Essay: The Neurobiology of Sound in Attention Deficit Disorder

            In the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5), attention deficit disorder (ADD) has lengthy criteria for diagnosis. The Center for Disease Control and Prevention (2020) provides this shortened form definition from the DSM-5: “A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development” (para. 7). Persons with ADD have unique neurobiology which has been linked to reduced dopamine and norepinephrine activity (Kolb et al., 2019). It has also been shown that attention deficit hyperactivity disorder (ADHD) brains have less volume in the frontal cortex, cerebellum, and subcortical structures as well as similar symptoms to those of persons with damage to these areas, such as inhibition and executive functioning (Herbert & Esparham, 2017). Medication is effective for many, but it is not for everyone. Even for those whom medication has proven useful, it does not control all symptoms, nor is it a cure. Psychiatrist William Dodson (2021) states, “Stimulant medications are very good at keeping the ADHD brain from getting distracted once they are engaged, but they do not help you get engaged in the first place” (para. 17). There exists a need for adjunct therapeutic options. The goal of this paper is to present a case for using sound as a therapeutic tool, in the absence of or in addition to medication, and for improving cognitive function in the ADD mind, with the ultimate goal of moving towards a state of coherence.

The Neurobiology of ADD and Sound Perception

Brain Activity

            Throughout this paper, the words “mind” and “brain” are used interchangeably. In addition, the acronyms ADD and ADHD will be used interchangeably in a narrative tone, when referring to attention deficit disorder and attention deficit hyperactivity disorder; when paraphrasing or quoting from published works, I will use the author’s term. 

            Childhood trauma expert, Dr. Gabor Maté (n.d.), characterizes attention deficit disorder by “the dis-order it creates in one’s life” (para. 27, 28), as well as by the persistent patterns of inattention, and/or hyperactivity, impulsivity, distractibility, tuning-out, and disorganization, such that it interferes with functioning or development. There are several regions of the brain involved in manifesting these patterns of disorder (Silver, 2021). And it may come as no surprise that they are all connected.

            The prefrontal cortex, also called the frontal lobe, is the most recently evolved region of the brain and governs executive functions like decision making, organization, and planning for the future. The limbic system, or limbic circuit, which includes the hippocampus, amygdala, and cingulate cortex, interacts directly with the hypothalamus; this circuit regulates emotional and motivated behaviors. The basal ganglia also plays a role; a subcortical collection of forebrain nuclei that are involved in controlling motor behavior (Kolb et al., 2019). And lastly is the reticular formation, a network of neurons in the brain stem which may play an important role in the circuitry of arousal (Maté 1999).

            This issue of arousal is an important one since the ADD brain is often characterized by a feature of arousal and emotional dysregulation (Bellato et al., 2020). Regulation refers to the Autonomic Nervous System (ANS), which balances internal functions and the two sub-branches of the ANS, the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS), which balance states of arousal and calm, respectively, by the vagus nerve pathway. Dysregulation then, is when these excitatory and inhibitory states are out of balance, as in hyper and hypo-arousal, which is what occurs in the ADD brain (Kolb et al., 2019). 

            Two neurotransmitters, norepinephrine, and dopamine have been found to play a role in the ADD brain (Herbert & Esparham, 2017); specifically, their reduced availability. Higher amounts of the dopamine transporter protein have been noted, which causes faster reuptake of dopamine back into the presynaptic neurons. Faster reuptake translates to reduced availability in the synaptic cleft, which is where a transmitter needs to be for neural utilization. Stimulant medications are thought to work by either blocking reuptake and allowing it to “hang out” longer in the synapse, and/or by reversing the transporter production thereby increasing the release of existing dopamine. (Kolb et al. 2019). 

The Importance of Environment

            ADD has been correlated to many factors including genetic predisposition, environment, brain structure, neural pathways, neurotransmitters, in-utero influences, as well as psycho-social adversity in childhood (Herbert & Esparham, 2017).

