diff --git a/nipype/algorithms/confounds.py b/nipype/algorithms/confounds.py
index ecb8d4e8a8..da75db9ace 100644
--- a/nipype/algorithms/confounds.py
+++ b/nipype/algorithms/confounds.py
@@ -599,11 +599,11 @@ class NonSteadyStateDetector(BaseInterface):
     output_spec = NonSteadyStateDetectorOutputSpec
 
     def _run_interface(self, runtime):
-        in_nii = nb.load(self.inputs.in_plots)
+        in_nii = nb.load(self.inputs.in_file)
         global_signal = in_nii.get_data()[:,:,:,:50].mean(axis=0).mean(axis=0).mean(axis=0)
 
         self._results = {
-            'out_file': _is_outlier(global_signal)
+            'n_volumes_to_discard': _is_outlier(global_signal)
         }
 
         return runtime
@@ -611,7 +611,7 @@ def _run_interface(self, runtime):
     def _list_outputs(self):
         return self._results
 
-def _is_outlier(points, thresh=3.5):
+def is_outlier(points, thresh=3.5):
     """
     Returns a boolean array with True if points are outliers and False
     otherwise.
diff --git a/nipype/algorithms/tests/test_confounds.py b/nipype/algorithms/tests/test_confounds.py
index 4eaa9dc073..7d6eff1283 100644
--- a/nipype/algorithms/tests/test_confounds.py
+++ b/nipype/algorithms/tests/test_confounds.py
@@ -7,7 +7,7 @@
 import pytest
 from nipype.testing import example_data
 from nipype.algorithms.confounds import FramewiseDisplacement, ComputeDVARS, \
-    _is_outlier
+    is_outlier
 import numpy as np
 
 
@@ -71,5 +71,5 @@ def test_outliers(tmpdir):
     in_data = np.random.randn(100)
     in_data[0] += 10
 
-    assert _is_outlier(in_data) == 1
+    assert is_outlier(in_data) == 1