ITS ALL IN THE PARAMETERS - A CRITICAL ANALYSIS OF SOME WELL-KNOWN NEGATIVE STUDIES ON LOW-LEVEL LASER THERAPY

Objective: Scientific studies include references to historical studies on low-level laser therapy (LLLT) in general and to old studies on th e specific subject in particular. Some studies are quoted often. It is fair to take a second look at these, since few people seem to have re ad them carefully, and others have read them only in the abstract form . This paper critically reviews the parameter pitfalls found in many o f the classic ''negative'' studies. Summary Background Data: A study o f 1,200 papers on LLLT has resulted in 85 positive and 35 negative dou ble-blind studies. The negative studies have been scrutinized carefull y in an effort to pinpoint possible reasons for the failures. In the f ollowing, the majority are double-blind studies, but some non-blinded and animal studies have been included to give typical examples of pitf alls.