Sound is a medium that is increasingly being used in both alternative and conventional medicine – through the use of both audible and inaudible frequencies. This article looks at studies, technologies, and methods of sound application.

What is Sound?

There are essentially two definitions of sound – one describing vibrations in the range of human hearing, and the other describing vibrations in general:

1. Vibrations transmitted through an elastic solid or a liquid or gas, with frequencies in the approximate range of 20 to 20,000 Hertz (Hz), capable of being detected by human organs of hearing
2. Transmitted vibrations of any frequency.

For the purpose of this discussion, we will be referring to the latter definition.

Frequencies above 20,000 Hz are referred to as ultrasonic, and frequencies below 20 Hz are referred to as infrasonic.

Why Use Sound Therapeutically?

The human body is wired to be exquisitely sensitive to sound. The faculty of hearing is one of the first sense to develop in utero, and the last to depart before death. In addition to perceiving sound through our ears, a recent NIH study published in the journal Nature (November, 2009) shows that we also "hear" the pressure waves of sound through our skin. Water, of which our bodies are largely composed, conducts sound at a rate approximately four times faster than air.

Our bones also conduct sound, as evidenced by newer hearing aids that conduct sound through the skull directly to the cochlea, and through the technique of using a vibrating tuning fork to determine if a bone is fractured. In this technique, the tuning fork is placed distal to the suspected fracture and the stethoscope is placed proximal to the injury on the same bone. A clear tone indicates an uninjured bone, whereas the sound is diminished or absent in the presence of a fracture (Moore, 2009).

It has been discovered that in addition to the traditionally viewed "lock and key" structure of receptors on cell membranes that receive and respond to physical molecules, there are also antenna – like structures ("primary cilium") that respond to vibrational frequencies. Bruce Lipton writes in The Biology of Belief (2005):

Receptor antennas can also read vibrational energy fields such as light, sound, and radio frequencies. The antennas on these energy receptors vibrate like tuning forks. If an energy vibration in the environment resonates with a receptor's antenna, it will alter the protein's charge, causing the receptor to change shape. Because these receptors can read energy fields, the notion that only physical molecules can impact cell physiology is outmoded. Biological behavior can be controlled by invisible forces as well as it can be controlled by physical molecules like penicillin, a fact that provides the scientific underpinning for pharmaceutical-free energy medicine.

These receptors are also described in a paper titled "The Primary Cilium as a Complex Signaling Center" (Berbari et al., 2009):

Fluid movement through the tubules and mechanosensory activities of the cilium may have an important impact on cellular responses. In addition to responses induced by fluid shear, cilia have important functions in pressure, touch and vibration sensation.

In addition to receiving vibrational information, these cilium also may also transmit information about the state of order or disorder within the cell.

Conventional vs. Alternative Perceptions of Sound Medicine

Broadly, conventional medicine employs sound frequencies in the ultrasonic and infrasonic ranges, while alternative medicine largely employs frequencies in the audible range. While the practice of using these ultrasonic and infrasonic frequencies is well-documented and widely employed in conventional medicine, there has been very little attention given to the use of audible frequencies. The two perspectives break down along distinct lines, with just a little overlap.

Uses of Sound in Conventional Medicine

Perhaps the best known and most widely employed use of sound in conventional medicine is the use of ultrasound. Most people are familiar with its use as a diagnostic technology, as in the use of sonograms for viewing of fetuses. The sound waves bounce off the bones and fluid and return the information to a transducer which translates it into a visual image. Medical sonography is also used diagnostically to discover pathologies within the body.

Ultrasound is also used therapeutically. Ultrasound therapy has been shown to cause increases in tissue relaxation, local blood flow, and scar tissue breakdown. The effect of the increase in local blood flow can be used to help reduce local swelling and chronic inflammation, reduce pain and, according to some studies, promote bone fracture healing (Hadjiargyrou et al., 1998). It is regularly employed by physical therapists and chiropractors.

However, despite over 60 years of clinical use there are few studies that definitively verify the efficacy of therapeutic ultrasound. One of the reasons for this is the challenge presented in double blinding the process (Robertson, Baker 2001). This issue makes studies on the effectiveness of sound challenging due to the aforementioned numerous channels of conductivity. Some more recent studies have been more conclusive – one shows a 44% reduction in trigger point sensitivity after just one five minute application of high-intensity ultrasound (Srebley, Dickey 2006).

Ultrasound can also be used to evoke phonophoresis, a non-invasive way of enhancing the absorption of analgesics and anti-inflammatory agents to tissues below the skin using ultrasonic waves (Byl, 1995).

Newer Applications of Ultrasound

Ultrasound is also being used as a non-invasive surgery technique. Magnetic resonance-guided focused ultrasound (MRgFUS) is a process that uses highly focused ultrasonic frequencies to destroy unwanted growths such as fibroids and even tumors by rapidly heating them. The magnetic resonance provides a precise guidance system to focus the sound beam on the specific areas and then raises the temperature to the point where the structural integrity of the growth is destroyed.