            In Maté’s book Scattered (1999), he addresses the nurture vs. nature argument, asserting that, “Genetic inheritance by itself cannot account for the presence of ADD features in people, but heredity can make it far more likely that these features will emerge in a given individual, depending on circumstances” (p. 59). These circumstances are early stressors that can show up in childhood, and they are what Maté believes makes ADD a developmental disorder rather than an inherited condition. There is another aspect that he highlights, a quality of the ADD brain that is not often mentioned: hypersensitivity (1999). “It is sensitivity, not a disorder, that is transmitted through heredity” (p. 59). 

            The dysregulation of the ANS and the inborn hypersensitivity to environment, underscore the importance of establishing a tailored management plan, with habits and routines that facilitate engagement (Dodson, 2020). Habits like consistent sleep-wake times, healthy meals, and physical exercise are the core foundation of such routines. 

            Behavioral therapies and pharmaceutical treatments have been shown to be quite effective at alleviating ADHD symptoms, especially when used together (Herbert & Esparham, 2017). Yet, medication is not a cure. Dr. Dodson of ADDitudeMag.com says, “Stimulant medications are very good at keeping the ADHD brain from getting distracted once they are engaged, but they do not help you get engaged in the first place” (2021, para. 17). Additionally, many standard treatments for ADD do not work or have unwanted side effects (Huang & Charyton, 2008). There is clearly a need for adjunct therapies and this is where sound therapy comes in.

Sound As Therapy

Brainwaves

            The brain’s electrical activity can be measured and recorded by an electroencephalogram (EEG). The EEG records this activity as waves, which can be matched to specific brain regions (Kolb et al., 2019), and each wave that the brain produces has an associated hertz (Hz), which is the repetition per second, a.k.a. frequency, as well as an amplitude (wave height).

Modulating these brainwaves is the basis for sound therapy. The brainwaves we look at are gamma, beta, alpha, theta, delta; hertz ranges noted below are approximated.

            Gamma waves are the fastest oscillating of the brainwaves, 30 Hz and higher. Gamma is associated with profound insight and peak states of awareness (Source Vibrations, 2019).

            Beta is a fast-wave pattern, associated with waking, thinking, and a general focused state, in the 13 to 30 Hz range. (Huang & Charyton, 2008). Excess beta can result in chronic stress, anxiety, and decreased cognitive performance (Source Vibrations, 2018). Many studies reference the ADD brain having high theta/low beta ratios in the frontal and midline areas (Herbert & Esparham, 2017). This could correlate to the inability to focus, common to the ADD brain. However, other studies show a null correlation with theta/beta ratios in ADD; while EEG recordings can be a useful guide, they have not yet been proven as a universal tool for ADHD diagnosis (Herbert & Esparham, 2017).

            The Alpha rhythm is a large, consistent wave in the 7 to 11 Hz frequency range. It is associated with calm, relaxed attentiveness and creative receptivity. Excess alpha can result in feeling scattered, overwhelmed, or lethargic (Source Vibrations, 2018). 

            Theta waves are at 4 to 7 Hz, associated with liminal states, trance states, dreaming, visions, and insight. Excess Theta waves may be connected to cognitive issues like ADHD and other psychological disorders; reduced theta may be related to sleep disorders (Source Vibrations, 2018).

            Delta waves are .05 to 4 Hz and slow with large amplitude. These waves are produced by deep, dreamless sleep, or deep meditation, yogic sleep, and unconsciousness (Source Vibrations, 2018). 

            In the scope of this paper, sound therapy can be defined as aural tones, rhythms, beats, acoustic harmonies, and/or vibrations, which aim to alter or change a brainwave state through external frequency stimulation, with the intention of moving the listener’s state towards one of synchrony (coherence) and away from stress and disorder (incoherence). There are different sound therapy modalities, and even Kundalini yoga, which uses rhythmic breathing, could be considered sound therapy under the definition provided. This paper will review shamanic drumming, binaural beats, solfeggio frequencies, singing bowls, the didgeridoo, and gonging, and then discuss the concept of brainwave entrainment, which all of the aforementioned modalities employ to achieve their results. 

