Effects of Binaural Beats in People with Anxiety: A Systematic Review and Meta-analysis Volume 55- Issue 5

Yidan Wang, Xiaotu Zhang and Ye Zhang*

• Department of Nursing, Changchun University of Chinese Medicine, China

Received: March 14, 2024; Published: March 25, 2024

*Corresponding author: Ye Zhang, Department of Nursing, Changchun University of Chinese Medicine, Chunchang, China

DOI: 10.26717/BJSTR.2024.55.008752

Abstract PDF

Introduction:Binaural beats are a perceptual phenomenon when two tones with slightly different frequencies are presented to each ear separately. It has been proposed that binaural beats, among other things, can alter cognitive and mental states, particularly in people with anxiety. However, the effects of binaural beats in anxiety treatment remain unproven.

Aim:The main objective of this study is to conduct a meta-analysis to summarize the effects of binaural beats on patients’ anxiety levels.

Design:PRISMA recommendations were followed when conducting a systematic literature review and metaanalysis.

Method:In this study, a systematic search was conducted using 5 databases. Eligibility criteria included studies that assessed anxiety as an outcome, used binaural beats, randomized controlled trials, and publications in English. The Cochrane Collaboration’s “Risk of Bias” (ROB) tool was used to assess the methodological quality of the included studies. A random effects model was applied in the meta-analysis to estimate the pooled effects of binaural beats. For statistical analysis, RevMan 5.3 was utilized.

Result:A total of 11 studies met the eligibility criteria, including 876 participants. Overall, binaural beats can reduce anxiety during treatment.

Implication for Practice:For people with anxiety who reside in medical centers or other long-term care facilities, binaural beats might be considered a helpful non-pharmacological remedy. For future investigations, a standard binaural beat approach may be required.

Keywords: Meta-Analysis; Non-Pharmacological Therapy; Anxiety; Binaural Beats

Anxiety has been steadily increasing, particularly among teen­agers and young adults in the past 24 years (Phillips, et al. [1]). The lockdowns due to the COVID-19 pandemic have further increased the prevalence of anxiety (Twenge, et al. [2]). Anxiety is a common cause of psychological stress in surgical patients. Although the operation is often performed under local anesthesia, most patients are awake during the operation and the surgical or therapeutic procedure is invasive, increasing the patient’s anxiety level and pain perception (Ölçücü et al. [3]). In addition, concerns about losing control, being in an unfamiliar environment, and the expectation of good surgi­cal results can cause high levels of perioperative anxiety in patients (Wiwatwongwana et al. [4]). Early stressful life events (ELS), which change the hypothalamic-pituitary-adrenal (HPA) axis’s function, are frequently the cause of anxiety (Juruena et al. [5]). ELS has the im­pact of adversely affecting a person’s development and all facets of their life, including their emotional, cognitive, behavioral, social, and physical well-being. Most research points to ELS as a condition that frequently alters the HPA axis permanently and can eventually lead to anxiety in adults (Green et al. [6]). Those with anxiety disorders have greater cortisol levels (Greaves-Lord, et al. [7]). This suggests that therapies targeting cortisol and other HPA axis elements may help treat anxiety.

There are many anxiolytic therapies, including anti-anxiety med­ications (benzodiazepines, selective serotonin reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors), cognitive strate­ gies, behavioral treatments (cognitive behavioral therapy, exposure, relaxation), mindfulness, and acceptance-based approaches (Mallik, et al. [8]). However, medications for anxiety response rates can be low, and many patients may experience adverse effects (Baldwin, et al. [9]). Many individuals with anxiety do not respond to typical ther­apy procedures (Gunter, et al. [10]). There is a particular need for a low-cost, user-friendly, quickly deployable, and effective treatment for anxiety that does not have the severe adverse reactions associated with anti-anxiety medicines (Zoteyeva, et al. [11]). Binaural beats are recommended in many treatment modalities to reduce anxiety and depression (Garcia-Argibay, et al. [12]). Binaural beats were discov­ered in 1839 by a German experimenter named H. W. Dove, but as late as 1915 they were considered a trivial special case of monaural beats (Oster, et al. [13]). Some researchers believe that binaural beats are a brainwave entrainment technique intended to put your brain in the same state of activity as when meditating using traditional methods (Rajan, et al. [14]).

