fix Maxwell bads filtering (#13280)

harrisonritz · pre-commit-ci[bot] · web-flow · commit 19264460d568 · 2025-06-08T17:41:26.000-04:00
Co-authored-by: pre-commit-ci[bot] &lt;66853113+pre-commit-ci[bot]@users.noreply.github.com&gt;
diff --git a/doc/changes/devel/13280.bugfix.rst b/doc/changes/devel/13280.bugfix.rst
@@ -0,0 +1 @@
+Fixed bug where :func:`mne.preprocessing.maxwell_filter_prepare_emptyroom` would not reliably identify meg channel types for matching bads across emptyroom and task, by `Harrison Ritz`_.
diff --git a/mne/preprocessing/maxwell.py b/mne/preprocessing/maxwell.py
@@ -172,7 +172,12 @@ def maxwell_filter_prepare_emptyroom(
     elif bads == "keep":
         bads = raw_er_prepared.info["bads"]
 
-    bads = [ch_name for ch_name in bads if ch_name.startswith("MEG")]
+    # Filter to only include MEG channels
+    meg_ch_names = [
+        raw_er_prepared.ch_names[pick]
+        for pick in pick_types(raw_er_prepared.info, meg=True, exclude=[])
+    ]
+    bads = [ch_name for ch_name in bads if ch_name in meg_ch_names]
     raw_er_prepared.info["bads"] = bads
 
     # handle dev_head_t

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Fixed bug where :func:`mne.preprocessing.maxwell_filter_prepare_emptyroom` would not reliably identify meg channel types for matching bads across emptyroom and task, by `Harrison Ritz`_.