Modern sounds/ Ancestral roots

Types of sound therapy

            Shamanic drumming is a fast-paced rhythm at 4 to 7 Hz (beats per second), and a similar frequency to that of theta waves. (Theta states are associated with trance, dreaming, visions, and insight.) The ancestral roots of sound began with the drum. Ritual drumming exists in almost every culture across the globe. It is used in shamanic journeying, tribal storytelling, celebrations of life, honoring the dead. It is both transportive and primal, familiar and sacred. The heartbeat is the first sound we hear when in utero. It seems hardly a coincidence that the drum which sounds like our mother’s heartbeat has remained a sacred tool for connecting to our ancient roots (Tarnacki, 2019).

            Binaural beats are a perceptual phenomenon, which happens when two slightly different frequencies are presented separately in each ear, and the brain bridges the gap by creating a single illusionary tone, that is equal to the mean frequency of the two tones together (Garcia-Argibay et al., 2019). Popular binaural beat tracks tend to use one or more frequencies, layered with relaxing music, and sometimes include what is called a carrier frequency. The Garcia-Argibay et al. study (2019) had positive outcomes for the potential benefits of using binaural beats, however, they suggest the possibility of carrier frequency playing a crucial role in binaural beat effectiveness, which might help explain why other recent studies have presented inconsistent data the efficacy of binaural beats.

            In 2008, Huang & Charyton published a comprehensive review that examined twenty peer-reviewed studies for psychological outcomes within a group of criteria and discovered relevant patterns, most notably an improvement of outcome when a combination of gamma/beta waves was used. And Garcia-Argibay et al. (2019) found that the magnitude of the experienced benefits was correlated with several factors, such as binaural frequency and duration of exposure, and that better results occurred when participants primed their brain by listening before, as well as before and during the task, vs. only during the task.

            Source Vibrations (2018) produces sound therapy music and brain “state training”, using “neuro-acoustic” beats and layered frequencies for brain entrainment and cite a cumulative effect of use. The more you use it, the easier it is for your brain to “drop-in” to the desired frequency. They claim that delta states are easiest to achieve first thing in the morning, or the last thing at night; theta is easiest first thing in the morning, especially if one is practicing any kind of self-hypnosis or trance; alpha sessions are easy to do any time of the day, as they facilitate calm, centered focus

            Binaural beats work by hearing two separate tones in each ear, so headphones are necessary for the best neuro-aerobic workout.

            Solfeggio frequencies are often found layered into binaural beats music, commonly at 528 Hz and/or 432 Hz tuning. However, solfeggio frequencies are controversial in origin and there are few if any studies on solfeggio frequency efficacy. Believers claim this “ancient tuning” to be aligned with Pythagorean geometry (Attuned Vibrations, 2019).

            Singing bowls were found to show favorable improvements in tension levels, anxiety, as well as increasing a sense of spiritual well-being (Goldsby et al., 2017).

            The didgeridoo, an Australian wind instrument, produces a deep, vibratory resonance, and has been found to relieve tension and increase relaxation (Hartley Phillips et al., 2019). The didgeridoo and the hanging gong are sound therapies that are ideally experienced in person, as they can be felt as well as heard, due to their vibratory resonance and reverberation; singing bowls produce a similar effect, but to a lesser extent.

            All of these modalities share something in common. They use brainwave entrainment; when rhythmic stimuli are presented at a target frequency, and that stimuli elicit a “frequency-following response” of the listener’s brainwaves, to match the frequency of the stimuli. This frequency-following response speaks to the tendency of the electrocortical activity of the brain to fall in synchronization with the externally presented sound, rhythm, etc. (Huang & Charyton, 2008). This could be interpreted as what we hear, we emulate. Herbert & Esparham (2017) posit that the brain states achievable in sound therapy are comparable to those of meditation and mindfulness training and may even facilitate overall coherence.