When a sound with steady intensity and frequency was presented to one ear and another with the same intensity but slightly different frequency, the brain would produce pulsations in the amplitude and localization same to the perceived sounds, which was known as “bin­aural beat (binaural beats)” or “binaural tone” (Dove H W [15]). The frequency difference between the two sounds must be small (30 Hz) for the binaural beats to occur; Otherwise, the two sounds would be captured separately by the two ears, and no beat would be perceived (Gao, et al. [16]). For example, a two-tone exposure of 400 and 410 Hz to each ear separately is perceived as a single tone with a frequency of 405 Hz, the amplitude of which changes by a frequency of 10 Hz (Moore, et al. [17]). When the carrier frequency is about 440 Hz, bin­aural beats are best perceived; Beyond this frequency, they become less noticeable, and beyond about 1000 hertz, they disappear com­pletely. They exist as a result of the interaction of perceptions within the brain and can be used to investigate some of the brain’s processes (Oster, et al. [13]). Cerebral activity as recorded by EEG is convention­ally divided into four categories. The most rapid pattern is the beta pattern with a frequency of 14 Hz to > 100 Hz. This is the pattern of normal waking consciousness and is related to concentration, alert­ness, arousal, and cognition.

At higher levels, the beta pattern is associated with anxiety. The delta EEG pattern (0.1– 4 Hz) is associated with dreamless sleep, the theta pattern (4–8 Hz) with random eye movement (REM) sleep, meditation, and creativity, and the alpha pattern (8–13 Hz) with re­laxation. Therefore, through brain entrainment, a 10 Hz binaural beat would encourage the brain to produce a 10 Hz beat corresponding to a relaxed (Alpha) state of consciousness (Padmanabhan, et al. [18]). The researchers tested five-minute binaural beats with four different frequencies: delta band (1 Hz), theta band (5 Hz), alpha band (10 Hz), and beta band (20 Hz). They observed an increase in RP in the theta and alpha bands and a decrease in the beta band during delta and al­pha binaural beat stimulations. RP decreased in the beta band during theta binaural beats, while RP decreased in the theta band during beta binaural beats (Gao, et al. [16]). Therefore, it is not yet clear wheth­er binaural beats are a brain wave entrainment technique. Binaural beat perception is caused by the main neural mechanism that enables sound localization (Kuwada, et al. [19]).

The simplest explanation of the neurological basis of binaural beats is that the number of nerve impulses from each ear and the path they travel to the brain is determined by the frequency of the incident sound and that the two neural signals interact somewhere in the brain. The brain strives to rectify the vibrational acoustic mu­sical frequency when applying sound vibrations that are different in each ear because there is a relationship between what humans hear and view and the consciousness of the mind (Rajan, et al. [14]). Some researchers have suggested that binaural auditory beats represent a neural entrainment technique. The theoretical idea behind neural entrainment is that rhythmic oscillatory activity within and between different brain regions can improve cognitive functions (Chaieb, et al. [20]). The basic theoretical assumption was that the human brain tends to change its dominant EEG frequency toward the frequency of external stimuli by entraining the brain to synchronize neural activity with binaural beats stimuli or other external stimulation.

Auditory beat stimulation (ABS) has long been studied for a va­riety of purposes, including researching the auditory steady-state re­sponse (ASSR) and monitoring audiometric parameters in the brain, as well as understanding the mechanics of sound localization (Kuwa­da, et al. [19]). A few studies also suggest that ABS can be utilized to reduce anxiety as well as improve mood states (Chaieb, et al. [20]). There is increasing support for the claim that binaural auditory beats affect cognition and psychophysiological states. For instance, theta/ delta-band frequencies have been used successfully to reduce anxiety (Garcia-Argibay, et al. [12]), and to increase hypnotic susceptibility (Stevens, et al. [21]). The value of music in decreasing anxiety be­fore surgery has been demonstrated in several recent studies (Lane, et al. [22]). Some of the positive impacts of Binaural Beats include enhanced attention, relaxation, improved focus levels, increased in­telligence quotient, increased immune system resistance, decreased cortisol levels, induced deep sleep, enhanced memory, improved learning skills, problem-solving skills, and controlling (Chaieb, et al. [14,20,23]).

