group differences across PMA windows?
- ### Statistical framework (locked version v3.2)
- - **Primary model**: Random-intercept linear mixed-effects model (LMM) with PMA centred at 32 weeks
- `burdjalov_total ~ pma_c * group + (1 | patient_id)`
- - **Random-slope model**: Explored as a covariance-structure diagnostic only; not used for inference when non-converged; no misleading AIC/BIC/LRT comparisons
- - **Sensitivity analyses**: Complete case, ≥4 PMA time points, categorical-PMA model, adjustment for GA/birth weight/sex, GEE (exchangeable correlation + robust SE), **SGA-adjusted models** (WS/T 800—2022 primary; Fenton 2025 sensitivity)
- - **SGA**: Derived from birth weight, sex, and completed gestational age using external percentile tables (primary: WS/T 800—2022; one infant at 23+6 weeks outside the primary standard range)
- ---
- ## Repository structure
- ```
- .
- ├── README.md # This file
- ├── requirements.txt # Python dependencies (recommended versions)
- ├── make_figures_v3.py # Standalone publication-style figure script
- ├── notebooks/
- │ ├── _build_notebook.py # Programmatic generator for the analysis notebook
- │ └── aEEG_analysis.ipynb # Main analysis notebook (v3.2 locked-candidate)
- ├── data/ # Input data (de-identify before public release)
- │ ├── aEEG_cleaned_longitudinal_dataset.xlsx
- │ ├── aEEG_analysis_ready_long.csv
- │ └── SGA_reference_updated_WS_T_800_2022_Fenton_2025.xlsx
- ├── results/ # Analysis outputs (CSV, Methods text, etc.)
- └── figures/ # Analysis and manuscript figures (PNG + PDF)
- ```
- ### Key code files
- | File | Role |
- |------|------|
- | `notebooks/aEEG_analysis.ipynb` | **Main pipeline**: data QC, SGA, descriptive statistics, LMM/GEE, ROC, sensitivity analyses, export tables and figures |
- | `notebooks/_build_notebook.py` | Notebook builder; run after editing analysis logic to regenerate `.ipynb` |
- | `make_figures_v3.py` | **Standalone figure script**: journal-style main and supplementary figures (reads the same `data/` and `results/` as the notebook) |
- ### Main notebook workflow (top to bottom)
- 1. Configuration and paths (`NOTEBOOK_VERSION`, `B8_ACTION`, SGA reference file)
- 2. Load cleaned data and SGA reference table
- 3. Variable mapping and QC (score ranges, B8 anomaly handling, total-score recalculation, missingness)
- 4. SGA classification (WS/T 800—2022 + Fenton 2025)
- 5. Table 1 baseline characteristics; Tables 2–4 by PMA
- 6. LMM for total and subscores; model comparison (random intercept vs exploratory random slope)
- 7. ROC by PMA; sensitivity analyses (including SGA adjustment)
- 8. Export to `results/` and `figures/`; Methods paragraph and manuscript bullets
- 9. Final locking checklist (`qc_locking_checklist.csv`)
- ### Outputs from `make_figures_v3.py`
- | File | Content |
- |------|---------|
- | `fig2_trajectory_combined` | **Combined trajectory figure**: Panel A total score + Panels B–E subdomains (single manuscript figure) |
- | `fig4_pma_forest` | PMA-specific between-group forest plot (from `table5c_group_effect_by_pma.csv`) |
- | `fig5_roc_curves` | ROC curves by PMA (AUC locked to `table7_roc_by_pma.csv`) |
- | `fig6_reference_template` | Reference-group maturation heatmap (colours normalised to theoretical subdomain maxima) |
- | `figS1_missingness` | Variable-level missingness |
- | `figS2_spaghetti` | Individual trajectories with group-median overlay |
- | `figS3_timepoints_distribution` | Distribution of distinct PMA time points per infant |
- > **Figure 1** (cohort/STROBE flow diagram) is prepared separately by the authors and is not generated by `make_figures_v3.py`.
- ---
- ## Environment and dependencies
- ### Python version
- Developed and validated on:
- - **Python 3.12.3** (recommended **≥3.10**)
- ### Core Python packages (versions tested locally)
- | Package | Version | Use |
- |---------|---------|-----|
- | pandas | 2.3.3 | Data I/O and wrangling |
- | numpy | 1.26.4 | Numerical computing |
- | scipy | 1.16.3 | Non-parametric tests, distributions |
- | statsmodels | 0.14.5 | LMM, GEE |
- | scikit-learn | 1.7.2 | ROC/AUC |
- | matplotlib | 3.9.2 | Plotting |
- | seaborn | 0.13.2 | Statistical plot styling |
- | openpyxl | 3.1.5 | Excel I/O |
- | nbformat | — | Notebook generation (`_build_notebook.py` only) |
- | jupyter / nbconvert | — | Notebook execution (optional) |
- | Pillow | — | Image export helper (optional TIFF conversion) |
- Install:
- ```bash
- pip install -r requirements.txt
- ```
- ---
- ## Quick start
- ### 1. Clone the repository and prepare data
- Place cleaned data files in `data/` (see file list above). **Do not upload raw clinical data with identifiers** to a public repository; use de-identified data or synthetic examples where appropriate.