The Goal: Coherence

Moving Out of Disorder

            Taking Gabor Maté’s viewpoint that ADD develops due to early traumas and hypersensitivity to one’s environment (1999), and that at its core, ADD is a condition of dysregulation (Bellato et al., 2020), it seems plausible to say that ADHD is a condition of being stuck in a state of dis-order that vacillates between hyper and hypo-arousal, likely as a learned coping mechanism. Dr. Stephen Porges, founder of the Polyvagal theory says, “When we are in safe states, we can access higher cortical functions, but when we are in danger states, those systems turn off and we’re defensive” (2018, 0:27). 

What is coherence?

            The HeartMath Institute, in their book called Science of the Heart (2016), defines coherence as “the measurement of the order, stability, and harmony in the oscillatory outputs of the body’s regulatory systems during any period of time”(p. 11)

            Emotional self-awareness and self-regulation are perhaps the most important skills to cultivate, according to HeartMath, because it is the neural systems that underlie all cognitive and emotional experiences. And it is our neural systems that, if they have an unstable baseline pattern, will perpetuate instability (McCraty, 2016). What is exciting is that the brain has the inherent trait of neuroplasticity and new patterns can be learned, especially when they are new patterns (Kolb et al., 2019). Through self-regulation techniques that begin with changing our brainwave states, we can move into deeper synchronization with our hearts and bodies, our partners and loved ones, our communities, and ultimately, our planet (McCraty, 2016). 

            The work and research of HeartMath unsurprisingly focuses on the heart, and specifically the heart rate variability (HRV). Heart rate variability is not the heartbeat itself, but the time between heartbeats, as it speeds up or slows down, and the ability to regulate those gaps relates to high HRV levels (McCraty, 2016). Studies have shown associations with higher levels of resting HRV and better performance of cognitive tasks and executive functions. Additionally, some of the same neural structures which are thought to play a role in ADD have also been found to show involvement in heart rate regulation: cortical, subcortical, and the medulla oblongata (McCraty, 2016). It is through the modulation of HRV that we can move into heart coherence. 

            HeartMath has developed various focused breathing techniques for increasing heart coherence. They have also created a heart coherence app and a wearable device. But it is their Heart-Focused Breathing that is simple and accessible to all. It includes focusing on the heart area, breathing in a rhythmic measured pattern of five breaths in, five breaths out, and generating a positively associated emotion, like love or gratitude (McCraty, 2016). Consciously slowing one’s heart rate and deepening breath increases the space between beats (HRV). Remember that the vagus nerves travel in both directions—afferently (from the heart to the brain) and efferently (from the brain to the heart). However, while efferent vagus nerve fibers are involved in the heart’s regulation, the majority of the vagus nerve fibers are afferent. This means “the heart sends more information to the brain than the brain sends to the heart” (McCraty, 2016). 

            The heart is the largest source of electromagnetic energy in the human body (McCraty, 2016). The electrical field that the heart generates is approximately sixty times greater than the electrical activity generated by the brain (in amplitude), and it can be measured by an EKG. 

The amygdala functions as an organizational center for familiar patterns. If the heart generates rhythm patterns that are discordant or chaotic, especially early on in childhood, the amygdala learns that a state of discord is the expected baseline. Yet, by becoming self-aware, especially in such moments of discord, and shifting focus to the heart area, as well as deepening breathing, especially on the exhale, it is possible to create new coherent patterns for the amygdala to organize (McCraty, 2016).

            The heart is the largest source of electromagnetic energy in the human body, and generates an electrical field that is approximately sixty times greater than the electrical activity generated by the brain, HeartMath sees coherence as an achievable state, with potential on a global scale (McCraty, 2016).

Conclusion

            Sound therapy has the power to connect us to our ancestral roots, adjust brainwaves and neuronal activity in positive ways, and establish new baselines for wellness. By starting where we are and changing our brains through daily habits and meaningful self-regulation, there is the potential to create lasting change in the ADD/ADHD mind and neuroplasticity supports us in these endeavors (Kolb et al. 2019). Such change may even ripple out in exponential ways on a global scale (McCraty, 2016). “We are coming to understand health not as the absence of disease, but rather as the process by which individuals maintain their sense of coherence (i.e. sense that life is comprehensible, manageable, and meaningful) and ability to function in the face of changes in themselves and their relationships with their environment” (McCraty, 2016, p. 9).