There are a variety of scientific reports on binaural beats, in which some researchers found positive effects of binaural beat exposure on anxiety or certain mood states, while others appeared to find no effect in the same aspects. Conflicting results have been reported on the ef­fects of applying binaural beat frequencies, which somewhat hampers further research to address the potential impact of other possible tar­gets on cognitive and emotional effects. Therefore, this meta-analy­sis aimed to evaluate the extent and direction in which anxiety levels are influenced by binaural beat exposure, to find patterns about the implicit mechanisms and the true expectations that can be achieved through the use of this technique.

Design

We follow the Cochrane Handbook for Systematic Reviews of In­terventions (Higgins & Thompson, et al. [24]) to conduct this system­atic review of randomized control trials (RCTs) to examine the effect of binaural beats on anxiety disorders. The Preferred Reporting Items for Systematic Reviews and Meta-analyses group (PRISMA) (Moher, et al. [25]) was used as the basis for reporting our review.

Search Strategy

We searched PubMed, Embase, the Cochrane Library, Cumula­tive Index of Nursing and Allied Health Literature (CINAHL), and ProQuest for English-language parallel group studies reporting the effects of Binaural beats in insomnia patients published up to Sep­tember 2022. The manual searching was also performed to include articles that might have been omitted from the electronic search. The MeSH terms used to develop the search included “Binaural beat” OR “Binaural beats” OR “Auditory Beats” OR “Binaural Auditory Beats” OR“Auditory beat stimulation ”AND “Anxiety” OR “Angst” OR“Social Anxiety” OR “Anxieties, Social” OR“Anxiety, Social” OR “Social Anxiet­ies” OR “Hypervigilance” OR “Nervousness” OR “Anxiousness”, AND “Randomized Controlled Trial” OR “Randomised” OR “Randomized” OR “Placebo” OR “RCT” OR “Random.”

Selection Criteria

Studies were selected for detailed review if they met the following population, intervention, comparison, outcome, and study design (PI­COs) framework (Amir- Behghadami, et al. [26]):

(1) Population: Participants with all forms of anxiety, and the eligibility was not limited by diagnostic status, medication use, or other characteristics (such as age or gender);

(2) Intervention: The experimental group accepted binaural beats provided by the professionals;

(3) Comparison: The comparison group accepted conventional control measures (e.g., a waiting list control); and

(4) Outcomes: studies assessed anxiety as an outcome.

(5) Study Design: published in the English language. The exclu­sion criteria were as follows:

1) Repeated published research;

2) A study with incomplete data that could not be transformed or merged; and

3) A trial in which participants were merely allowed to listen to binaural beats through headphones, with no therapeutic process or blank compare group.

After deleting duplicates using EndNote software, two writers in­dependently assessed all titles and abstracts against the stated qual­ifying criteria. The authors utilized the PRISMA flowchart to report research eligibility, independently executed the selection process for all studies, and obtained full texts for those studies that passed the first-level screening. Every study received a full-text evaluation, and data extraction was done in duplicate by two reviewers. The accord was established by mutual agreement. All disagreements were ironed out with the help of a third author. Figure 1 depicts the selection pro­cedure for identifying the sources included in this study as a PRISMA flowchart.

Figure 1

Two writers independently extracted data from each study, while a third author evaluated the reliability of the data extraction and han­dled any disagreements. The author, publication year, country, study design, intervention setting, participants’ demographic data (e.g., to­tal participants, participant types, age, and total number of study pop­ulation), intervention details (e.g., intervention types), the frequency and duration of each intervention session, the moment of exposure, binaural beats masking, outcomes, and the comparison group were all extracted fields. Table 1 shows the basic characteristics of the stud­ies that are eligible.

