A Freshening Breath of Insight

In this article we attempt to take a few concepts that are coming from different fields and integrate them into a somewhat new understanding of biofeedback, interoceptive exposure, and breathing training. Let us begin with the concept of exposure: There is general agreement that exposure therapy is one of the leading methods in current cognitive behavioral therapy interventions. Exposure therapy takes a prominent place in international guidelines for the treatment of anxiety disorders (e.g., National Institute for Health and Clinical Excellence, 2011).

The exposure treatment that began in the late 1950s with systematic desensitization by Wolpe (1958, 1961), for a flooding treatment (Marks, 1975), and implosive therapy by Stampfl and Levis (1967) has been used in many ways over the years. It is essential to note that, though exposure originally was part of cognitive behavioral therapy, it soon became part of any psychotherapy. One can see a patient's confrontation with unconscious content, such as conflicts or wishes, another form of exposure. Even in experiential treatments such as Gestalt (Abramowitz, Deacon, & Whiteside, 2011) and accelerated experiential dynamic psychotherapy (cf. Fosha, 2005), the patient is confronted with the information he chooses to avoid.

Biofeedback as a treatment is based on theoretical foundations of behavioral methodology. However, the concept of exposure was not integrated very well in biofeedback literature. For example, Khazan's (2013)The Clinical Handbook of Biofeedback: A Step-by-Step Guide for Training and Practice with Mindfulness contains an instrumental series of protocols, but none of them includes a classical exposure stage. Schwartz and Andrasik's Biofeedback: A Practitioner's Guide, did not include exposure as a part of biofeedback training. It wasn't until the fourth edition of the Biofeedback Practitioner's Guide (2017) that Hamiel and Rolnick (2017) and Rolnick, Gal, Basset, and Barnea (2017) included a definite stage of exposure in their protocols.

Indeed, a particular type of exposure is now included throughout various stages of biofeedback, beginning with psychophysiological profile, where the patient is exposed to multiple stimuli, to the stage where he incorporates his ability to use the regulation techniques he acquired in anxiety-provoking situations.

Interoceptive Exposure

Interoceptive exposure (IE) is a behavioral intervention designed to reduce anxiety and distress associated with somatic sensations. IE is well established in the treatment of panic disorder and increasingly used to target anxiety-provoking physical sensations in other disorders (Boettcher, Brake, & Barlow, 2016). IE can be induced with a wide variety of provocation procedures such as CO₂ inhalation, lactate infusions, or caffeine. These procedures include methods such as hyperventilating, breathing through a straw, spinning, running in place or step-ups, muscle tensing, head shaking (Lee et al., 2006). Nonetheless, Barlow's view of the IE application does not designate any other therapeutic role for the therapist besides exposure facilitation. We will demonstrate the importance of the therapist's stance and actions through the process of IE.

The focus of the discussion in this article is the relatively new modality of biofeedback therapy—capnometry. The aim of introducing this modality is threefold. We want to demonstrate (a) the presence of exposure in the treatment of biofeedback in less likely places; (b) the benefit of focusing on interoceptive experiences; and (c) the integrative potential inherent in biofeedback-based interventions. First, we suggest using IE as a part of breathing training using capnometry.

Capnometry-Assisted Biofeedback

Capnometry is a relatively new modality of biofeedback. Capnometry has still not been widely adopted compared with other familiar biofeedback modalities. In recent years, it has gained momentum primarily in the treatment of panic disorder (Kim, Wollburg, & Roth, 2012; Meuret, Ritz, Wilhelm, Roth, & Rosenfield, 2018), fear of needles and blood (Meuret et al., 2018; Mennitto et al., 2018), and asthma (Ritz, Rosenfield, Steele, Millard, & Meuret, 2014). Capnometry-assisted biofeedback is based on a measurement of end-tidal pCO₂, which reflects the degree of gas exchange in the breath, which in turn indicates the degree of blood alkalosis. The medullary brain stem regulates spontaneous breathing through information coming from chemoreceptors (pH, CO₂). Changes in blood acidosis/alkalosis levels lead to decelerating/accelerating respiration. Breathing acceleration leads to too much CO₂ emission and hypocapnia.

