Errors with `read_raw_bids` with `.edf` files

**:question: Errors with read_raw_bids with .edf files

  • MNE version:

  • operating system: Manjaro 21.2.0

I’m having a problem with .edf files in the dataset ds002720 found in the OpenNeuro repository.
I’ve succeeded in working with other datasets, so I don’t know if the bug is in the dataset in the MNE library.
In the MNE GitHub account, I’ve found that you have to set the verbose to load the wrong channels.
I’ve done it, and I’m still getting an error, and I didn’t do any processing yet, just trying to read the raw data.
I’m sending a jupyter notebook with the error; I’ve used the tutorial jupyter notebook on the MNE site and just changed the dataset.
Thank you a lot, guys
Best regards

Hello @AngelicaRibeiro and welcome to the forum!

I couldn’t access your notebook (but requested permission), so I cooked up a minimal working example:

# %%
from pathlib import Path
import openneuro
import mne_bids

bids_root = Path('/tmp/ds002720')

# %%

# %%
bids_path = mne_bids.BIDSPath(
raw = mne_bids.read_raw_bids(bids_path=bids_path)

This yields the following error message:

ValueError                                Traceback (most recent call last)
Untitled-4 in <module>
      23     root=bids_root
      24 )
----> 25 raw = mne_bids.read_raw_bids(bids_path=bids_path)

<decorator-gen-557> in read_raw_bids(bids_path, extra_params, verbose)

~/Development/mne-bids/mne_bids/ in read_raw_bids(bids_path, extra_params, verbose)
    691                                           on_error='warn')
    692     if events_fname is not None:
--> 693         raw = _handle_events_reading(events_fname, raw)
    695     # Try to find an associated channels.tsv to get information about the

~/Development/mne-bids/mne_bids/ in _handle_events_reading(events_fname, raw)
    400     if trial_type_col_name is not None:
    401         # Drop events unrelated to a trial type
--> 402         events_dict = _drop(events_dict, 'n/a', trial_type_col_name)
    404         if 'value' in events_dict:

~/Development/mne-bids/mne_bids/ in _drop(data, values, column)
    110     # FutureWarning, see
    111     #
--> 112     values = np.array(values, dtype=new_data_col.dtype)
    114     mask = np.in1d(new_data_col, values, invert=True)

ValueError: could not convert string to float: 'n/a'

Seems like a bug in MNE-BIDS.

@sappelhoff can you take a look if you have time?

Best wishes,

Hello @AngelicaRibeiro,

the cause of the issue is that the *_events.tsv files in the dataset are empty (except for the column names). The BIDS spec isn’t clear on whether this is valid. In any case, MNE-BIDS doesn’t handle this situation gracefully.

Simply removing the *_events.tsv files fixes the issue.

btw another aspect that this dataset isn’t doing great is that apparently it encodes runs as “tasks”. May seem like a formality only, but it’s clearly not how BIDS envisioned things to be…

Best wishes,

Edit: I’ve opened an issue at

1 Like

seems like it … I’ll look into it and will maybe make a PR to the spec and the validator.

1 Like

I’ve gave you permission, to access the file.
And its the same ‘NaN’ error that you reproduced.
I’ve noticed that they are using run as tasks, to work around this problem, I’ve settled up like :

dataset ='ds002720'
subject = ['01','02','03','04','05','06','07','08','09','10','11','12','13','14','15','16','17','18']
session = None
task=['run1','run2', 'run3', 'run4', 'run5','run6', 'run7','run8','run9']
acquisition = None
run = None
processing= None
recording= None
space= None
split = None
suffix = ['channels', 'eeg', 'eeg', 'events', '.events']
extension = ['.tsv', '.edf', '.json', '.json', '.tsv' ]
datatype = 'eeg'
check = True

Thanks again