Table 1:

One of the most significant steps in a systematic review and assessment of the study’s internal validity is the risk of bias (ROB) assessment. Finally, the ROB assessment allows the strength of the evidence to be determined (Hartling, et al. [27]). As a result, ROB was assessed as the first stage in a systematic review. This strategy is used to explain study quality. A meta-analysis was performed to summarize the individual study results to determine the influence of binaural beats therapy on the specified variables. Two authors in­dependently assessed the quality of the included studies using the Cochrane Collaboration’s ‘risk of bias (ROB)’ tool, as illustrated in Figure 2 (Higgins, et al. [28]). Random sequence generation, alloca­tion concealment, subject and personnel blinding, result assessment blinding, insufficient outcome data, selective outcome reporting, and other types of bias are all assessed using the Risk of Bias tool. We classified the studies’ ROB as “low risk,” “high risk,” or “unclear risk.” Nine of the 11 RCTs were found to have a low risk of bias, indicating a high-quality study. When the method of random sequence genera­tion used to detect selective bias was reviewed, 7 RCTs were rated as having a low risk of bias since they used simple randomization using a computer or a coin flip. For example, if subjects with even numbers were assigned to the experimental group, the study was deemed to have a high risk of bias because the odd or even numbers of a table list represent a systematic or non-random approach when compared to computer-generated sequence generation, random number gener­ation, or coin toss (Higgins, et al. [28]).

Figure 2

Uncertain bias was assigned to studies that did not include a definition of selection bias. Blinding was determined by whether or not research participants and key study personnel were unaware of the study design and methodology. Although binaural treatment is a non-pharmacological intervention, double blinding can be employed in the experimental group since both listeners and examiners are blindfolded. According to the descriptions of all included studies, 8 of them were double-blind. We evaluated one RCT with a high risk of bias and two trials with uncertain blinding procedures. For the exam­ination of incomplete outcome data, 11 of 12 RCTs were classified as having a low risk of bias. The evaluation of selective result reporting was separated into two categories: reported outcomes and unreport­ed outcomes. One of the 11 RCTs was rated as “high risk” of bias be­cause the studies did not publish data for all of the outcome variables indicated in the Methods section. For the examination of incomplete outcome data, 11 of 12 RCTs were classified as having a low risk of bias. The evaluation of selective result reporting was separated into two categories: reported outcomes and unreported outcomes. One of the 11 RCTs was rated as “high risk” of bias because the studies did not publish data for all of the outcome variables indicated in the Methods section.

A meta-analysis of 11 studies was conducted using Comprehen­sive Meta-Analysis Software® (RevMan version 5.3) to estimate the overall effect size of the intervention. When the reviewed studies used different scales to measure the same outcomes, data were syn­thesized using standardized mean difference (SMD) with 95% confi­dence interval (CIs). Effect sizes with a p-value of < 0.05 were consid­ered significant. To assess the heterogeneity of the results, we used Cochran’s Q test and I-squared (I2) statistical tests. The I2 statistic was an effective predictor of heterogeneity, with values of 25%, 50%, and 75% corresponding to low, medium, and high heterogeneity (Hig­gins, et al. [28]). All analyses were conducted using a random effects model. We used sensitivity analysis to examine the stability of study results by removing individual studies to determine whether the re­moved study had a particular impact. In addition, a sensitivity analy­sis was performed while excluding studies with a high risk of bias. We constructed funnel plots and visually examined signs of asymmetry to examine publication bias. If data were missing, we contacted the au­thors to request additional information. If data could not be collected, we did not include the study in the meta-analysis.

Study Characteristics

Initially, a total of 130 studies were retrieved. Finally, 11 studies were included in our review and meta-analysis (Figure 1). Table 1 provides a summary of the main characteristics of the eligible stud­ies. A total of 11 studies with 876 participants were included in our meta-analysis. Among 876 participants in each of the 11 studies. The year of publication ranges from 2005 to 2022. The largest sample consisted of 229 participants (lct et al. 2021), and the smallest sample consisted of 14 participants (Gálvez, et al. [29]). Six of the 11 studies came from developed countries and five from developing countries. Eight of the studies related to anxiety caused by surgery, two of these studies related to dental surgery, and two studies involved eye sur­gery. Two studies incorporated anxiety induced by physical examina­tion procedures. The average age of subjects in the intervention and the control group were 49.0 and 50.4 years, respectively. The dura­tion of each exposure ranged from 12 to 60 minutes. These studies did not provide information about the age of the sample (Gálvez, et al. [29,18,30]). All studies examined levels of anxiety using either the Visual Analog Scale (VAS) or the State Anxiety Inventory (STAI) and excluded subjects who had communication problems due to visual and/or hearing impairments.

