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

  HASYOKOGAWA tests whether the data input toolbox for MEG systems by
  Yokogawa (www.yokogawa.com, designed by KIT/EagleTechnology) is
  installed. Only the newest version of the toolbox is accepted.
 
  Use as
    string  = hasyokogawa;
  which returns a string describing the toolbox version, e.g. "12bitBeta3",
  "16bitBeta3", or "16bitBeta6" for preliminary versions, or '1.5' for the
  official Yokogawa MEG Reader Toolbox. An empty string is returned if the toolbox
  is not installed. The string "unknown" is returned if it is installed but
  the version is unknown.
 
  Alternatively you can use it as
    [boolean] = hasyokogawa(desired);
  where desired is a string with the desired version.
 
  See also READ_YOKOGAWA_HEADER, READ_YOKOGAWA_DATA, READ_YOKOGAWA_EVENT,
  YOKOGAWA2GRAD