Treatment protocol of capnometry-assisted biofeedback contains three steps:

1. Acquisition of respiratory mechanics: diaphragmatic breathing.

2. Reducing the amount of end-tidal pCO₂ by training with capnometer.

3. Adjusting the optimal respiratory rate while maintaining the optimal amount of end-tidal pCO₂ emitted during respiration. This therapeutic protocol differs from the proposed protocol for the treatment of a panic disorder.

Meuret, Wilhelm, Ritz, and Roth (2008) recommended short therapy that contains psychoeducation, the acquisition of respiratory rate, and subsequently the control of optimal end-tidal pCO₂. Home training includes a paced breathing phase and transfer phase protocol that lasts 4 weeks with a home device.

Training can be even shorter when it comes to blood injection injury phobia. Moreover, its efficacy appears to be equivalent to the applied tension technique, which is considered the gold standard in the treatment of blood injection injury phobia (Meuret et al., 2018; Öst & Sterner, 1987).

Meuret et al. (2018) reviewed research data collected by capnometry-assisted biofeedback as containing an IE component, interoception of dyspnea. Dyspnea is a sensation characterized by chest tightness, air hunger, and breathing effort (Davenport & Vovk, 2009). The higher the level of dyspnea throughout the exercise, the lower the level of panic symptoms was in the subsequent exercise. Thus, as the exercises were mainly related to dyspnea and did not raise the level of anxiety, the symptomatic improvement was more significant. These findings have led to the conclusion that exposure at moderate to lower levels of anxiety results in the improvement of panic symptoms in contrast to previous models of exposure therapy such as flooding.

The conclusions of the review by Meuret et al. (2018) lead us to look at additional biofeedback techniques as containing a component of interoceptive exposure. These may be mainly techniques that raise awareness of internal processes so that practicing breathing techniques and muscle contraction include interoceptive exposure. Perhaps a different model for conceptualizing biofeedback therapy will be required. Such a model should consider the interoceptive component.

Mentalized Homeostasis

The first model that comes to mind is Miller and Dollard's (1941) stimulus-response theory of learning. This model asserts the importance of drives or internal cues in the development of an infant. Through interoceptive awareness to drive (cue) and the drive's satisfaction (reward), the infant learns how his body functions as well as how to manipulate his caregiver. Applying this model for capnometry-assisted biofeedback will clarify the processes it contains.

The first process in capnometry-assisted biofeedback is drive-evoking. By introducing the client to respiratory rate training, air hunger (drive) is evoked, leading to dyspnea (cue). Drive-evoking repeats at the acquisition of diaphragmatic breathing while reducing the amount of end-tidal pCO₂. The second process is a cue-produced response. The expected response is adapting to respiratory rate and normocapnic range. The third process is a twofold response–reward linking. We are linking the behavior (e.g., respiration at a specific rate) and feedback on screen, and the practice with less panicogenic cognitions.

Nevertheless, this model does not elucidate the role of anxiety rise through these processes. An explicating theory is the theory of mentalized homeostasis by Fotopoulou and Tsakiris (2017). Mentalized homeostasis theory is an interdisciplinary approach to the reciprocal relationship between social cognition formation and physiological development. In this short article we can present only a limited discussion of this topic.

Drawing from neuroscience, philosophy, and attachment, Fotopoulou and Tsakiris (2017) defined the concept of mentalized homeostasis. They postulate that the neurological mechanism that enables body awareness, feeling of agency, and selfhood, is also used for inferring about body signals and operates in social interaction aimed at achieving homeostasis (e.g., caregiver calming an infant) as well. Fotopoulou and Tsakiris (2017) conceived interoception as part of the homeostatic process. By this process, information from within the organism is aggregated and then used to infer about homeostatic needs. This information is shaping body perception and sense of self. In other words, unless a person keeps in mind (mentalizes) bodily occurrence sensations (interoception) and trusts its accuracy, inferences on body safety and security will be compromised. Sensations of insecurity, in return, will result in anxiety.

Interoception inaccuracy is related to known psychopathologies (Herbert & Pollatos, 2012; Pollatos et al., 2008; Schultchen et al., 2019). Following the theory of mentalized homeostasis, anxiety is evoked when information gathered through the interoceptive process is inaccurate. Therefore, we can hypothesize that the anxiety level during capnometry exercises reflects the interoceptive accuracy. If interoception is reasonably accurate, the level of anxiety is at a low-to-moderate level.