Binaural beat-only interventions were conducted in 8 studies, while the rest of the studies conducted binaural beats with music or masked by pink noise. Interventions using earphones with no sound or music, pink noise like the sound of the sea, or routine nursing care were included in the control group. Anxiety was evaluated to mea­sure the effects of the interventions. Systolic blood pressure, diastolic blood pressure, and heart rate were objective measures of anxiety. Anxiety, Pain, Systolic blood pressure, Diastolic blood pressure, and Heart rate were selected to measure the effects of binaural beats. All RCTs assessed the effects of binaural beats on anxiety. In 8 of these RCTs, anxiety was measured using the self-reported STAI, and the re­maining 3 RCTs used the VSA as an observed scale. The meta-anal­ysis was conducted post-treatment and included 876 participants. Meta-analysis of the random effects model showed that the SMD was -0.74 (95% CI: -1.29 to -0.18, p < 0.05, I2 =93%). Detailed information can be found in Figure 2. Based on the high heterogeneity indicated by Cochran’s Q statistics (p < 0.1) and I2 values (>75%). Anxiety was divided into two groups for subgroup analysis: trials measured with VAS (n = 3) and measured with STAI (n = 8). Regarding the three stud­ies measured by the VAS, the I2 value was 49% and p<0.01.

The overall mean effect size was 0.37 (95% CI: 1.70 to 0.27, Z = 1.86, p = 0.006), indicating that anxiety did not decrease in the bin­aural beats group compared to the control group was significantly reduced and the statistics for VAS were not significant. A random ef­fects model was used due to the substantial heterogeneity revealed by Cochran’s Q statistic (p < 0.1) and I2 values (>50%) for the STAI variables. The mean effect size from these 8 RCTs that included STAI was -0.9 (95% CI: -1.65 to -0.16, Z = 2.37, p = 0.02). Detailed infor­mation can be found in Figure 3. All 11 RCTs measured the effects of binaural beats on anxiety in different countries. For the subgroup analysis, countries were divided into two groups: developing coun­tries (n=6) and developed countries (n=6). The results of our sub­group meta-analysis showed that binaural beats were more effective in reducing anxiety in developed countries (SMD = -1.65, 95% CI: -3.08 to -0.21, p < 0.05, I2=96%) compared to developing countries (SMD = -0.24, 95% CI: -0.79 to 0.30, p < 0.05, I2=89%). Detailed infor­mation can be found in Figure 3. As an objective measure of anxiety, three original studies examined the effects of binaural beats therapy on systolic blood pressure, Cochran’s Q statistic (p<0.1), and I2 value was 0. The results showed low heterogeneity, therefore a Fixed effect model was used.

The overall mean effect size for depression was −6.34 (95% CI: −11.23 to −1.45, Z = 2.54, p<0.01), indicating that the systolic blood pressure was significantly decreased in the binaural beats group com­pared to the control group. In contrast, no significant statistical differ­ences were found in the effects of binaural beats therapy on diastolic blood pressure. The overall mean effect size from 3 RCTs, including the diastolic blood pressure variable was -1.41 (95%CI: -3.95 to 1.13, p >0.05, I2 =39%). Four RCTs observed changes in heart rate in pa­tients after interventions for anxiety. The overall mean effect size for depression was −1.33 (95% CI: −3.99 to 1.32, Z = 0.98, p<0.33), and no significant statistical differences were found. The results suggest that binaural beats have no effect on improving heart rate in anxiety patients (Figure 4).

Figure 3

Figure 4

After sensitivity analysis of these study data, two studies out of 8 RCTs showed greater heterogeneity. Sensitivity analysis indicated significant changes in SMD when individual studies were removed, and heterogeneity did not remain present after removing the high­est-weight studies. When we removed the two studies, Cochran’s Q statistics (p > 0.1) and I2 values were 37%, and the overall mean effect size was −0.51 (95% CI: −0.74 to −0.29, Z = 4.46, p<0.1) with statistical effects. The results of our subgroup meta-analysis showed that binaural beats significantly improved anxiety compared to the control group.

