“Miracle” or “Medicine”: A Turning-Point Analysis of Patients' and Physicians' Shifting Views on Acupuncture

Abstract

Objective: Acupuncture is one of the most widely used treatments of complementary and alternative medicine (CAM) within the military's health system. The success of CAM integration is partially dependent on both providers' and patients' perceptions that acupuncture is health-promoting. The aim of this research was to identify turning points, or changes, across treatments that enhanced or inhibited physicians' and patients' perception of acupuncture as health-promoting.

Materials and Methods: Using a retrospective-interview approach, interviews were conducted with 15 family medicine physicians practicing medical acupuncture in a family medicine setting and with 17 patients (N = 32). Turning points were separated into 2 groups (health-promoting or health-inhibiting). Similarities and differences between perspectives were noted.

Results: Patients and physicians identified two changes that enhanced their perspective of acupuncture as health-promoting: (1) observed health changes and (2) pain-medicine/narcotic reduction/elimination. Patients identified their ability to fulfill personal or professional roles, whereas physicians identified (1) training experiences and (2) enhanced relationships with patients. Health-inhibiting changes in perspective were identified as logistical constraints/barriers by both parties, although their perspectives differed to some degree. Turning points that were viewed as health-inhibiting treatment were identified as clinical challenges by physicians and as a lack of consistency in care by patients.

Conclusions: The insight from these findings can help identify areas where medical acupuncture can be improved to promote successful integration in conventional medicine settings, as well as how providers can tailor communication with patients about acupuncture.

Introduction

Complementary and alternative medicine (CAM) use is expanding. The military health system (MHS) has been a forerunner in integrating CAM in conventional-medicine settings. In the last decade, MHS providers have notably increased CAM services,¹ and the rate of patients utilizing CAM has doubled between 2010 and 2016.² More than 83% of military treatment facilities (MTFs) provide at least 1 CAM service (treating 76,000 patients per month), often for conditions that cannot be managed with conventional medicine, according to a 2017 system-wide review of MTFs.³

Acupuncture (both Traditional Eastern Medicine acupuncture and Westernized or medical acupuncture) is one of the most widely used CAM treatments within the MHS as well as across the United States, helping improve quality of life for patients facing chronic or acute mental and physical ailments.⁴ For example, acupuncture clinical trials have shown success in managing or reducing symptoms associated with fibromyalgia,⁵ anxiety/depression,⁶ endometriosis,⁷ and chronic obstructive pulmonary disease (COPD).⁸ Additionally, acupuncture is widely used to treat chronic/acute pain, including during intra- and postoperative periods,^9–11 pregnancy-associated low-back and pelvic pain,¹² headache/migraines,¹³ acute pain in emergency departments,¹⁴ and sore-throat pain.¹⁵

The success acupuncture has shown in improving health, as well as this modality's cost-effectiveness^16,17 and low risks, compared to conventional therapies such as narcotics,¹⁸ has increased health researchers'/professionals' support of integration into conventional medical settings. The National Institutes of Health (NIH) acknowledged the value of acupuncture at the first Consensus Development Conference on Acupuncture, and stated that “there is sufficient evidence of acupuncture's value to expand its use into conventional medicine and to encourage further studies of its physiological and clinical value.”¹⁹ Despite the notable success of acupuncture integration within the MHS, integrating CAM remains a challenge. Studies examining patients' inclinations to try the treatment are minimal. Research focused on changes or turning points experienced by patients and physicians across treatment that impact perception of acupuncture's health-related effects—a perception that ultimately influences treatment adherence and practitioners' ongoing integration—is even more limited.²⁰

To identify these turning points better, an acupuncture integration program within the MHS was focused on, given its history of success with integrating CAM in conventional-medicine settings. The goal was to identify factors in the program (that began in 2015 and was integrated into family medicine physicians' clinical practices) that present themselves early and could enhance or inhibit long-term acupuncture integration.