- ### 2. Run the main analysis notebook
- ```bash
- # Optional: regenerate the notebook from _build_notebook.py
- python notebooks/_build_notebook.py
- # Run top-to-bottom (requires Jupyter)
- jupyter notebook notebooks/aEEG_analysis.ipynb
- ```
- Or execute headlessly with nbconvert:
- ```bash
- jupyter nbconvert --to notebook --execute notebooks/aEEG_analysis.ipynb \
- --ExecutePreprocessor.timeout=600
- ```
- Outputs are written to `results/` and `figures/`.
- ### 3. Generate publication-style figures
- ```bash
- python make_figures_v3.py
- ```
- Figures are saved to `figures/` (PDF + 600 dpi PNG).
- ### 4. Key configuration (notebook header)
- | Parameter | Description |
- |-----------|-------------|
- | `NOTEBOOK_VERSION` | Currently `v3.2_locked_candidate` |
- | `B8_ACTION` | Handling of the B8/PMA 36 out-of-range record: `mean_imputed_pma36` (default), `source_corrected_to_2`, `exclude_record`, `flag_only_not_locked` |
- | `SGA_REFERENCE_FILE` | Path to SGA percentile reference table |
- ---
- ## Main output files
- ### Primary tables (`results/`)
- - `table1_baseline.csv` — Baseline characteristics (including WS/T 800—2022 SGA)
- - `table2_records_by_pma.csv` — Record counts by PMA
- - `table3_total_by_pma.csv` / `table4_subscores_by_pma.csv` — Descriptive statistics by PMA
- - `table5_lmm_total.csv` — Primary LMM fixed effects
- - `table5c_group_effect_by_pma.csv` — Group effects at each PMA from the categorical-PMA model
- - `table7_roc_by_pma.csv` — ROC/AUC by PMA
- - `table_sensitivity_lmm.csv` — Sensitivity analysis summary
- ### QC and supplementary (`results/`)
- - `qc_sga_classification.csv`, `qc_locking_checklist.csv`
- - `qc_out_of_range_before_action.csv`, `qc_score_correction_log.csv`
- - `supplementary_table_S2_timepoints_per_infant.csv`
- - `supplementary_table_S3_sga_definition.csv`
- - `methods_paragraph.txt`, `manuscript_bullets.txt`
- ---
- ## Data and ethics
- - Data originate from clinical NICU aEEG and chart records. **Identifiable individual-level data must not be shared without institutional review board approval and appropriate data-use agreements.**
- - For public GitHub release, upload analysis code and de-identified or aggregated outputs only, or provide a data-access statement. Do not upload raw collection workbooks (e.g. original hospital identifiers).
- ---
- ## Version history (summary)
- | Version | Highlights |
- |---------|------------|
- | v3.2 | SGA (WS/T 800—2022 + Fenton 2025), configurable B8 QC, locking checklist, random slope exploratory only |
- | v3.1 | Consistent narrative for non-converged random-slope model; sensitivity table and Methods aligned |
- | v3 figures | `make_figures_v3.py`: journal style, combined Fig 2+3, forest Fig 4, normalised Fig 6 |
- ---
- ## Citation and licence
- Add the formal citation once the manuscript is published. Choose a code licence (e.g. MIT) and add a `LICENSE` file before public release.
- ---
- ## Contact
- (Add corresponding author or maintainer email / ORCID before uploading to GitHub.)
ReadMe.md at commit ac7c29c, under MIT · at the source
Overview
Abstract
Objective: To characterize postmenstrual-age (PMA)-specific Burdjalov maturation trajectories in extremely preterm infants and to evaluate how imaging-defined major brain injury was associated with these trajectories and with apparent within-cohort discrimination between imaging-defined groups across PMA windows.
Methods: We conducted a single-center retrospective cohort study of 156 infants born before 28 weeks’ gestation, comprising 109 infants without major brain injury (reference group) and 47 with brain injury, defined as grade III–IV intraventricular hemorrhage or white-matter injury. These infants contributed 723 analyzable serial amplitude-integrated electroencephalography (aEEG) recordings across PMA 26 to 36 weeks. Burdjalov scores were analyzed using linear mixed-effects models, categorical-PMA contrasts, a patient-clustered ordinal model, complete time-window sensitivity analyses, and joint patient-level bootstrap comparisons of PMA-specific areas under the curve.
