NEWARK — Accused of sexually assaulting a severely mentally disabled man, Rutgers-Newark professor Anna Stubblefield had sought to present an expert at her upcoming trial to show the alleged victim was able to give his consent.

But since that defense expert improperly assisted the man during an examination, a Superior Court judge said on Thursday that the evaluation cannot be presented to the jury.

Judge Siobhan Teare ruled the expert, Rosemary Crossley, will not be allowed to testify in regard to her assessment of the alleged victim, known as D.J. The evaluation was meant to test D.J.'s ability to communicate.

The judge found Crossley's methods were "unreliable," because she assisted D.J. in moving a communication device during the assessment.

But Stubblefield's attorney, James Patton, said he is still requesting that Crossley be permitted to testify at the trial about the methodology used by the state's experts in evaluating D.J., if those experts are allowed to testify.

Those experts have determined D.J. did not have the ability to consent to the sexual activity.

Crossley, who lives in Australia, has said she is an "AAC specialist," referring to augmentative and alternative communication. In her evaluation, Crossley said she found D.J. "wanted to communicate and was able to communicate, given appropriate strategies."

Stubblefield, 45, of West Orange, has been charged with repeatedly sexually assaulting D.J. in her Newark office in 2011. She was indicted in January 2013 on two counts of aggravated sexual assault.

Rutgers placed Stubblefield on administrative leave without pay and stripped her of the title of chairwoman of the philosophy department after the sexual assault allegations surfaced.

Her trial is scheduled to begin in April.

Teare ruled last month that a document detailing the sexual relationship is admissible at the trial. Stubblefield's ex-husband had turned over that document to prosecutors.

At the center of the case is a controversial technique championed by Stubblefield, known as "facilitated communication."

Stubblefield has asserted that the technique allows the disabled to communicate with the assistance of a "facilitator," who helps guide the individual's hand as it moves over a keyboard or steadies the body so he or she can strike keys.

After meeting D.J. in 2008 through his brother, Stubblefield allegedly worked with him with the technique and brought him along to conferences, where she held him out as a success story, according to a lawsuit filed against her by D.J.'s family.

Stubblefield revealed to D.J.'s mother and brother in May 2011, during a meeting at their home, that she had sexual relations with D.J, the lawsuit states. In August 2011, the family went to Rutgers police, who contacted Essex County prosecutors.

But Teare ruled last year that expert testimony about facilitated communication was inadmissible at the trial, because she determined it is an "unrecognized field of science," the judge said on Thursday.

Since the methods used by Crossley were similar to facilitated communication, her analysis is invalid, according to Teare.

After the hearing, however, Patton argued Crossley's assessment of D.J. did not involve facilitated communication.

"It was an assessment of his ability to communicate," Patton said outside the courtroom, adding that "the assessment was not based on facilitated communication. It did not comment on facilitated communication."

Bill Wichert may be reached at bwichert@njadvancemedia.com. Follow him on Twitter @BillWichertNJ. Find NJ.com on Facebook.