Chronic subjective idiopathic tinnitus (CIST) is the most prevalent type of tinnitus. The main symptom of CIST is the conscious belief of phantom sounds and/or noises inside the ear(s) and/or head in the absence of internally- or externally-induced stimuli that may evoke the repeated occurrences of these sounds/noises. In most patients with CIST, symptoms typically last > 12-36 weeks. Therefore, CIST is usually reported as chronic tinnitus [1].

In the absence of objectively reported causes, only patients with CIST experience this tinnitus. The physician, relatives, or others cannot hear this type of tinnitus. Hence, CIST is termed subjective idiopathic tinnitus [2]. CIST affects 15% of the adult population worldwide [3].

The prevalence of CIST is reportedly higher among individuals with obesity than among those with normal weight. A body mass index (BMI) > 30 kg/m² has been recognized as a causal factor for tinnitus [4]. Furthermore, apart from being novel risk parameters for tinnitus [5], distributed lipid metabolism and obesity-induced hyperlipidemia [6,7] have been reported in 5.1% of patients with tinnitus [6].

Individuals with tinnitus have higher blood lipid levels than their age- and sex-matched healthy counterparts. Accumulated lipids in the end arteries in the ear, accelerated local oxidative damage, documented within-ear atherosclerotic changes, constriction of blood vessels in the ear, reduced or compromised cochlear blood supply, probable chronic hypoxia, and impaired cochlear metabolism are the potential causes or mechanisms of hyperlipidemia-induced subjective tinnitus [5].

Therefore, unsurprisingly, patients with CIST frequently experience discomfort, sadness, and overall disappointment with medical therapeutic options, given the inefficacy of multiple accessible pharmaceutical therapies and the uncertainty of objective causation for this type of tinnitus [8].

Acupuncture, a traditional Chinese medicinal modality [9], has long been used as a complementary treatment for tinnitus [10] and dyslipidemia [11-15]; however, studies investigating changes in lipid profile and tinnitus-related quality of life responses to acupuncture therapy (AT) among obese patients with CIST are lacking.

The aim of this trial is to determine whether AT effects changes in triglycerides (TG_s), low-density lipoproteins (LDL_s), high-density lipoproteins (HDL_s), cholesterol (C), and tinnitus handicap inventory (THI; a validated measurement tool to assess tinnitus-related quality of life) among obese patients with CIST.

1. Ethical approval

This trial conformed to the Helsinki declaration. All patients provided consent, and institutional board provided approval (The Research Ethics Board, Physiotherapy Faculty, Cairo University, approval number P.T.REC/012/003525). The trial is registered with the national trial registry (NCT05188365).

2. Study design and blinding

This randomized controlled trial enrolled participants prospectively and all procedures were singly blinded. The medical analysis specialist assessing the lipid profile of the participants was blind to the nature or type of AT the patient was allocated to.

3. Trial setting

Patients with tinnitus were recruited using posters affixed on the walls of the outpatient clinic for ear, nose, and throat diseases (MeetGhamr General Hospital). At a physiotherapy center, AT was administered to obese participants with CIST from December 6, 2021, to April 30, 2022.

4. Inclusion criteria

Obese (BMI > 30 kg/m²) patients with CIST (i.e., > 6 months) were included. Besides the exclusion of pregnant/lactating women with tinnitus, active smokers and/or alcohol consumers, those with psychiatric ailments, those with glucose homeostasis disorders, ear pathologies, cardiovascular or systemic conditions, hearing loss, rheumatologic pathologies, local neurological dysfunctions, and autoimmune diseases were excluded. Participants with tinnitus who followed a diet or exercise recommendations, pharmacologic prescriptions for weight loss and/or tinnitus, and complementary medicines were also excluded.