Although this treatment has been in use since 1994 and has been used on fibroids, breast tumors, prostate tumors and more, showing highly successful results, it has been slow to catch on (Wilkins, 2008). An important difference between high-intensity focused ultrasound and many other forms of focused energy, such as radiation therapy or radio surgery, is that the passage of ultrasound energy through intervening tissue has no apparent cumulative negative effect on that tissue (Wilkins, 2008).

Another sound application in conventional medicine is the practice of lithotripsy, a technology that targets stones in the kidney, gall bladder, or liver with pulsed infrasonic sound waves in the range of 4-12 Hz, for the purpose of breaking them up into smaller pieces that are more easily passed by the body. It was developed in the early 1980s in Germany and has since become more widely used but can have complications rates of 5-20% and result in a sensation akin to "being punched in the kidney" (Saher, 2004).

Lastly, a search of sound therapy in a medical database will bring up mostly articles about the use of Tinnitus Retraining Therapy (TRT) to treat tinnitus, the phenomena of a constant ringing or roaring in the ears. While apparently no cure for this has been determined, TRT is an ongoing process that uses sound generators to help the sufferer retrain their relationship with the issue so that it no longer bothers them as much, a process that can take upwards of two years to be truly effective (Gold et al 2000).

Sound Medicine Used in Both Alternative and Conventional Settings

Music therapy, vibroacoustic therapy, and the Tomatis Method are three techniques that are used both conventionally and alternatively. All three fall into the category of sound therapy.

Music has been used clinically in the United States since WWII, when it was used to treat returning soldiers for what is now known at post traumatic stress disorder or PTSD. Since then it has become more widely employed, and is now used in hospitals, nursing homes, institutions, and other rehabilitative settings. Music therapists work to help clients improve their level of functioning and quality of life by using music experiences such as singing, songwriting, listening to and discussing music, and moving to music, to achieve measurable treatment goals and objectives.

Music therapy has been shown to be particularly effective with some of the more challenging members of the population, especially those with Alzheimer's and dementia, autistic spectral disorders, stroke victims, and even prisoners. A study on a group of women in prison in Israel who all participated in a choir showed that group members "experienced a sense of community and togetherness as a result of the exercise" (Silber, 2004). Alzheimer's patients demonstrate less agitation and confusion when engaged in group or individual music exercises, as opposed to being left alone in front of a TV (Darrow, 2004). Autistic children are able to be more expressive and engaging when involved in musical activities (Kim, 2009).

Music is also gaining more acceptance in the medical field, being used both during surgery and post-op; and especially in the practice of music thanatology, which combines music – often harp music – with end of life care. It is being used to help people manage pain, anxiety, stress and a surprisingly wide range of other issues.

Studies have shown (Rider, 1985) the method of music therapy that works most effectively utilizes the principles of resonance and entrainment. Entrainment music therapy is described as "any stimuli that matches or models the current mood state of the individual and then moves the person in the direction of a more positive or pleasant mood state" (Freeman, 2004). For example, if a person is initially agitated, music selected will match that agitation initially (resonate with), and then move slowly into a melodic piece that can lead to anxiety reduction (entrain to). This technique has been used successfully in reduction of both pain and anxiety.

Vibroacoustic Sound Therapy (VST) incorporates both music therapy and sound frequencies. VST is the transduction of both sound and music through specially designed beds, tables, or chairs, with speakers arranged in such a way that the sound currents travel directly through the body. Lower frequency waves, in the range of 30-100 Hz are generally used, and sessions can last from 10-45 minutes (Boyd-Brewer, 2004). This technology originated in Sweden in the 1970s and now has grown to be used worldwide in settings from hospitals to spas. Numerous studies have been conducted on this technology and have demonstrated that it is beneficial for a wide range of ailments, from pain and anxiety reduction to reducing problem behavior in autistic adults and children. One study found that negative stereotypical behavior was reduced upwards of 40% in autistic adults (Boyd-Brewer 2003).

VST can be utilized with just music, pulsed sound waves and music, and in some technologies, combined with visual light stimulation. Most studies have determined that VST is most beneficial when pulsed sound is combined with music, and nearly all studies have shown that it brings improvement to a wide range of disorders (Boyd-Brewer, 2004).

The Tomatis Method, and a somewhat similar technology called Auditory Integrative Training are other sound therapy techniques that have undergone some, but not many, rigorous studies. While these therapies are fundamentally different, both involve listening to specially created music through headphones for the purpose of retraining the auditory system and creating symptomatic improvement for issues such as autism, learning disorders, hearing disorders, ADHD, and more. The treatment of autism has been the most studied with these techniques, as they are generally effective at reducing the sound sensitivity so common in the disorder, resulting in improved interaction with their environments (Edelson et al. 1999).

Sound in Alternative Medicine

The use of sound in alternative medicine is much more broad and deep than conventional uses. For the purpose of this part of the discussion, it is important to distinguish between what is sound healing and what is sound therapy. Sound healing refers to the more general field of therapeutic sound use, including signing, drumming, rattling, toning, etc. – whereas sound therapy refers to aspects of the practice that are more clinical and structured. In alternative medicine, sound therapy is a sub-group of sound healing.