The purpose of the present work was to provide an assessment of the effectiveness of binaural beats for anxiety through a meta-analysis and to support the results through a systematic review of the selected studies. Eleven studies were analyzed, including 876 patients. The re­sults of the current meta-analyses showed that binaural beats therapy has a significant effect on regulating the anxiety of patients, especially those who would undergo surgery, which is similar to the results of the recent meta-analysis study on binaural beats can impact cognition and mental states among others. (Garcia-Argibay, et al. [12]). Howev­er, this meta-analysis only examined the effects of binaural beats on cognition, anxiety, and pain perception, thereby omitting the evidence for the specific treatment effect of binaural beats on anxiety. The re­sults also suggest that binaural beats therapy can reduce systolic blood pressure in patients. Binaural beats consistently demonstrat­ed effectiveness in reducing preoperative or intraoperative anxiety, as reflected in Studies 1–8 and 10. One possible reason for this was that mood effects were mediated by changes in the level of central nervous system arousal induced by binaural beat stimulation. These signals resulted in corresponding EEG frequencies and increased rel­ative EEG spectral power in the beta or theta/delta band.

Low-frequency binaural beats are distracting and can cause a va­riety of changes in the listener’s state of consciousness, diverting the patient’s attention from negative stimuli and thus alleviating anxiety (Lane, et. [22]). Since anxiety symptoms can vary depending on the disorder, there are different reactions to binaural beat therapy. For example, the participants in the study were 11 Parkinson’s patients. Parkinson’s disease (PD) is characterized by achronic and progres­sive neuronal degeneration mainly in the substantia nigra, leading to a significant decrease in dopamine levels (G´alvez). In addition to mo­tor symptoms, PD often manifests with other non-motor symptoms as the disease progresses, including depression, sleep disturbances, mood changes (apathy), cognitive problems, unexplained pain, loss of autonomy, urinary dysfunction, and fatigue. Sound is characterized by many different parameters such as frequency, duration, and inten­sity. In this study we focus on rhythm, which is a critical factor in this disease. In PD, rhythm appears to be a crucial factor when design­ing sound stimulation, which is the key parameter for improving gait characteristics (speed, step time, and cadence step) and for removing the “freeze-gait”.

Dopaminergic therapies have been reported to be associated with a decrease in beta-band coherence at rest and an increase in beta-band performance during executive tasks. Most patients with bronchial diseases report feeling worried that the procedure will be painful, and may exhibit aspiration, breathing difficulties, and com­plications. There may also be anxiety about the risk of bronchial tu­mors. Therefore, anxiety in the study 10 of participants was more complicated than in dental patients. One reason for the high hetero­geneity could also be the different management of binaural beats. The individual differences in intervention methods were large, and there was no unified standard for binaural beating intervention. However, binaural beats therapy failed to significantly reduce diastolic blood pressure and regulate patients’ heart rate. Therefore, further exper­imental studies may be needed to test the effect of binaural beats on diastolic blood pressure and heart rate. Subgroup analyzes of differ­ent countries and intervention sessions showed that binaural beats significantly improved anxiety in developed countries. This may be because developed countries have more advanced hardware equip­ment and experimental environments, and the professional quality and ability of binaural beat implementers are stronger than those in developing countries.

In addition, the overall medical level in developed countries is higher, and patients are less worried about their own health. Anoth­er possible reason was that participants from developed countries in the included studies were more educated and cooperative in the study. The current meta-analysis applied tight inclusion criteria and included more recent RCTs, resulting in a larger effect size that should be regarded as trustworthy. The persistent binaural beat frequencies reverberating throughout the brain via the ‘frequency following re­sponse’ (FFR) appear to be the mechanism underpinning the effec­tiveness of binaural beats in lowering anxiety levels. This can lead to changes in arousal levels via activation of the reticular-thalamic activating system. Music with slow melodies provides emotional and physical relaxation for the listener. These features make the music ‘neutral’ and free from the feeling that other options might trigger physiological reactions in the patient (Menziletoglu, et al. [31]). Opi­ate, cytokine, nitric oxide, and hormone expression in listeners can be mediated by music (Salamon, et al. [32, 33]). Thanks to these neu­rochemical systems, melodic, soft, and soothing music can calm and relax people.