5. Randomization

Patients were randomized using the concealed envelope allocation technique. Randomization was executed by a female physiotherapy assistant (FPTa) who was not made aware of the design, aims, steps, and outcomes of this AT trial. Given the allocation ratio of 1:1, the FPTa was asked to randomly assign the names of obese patients with CIST to one of the treatment groups, labeling them as group A or B. Each group included 30 patients. After allocation, the FPTa sealed the envelopes. Before starting the first AT session in both groups, another FPTa who was not a part of the study opened the sealed envelopes to determine the identify the patient allocation.

6. AT protocol in this trial

Group A participants underwent an 8-week AT program that was executed thrice weekly. According to the 3 previously published studies [2,11,13], the following acupoints were selected to be punctured unilaterally on the ipsilateral side of the tinnitus in patients with unilateral tinnitus or bilaterally in participants with bilateral tinnitus: TE3, TE5, TE17, TE18, TE19, TE20, TE21, TE22, GB2, GB8, GB20, LI4, LI11, KI3, SP6, and ST36. Two additional acupoints, ST25 and GB28, located on the abdominal area were punctured bilaterally for both patients with unilateral or bilateral tinnitus. Furthermore, 3 additional acupoints, CV4, CV9, and CV12, located on the midline of the abdomen were punctured in obese participants with unilateral or bilateral tinnitus. Manual AT was applied by an acupuncturist with 10 years of experience using 4-cm stainless needles (CE/0197, made in China), who applied acupuncture on all the aforementioned acupoints except for the bilateral ST25 and GB28 acupoints which were stimulated via electroacupuncture therapy.

Among obese patients with CIST who completed this AT trial, the average needle penetration depth was 5-10 mm, and it varied for each patient given anatomic differences at the acupoints. The penetrating needles were left in place until the participants attained the De-qi sensation, which was reported as heaviness around the penetrated acupoints. After the participants reported attaining the De-qi sensation, the needles were left in place for 20 minutes and then removed.

For the bilateral ST25 and GB28 acupoints, after the confirmation of De-qi sensation by all participants with CIST, 4 electric wires were used to connect the needles inserted in these acupoints to a Ying-Lee AT device (KWD808 electrical stimulator). The parameters of the electrical current used were as follows: 30-40 Hz, dense/dispersed wave, 390-microsecond pulse duration, square pulse, and maximum bearable intensity (highest intensity that did not evoke pain). After a 20-minute electro-acupuncture, the device and needles were withdrawn.

Participants in group B received sham acupuncture needle insertion (CE/0197, made in China; 0.3 cm lateral to the actual locations of the selected acupoints for CV4, CV9, and CV12. For the other selected acupoints, TE3, TE5, TE17, TE18, TE19, TE20, TE21, TE22, GB2, GB8, GB20, LI4, LI11, KI3, SP6, and ST36, the needles were inserted 0.5 cm above and lateral to the actual anatomic location. In addition, for the bilateral ST25 and GB28 acupoints, the wires used to connect the inserted needles to the Ying-Lee AT device, KWD808 electrical stimulator, were disconnected. For all punctured acupoints in group B, the needles were inserted as superficially as feasible thrice weekly. The needles were left in the participant’s skin for 20 minutes and then removed.

Participants in both groups were informed of the fixed-timed schedule of their AT plan. This plan was devisesd to treat each participant independently at various times to avoid the circulation and transfer of experiences gained from implementing the AT program.

7. Outcome measures

The THI is a 25-item questionnaire that estimates the quality of life of patients with tinnitus. It was the main outcome measure in this trial. For every item in this questionnaire, a score of 4 is awarded for the response “yes”, 2 for the response “sometimes”, and zero for the response “no”. A decrease in the total THI score after therapy was considered an improvement in tinnitus-related quality of life [16,17].

Furthermore, the perceived severity of tinnitus was subjectively measured using the visual analogue scale (VAS). The author would draw a 10-cm horizontal line on a blank white sheet; the right end represented “no tinnitus”, and the left end represented “highest tinnitus severity”. A decrease in VAS score after the 8-week AT was considered an improvement in the perceived severity of tinnitus.

