(a) It is unlawful for any person to administer detection of deception examinations, or attempt to hold himself or herself out as an Examiner, unless registered or licensed by the Department. However, this shall not prohibit the use of detection of deception equipment by a person licensed to practice medicine in all its branches under the Medical Practice Act of 1987 when the results are to be used in research.
     (b) Nothing in this Act prohibits the use of a voice stress analyzer by any fully trained full time certified law enforcement officer of a law enforcement agency in the course of its duties as an investigative aid in a criminal investigation. Law enforcement users of a voice stress analyzer shall be trained in a manner approved by the Illinois Law Enforcement Training Standards Board. The use of a voice stress analyzer shall be conducted only with the prior written consent of the subject of such investigation. Surreptitious use of a voice stress analyzer is prohibited. Use of a voice stress analyzer is prohibited when a State or local law enforcement officer stops a motorist for an alleged violation of the Illinois Vehicle Code. A voice stress analyzer is prohibited for use in pre-employment screening and for internal investigations. For the purposes of this subsection (b), “voice stress analyzer” means an investigative tool that records voice stress factors related to frequency modulations in the human voice.