The study referenced below shows that a small number of weekly audio sessions using theta / delta binaural beat frequencies appears to have benefits in anxiety treatment.
Almost all self-improvement programs that utilize binaural beats and other entrainment techniques claim this benefit. The MindFusionX program uses a wide variety of techniques to reduce stress and lower the likelihood of anxiety in healthy individuals. Although this effect is interesting, it is much smaller effect than that generated by our multi-faceted approach we use.
Alternative Therapies in Health and Medicine (2001, January; vol 7:1). Use of Binaural Beat Tapes for Treatment of Anxiety: A Pilot Study of Tape Preference and Outcomes. René-Pierre Le Scouarnec, PhD, Roger-Michel Poirier, MD, et. al.
http://www.alternative-therapies.com/