BrainVision event parser doesn't handle my data correctly

The event parser for BrainVision files generates seemingly arbitrary event codes for my data. This is a problem that was first mentioned in #6267 and supposedly fixed. However, the fix introduced special handling depending on the detected event type:

https://github.com/mne-tools/mne-python/blob/70789c466133eaba410e1fc254c4b88723e30b77/mne/io/brainvision/brainvision.py#L825-L829

In the vmrk files generated in our lab using PyCorder, all stimulus and response events are simply labeled as Event (i.e., not Stimulus or Response, respectively). Therefore, they get assigned IDs 10001+, and the IDs we assigned to them during recording are basically ignored, yielding the issue(s) brought up in #6267.

When I change the line

_BV_EVENT_IO_OFFSETS = {'Stimulus/S': 0, 'Response/R': 1000, 'Optic/O': 2000}

to include Event markers:

_BV_EVENT_IO_OFFSETS = {'Stimulus/S': 0, 'Event/': 0, 'Response/R': 1000, 'Optic/O': 2000}

all works as expected and I can do

data = mne.io.read_raw_brainvision('data.vhdr')
events, _ = mne.events_from_annotations(data)
event_id = {'fixation': 100,
            'stim_a':   110,
            'stim_b':   120,
            'stim_c':   160,
            'response': 230}
epochs = mne.Epochs(data, events=events, event_id=event_id)

as would be expected.

This was tested with master.

x-ref https://github.com/cbrnr/mnelab/pull/50 cc @ArndalAndersen

[larsoner]

Maybe just modify an existing vhdr file to have Event/ rather than Stimulus/, that way you don’t even need to add a new file (or even a new test, since it should show up the same way)

[agramfort]

You mean, replacing some existing Stimulus/S markers with Event/?

yes