First of all what are binaural beats?
Binaural beats are the subjective experience of a beating tone with a frequency that corresponds to the frequency difference between two binaurally presented tones. In simple words, when you are listening to a stereo sound with two different tones the brain creates a response (binaural beat) which is hearing and responding to the difference between the tones, not the actual tones themselves.

How does binaural beats affect your brain?
The idea is that the brain “takes over” or synchronises its activity on the base of the binaural beats. That is, binaural beats can entrain the brain to different states that can enhance cognitive functioning.

Binaural beats facilitate multitasking
In our new published study we tested the idea that binaural beats enhance multitasking, the ability to do different activities at the same time. In real life examples of multitasking are talking on the phone and at the same time writing a tweet.

In our study people listened to binaural beats in the gamma range (40 Hz) or to a control beat ( constant tone) and performed two tasks (identify digits larger or smaller than 5) on the computer screen. Our results demonstrate that when people listened to binaural beats they were faster in multitasking. Even if there is the need of more research, we can conclude that binaural beats may act as a cheap and useful cognitive enhancer.

Reference: Hommel B, Sellaro R, Fischer R, Borg S and Colzato LS (2016) High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk. Front. Psychol. 7:1287. doi: 10.3389/fpsyg.2016.01287