Effect of binaural beat music and noise cancelling headphones on intraoperative anxiety in patients undergoing spinal anaesthesia – A randomised controlled study

ABSTRACT

Background and Aims:

This study aimed to determine the effects of music and active noise cancellation on intraoperative anxiety in patients undergoing lower limb surgeries under spinal anaesthesia.

Methods:

After obtaining ethical approval, this randomised controlled study was conducted in adult patients (18–50 years of age) of either gender. Patients were randomly allocated to binaural beat music (Group A), noise cancellation (Group B) or no headphones (Group C) group (n = 36 in each group). State-Trait Anxiety Inventory-6 (STAI-6) score and Visual Analogue Score for Satisfaction (VAS-S) were noted preoperatively and at the end of surgery. In addition, Ramsay sedation scores and Likert communication difficulty scores were noted at 30 min intraoperatively. Haemodynamic parameters were noted preoperatively and at different intervals intraoperatively till the end of the surgery.

Results:

There was a significant decrease in anxiety scores in Group A, Group B and Group C with postoperative STAI-6 scores (mean ± standard deviation) of 7.8 ± 1.7, 11.7 ± 4.2 and 14.7 ± 5.3, respectively. The difference was significant in Groups A and B compared to Group C (P < 0.001). Patient satisfaction scores in Groups A and B were better than in Group C (7.3 ± 1.7 and 6.2 ± 1.6 vs. 5.2 ± 1.3, respectively). Sedation scores and communication difficulty was significantly better in Groups A and B compared to Group C. Systolic blood pressure was significantly better intra- and postoperatively. There were no significant differences in other haemodynamic parameters on most occasions.

Conclusion:

Music and noise-cancellation headphones can reduce anxiety and improve satisfaction and sedation scores in patients undergoing spinal anaesthesia.

INTRODUCTION

Patients undergoing procedures under regional anaesthesia alone frequently become anxious since they know their surroundings. Loud noises and sounds in the operating room are unnerving and anxiety-inducing.[1] This could affect physiological and psychological reactions such as pain perception, plasma stress hormone concentrations, respiratory rate, heart rate, blood pressure, susceptibility to infection and postoperative recovery times.[2,3]

The use of opioids and benzodiazepines to alleviate anxiety can slow recovery from anaesthesia due to their sedative and emetic effects. Binaural beats are an auditory illusion when two tones with slightly different frequencies, one in each ear, are listened simultaneously.[4] The difference in the frequencies presented to each ear is perceived to originate from the brain. Binaural beats are related to five distinct brain waves: alpha (8–14 Hz), beta (14–30 Hz), gamma (30–100 Hz), delta (1–4 Hz) and theta (4–8 Hz). The delta wave is linked to healing, pain relief, deep sleep and meditation. Binaural beat music can avoid the unwanted effects of drugs and provide physiological benefits such as perioperative relaxation, pain reduction and anxiety relief and improved haemodynamic stability. The noise-cancellation headphones block the ambient noise and sounds of the monitors.[5]

This study aimed to assess and compare the effect of binaural beat music and active noise cancellation on intraoperative anxiety in patients undergoing lower limb surgeries under spinal anaesthesia. The study’s primary objective was to determine the effect of music and noise cancellation on intraoperative anxiety using the State-Trait Anxiety Inventory-6 (SATI-6) score in patients pre-and post-surgery. The secondary objectives were to determine the effect of music/noise cancellation on patient satisfaction, sedation, communication difficulty and haemodynamic parameters.

METHODS

After receiving approval from the institutional ethics committee and the research review board (vide approval number 122/MC/EC/2020), the study was registered in the Clinical Trials Registry - India (www.ctri.nic.in, vide registration number CTRI/2021/08/035923). This hospital-based, randomised controlled study was carried out according to the principles of the Declaration of Helsinki, 2013. Written informed consent was obtained from patients to participate in the study and use the patient data for research and educational purposes.

The study was conducted on adults of either gender, between the ages of 18 and 50, with American Society of Anesthesiologists physical status I or II, who underwent lower limb surgeries under spinal anaesthesia at a tertiary care hospital between September 2021 and December 2021. The study excluded patients with hearing impairment, mental illness, spinal deformity, pregnant and lactating mothers.

Patients were randomised into three groups: the binaural beat music group, the noise cancellation headphone (Model-JBL Tune 760NC) group and the no headphone group. Randomisation was done using computer-generated random numbers, and patients were allocated to the three groups using a sequentially numbered opaque sealed envelope technique. Each of the 108 chits of the study groups was put into envelopes and sealed. Colleagues who were not engaged in the study helped record the findings [Figure 1].

Figure 1.