Following this line of thought, perhaps we should consider training for interoceptive accuracy in biofeedback sessions. One way of training is by using current techniques while suggesting the client take note of his internal reactions (e.g., noticing a sense of dyspnea on capnometry training). The second way of training is concrete training for interoceptive accuracy. Such training was proposed by Schandry and Weitkunat (1990). Through this training, participants get tonal feedback for each heartbeat and then press a button. The training improved their interoceptive accuracy (Meyerholz, Irzinger, Witthöft, Gerlach, & Pohl, 2019). A version of it seems to reduce state anxiety (Sugawara et al., 2020).

Another conclusion deriving from the mentalized homeostasis theory is the importance of the therapist's presence. Fotopoulou and Tsakiris (2017) observed the interpersonal foundation of mentalized homeostasis. They set the example of collective wisdom of calming a baby. It is easier to calm a baby while standing and pacing than seated in a chair. This observation, backed up with empirical finding (Esposito et al., 2013), supports the idea that the embodied caregiver–baby interaction constitutes the primary feeling of selfhood. These interactions wrap together with the baby's interoceptive information and the external stimuli from the caregiver. Furthermore, this binding initially shapes the baby's interoceptive awareness and will further evolve into a socially bounded modulation of mentalized homeostasis.

Fotopoulou and her colleagues tested this assumption using pain to trigger an interoceptive sensation of compromised homeostasis. They demonstrated a social modulation of adult pain perception. Namely, pain perception is formed by nociceptive information and a prediction of how much social support is possible (Decety & Fotopoulou, 2015; Krahe, Springer, Weinman, & Fotopoulo, 2013). We would like to propose that biofeedback therapists have within their capacities: (a) the option of viewing interoceptive sensations on screen, and (b) the option to socially modulate it.

Aporetic Feelings

Another way of looking at interoception, capnometry, and breath training is through its application for psychotherapy. Interoceptive accuracy is related to emotion regulation and emotional intensity (Critchley & Nagai, 2012). Common phenomena of breath training as part of psychotherapy is abreaction following breathing exercises. Abreaction, for that matter, is reflecting high interoceptive accuracy.

At the other pole of the emotional spectrum are aporetic feelings. Jurist (2005) made a distinction between two types of emotions that appear in the treatment of strong emotions and aporetic feelings. The intense emotions are characterized by clarity and vibrancy. On the other hand, Jurist (2005) placed the aporetic feelings. The term aporetic derives from the word aporia in Greek, which means “difficulty in crossing.” It characterizes these emotions in two forms: unformulated feelings and conflicted or contradictory feelings, which are either vague or confusing, respectively. In line with previous conceptualization, strong emotions occur in times of interoceptive accuracy, and aporetic feelings arise in times of interoceptive inaccuracy.

Both psychodynamic and behavior therapists relate to emotion and conceptualize emotion regulation as a therapeutic task. They both address this task by naming, processing, and expressing emotions. However, they may use different techniques. The psychodynamic therapist differs from the behaviorist counterpart when considering the role of therapist presence. As mentioned above, Barlow does not consider the therapist's presence during exposure to be an essential factor. Nevertheless, neither the psychodynamic therapist nor the behavior therapist will implement different techniques for different emotions (strong feelings vs. aporetic feelings).

A biofeedback therapist, in contrast with a psychodynamic therapist, will suggest his client try interoception-enhancing exercises when he feels confused. This therapeutic strategy has benefits over psychodynamic elaboration of emotion meaning. It offers the client a tool for clarifying his emotions. In contrast with a behavior therapist, the biofeedback therapist will reinforce the client's feeling of security and safety by interpreting anxiety-provoking sensations as regular biological occurrences. For example, he will socially modulate the client's anxiety during breathing exercises by relating the client's body's sensations to dyspnea. The therapist may ask the client to note that his anxiety level is decreasing as his therapy sessions progress, and the therapist may support this observation with measurement of electrodermal activity level.

In summary, drawing from research in breath training, neuropsychoanalysis, and behavior therapy, we can conclude that breath training is not merely a relaxation technique. It entails interoceptive awareness and exposure. Hence, more training facilitation requires a therapist as a biological imperative. Extrapolating this conclusion to the practice of biofeedback therapy in general implies accounting for the therapist's part in establishing the safe atmosphere.