A forensic scientist studies material, draws on training, experience and skill to form educated conclusions. A forensic psychiatrist or psychologist is a forensic scientist or, in a different field, a forensic investigator might be a better term.  An “expert witness” is someone whose opinions help a jury to understand what the investigator has found and how that might impact their decisions about the damages experienced by the injured party. An expert witness who explains a construction defect that led to an injury, for example, will help the jury decide how much the construction defect contributed to losses.  Punitive damages also can be impacted if liability is proven to have been avoidable or untenable.  In your case, you are probably both investigator and expert inasmuch as you may conduct an IME and review records.

In short, a forensic professional conducts a thorough investigation of the circumstances giving rise to a lawsuit.  They provide their conclusions to the parties. An expert witness is officially named to the Court and all parties, and then has certain legal obligations associated with the expert’s role and testimony.

If that doesn’t answer your question, let me know in the comments below and I’ll try to get you more answers.  I’m not an attorney. State and federal laws govern the obligations and limitations of an expert witness and these questions are best directed to a lawyer.