Patients' CAM Adherence in Integrative Medicine

The shift in conventional medicine from outright hostility to embracing CAM integration has slightly impacted perceptions, but the challenge of convincing patients to adopt the treatment and getting physicians to integrate it still exist.^21,22 While patients' adherence to varied treatments in conventional medicine have been examined,²³ adherence to CAM therapies has received minimal attention. A majority of research has focused on the willingness of patients to try CAM (uptake) instead of examining ongoing adherence by patients²⁴ or what affects the willingness of physicians to sustain the practice. The most insight on CAM adherence in conventional-medicine settings was provided in 2 systematic reviews.^25,26

A 2017 systematic review of 18 qualitative studies based on providers integrating acupuncture emphasized the importance of avoiding adverse effects and valuing the holistic approach. Additionally, a lack of knowledge or institutional support were factors that also inhibited integration.²⁵ Similarly, a 2018 systematic review that included reports from both patients and providers indicated that positive attitudes about CAM and their physicians, costs, beliefs in holistic medicine, and efforts to see therapist all impacted patients' adherence.²⁶ This review highlighted the importance of patients' perception that the treatment was working (efficacy), which has been identified as a critical factor in patients' willingness to try acupuncture.²⁰

Patient–Physician Interaction and Acupuncture Efficacy Success

Despite the limited number of studies citing what impacts patients' (or providers') perspective that acupuncture is working, research does suggest that patient–provider communication about treatment efficacy (that it is health-promoting) is vital to adherence. For example, one study showed a link between patients' perception of the treatment working (i.e., effectiveness) and when treatment efficacy is talked about.²⁰ Another study demonstrated that better health outcomes, and patient treatment satisfaction, were associated with providers who communicated their optimism about treatment effectiveness to patients.²⁷

At the 2007 Society of Acupuncture Research Symposium, researchers/clinicians noted the important role of provider–patient interaction in acupuncture success and expressed a need for more research. Qualitative scholarship has been advocated by researchers, as this methodological approach can help bring the voices of both providers and patients to the forefront, and highlight contextual nuances specific to acupuncture.^19,28,29 Additionally, researchers have advocated collaboration between clinicians and communication scientists to capture how physicians should tailor communication with patients.³⁰

Research Focus: Turning Points and Perceptions of Acupuncture Efficacy

The success of medical acupuncture integration is dependent upon both parties perceiving it as health-promoting. Therefore, the current authors sought to extract those turning points that impact patients' and physicians' perceptions of acupuncture efficacy (or why it is perceived as health-promoting versus inhibiting) to identify issues better that providers (and medical trainers) should be conscious of when communicating in order to promote treatment engagement. Given that studies typically do not focus on experiences across treatment or capture a dyadic perspective, the current authors utilized a turning-point approach to recognize that experiences might differ for patients in comparison to physicians.³ⁱ Turning-point analysis is frequently used to study relational communication changes or relational development in the communication studies field.^32,33 This method is also viable to capture transformations or turning points across time (including across treatments) that impact one's health or illness.^34–37

Using a turning-point approach, the following inquiry was posed: What turning points do patients and physicians encounter across treatment that enhance or inhibit their perspective of medical acupuncture as a health-promoting treatment?

Materials and Methods

Upon institutional review board approval, individual, semistructured, indepth interviews were conducted with family medicine physicians and patients at a U.S. military medical center. Interviews were conducted over several on-site visits by 2 of the current authors. Interviews were conducted in a private clinic room to decrease burden and lasted about 60 minutes.

Participant Recruitment

Research coordinators recruited patients and physicians from a U.S. military medical center providing acute/emergency care to more than 50,000 patients. Interviews were conducted with 15 family medicine physicians and 17 patients (N = 32). Department of Defense beneficiaries, ages 18 and older, who had received acupuncture treatment, and acupuncture providers were eligible to participate. All eligible patients received a recruitment letter during their clinic visits to see their primary care manager. The primary care team gave patients a recruitment letter that detailed the study and provided an area to enter their contact information. The primary care manager identified potential patients and provided them with the contact information of the research team, or provided the research team with the patients' information (patient-provided oral or written approval), or brought a member of the research team to speak with the patients directly. Members of the research team recruited any patient under the care of a participating physician directly in order to prevent any misconception of coercion or undue influence.

Family medicine physicians were recruited during a clinic meeting. Afterward those who were interested volunteered to participate by speaking with a member of the research team.

Physicians had completed a 300-hour medical acupuncture course using Acus™ methods, and patients had received acupuncture within the previous 6 months. Tables 1 and 2 report these demographics.

Table 1.

