Illusory Effect

Background
Binaural beats are illusory beats that the brain generates when two tones of slightly differing frequencies are administered into each ear of the patient dichotically. The frequency administered to the left ear is slightly different than the frequency delivered to the right ear during the administration of binaural beats as is seen in Figure 1. The administration of binaural beats is an emerging alternative therapeutic technique that has been proven to have positive cognitive effects on the memory, mood states, and perception of chronic pain in patients.

Figure 1. An example of the experimental induction of binaural beats.

The frequency difference of the binaural beats are significant because the illusory beat produced in the brain generates a brain wave of the same frequency. The presence of brain waves, or neural oscillations, are integral to the function of the brain and the central nervous system. Brain waves are involved in the modulation of the action potentials and connectivity of neurons. Typically, the higher the frequency of the brain wave, the more activity is occurring in the brain and the more focused the individual, while low brain wave frequencies are

The brainstem neurons inside of the superior olivary nuclei then fire action potentials at a rate corresponding to the difference in frequency of the binaural beat (2). In addition to the effects of binaural beats on the brainstem, electroencephalograms (EEGs) of patients listening to binaural beats have shown altered brain wave activity of the temporal and parietal lobes (2). It is through this altered neurophysiology that it has been hypothesized that binaural beats bring about changes in the memory, mood states, and perception of chronic pain in a patient