Vicarious breathlessness: an inferential perceptual learned transposition process that may not be inconsequential to either patient or caregiver

People with common chronic cardiorespiratory conditions can live with chronic breathlessness for years [1]. Disabling chronic breathlessness, persisting despite optimum treatment of the underlying cause [2], is experienced by almost all patients with advanced lung disease, such as chronic obstructive pulmonary disease (COPD) [3], and carries a significant emotional, social, health and economic load. Intimately related to physical activity, chronic breathlessness reduces the ability to carry out activities of daily living [4] and restricts the role in the family, workplace or wider society [5]. These consequences, with additional frightening severe episodes of breathless crises, lead not only to acute emotional responses that not only widely activate a multitude of brain regions [6], but also promote the insidious development of depression, anxiety and panic, and a reduction in physical and mental quality of life proportionate with the severity of breathlessness [7].

Inevitably, the responsibility to support daily physical and psychological needs falls to life partners or family members, very few of whom anticipated such a situation at the outset of the relationship, and none of whom volunteered to be destined into a family with such a challenge. Family and friends make up a large workforce who provide care for people with chronic conditions around the world (an estimated 6.5 million in the UK [8] and 65 million in the USA [9]), and include the 7–10% of the population who have given hands-on personal care for someone at the end of life in the previous 5 years [10, 11]. The number of people providing informal care for someone with chronic breathlessness is less well delineated, but 66–77% of people with advanced lung cancer [12], COPD [13, 14], neuromuscular disease [15] or cystic fibrosis [16] reportedly have a family caregiver. This often unrecognised and relatively unsupported community manages complex medication and oxygen regimens, with vigilance (often at night) for breathlessness crisis which is frightening for both patient and caregiver. This caregiver role often brings detriment to their own social/work life balance, as well as to physical and mental health, and is usually provided with no or suboptimal training. Consequently, many caregivers may have poor confidence, be overprotective [17], drive increased emergency health service use [18, 19] and may frustrate the patient [20]. A systematic review and synthesis of 101 qualitative studies of patient, caregiver and clinician experience of chronic breathlessness described the complex interplay between the patient's and caregiver's coping and help-seeking behaviours around breathlessness, and the clinician's attention to breathlessness, as well as to treatment of the disease [5]. One of the prominent conclusions from this review was that engaged coping strategies and appropriate help-seeking practices allowed maximum “breathing space” for the patient.

But what about the caregiver? The important information provided in this issue by Herzog et al. [21] begins to address this issue. If caregivers witnessing severe breathlessness also experience vicarious breathlessness, then this phenomenon may add fuel to a desire to restrict exertion (with accompanying deleterious patient deconditioning) or to facilitate unnecessary calling of emergency services for a self-limiting breathlessness crisis.

The process through which the transfer of perceptual breathlessness from the patient to the caregiver occurs is unclear. To a certain extent, there needs to be a priori familiarity with the concept of breathlessness, something that is naturally acquired from very early in life through physical activity, particularly during peaks of anaerobic activity that characterise child play [22]. However, such familiarity and learned perception do not necessarily foster the concurrent emotional empathy response to the visual observation of a patient manifesting symptoms and signs of breathlessness. The latter is clearly an additional learned process, which is further strengthened through the assumption of the caregiver role. The concurrent association of learned breathlessness awareness and learned emotional response to the latter is likely the basis for the inferential perceptual transposition that Herzog et al. [21] report in their study. To better understand the potential ramifications of this phenomenon, it is important to address, if only very briefly, the cognitive processes that prescribe the emergence of vicarious breathlessness. Contemporary theory in the field of cognitive neuroscience readily discriminates among the processes and utilities that serve to categorise sensory experiences, i.e. the existence of both explicit and implicit systems of category learning. These highly divergent systems will progressively acquire category rules by active hypothesis testing or adaptive behaviours by association and reinforcement, respectively [23, 24]. In a setting of visually perceived stimuli such as breathlessness, the implicit system will learn using multidimensional processes that integrate across stimulus features, and this process will depend on associative-learning pathways to link breathlessness in the patient to adaptive responses by the caregiver (e.g. discontinue physical activity or provide a treatment intervention to patient even if not always required). Thus, implicit learning produces category knowledge that is opaque to declarative consciousness, a process that could hamper conscious judgement in decision-informed approaches, unless the process of vicarious breathlessness is modulated by specific and concurrent formal training using explicit learning paradigms.

Education and training for caregivers is therefore crucially important. Although clinicians endorse the need for joint patient/caregiver training to help with confidence and self-efficacy, implementation of this desirable goal is usually provided in an ad hoc manner only during clinic appointments [25]. Farquhar et al. [26] identified six key caregiver-reported areas for education: 1) understanding breathlessness; 2) managing anxiety, panic and breathlessness; 3) managing infections; 4) keeping active; 5) living positively; and 6) knowing what to expect in the future. Many of these areas are very relevant if the caregiver is also experiencing breathlessness. In the study by Herzog et al. [21], the participants were students or healthy volunteers, many were women, and many of their previous experiences with respiratory conditions, including their familiarity with breathlessness, were not specifically sought. It would therefore be interesting to see how findings would compare if participants were caregivers of patients with respiratory disorders with either no experience or varying degrees of previous exposures to breathlessness crises. The other factor to consider is that many caregivers may have morbidity of their own with personal experience of chronic breathlessness. Central perception of breathlessness in people living with chronic breathlessness involves the pre-frontal associative cortex (fear and memory) in addition to multiple other central pathways previously delineated in healthy subjects [27, 28]. If both patient and caregiver have COPD, then vicarious breathlessness might contribute to an increasing spiral of breathlessness in both, a process that could be further amplified by their intrinsic and vicarious antecedent memories of frightening breathlessness. Thus, improved understanding of the conglomerate of interdependencies and mechanisms underlying chronic and acute breathlessness in the patient and its vicarious counterparts in the caregiver will be critically important for the patient, the caregiver and the clinical team, and form part of the “thinking” approach to management in the recently proposed “breathing, thinking, functioning” model of respiratory disease management [29].