Consolidated standards of reporting trials (CONSORT) flow chart of study participants

After a thorough pre-anaesthetic check-up, an electrocardiogram, non-invasive blood pressure and pulse oximetry monitors were attached. Baseline vitals were taken [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) and heart rate]. Also, the baseline STAI-6 scores and the Visual Analogue Score for patient Satisfaction (VAS-S) were recorded at this point. Patients were given spinal block in L3–4 or L4–5 interspaces in the lateral decubitus or sitting position with a dose of 15 mg (3 ml) 0.5% hyperbaric bupivacaine. Patients were then made supine, and a sensory level up to T8 was confirmed, after which these patients received one of the three interventions. For Group A patients, headphones were attached, and music (binaural beats) was started; for Group B, headphones were connected, but no music was played (noise cancellation group); and for Group C patients, no headphones were attached, no music was played. The haemodynamic parameters were noted again at 1, 10, 20, 30, 40, 60 min and every 20 min till the end of surgery. In addition, the Ramsay Sedation Scale score and Likert communication difficulty score were noted intraoperatively at 30 min post-spinal anaesthesia. At the end of the surgery, STAI-6 and VAS-S were noted, and the headphones were cleaned with spirit.

The STAI-6, a Spielberger’s approved instrument, was used to calculate anxiety scores.[6] We employed the abbreviated, validated STAI-6 tool for this study. In STAI-6, there are six questions, each with a Likert scale value ranging from 1 to 4. This gives us a total score between 6 and 24.[7] It was originally available in English but was translated to Hindi since most of our patients were comfortable only in Hindi.

The patient’s satisfaction score was recorded using a 10-point visual analogue scale,[6,8] with 0 being the worst experience possible and ten being the best one possible.

With the help of the Ramsay Sedation Scale, participants’ states of consciousness were evaluated.[9,10] The scale was graded on six elements, with points 1, 2 and 3 denoting a person’s level of wakefulness and 4, 5 and 6 indicating a person’s level of sedation. The first three reactions were tested on awake patients, while the latter three responses were tested with either a glabellar tap or a loud auditory stimulus. A 5-point Likert scale evaluated communication difficulties between the observer and the patient, with a score of 1 corresponding to strong disagreement and five related to strong agreement.[6]

The sample size was determined at 80% research power and 0.05 alpha error, assuming a standard deviation (SD) of 4.8[11] in STAI-6 anxiety levels following the intervention. Results were analysed using the Statistical Package for Social Sciences, version 21 for Windows (SPSS Inc., Chicago, IL, USA). The categorical data were presented as numbers (percentages) and were compared among groups using the Chi-square test. The quantitative data were presented as mean ± SD and were compared by the analysis of variance (ANOVA) test. Probability was considered significant if P value is less than 0.05.

RESULTS

Patient demographic parameters were comparable in all the groups [Table 1]. The preoperative mean STAI-6 score was statistically non-significant among the three groups [Table 2]. Although there was a significant decrease in postoperative anxiety scores in all the groups [Table 2], the values were reduced more in groups A and B than in Group C [Table 3].

Table 1.

Baseline demographic parameters of the patients in the three groups

Characteristics	Group A (n=36)	Group B (n=36)	Group C (n=36)	P
Age (years)	33.53±12.37	34.97±9.88	32.67±11.99	0.744
Gender (Male:Female) (number)	18:18	18:18	18:18	1
SBP (mmHg)	127.72±10.79	128.53±12.31	126.92±13.24	0.853
DBP (mmHg)	82.64±9.34	82.75±7.37	80.94±10.63	0.648
MBP (mmHg)	96.31±8.99	99.44±10.87	95.33±11.27	0.221
HR (beats/min)	88.08±14.79	92.08±13.63	90.06±16.76	0.534

DBP=diastolic blood pressure, HR=heart rate, MBP=mean blood pressure, SBP=systolic blood pressure. Values are represented as mean and standard deviation or numbers

Table 2.

Comparison of anxiety scores and satisfaction scores

	Group A (n=36)	Group B (n=36)	Group C (n=36)	P a
Preoperative STAI-6 score	20.6±2.5 (19.78–21.42)	20.2±2.6 (19.35–21.05)	20.4±2.3 (19.64–21.15)	0.628
Postoperative STAI-6 score	7.8±1.7 (7.25–8.35)	11.7±4.2 (10.32–13.07)	14.7±5.3 (12.97–16.53)	<0.001
P b	<0.001	<0.001	<0.001
Preoperative VAS-S	3.2±1.5 (2.67–3.72)	3.1±1.2 (2.71–3.49)	3.2±0.82 (2.93–3.46)	0.954
Postoperative VAS-S	7.3±1.7 (6.74–7.85)	6.2±1.6 (5.67–6.72)	5.2±1.3 (4.75–5.62)	<0.001
P b	<0.001	<0.001	<0.001

Values are represented as Mean±SD(95% CI). a-P value for comparison between the groups, b-P value for comparison of preoperative and postoperative parameters in a group. CI=Confidence interval, SD=Standard deviation, STAI-6 score=State-Trait Anxiety Inventory Score, VAS-S=Visual Analogue Satisfaction Scale

Table 3.