Finally, besides the measurements of BMI and waist circumference (WC), serum lipid levels (LDL_s, TG_s, HDL_s, and C) were measured in participants of both groups.

8. Sample size calculation

The maximum allowable type I and type II error probabilities of 5% and 80%, respectively, were set for the primary outcome, THI, on the statistical software G*Power. An estimated effect size of 0.73 achieved with 16 participants alarmed the author for the need for 24 patients in every group. The author further increased the number of participants required to 30 patients in every group to account for patient dropout, which was estimated at 20%.

9. Statistical analysis of this AT trial

The Smirnov test in SPSS (version 18) confirmed a normal distribution of the obtained data. Hence, unpaired and paired t tests were used. Intra-group comparisons were performed using the paired t test, and between-group comparisons were performed using the unpaired t test. A p < 0.05 was considered statistically significant.

Sixty patients were randomized to one of the 2 treatment groups: group A (real AT group; n = 30 [18 women and 12 men]) or group B (sham AT group; n = 30 [21 women and 9 men]). No participant dropped out of the study (Fig. 1).

Figure 1. Consort flow chart of the obese tinnitus participants.

1. Participant demographics

The mean ± standard deviation (SD) participant age was 44.81 ± 3.70 years. Before the intervention, no differences were observed in the groups regarding the duration of tinnitus, laterality (right, left, or bilateral), or demographic data (age, WC, and BMI of obese patients with tinnitus), as described in Table 1.

Age, tinnitus duration, body mass index, and waist circumference are expressed as Mean ± standard deviation; *The represented p-value of this table is > 0.05 so it is non-significant..

&md=tbl&idx=1' data-target="#file-modal"">Table 1

The based data of obese groups with tinnitus.

Data	Group A (n = 30)	Group B (n = 30)	p-value*
Age (year)	44.10 ± 3.69	45.53 ± 3.62	0.135
Tinnitus duration (year)	4.28 ± 0.91	4.48 ± 0.94	0.405
Body mass index (kg/m2)	33.82 ± 2.51	33.78 ± 3.32	0.958
Waist circumference (cm)	112.66 ± 17.37	110.33 ± 20.10	0.632
Tinnitus-side (right/left/bilateral) frequencies	8/16/6	10/13/7

Age, tinnitus duration, body mass index, and waist circumference are expressed as Mean ± standard deviation; *The represented p-value of this table is > 0.05 so it is non-significant..

2. THI scores

The THI score did not differ between the groups before treatment (group A: 50.60 ± 18.24; group B: 53.53 ± 16.58; p > 0.05). The paired t test showed significant inter-group improvements in the THI score post treatment for both groups (50.60 ± 18.24 vs. 38.73 ± 17.87, p < 0.001). The unpaired t test after completion of the scheduled acupuncture interventions in both groups showed significantly greater improvements in THI scores in group A (Table 2).

Group A = real acupuncture-therapy group; Group B = sham acupuncture-therapy group; TG_s = triglycerides; *When this symbol marks any p-value in this table, it means that this p-value is < 0.05 so it is significant; BMI = body mass index; LDL_s = low density lipoproteins; THI = tinnitus handicap inventory; WC = waist circumference; C = cholesterol; VAS = visual analogue scale; HDL_s = high-density lipoproteins. In this obesity-induced tinnitus study, paired and unpaired t tests was used to analyze the results within and between acupuncture groups, respectively..

&md=tbl&idx=2' data-target="#file-modal"">Table 2

Outcomes of obese tinnitus groups (the table’s data are expressed as mean ± standard deviation).

