Indiana Code Title 8. Utilities and Transportation § 8-6-2.1-24

Sec. 24. If any person having an interest in land affected by the proceedings is mentally incompetent or under the age of eighteen (18) years, the board shall certify that fact to its attorney.  The attorney shall apply to the proper court and secure the appointment of a guardian for the person under eighteen (18) years of age or mentally incompetent person.  The board shall give notice to the guardian, who shall appear and protect the interest of the protected person.  If the person under eighteen (18) years of age or mentally incompetent person already has a guardian, the notice shall be served upon the guardian.  The requisites of notice to the guardian shall be the same as for other notices.