We have our brains and our hearts on our side. It is up to us to make use of these wonderful, wired connections of rhythm and possibility. 

 References

Attuned Vibrations. (2019). What is 432 Hz tuning? attunedvibrations.com. https://attunedvibrations.com/432hz/

Bellato, A., Arora, I., Hollis, C., & Groom, M. J. (2020). Is autonomic nervous system function atypical in attention deficit hyperactivity disorder (ADHD)? A systematic review of the evidence. Neuroscience & Biobehavioral Reviews, 108, 182-206. https://doi.org/10.1016/j.neubiorev.2019.11.001

Center for Disease Control and Prevention (21 September, 2020) https://www.cdc.gov/ncbddd/adhd/diagnosis.html

Dodson, William (2021, February 5). 3 defining features of ADHD that everyone overlooks. ADDitude. https://www.additudemag.com/symptoms-of-add-hyperarousal-rejection-sensitivity

Garcia-Argibay, M., Santed, M. A., & Reales, J. M. (2019). Efficacy of binaural auditory beats in cognition, anxiety, and pain perception: a meta-analysis. Psychological Research, 83(2), 357-372. https://doi.org/10.1007/s00426-018-1066-8

Goldsby, T. L., Goldsby, M. E., McWalters, M., & Mills, P. J. (2017). Effects of singing bowl sound meditation on mood, tension, and well-being: An observational study. Journal of Evidence-Based Complementary & Alternative Medicine, 22(3), 401-406. https://doi.org/10.1177/2156587216668109

Herbert, A., & Esparham, A. (2017). Mind–body therapy for children with Attention-Deficit/Hyperactivity Disorder. Children, 4(5), 31). https://doi.org/10.3390/children4050031

Huang, T. L., & Charyton, C. (2008). A comprehensive review of the psychological effects of brainwave entrainment. Alternative Therapies in Health and Medicine, 14(5), 38-50. https://www-proquest-com.ciis.idm.oclc.org/scholarly-journals/comprehensive-review-psychological-effects/docview/204837524/se-2?accountid=25260

Kolb, B., Whishaw, I. Q., & Teskey, G. C. (2019). An introduction to brain and behavior (Sixth ed.). Worth Publishers/Macmillan Learning.

Maté, G., (n.d.) Faq AD(H)D, para. 27, 28. https://drgabormate.com/topic/adhd/ .

Maté, G. (2000). Scattered. Penguin Publishing Group.

Mccraty, R. (2016). Science of the heart, volume 2, Exploring the role of the heart in human performance: An overview of research conducted by the HeartMath Institute. HeartMath Institute. https://doi.org/10.13140/rg.2.1.3873.5128

Philips, K. H., Brintz, C. E., Moss, K., & Gaylord, S. A. (2019). Didgeridoo sound meditation for stress reduction and mood enhancement in undergraduates: A randomized controlled trial. Global Advances in Health and Medicine, 8, 216495611987936-2164956119879367. https://doi.org/10.1177/2164956119879367

Porges, Stephen (PsychAlive, 2018, 0:27). https://www.youtube.com/watch?v=ec3AUMDjtKQ 

Silver, L. (2021, February 5). The neuroscience of the ADHD brain. ADDitude https://www.additudemag.com/neuroscience-of-adhd-brain/

Source Vibrations – International Music. (2018, November 6). State training with brainwave entrainment ~ Module 1: Introduction and overview [Video]. YouTube. https://youtu.be/kdom2amIrNU

Tarnacki, J. (2019). This is Your Brain on Drumming. Medium.com. https://medium.com/swlh/this-is-your-brain-on-drumming-8ed6eaf314c4

Author: libra kaplan

Artist, dreamer, graduate student, & aspiring psychologist

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