Physician Demographics (n = 15)

Demographic characteristics	Statistics
Gender
Female	3 (20%)
Male	12 (80%)
Years practicing medicine	Mean: 3.73 (SD: 1.94)
Years practicing medical acupuncture	Mean: 2.00 (SD: 1.31)

SD, standard deviation.

Table 2.

Patient Demographics (n = 17)

Demographic characteristics	Statistics
Age in years
Gender:	Mean: 52.18 (SD: 13.93)
Female	10 (58.8%)
Male	7 (41.2%)
# of acupuncture treatments received:
Low utilizer (up to 5 treatments)	4 (23.5%)
Medium utilizer (6–20 treatmnets)	9 (52.9%)
High utilizer (more than 20 treatments)	4 (23.5%)
Primary reason for receiving acupuncture treatmenta
Chronic painb	8 (47.1%)
Musculoskeletal injury or pain	5 (29.4%)
Stress/anxiety	4 (23.5%)

^aList indicates primary reason for receiving acupuncture. Multiple patients reported receiving acupuncture for more than one reason.

^bIncludes persistent migraine.

SD, standard deviation.

Data Collection

A retrospective interview technique with a turning-point graph was used to capture turning points that inhibited or enhanced perspectives of acupuncture as a health-promoting treatment. Time was represented on the horizontal axis and perception of health promotion on the vertical axis using a 0–5 point scale (with 5 as the highest health rating). Prior to treatment, patients rated their levels of health and then plotted any changes in health attributed to acupuncture up to the present day. Physicians plotted turning points that changed their perspectives of acupuncture as a viable treatment, both the “good” and the “bad” across training and as they integrated it into practice. Graphs were used to navigate discussions.

Data Analysis

Using a constant-comparative method,³⁸ a thematic analysis was conducted using the interview transcripts (812 pages).³⁹ Two coders were trained by the team's qualitative expert to analyze data separately, keeping the groups separate for comparison. Analyses were compared and collapsed in the development of a final set of themes (turning points). A thematic-saturation decision criterion of 50% (in each group) was used to identify turning points.

Results

Turning points were grouped as either health-promoting or health-inhibiting with similarities and differences between perspectives noted to identify unique experiences better that would allow for these findings to be used in tailoring patient–provider communication and medical education.

Health-Promoting Turning Points

Five themes were identified as health-promoting turning points. Patients and physicians identified (1) observed health changes and (2) pain-medicine/narcotic-reduction/elimination as changes that enhanced their perspectives. Physicians also identified (1) training experiences and (2) enhanced relationships with patients, whereas patients identified their (3) ability to fulfill personal or professional roles.

Shared Perspectives on Health-Promoting Aspects

Theme 1: Observed health changes

Patients and physicians reported experiencing/observing physical and psychologic health turning points (e.g., less pain, more mobility, less fatigue, enhanced mood). Patients noted immediate changes, as the following patient recalled:

The pain relief is unbelievable…so much swelling. … The day I had acupuncture, that night I was feeling it. … Immediately I felt better. The next morning, I woke up and my swelling was, like 80 % reduced. … [6]

Patients emphasized that the health changes experienced were life-changing, giving the patients “normal” lives again:

I walked in here with a cane. When I walked out of here I was looking for a garbage can to put that cane in. … [My doctor] had me walk down the hall. I did it without a cane. … You can be normal. [9]

Physicians also observed immediate physical and mental effects and changes over time: “You can see a difference at least right when people leave and then when you follow-up with them” [7]. This enhanced physicians' belief in acupuncture, motivating them to continue integrating the treatment:

I do see my patients differently now. … [With conventional medicine], they're still in pain. … I do acupuncture and lo and behold, whoa! They're actually feeling better now, and they're getting off their medications, and they're able to go back to physical activity again. To me that's just like, wow!, I can offer something to my patients that other doctors can't. [13]

[The] peace they feel after one of our powerful chill-out kind of treatment, it's pretty profound. It's like a different person entering the room. … When you look at how many man-hours that are lost to sickness,… it's vastly, vastly cheaper and [a] more-efficient and better use of resources to enter into acupuncture. … Not just pain, but like PTSD in the military. … It's absolutely critical that you have something like that available. … Down the road, it's going to be a lot worse. … you may be dealing with suicides. [11]

Theme 2: Pain medicine/narcotic reduction/elimination

Participants reported medication reduction/elimination as a turning point central to adherence:

