diff --git a/moabb/evaluations/splitters.py b/moabb/evaluations/splitters.py
index 3c20d5dd1..aa6175910 100644
--- a/moabb/evaluations/splitters.py
+++ b/moabb/evaluations/splitters.py
@@ -78,7 +78,7 @@ def get_n_splits(self, metadata):
 
     def split(self, y, metadata, **kwargs):
         all_index = metadata.index.values
-        subjects = metadata.subject.unique()
+        subjects = metadata['subject'].unique()
 
         # Shuffle subjects if required
         if self.shuffle_subjects: