mep-cmap-analyser 0.9.4

BIDS-compliant TMS/EMG neurophysiology analysis tool for MEP and CMAP quantification

MEP-CMAP Analyser

Version 0.9.4 | May 2026
Author: Justin Andrushko PhD, Northumbria University

A BIDS-compliant, open-source tool for processing and quantifying TMS-evoked motor evoked potentials (MEPs) and cortical silent periods (cSPs) from Spike-2 and LabChart EMG recordings.

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Features

• Dataset Setup — multi-file session management with a persistent file queue, BIDS folder auto-detection, processing status tracking, and excluded-file management across sessions
• BIDS-compliant derivatives output with automatic participant/session naming
• Per-trial MEP quantification — PTP amplitude, onset latency, AUC, cSP duration, paired-pulse ratios
• Physiologically-bounded MEP onset detection — peak-anchored backward scan with per-stim-type latency profiles derived from published normative data (TMS: hand/FDI 18–30 ms, vastus lateralis 18–35 ms, leg 28–45 ms; peripheral nerve: upper limb 2–12 ms, lower limb 4–18 ms)
• Cortical silent period (cSP) detection using a vectorised bootstrap threshold method with MEP-anchored search cap
• Auto AUC — onset-to-cSP start computed automatically for all event types; user can override via drag selector
• Auto SP and AUC for unreviewed segments — silent period and AUC computed in the pipeline for any segment not manually reviewed in the Data Inspector
• M-wave normalisation with plateau-based Mmax detection
• Paired-pulse ratios (SICI, ICF, etc.) with flexible per-stim reference assignment in Stage 1a
• Data Inspector — interactive per-trial review with draggable markers, zoom toolbar, AUC selector, silent period annotation; all edits persist across reruns
• Filter preview — real-time frequency response and wavelet time-frequency display
• Outlier detection with interactive review and Z-score thresholding
• Multi-channel support — additional EMG and force channels for visual inspection
• Full session persistence — every adjustable setting (filters, onset detection, CSP, latency profiles, normalisation, inspector edits, analysis options) is saved and restored automatically per file
• Group analysis — Stage 2 merges all processed sessions into a single LME-ready CSV with study design columns (between/within-subject factors, stim roles)
• LME-ready trial-level CSV output with Z-scores, detrended values, normalised PTP, and pooled statistics
• Cross-platform — Windows, macOS, and Linux supported

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Installation

Option 1: pip (recommended for Python users)

pip install mep-cmap-analyser
mep-cmap

Python 3.9+ required. Tkinter must be available:

• Windows / macOS: included with standard Python
• Linux (Ubuntu/Debian): sudo apt install python3-tk

Option 2: Compiled binaries (no Python required)

Download the latest release for your platform from the Releases page:

Platform	File
Windows	MEP-CMAP_Analyser_Windows.zip
macOS	MEP-CMAP_Analyser_Mac.zip
Linux	MEP-CMAP_Analyser_Linux.tar.gz

Unzip and run the executable — no installation required.

Option 3: Run from source

git clone https://github.com/justinAndrushko/mep-cmap-analyser.git
cd mep-cmap-analyser
pip install -r requirements.txt
python -m mep_cmap

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Quick Start

# Launch the GUI
mep-cmap

# Or from Python
from mep_cmap import run_app
run_app()

Scripted pipeline (no GUI)

from mep_cmap import run_pipeline, PipelineConfig

run_pipeline(
    input_path  = "path/to/recording.txt",
    pre_ms      = 20,
    post_ms     = 400,
    ptp_start   = 10,
    ptp_end     = 50,
    prestim_ms  = 100,
    marker_name = "Keyboard",
)

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Workflow

The tool is organised into four tabs:

Dataset Setup

Load a study folder or individual files. The tool auto-detects rawdata/ and derivatives/ subfolders (BIDS structure) or accepts manual folder selection. The derivatives folder is always placed beside rawdata/, never inside it. A persistent file queue tracks processing status across sessions — files are marked Not started, In progress, Needs review, Complete, or Stale.

• Double-click any file to load it
• Use Run all unprocessed to batch process
• Use Refresh to detect newly added files (previously excluded files are remembered and not re-added)
• Right-click → Show excluded files to restore previously removed files
• Queue state is saved to dataset_session.json in the derivatives folder

Stage 1a — Labels & Analysis Setup

Appears automatically after a file is loaded. Configure per-stim-type settings:

• Label, colour, gap (ms), CSP detection toggle
• Stimulation type and muscle group (sets physiological latency bounds for onset detection)
• Internal normalisation references and plateau tolerance for Mmax detection

Confirming setup auto-switches to Stage 1b. Settings persist between files.