Intergroup analysis of STAI-6 scores

	Postoperative STAI-6 (n=36), Mean±SD (95% CI)	P
Group A	7.8±1.7 (7.25–8.35)	<0.001
Group B	11.7±4.2 (10.32–13.07)
Group A	7.8±1.7 (7.25–8.35)	<0.001
Group C	14.7±5.3 (12.97–16.53)
Group B	11.7±4.2 (10.32–13.07)	0.009
Group C	14.7±5.3 (12.97–16.53)

Values are represented as Mean±SD (95% CI). CI=confidence interval, SD=standard deviation, STAI-6 score=State-Trait Anxiety Inventory Score

The postoperative patient satisfaction scores for groups A and B were also higher [Table 2]. The VAS-S scores were 7.3 ± 1.7 and 6.2 ± 1.6 in groups A and B, respectively, with statistically significant differences (P = 0.03) compared to Group C (5.2 ± 1.3).

Ramsay sedation score was significantly higher in Group A and Group B compared to Group C [Table 4]. However, when the scores were compared between Group A and Group B, they were statistically non-significant. Comparison of the intraoperative mean Likert communication difficulty score of observers among Group A, Group B and Group C were comparable (P > 0.05) [Table 5].

Table 4.

Comparison of Ramsay sedation scores among the groups

	Group A No.	Group B No.	Group C No.
Score 1	1	0	1
Score 2	6	6	19
Score 3	13	16	14
Score 4	13	8	2
Score 5	3	6	0

Values are represented as numbers

Table 5.

Likert communication difficulty scores

	Group A No.	Group B No.	Group C No.
Score 1	0	0	0
Score 2	2	1	1
Score 3	12	8	6
Score 4	2	25	27
Score 5	0	2	2

Values are represented as numbers

A fall in SBP in Group A was significant on a few occasions compared to Groups B and C. However, no effect was seen on other haemodynamic parameters such as diastolic blood pressure, mean blood pressure or oxygen saturation [Figure 2].

Figure 2.

Haemodynamic parameters in groups. X axis is time interval (minutes), Y axis is Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) in mm of Hg. Unit – mm of Hg, Colour Coding- Navy blue- Group A SBP, Grey - Group B SBP, Sky blue - Group C SBP, Orange Group A DBP, Yellow- Group B DBP, Green - Group C DBP

DISCUSSION

Our study found that the STAI-6 anxiety score was better with binaural beat music (Group A) or noise cancellation headphones (Group B) compared to no music or noise cancellation. Furthermore, when intergroup comparison was made, we found that the STAI-6 score was significantly better in Group A than in Group B.

The effectiveness of intraoperative music therapy and noise-cancelling headphones is demonstrated in our results, which align with those of other studies.[2,5,12] Our results were similar to those of Wiwatwongwana et al.[11] Kukreja et al.[13] also found that the anxiety score was better in the music group compared to the no music group in patients undergoing surgeries, while Gupta et al.[12] concluded that music did not reduce anxiety, pain and disruptive behaviour. The conflict in the results might be due to the paediatric age group selection in the study of Gupta et al.[12]

VAS-S score was better in groups A and B than in Group C. Graff et al.[6] obtained similar results when using this scale to compare patient satisfaction with music or midazolam during preoperative block placement. In the study of Allred et al.,[14] music therapy under spinal anaesthesia resulted in a statistically significant decrease in anxiety levels and the need for sedation and improvement in patient satisfaction scores.

Also, we deduced that, compared to the control group, music is beneficial in lowering SBP during and after surgery [Figure 2]. Similar results were reported by Bansal et al.[2] and Hassan et al.[15] In our study, music had no measurable impact on other haemodynamic variables, including heart rate, diastolic blood pressure and mean blood pressure. Sarkar et al.[16] found no correlation between listening to music and variations in systolic, diastolic or respiratory rates. We attribute the lowering of SBP to lower anxiety levels in the study groups.

The present study found that Ramsay’s sedation score was significantly higher in the music and noise cancellation groups compared to the no headphones group. Communication difficulty was more in patients of group A and group B compared to group C. This may be because the music/noise cancelling headphones obscure the ambient voice.

This study has limitations. The first one is a small sample size. Second, the music presented was the same for all the patients in the music group, instead of being of their choice. The translated STAI-6 score is not a validated tool. However, we included a control group (group C) with no intervention and found gross differences in the scores even in the control group. Last, the quality of the headphones might affect the noise cancellation property, which may alter the results. Further large-scale randomised controlled trials are needed to verify the benefits of music to patients.

CONCLUSION

Music and noise cancellation headphones reduce anxiety and improve satisfaction and sedation scores in patients posted for surgery under spinal anaesthesia. Music also stabilises SBP. However, it does not affect diastolic blood pressure, mean blood pressure and heart rate. In addition, using noise-cancellation headphones with or without music may create difficulty in communication between the physician and the patient.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.