The Human Voice

Conscious and intentional use of the human voice in chanting, singing, and toning has been used for millennia, often within a religious or devotional context. Numerous studies have been done to determine what exactly happens when we chant or sing or tone, whether alone or in groups. Neurological imaging has shown changes in blood flow to the brain, in addition to other biological markers of increased well-being, when experienced meditators are engaged in chanting meditation (Lazar, 2000). One study demonstrated a positive emotional effect and immune competence confirmed by the increased presence of secretory immunoglobulin A in saliva swabs after a choir rehearsal, and even more marked increase after a performance (Kreutz et al, 2006).

The process of toning, which has gained some popularity in recent years, is a sort of informal chanting where the individual simply intones extended vowel sounds which are supposed to help release energy blockages from the body. Chanting is said to have a similar result of facilitating the flow of energy through the body.

Tuning forks and singing bowls

Acoustic instruments such as tuning forks and crystal or Tibetan bowls are widely used in sound healing in a variety of different ways. One of the best known tuning fork practices is called Acutonics, a system developed by an acupuncturist, that uses vibrating weighted tuning forks on acupuncture points. It works on the same premise as acupuncture – that stimulation of these particular areas unblocks stuck or stagnant energy, improving energy flow through the body and supporting the body in healing itself. Acutonics is used in a variety of settings including some hospitals.

Crystal and Tibetan bowls are struck or rubbed to produce pure, penetrating tones, not very different from tuning forks. Metal bowls have been used in Tibet for centuries as an aid to meditation, while crystal bowls are a relatively recent development but the two are used similarly. Dr. Mitchell Gaynor, an oncologist and author of The Healing Power of Sound (2002), began integrating music, vocalization, breathing, bowls and meditation techniques in his work with patients in 1991, after first being exposed to a Tibetan bowl through one of his patients. He has observed many beneficial outcomes as a result of this integration.

The use of tuning forks, bowls and gongs, along with certain types of music appears to stimulate the relaxation response in the body. This may be due in part to the biological process of Nitric Oxide (NO) release in the body. According to John Beaulieu, tuning fork expert and one of the authors of Sound Therapy Induced Relaxation: Down Regulating Stress Processes and Pathologies (2003), NO appears to be released in the presence of certain music and sounds. According to Beaulieu, nitric oxide is not only an immune, vascular, and neural signaling molecule, it is also "antibacterial, antiviral, and it down-regulates endothelial and immunocyte activation and adherence, thus performing vital physiological activities including vasodilation" (Salamon et al. 2003).

Sound Technologies

Binaural beats are created when two tones are detuned from each other by a small amount. The resulting third oscillation, which is the difference between the two frequencies, will automatically entrain the brain into different brainwave frequencies. For example, if 315 Hz is played into the right ear and 325 Hz played into the left ear, the brain becomes entrained towards the beat frequency of 10 Hz, which is in the Alpha brain wave range. Since the Alpha range is associated with relaxation, this is supposed to have a relaxing effect. Binaural beats are embedded in music, or simply as repeated tones, and listened to through headphones.

Studies suggest therapeutic application of binaural beat technologies can be beneficial for anxiety, mood improvement, behavior disorders in developmentally disabled children, and stress reduction in patients with addictions and focus and attention (Wahbeh et al, 2007).

BioAcoustic therapy is the use of human voice analysis to provide a representation of a person's state of health. Developed by sound pioneer Sharry Edwards, this technology reads the frequencies present in a person's voice and determines what important frequencies are missing. Once appropriate sound formulas are ascertained, they are programmed into a Square 2 tone box, a portable analog frequency generator, allowing an individual to listen privately through headphones or subwoofer (Blachly 2005). According to their website, BioAcoustic Therapy has had success with varying issues during their research efforts but several specific areas of expertise have emerged: sports injuries and structural problems, pain management, nutritional evaluation, and tissue regeneration being among the most successful.

It is noteworthy to point out that the new 2nd edition of Alternative Medicine: The Definitive Guide has included BioAcoustics as a recommended alternative therapy, and one of only four sound therapies listed, and that in 2009 Edwards received the Scientist of the Year Award from the International Association of New Science.

The Cyma-1000 is a frequency generating device that was developed by Dr. Peter Guy Manners, a British Osteopath, beginning in the 1960s. This device emits over 500 different frequencies and fifty years of research has determined which frequencies and combinations of frequencies treat which ailments. It uses an applicator to deliver precise combinations of frequencies associated with healthy tissue and organ systems, and is registered in the United States with the FDA as an "acoustic massager."

The theory is that these sound waves help to normalize imbalances and synchronize the cell's frequency back to its natural healthy state of vibrational resonance. This technology is used and accepted in the United Kingdom (where it is referred to as "advanced medicine", rather than alternative medicine) but not so much in the United States.

Numerous other technologies and techniques utilizing the properties and benefits of frequency are currently on the market and coming to market, and the use of tuning forks, gongs, and singing bowls is also on the rise. The therapeutic use of sound has been called one of the most exciting and innovating frontiers of Integrative medicine.