Stage 1b — Single File Processing

Filter settings (bandpass, notch, mains noise canceller), time window and MEP onset detection parameters, CSP detection settings, outlier review, and analysis options. All settings are saved per file and restored on reload.

When reloading a previously processed file:

• Option to reuse the saved data range, select a new range, or use the whole file
• Previously adjusted marker positions, notes, exclusions, and AUC windows are restored and carried through the re-analysis

Stage 2 — Group Analysis & LME Setup

Scan the derivatives folder to discover all processed sessions. Assign study design columns (e.g. Group, Condition, Timepoint), configure stim type roles (Reference, Conditioned, M-wave), and click Build group analysis file to merge all selected sessions into a single group_level_LME_ready.csv.

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Input Formats

Spike-2 text export (.txt)

Files contain waveform channels (EMG, force, etc.) and DigMark event timestamps. Files should follow BIDS naming conventions for automatic metadata parsing:

sub-001_ses-01_limb-left_recording.txt

LabChart text export (.txt)

LabChart exports are auto-detected by their Interval= header. Each recording block is treated as a trial — no DigMark channel is required as LabChart pre-aligns each block to the stimulation event.

Both single-file recordings with multiple stimulus types and multi-file sessions (one file per condition) are supported.

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Output

Results are saved to a derivatives/ folder beside the raw data folder, following BIDS structure:

study/
├── rawdata/
│   └── sub-001/ses-01/...
└── derivatives/
    ├── dataset_session.json               ← queue state, processing status, excluded files
    ├── group_level_LME_ready.csv          ← merged group-level output (Stage 2)
    └── sub-001/
        └── ses-01/
            ├── results/
            │   ├── sub-001_ses-01_limb-left_All_stims_trial_summary.csv
            │   ├── sub-001_ses-01_limb-left_All_stims_trial_summary.json
            │   ├── sub-001_ses-01_limb-left_ptp_results.csv
            │   └── sub-001_ses-01_limb-left_ptp_results_with_outliers.csv
            ├── figures/
            └── sub-001_ses-01_limb-left_session.json  ← per-file session state

Trial-level CSV columns

Column	Description
PTP(mV)	MEP peak-to-peak amplitude
Latency(ms)	MEP onset latency
cSP_Duration(ms)	Cortical silent period duration
cSP_MEP_Offset(ms)	Time from stim to cSP onset
cSP_EMG_Return(ms)	Time from stim to EMG return after cSP
MEP_cSP_Ratio	PTP / cSP duration (Orth & Rothwell, 2004)
AUC(mV*s)	Area under the rectified EMG curve (onset to cSP start)
Normalised_PTP	PTP / reference mean (Mmax or single-pulse reference)
Reference_Type	How the reference mean was computed
Reference_Mean(mV)	Reference amplitude used for normalisation
Z_PTP_Within	Z-score within stim type
Z_PTP_Pooled	Z-score pooled across all conditions
PTP_Detrended(mV)	Linearly detrended PTP amplitude
Outlier_Decision	Include / Exclude / Reviewed
Manual_Note	Annotator note from Data Inspector

Group-level CSV additional columns

Column	Description
participant_id	BIDS participant identifier
session	Session label
task	Task label (if assigned)
timepoint	Timepoint label (if assigned)
Limb	Limb identifier parsed from filename
Stim_Role	Role assigned in Stage 2 (Reference, Conditioned, M-wave, etc.)
[custom columns]	User-defined between/within-subject factors

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Building from Source (Developers)

# Windows
python build_windows.py

# Linux
python3 -m venv venv_linux
source venv_linux/bin/activate
pip install -r requirements.txt
python3 build_linux.py

# macOS
python3 build_mac.py

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Citation

If you use this tool in your research, please cite:

Andrushko, J.W. (2026). MEP-CMAP Analyser (Version 0.9.4) [Software]. Northumbria University. https://doi.org/10.5281/zenodo.XXXXXXX

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References

• Orth, M., & Rothwell, J.C. (2004). The cortical silent period: intrinsic variability and relation to the waveform of the transcranial magnetic stimulation pulse. Clinical Neurophysiology, 115(5), 1076–1082.
• Hupfeld, K.E., Swanson, C.W., Fling, B.W., & Seidler, R.D. (2021). TMS-induced silent periods: A review of methods and call for consistency. Journal of Neuroscience Methods, 346, 108950.

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License

MIT License — see LICENSE for details.