# The Efficiency of Binaural Beats on Anxiety and Depression--A Systematic Review
## 3 Results
### Anxiety Evaluation  
Recently, medical experts have been investigating the possible benefits of this new technology as an adjunct therapy for the treatment of anxiety.  
Most of the studies included in this literature review included an anxiety evaluation using either the State-Trait Anxiety Inventory (STAI) [33] questionnaire or the Visual Analog Scale for anxiety [34; 35]. Seven studies applied the STAI questionnaire [20; 23; 25; 26; 27; 28; 30], while VAS was only used in five papers [19; 24; 25; 27; 31]. For the studies using the STAI test as the primary evaluation standard, [PERSON], [PERSON] et al. [20] stated that in the initial assessment, no differences were found in the \"trait\" part of the questionnaire (STAI-T) between the three groups. In contrast, for the STAI-S (State) questionnaire, the binaural beats group scored highest on the initial assessment among the three groups. In the final assessment, patients in the group using binaural beats showed a decrease in the STAI-S score of 26.3% (\(p\) = 0.001 vs. audio group, \(p\) < 0.0001 vs. no intervention group) compared to the audio group, which showed a decrease of 11.1%, and the no intervention group showed a decrease of only 3.8%. In addition, [PERSON], [PERSON] et al. [23] obtained a significative reduction in the STAI-S score compared to the control condition (\(p\) = 0.009). [PERSON] et al. [27] used the STAI-S evaluation to determine the change in anxiety symptoms for their two types of medical procedures. They showed a decrease in the STAI-S scores for both study groups when comparing the experimental condition with the control condition, and \(p\) < 0.001 for the DCG group and the USRG group. On the other hand, [PERSON], [PERSON] et al. [26] concluded that the anxiety score evaluated with the STAI questionnaire decreased and patients felt fewer anxious symptoms, but when the comparison between the experimental group and the music group was made, the result did not offer a significant value from a statistical point of view. Compared with the no-intervention group, the STAI-S score was statistically significant at \(p\) < 0.001.  
The following method of evaluating the effect of binaural beats on anxiety was represented by VAS [36]; [PERSON] et al. [19] used the VAS scale to evaluate the effects of binaural beats on anxiety before a medical procedure. An evaluation after the intervention showed that the patients in the experimental group felt an improvement in the degree of anxiety compared to the control group with \(p\) < 0.001. In another study conducted by [PERSON], [PERSON] et al. [25], it was found that between the binaural group and the control group, there was a statistically significant difference in the VAS score at \(p\) = 0.003, but at the same time, there were no differences between the binaural beats group and the music group with a \(p\)-value of 1.  
Another form of assessment for anxiety involves measuring the blood pressure and heart rate. We found five eligible studies that used the BP and HR to assess the degree of anxiety felt by patients [23; 25; 26; 31; 32]. One of the studies was conducted by [PERSON], [PERSON] et al. [23]. They concluded that using binaural beats reduced systolic blood pressure by an average of 9.89 (\(p\) = 0.002) compared to the music and control groups, where they did not find significant differences in systolic blood pressure. In the same study, diastolic blood pressure decreased in the binaural group compared to the control group, with a \(p\)-value of \(p\) = 0.016. [PERSON], [PERSON] et al. [26] measured the heart rates of the patients undergoing cataract surgery to assess their anxiety symptoms. They noted that within the 20 min after the surgery began in the binaural group, the heart rates of the patients were lower compared to those of the music-only group (\(p\) < 0.05) and the control group (\(p\) < 0.001).