Results: The Burdjalov total score increased by 0.92 points per week of PMA. Infants with brain injury scored on average 1.45 points lower at PMA 32 weeks (95% confidence interval −1.65 to −1.25). Although the continuous-scale model produced a positive PMA-by-group interaction, its magnitude and statistical significance varied across analysis windows and it was not reproduced by the ordinal model (p = 0.979). Categorical-PMA estimates showed a non-monotonic pattern across the full observation period: the imprecise difference at PMA 26 weeks was followed by the largest observed difference at PMA 28 weeks and progressively smaller differences thereafter. At PMA 36 weeks, 87.4% of reference-group and 27.3% of brain-injury recordings reached the maximum score. The largest observed area under the curve was at PMA 32 weeks (0.886, 95% confidence interval 0.824 to 0.940), but joint patient-level bootstrap comparisons did not distinguish PMA 32 from PMA 28, 30, or 36 weeks.
Conclusions: Imaging-defined major brain injury was associated with persistently lower Burdjalov scores. The unstable linear interaction on this bounded scale should not be interpreted as biological recovery or catch-up maturation. The retrospective within-cohort discrimination estimates do not establish predictive, diagnostic, screening, or clinical decision utility.
Reproduced under the paper's license (CC BY), from the paper cited above.
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MdXuDeKai/AEEG
ac7c29c7b31b308fec02977d7c7de61acf44153c, 17 June 2026Availability: 1 check, the latest on 27 September 2026: the link answers
- 27 September 2026: the link answers
1 file
- ReadMe.md, Text, 214 lines
The paper's code and data availability statement is in the Data section.
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Data
No dataset and no data link were found in the paper.
Cohort characteristics and aEEG data availability
Of 274 screened infants, 98 did not contribute analyzable longitudinal data: life-sustaining treatment was withdrawn at the family's request in 49, 8 died despite full intensive care, and 41 did not accumulate three qualifying recordings. In 14 of these 41 infants, data collection closed before a third PMA window was reached; in the remaining 27, the reason could not be reliably reconstructed. The remaining 176 infants underwent formal eligibility assessment. After exclusion of 20 infants (necrotizing enterocolitis during the monitoring period, n = 2; intracranial infection during the monitoring period, n = 2; clinical or electrographic seizures, n = 1; incomplete clinical or imaging data, n = 15), 156 infants formed the final analytic cohort (Figure 1 and Supplementary Table S19). The cohort comprised 109 reference/
Baseline perinatal characteristics did not differ significantly between the brain-injury and reference groups (all p > 0.05; Table 1), including gestational age, birth weight, sex, antenatal corticosteroid exposure, mode of delivery, assisted reproduction, and the small-for-gestational-ag
Within the reference group, 9/
The reliability sample comprised 219 recordings from 45 infants. For the total score, inter-rater exact agreement was 91.8%, agreement within one point was 98.6%, weighted κ was 0.994 (95% cluster-bootstrap CI 0.990 to 0.997), and ICC(A,1) was 0.994. Inter-rater reliability results for all subscores are reported in Supplementary Table S17.
Reproduced under the paper's license (CC BY), from the paper cited above.
Data availability statement
The analysis code supporting the findings of this study is publicly available at https://
Reproduced under the paper's license (CC BY), from the paper cited above.
Software and data availability
All analyses were performed in Python 3.12.3 using statsmodels 0.14.5 for the linear mixed-effects model and the generalized estimating equations (26), scikit-learn 1.7.2 for the receiver-operating characteristic analysis (27), pandas 2.3.3, and numpy 1.26.4. The analysis code is publicly available at https://
Reproduced under the paper's license (CC BY), from the paper cited above.
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Version 1, 27 September 2026: the first record
Recorded: type, language, journal, volume, pages, dates, 6 authors, 8 keywords, 35 references.
Cite
This paper
Zhang, Y., Xu, D., Luo, G., Xu, Y., Yang, Y., & Ji, Y. (2026). Serial amplitude-integrated electroencephalography trajectories and brain-injury-associated functional immaturity in extremely preterm infants. Frontiers in pediatrics, 14, 1912111. https://
BibTeX
@article{zhang2026serial
author = {Zhang, Yong and Xu, Dekai and Luo, Guoyong and Xu, Yongping and Yang, Yujing and Ji, Yong},
title = {{Serial amplitude-integrated electroencephalography trajectories and brain-injury-associated functional immaturity in extremely preterm infants}},
journal = {Frontiers in pediatrics},
year = {2026},
month = aug,
volume = {14},
pages = {1912111},
publisher = {Frontiers Media SA},
issn = {2296-2360},
doi = {10.3389/
url = {https://
pmid = {42718659},
pmcid = {PMC13553765}
}
RIS
TY - JOUR
AU - Zhang, Yong
AU - Xu, Dekai
AU - Luo, Guoyong
AU - Xu, Yongping
AU - Yang, Yujing
AU - Ji, Yong
TI - Serial amplitude-integrated electroencephalography trajectories and brain-injury-associated functional immaturity in extremely preterm infants
T2 - Frontiers in pediatrics
J2 - Front Pediatr
PY - 2026
DA - 2026/
VL - 14
SP - 1912111
SN - 2296-2360
PB - Frontiers Media SA
DO - 10.3389/
UR - https://
LA - en
ER -
CSL-JSON
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