Anthropometry, lipids, and tinnitus parameters	Group A	Group B	p-value (between group A and B)
THI
Pre	50.60 ± 18.24	53.53 ± 16.58	0.517
Post	38.73 ± 17.87	52.90 ± 16.17	0.002*
p-value (within tinnitus groups)	< 0.001*	0.089
BMI (kg/m2)
Pre	33.82 ± 2.51	33.78 ± 3.32	0.958
Post	32.75 ± 2.49	33.75 ± 3.29	0.189
p-value (within tinnitus groups)	< 0.001*	0.580
WC (cm)
Pre	112.66 ± 17.37	110.33 ± 20.10	0.632
Post	109.66 ± 17.80	109.83 ± 19.60	0.972
p-value (within tinnitus groups)	< 0.001*	0.184
C (mg/dl)
Pre	199.43 ± 41.07	201.30 ± 39.45	0.857
Post	155.20 ± 35.27	200 ± 38.77	0.0001*
p-value (within tinnitus groups)	< 0.001*	0.091
TGs (mg/dl)
Pre	176.53 ± 87.70	179.86 ± 88.63	0.884
Post	139.53 ± 58.38	178.49 ± 87.11	0.046*
p-value (within tinnitus groups)	< 0.001*	0.215
LDLs (mg/dl)
Pre	114.58 ± 37.13	117.75 ± 36.74	0.740
Post	80.76 ± 13.16	115.80 ± 34.73	0.0001*
p-value (within tinnitus groups)	< 0.001*	0.083
HDLs (mg/dl)
Pre	50.75 ± 11.17	49.35 ± 10.56	0.619
Post	52.64 ± 9.80	49.46 ± 10.56	0.231
p-value (within tinnitus groups)	0.044*	0.437
VAS
Pre	6.04 ± 2.39	5.61 ± 2.56	0.503
Post	2.65 ± 1.91	5.31 ± 2.47	0.0001*
p-value (within tinnitus groups)	< 0.001*	0.184

Group A = real acupuncture-therapy group; Group B = sham acupuncture-therapy group; TG_s = triglycerides; *When this symbol marks any p-value in this table, it means that this p-value is < 0.05 so it is significant; BMI = body mass index; LDL_s = low density lipoproteins; THI = tinnitus handicap inventory; WC = waist circumference; C = cholesterol; VAS = visual analogue scale; HDL_s = high-density lipoproteins. In this obesity-induced tinnitus study, paired and unpaired t tests was used to analyze the results within and between acupuncture groups, respectively..

3. Secondary outcome measures

The unpaired t test showed no significant differences between groups in TG_s, C, HDL_s, LDL_s, and VAS scores before AT (p > 0.05), as summarized in Table 2.

The paired t test showed significant improvements in BMI, WC, TG_s, C, HDL_s, LDL_s, and VAS scores in group A after AT (p <0.05). However, the differences were not significant in group B (p > 0.05; Table 2).

Between-group comparisons showed significantly greater improvements in LDL_s, TG_s, C, and VAS score in group A (Table 2). However, the difference was not significant for HDL_s, BMI, and WC.

4. Safety profile

No adverse outcomes were reported in either group during or after the trial.

A recent study from Turkey published in 2021 reported higher blood lipid levels in patients with tinnitus than in age- and sex-matched healthy counterparts [5]. Higher blood lipid levels are associated with obesity. Obesity is the primary risk factor for body/abdominal fat accumulation and aggravated tinnitus symptoms in patients with CIST. Although weight loss programs such as diet restriction and/or increased energy expenditure programs have been shown to resolve tinnitus symptoms and reduce general or local fat accumulation in patients with tinnitus with a BMI > 30 kg/m² [18], patient compliance to these types of programs is inadequate [19]. Acupuncture is an anti-hyperlipidemic, safe, effortless, and effective weight-loss option that can replace the traditional diet and/or exercise programs [20].

The mechanism of AT-induced weight loss has not yet been fully explained. A hypothesis is that the stimulation of peripheral nerves around the punctured acupoints carries a torrent of electrical signals to modulate and/or control mood and satiety of the patient with obesity [21]. In humans, electroacupuncture may relax the sphincter of Oddi (SoD). Electroacupuncture-induced relaxation of SoD can increase the sensation of satiety and hence decrease the frequency of binge eating [20].