Right away, there was no pain. Since the first treatment I had, I have never gone back on the meds. I have never had another cortisone shot, and I didn't have an operation. It's amazing. I was in constant pain before I came. [14]

Patients felt that they could not function “normally” on narcotics. Physicians were struck by how acupuncture could allow patients to eliminate narcotics completely—a long-term benefit:

I haven't written for any narcotics in probably a year. … I'm not using narcotics anymore in this setting. That's one benefit: I can get patients back to work, off the medications. So no lost manpower, man-hours, and the patients aren't altered at all. [9]

Different Perspectives on Health-Promoting Aspects

Theme 3: Physician perspective—training experiences

Physicians reported training experiences shifting previous skeptical perspectives such as observing mentors' practice, reading studies, and advancing individual practice during training. Multiple physicians described previous perspectives of acupuncture as voodoo, witchcraft, hippie stuff, and quackery. Training shifted their perspectives to viewing acupuncture as an efficacious practice. A physician described this while shadowing a mentor:

[Had a] Navy guy…hunched over…complete flat-out back, just really depressed. By the time he left, he was able to roll his shoulders back. … It was wild!. … This is what every physician would be frustrated with…opioid medication [with] side-effects…constipation, depression. … He was stuck in this vicious cycle. … We treated him one time with acupuncture, and he walked out with a smile. His dad was crying. It was really cool. [6]

Theme 4: Provider perspective—enhanced relationship with patients

Physicians described relational changes with patients. Acupuncture provided these physicians with another option when conventional medicine failed and enhanced their ability to relate to patients:

It changed my perception of management…[and] changed my empathy towards patients because these were frustrating patients that we had no cure for. … [From] a Western perspective, … these are the “difficult” patients. … [We've done] endoscopy, the diagnostic studies…[with] negative or inconclusive,—no answers. … [Acupuncture] helped me to relate more to my patients because there's a different answer there. There's a different dialogue that comes from “I've got nothing for you” to “here's something that I can do.” [2]

Physicians also described the relational shift due to more communication time:

I was amazed at how…effective it was for people. What a good tool it is for…opening up lines of communication with your patients as well. If you're able to actually touch them, do these things that help their pain, then they're able to kind-of open up and tell you more, like, “oh, well, Doc, this has been happening.” [10]

Theme 5: Patient perspective—ability to fulfill personal or professional roles

The ability to fulfill personal roles (being a mother) and professional roles (doing one's job) was critical and previously inhibited due to conditions and narcotics. One patient explained:

I know a lot of moms that are stay at home moms. … [They say ] “I can't take [narcotics] and have the kids!”. … So, they're not taking [the narcotics]. So, as far as pain control [the doctor is] not controlling their patients' pain. … Acupuncture can help with that” [6]

The patients regained the ability to fulfill roles that were critical to their well-being/identity:

I yell less. My son is ADHD and so that's very challenging and it's a lot of work, and I'm able to help him cope with himself better when I'm calmer. So, the more stressed out and out of control I am the worse we all are. And so, [acupuncture] kind-of just calmed everything down a lot. … I feel like it helps. I feel like it is my medicine. [7]

This was also true professionally. Patients said that they could do their jobs better because their health improved. Some said narcotics halted their professional roles (e.g., as pilots) and emphasized that acupuncture gave them back their abilities.

Health-Inhibiting Turning Points

Three themes were identified as health-inhibiting. Patients and physicians identified logistical constraints/barriers as health-inhibiting, with differing perspectives. Physicians identified clinical challenges, whereas patients identified a lack of consistency in care.

Shared Perspectives on Inhibiting Aspects

Theme 1: Logistical constraints/barriers

For patients the major constraint was obtaining appointments. As 1 patient recalled:

[My doctor said] “well, don't be surprised. This will be maybe your one and only session, because I'm so backed up.” And I'm thinking to myself, then, why am I?—why are we doing this if it's going to [take] several treatments as he indicated to me? [17]

Appointments were scarce, and patients had difficulty reaching staff to schedule by telephone:

My back hurt. … I would call and they would say, “okay, we can get you in 7 days.” I'd say, “okay, thank you. No, thank you.” I would go to my chiropractor. … My back doesn't want to wait 3–4 weeks. [3]

Physicians focused on logistical constraints such as resources, time, and space:

