Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_headmodel_asa”.

  FT_HEADMODEL_ASA reads a volume conduction model from an ASA *.vol
  file
 
  ASA is commercial software (http://www.ant-neuro.com) that supports
  among others the boundary element method (BEM) for EEG. This function
  allows you to read an EEG BEM volume conduction model from an ASA
  format file (*.vol) and use that for leadfield computations in
  MATLAB. Constructing the geometry of the head model from an anatomical
  MRI and the computation of the BEM system are both handled by ASA.
  
  Use as
    headmodel = ft_headmodel_asa(filename)
 
  See also FT_PREPARE_VOL_SENS, FT_COMPUTE_LEADFIELD