Acupuncture-induced release of neurotransmitters such as serotonin and endorphins is a hallmark of AT, particularly in the absence of accompanying treatments such as exercise and/or diet restriction programs [22-24]. The release of these neurotransmitters reduces the reported stress, depression, and hunger [11]. Experimental studies have supported the efficacy of AT in reducing hunger in obese rats as a result of AT-induced increase in electrical signals that inhibit the feeding-regulation center or stimulate the satiety-regulation center in the hypothalamus [23-26].

A significant decrease in the WC of obese patients in this study is associated with the application of electroacupuncture proximal to the most common site of local fat accumulation, the abdomen. The documented strong lipolytic activity of electroacupuncture and electroacupuncture-induced destruction and/or redistribution of local abdominal fats could explain the WC decrease observed in this trial [27].

With regard to decreased tinnitus severity perception after AT application, besides the gained control and/or modulation of tinnitus-associated depression and emotional distress via AT-induced stimulation of the limbic system, AT-induced activation of the olivocochlear system that regulates and/or controls the perception of loud noises in tinnitus population could be responsible for the achieved improvement. AT-associated increase in the excretion of opioids, decrease in perceived tinnitus-associated local pericranial muscular tenderness and/or tension, increase in blood flow to the ear region associated with ear dysfunctions/pathologies, and increase in pain tolerance are the mechanisms suggested to explain the role of acupuncture in reducing tinnitus perception, sleeping difficulties, and other factors decreasing tinnitus-related quality of life [2,28].

The combined needling of local and peripheral acupoints in this study likely effected the significant improvement in the outcome measures(VAS and THI). The following 3 hypothesized mechanisms could explain the role of this combined needling in effecting the improvements. The first hypothesis is that the combined application of acupuncture on local acupoints located around the ear(s) and peripheral acupoints located in the upper/lower limbs and scalp enhances the AT-effected resolution of tinnitus [29]. The second hypothesis is that the stimulation of the gall bladder and kidney meridians by AT corrects the qi imbalance of the meridians around the ears [30]. The third hypothesis suggests that acupuncture at the ST36 acupoint is able to correct the tinnitus-related imbalance of the autonomic nervous system [2].

Supporting the results of this study, the study by Hsu et al. (2005) [27] also reported that the combined application of manual AT and abdominal electroacupuncture for 6 weeks in obese patients significantly decreases their WC and BMI. Furthermore, the study by Lee et al. (2006) [31], reported that a 3-week 10-session abdominal electroacupuncture application significantly decreased the WC and BMI of women with obesity Another study reported significant decreases in WC and BMI among women with abdominal obesity receiving 5-week electroacupuncture on real acupoints compared to the women who received electroacupuncture on fake acupoints [32].

Another study wherein Egyptian women with hyperlipidemia underwent 6-week electroacupuncture at the acupoints LR14, LR3, ST36, GB34 showed significant improvements in C, TG_s, and LDL_s levels among women who received the therapy at the real acupoints compared to those who did on fake acupoints [15].

The studies by Draz et al. [14] and Taha et al. [15] showed that patients with fatty liver who received electroacupuncture at LR14, LR3, ST36, and GB34 acupoints had a significant decrease in TG_s levels. Another study conducted in 2018 reported that 8-week electroacupuncture treatment in obese patients’ bilateral ST25 and GB28 acupoints significantly decreased their blood lipid levels [13]. Furthermore, another study applying 2 courses of daily 30-minute electroacupuncture therapy which were separated with a 2-day rest period showed a decrease in blood lipid levels among patients with simple obesity [33].

Another study that administered a 6-week electroacupuncture regimen at bilateral ST25 and GB28 acupoints along with manual acupuncture of other selected acupoints such as CV4, CV6, CV9, CV12, CV6, CV11, ST40, and SP9 supports our results by reporting significant improvements in WC, BMI, and lipid levels in patients with obesity. However, contrary to the results of this study, significant improvement in the blood lipid profile was seen even in the sham needle insertion group in this study. This difference could be explained by patient adherence to a hypocaloric diet [11].