It's still tough to provide what I consider to be good care and do acupuncture all in one appointment. … It's a tough time pyramid. I do feel strained and sometimes pushed and torn in that respect. … I want to do both, but limitations don't [allow for it]. [6]

Clinics aren't—especially family medicine—aren't set up to be able to do acupuncture on a regular basis. … If we can work our way into the flight community or flight medicine more, and they're willing to help us treat these patients, … acupuncture can provide a long-term benefit to those who are beating themselves up to serve our country. [16]

Physicians also expressed concern about their ability to maintain their skills:

I even have trepidation about it from time to time. How am I going to make this fit? How am I going to do this right? Wow—how long has it been since I did my last treatment? Okay, I've got get my mind back into it. [15]

Different Perspectives on Inhibiting Aspects

Theme 2: Physician perspectives—clinical challenges

Physicians described personal challenges after training about self-confidence and skills, which inhibited their perspectives of whether or not acupuncture worked:

When I first started and it's just like—oh my gosh—am I ever going to be able to put needles in without hurting [patients]? Is everybody going away from me because I have terrible technique?. … A little bit of time, a little bit of intention, and some practice has helped that. … Just don't get flustered. … Take a breath. Reset. Talk to the patient and get that feedback. [15]

Physicians also described clinical challenges due to “slow strides” with “difficult patients”:

I got a little frustrated, because I was seeing people back and back and back, and it wasn't marking any progress. … It was working, but on some patients it wasn't working. And then we'd have another training, and the same thing would happen. I would feel good then I'd get frustrated again.” [16]

Theme 3: Patient perspectives—lack of consistency in care

Turning points were highlighted by patients when care was not consistent. Although they may have had immediate health-promoting effects, it did not last:

I was just wanting it to make that pain go away just like that. … I was expecting it to just do the miracle, and it wasn't [3].

Some patients indicated they needed to give treatment more time to work, whereas others described inconsistencies with outcomes. Sometimes this was linked to seeing different physicians:

The one doctor—the one that had the attitude—[was] not so great for some reason. … I think he was distracted with something else. [12]

Discussion

Patients and physicians benefit from acupuncture. The dyadic approach used revealed that turning points can be physician- and patient-specific when impacting their perspectives of whether or not acupuncture is working (and is health-promoting). Thus, factors that affect adherence likely differ and should be taken into consideration to promote successful integration of acupuncture in other conventional medicine settings. In order to optimize the translational value of these findings in promoting patient-treatment engagement and acupuncture integration in conventional-medicine settings, two points can be used to tailor patient–provider communication and medical education tools: (1) a longitudinal perspective of efficacy perceptions and (2) unique perspectives.

Shifting Beliefs about CAM—a Longitudinal Perspective

Turning points that shifted belief systems about acupuncture were described by both patients and physicians. The longitudinal approach turning-point analysis affords enabled identification of shifts across both a training and treatment trajectory, beginning with perceptions prior to trying acupuncture (either as a practice or treatment). Understanding these beliefs and what turning points may impact them is important from an integration and treatment adoption standpoint.

For example, physicians in this study admitted to previously having a biased view of CAM and emphasized the importance of how their training shifted that belief. Training is perhaps key for shifting physicians who are hesitant to integrate this therapy into their own practices. The training they receive may be key to shifting the perspective of acupuncture from voodoo to medicine. The impact of training as a turning point could be unpacked in future studies, with a focus on examining which aspects of training are most influential and what role continuing education can play in physicians' ongoing integration (given their concerns with skill maintenance).

Physicians who began integrating the treatment into practice identified a turning point when their relationships with their patients shifted because of acupuncture, which further impacted their perception of acupuncture as an efficacious treatment option. There were two aspects to this revelation. First, acupuncture enabled physicians to help patients (when other modalities had failed). Second, it improved physicians' relatability to patients. Research shows that patients view physician's communication skills positively with regard to empathy, compassion, and respect, and that “perceived similarity to the physician made communication more agreeable.”⁴⁰ Furthermore, improved patient outcomes is associated with effective communication between patients and physicians.⁴¹ By extension, this would suggest that acupuncture contributes to improved outcomes both medically and through relational enhancement. The long-term impact of this shift in relationship, both for patients' adherence and physicians' well-being, is worthy of investigation in future scholarship. For instance, acupuncture might decrease levels of emotional exhaustion and depersonalization characterized by physician burnout and, thus, enhance physicians' motivation to integrate acupuncture into their practices.