Based on our results, we can observe that exposure to alpha, beta, and theta binaural beats affect anxiety reduction performance and that the direction of this effect depends on the frequency used. Increased anterior-posterior intracerebral connectivity in the theta band was observed under binaural delta, alpha, and beta beats (Gao, et al. [16]). It has been suggested that tones with a frequency between 200 and 900 Hz are more effective in triggering binaural beats than tones above 1000 Hz (Wahbeh, et al. [34,35]). Some statistical het­erogeneity was noted in our meta-analysis. The differences between RCTs should be taken into account when interpreting our results. First, several different scales have been used to assess anxiety out­comes, and the units of measure vary. Second, population character­istics, diagnostic results, sample size, and music therapy parameters also varied greatly from one study to another. Finally, a variety of study designs may also contribute to heterogeneity. It is important to understand why certain research was unable to detect these dif­ferences, even though most studies reported significant differences between binaural beat stimulation and control conditions.

Certain variables could potentially explain disparities in study ef­fectiveness. One aspect that could be important in the efficiency of binaural beats is the carrier frequency, which should be investigat­ed further in future studies to see if other frequency ranges create different results. In this meta-analysis, we also took into account the exposure period, the timing of exposure, and the kind of sound that was utilized to mask the binaural beats as additional factors that can reduce their efficacy. Furthermore, we shouldn’t ignore the fact that there are variances in how males and females perceive binaural beats (Oster, et al. [13,36) and that these and other inter-individual vari­ables may attenuate the findings. For example, individual mesostria­tal dopamine levels, measured indirectly through spontaneous blink rate, have been found to determine the degree to which binaural gam­ma beats influence perception. (Reedijk, et al. [37-39]). The results of this meta-analysis are encouraging and should be validated by studies with larger sample sizes to ensure that the observed effects can be replicated and applied to other areas such as psychotherapy and neu­rological and cognitive rehabilitation.

Furthermore, future RCTs may necessitate the development of a global standard technique for administering binaural beats therapy to improve comparability and ensure the best possible result for pa­tients. As part of the intervention protocol, the interdisciplinary facil­itator, as well as the frequency and duration of binaural beats therapy, should be evaluated.

Several limitations may have influenced the results of this me­ta-analysis. First, the characteristics of each included study varied greatly. As a result, because only a small number of studies were avail­able for the respective analyses, some statistical analyses, such as me­ta-regression and moderator analysis, were unable to be performed; as a result, existing variations in intervention content that could po­tentially influence the overall effect sizes calculated for the current review could not be further examined. Second, the included RCTs dis­played variable levels of bias risk, implying that more rigorous RCTs are required in the future. Furthermore, despite its importance, we were unable to use carrier frequency in our analysis because several of the included studies did not record this information. Finally, the study focused solely at earlier studies published in English, which may have resulted in the exclusion of important data from original papers published in other languages.

In summary, the results of the current study showed that binau­ral beats were effective in reducing anxiety levels and systolic blood pressure in patients, although further collaborative research is need­ed to ensure that these effects are controlled by therapy without per­formance bias. This study, however, found no effect on diastolic blood pressure or heart rate. This study’s findings revealed that delivering binaural beats was advantageous to study participants. This research could help shape future clinical practice and encourage the use of bin­aural beats as a non-pharmacological way to enhance anxiety care at home or in other medical settings. Finally, a variety of study designs may also contribute to heterogeneity. With the increased clinical in­terest and technical capabilities of binaural beats to intervene in anx­iety, it is critical for future studies to better understand how and to what degree these particular tones can impact anxiety state.

The authors declare that they have no competing interests.

Registration number: CRD 42022359497.

Ethical statements and Data sharing is not applicable to this arti­cle as no new data were created or analyzed in this study.

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