Another Egyptian study that included obese patients who received manual acupuncture and were on a hypocaloric diet for 3-6 months reported significant improvements only in TG_s and C levels, as seen in this study, but not in HDL_s and LDL_s levels. This difference could be attributed to differences in factors such as age, ethnicity, pubertal phase, severity of adiposity, and distribution of fat mass [22]. Another study that applied 20-day auricular and body electroacupuncture in obese women reported significant improvement in their weight and lipid levels (except for HDL_s) [34].

We observed significant improvements in THI scores and the perceived severity of tinnitus (assessed using VAS). Another study conducted in 2016 applied 40-minute electroacupuncture bilaterally on the scalp in patients with tinnitus for 5 weeks. This study reported significant improvements in both THI score and perceived tinnitus severity [35].

Another recent study conducted in 2020 that compared the THI and VAS outcomes with a 5-week manual acupuncture treatment between patients receiving real and sham acupuncture showed similar results, with significant improvements in THI and VAS scores observed in the real treatment group [36]. Similarly, Harry et al. [37] reported a significant decrease in THI of 16 patients with manual acupuncture. Their results are in line with those of our study.

The results of 2 studies published in 2016 [38] and 2012 [39] that compared real and sham application of long-term manual acupuncture on tinnitus-related acupoints reported significant improvements in THI in the real treatment group and hence provide further support to our results.

In this study, we applied acupuncture to the most possible acupoints around the ear and the body overall. Our application pattern is supported by a recent study that recommended stimulating the largest possible number of acupoints around the ear or in various parts of the body to achieve the desired outcome from the application of AT in patients with tinnitus [40].

Kim et al. [29] offered a 4-week AT program to patients with tinnitus and reported contradictory results to those of our study. In their study, the patients were administered one of the 3 AT protocols, and patient assignment was not blinded. The first protocol applied manual acupuncture on some selected periauricular (TE17, TE21, SI19, GB2, and GB8), upper-limb (TE3 and TE9), and lower-limb acupoints (ST36 and ST37). The second protocol used an electroacupuncture program on the periauricular acupoints TE17 and TE21 only. The third protocol used an electroacupuncture program on the same upper-limb and lower-limb acupoints considered in the first protocol. The open-labeled assignment of the treatment protocol could have resulted in the non-significant effect observed. Familiarizing the patients with the positive effects of acupuncture on most diseases (including tinnitus) experienced by Korean patients could have yielded significant improvements.

1. Limitations and future direction

In this trial, we did not add a diet and/or exercise program to achieve greater improvements in weight loss, blood lipid levels, and tinnitus outcomes. Future studies should consider including a diet or exercise regiment to explore the combined effect of acupuncture and such regimens on CIST treatment.

Acupuncture yielded significant improvements in BMI, tinnitus-related quality of life, and WC in obese patients with CIST. Furthermore, it is a safe treatment option in such patients.

If there is a scientific justified request to convince the corresponding author to share the data of this tinnitus research, data will be sent via electronic mail.

No acknowledgments.

No funding.

Conceptualization of this acupuncture trial, Ali Mohamed Ali Ismail; Data curation, Ali Mohamed Ali Ismail; Formal analysis, Ali Mohamed Ali Ismail; Funding acquisition, Ali Mohamed Ali Ismail; Investigation, Ali Mohamed Ali Ismail; Methodology, Ali Mohamed Ali Ismail; Resources, Ali Mohamed Ali Ismail; Supervision, Ali Mohamed Ali Ismail; Visualization, Ali Mohamed Ali Ismail; Writing – original draft, Ali Mohamed Ali Ismail; Writing, review and editing of this acupuncture trial, Ali Mohamed Ali Ismail.

The authors declare no conflict of interest.