Various changes were noted by patients—and some changes that were perhaps gradual across the treatment process—that enhanced their perception of efficacy (e.g., reduction of medication usage), but there were also changes that created challenges (e.g., lack of consistency in care) that could occur at various points across treatment. Most central to their perceptions of efficacy, perhaps, was the experience that helped them regain self-identity, which was described as allowing them to live what they perceived to be fulfilling or “normal” lives again. This is consistent with studies illustrating the detrimental effect of ailments such as pain on one's ability to function in daily life.⁴² However, this finding emphasizes the importance of addressing this outcome in conventional medicine, where perhaps, more biomedical benefits are prioritized. The psychosocial benefits for patients are integral to their personal and professional livelihoods.

Comparison of Perspectives

Shared turning points were reported between patients and providers, such as improvements in health and reduction of medication usage. The value of integrative medicine has been illustrated by previous studies that have established the association between acupuncture and decreased narcotic, benzodiazepine, and muscle-relaxant use to treat chronic pain.⁴² Likewise, patients' and physicians' turning points were both linked to constraints of a primary-care clinic (e.g., access). Yet, even in their similar reports, differences emerged.

For example, one related but patient-specific turning point, was care consistency or patients not experiencing the same benefits, which they then linked to seeing different physicians. This made patients question the effectiveness of acupuncture, which has the potential to impact long-term adherence. Yet, perhaps related to this patient turning point was that physicians acknowledged at times a lack of confidence in their own skills. This could have been due to the fact that some physicians had completed their training recently. This outcome reinforces the importance of not only training, but ongoing education/training after course completion in terms of fostering physicians' skills and confidence and enhancing care consistency. Future research should focus on a more-longitudinal approach to medical education as well as patient–provider communication training that addresses turning points impacting treatment efficacy perceptions across appointments or across care plans.

Tailoring Patient–Provider Communication

These findings help illustrate that exposure to training, health changes, enhanced relationships between physicians and patients, and ability to fulfil personal/professional roles all advance patients' and physicians' perspectives on the effectiveness of medical acupuncture, promoting adherence of acupuncture both for patients and physicians. At the same time, barriers to care (consistency, clinical challenges) were identified that can inhibit efficacy perceptions. These turning points could be incorporated into medical education and communication tools to help providers integrate communication of treatment efficacy across care plans For instance, turning points identified as central to promoting treatment efficacy perceptions could be discussed to encourage patients' adoption (or providers' integration) of acupuncture treatment. Furthermore, turning points that patients are likely to encounter (e.g., lack of consistency in care or clinical challenges) that inhibit efficacy perceptions should be addressed prior to treatment beginning to encourage treatment adherence and long-term integration into practice (providing both patients and providers with realistic treatment expectations).

Conclusions

The findings represent turning points impacting patients' and providers' perceptions of early in the integration of acupuncture into practice and early in patients' treatment experiences. While these findings are helpful to other medical settings to identify turning points that will arise early in the integration and treatment experience, a more-longitudinal examination is warranted to ensure turning points that might arise later (and impact long-term integration) are identified.

Notable limitations to this study were related to the nature of the single military hospital where interviews were conducted. First, this hospital encourages its physicians to complete medical acupuncture training, resulting in a culture that is accepting of this treatment modality. Second, while researchers invited patients who had reported both successful and unsuccessful treatment of acupuncture, patients might be more inclined to speak about successful treatment experiences. Furthermore, the military-clinic setting can also be viewed as a limitation.

Although the participants represented both active/nonactive service members and civilians (the dependents), it is possible that these individuals have unique cultured experiences that impact their perceptions. These findings could be useful across conventional-medicine settings but the current authors recommend future studies in various conventional-medicine departments (e.g., pediatric medicine, geriatric care, surgery) as well as those outside military populations to enhance understanding of acupuncture engagement and integration further. Additionally, future studies involving in specific acupuncture experiences and outcomes (e.g., negative and positive) might consider using a purposive sampling approach to ensure that both experiences are represented fully. Researchers interested in using a quantitative design to examine these experiences could build from these qualitative findings.

Author Disclosure Statement

No financial conflicts of interest exist.

Funding Information

This work was supported by the Acus™ Foundation. The funder had no role in any aspect of this study.