What do clinicians come to know about their patient’s heart sensations?

What do clinicians come to know about their patient’s heart sensations? This is not a simple question, as it simultaneously looks at patients as people with bodily experiences, but also as humans understood as systems, as a sort of living machine. What is more intimate than our heart-beating, a familiar yet mysterious sensation we know to be at the very basis of our ongoing experience? Feeling a change in the rhythm or intensity of this fundamental aspect of our embodied existence can be very worrisome. Should clinicians believe patients who complain of cardiac rhythm changes? How accurate are people at detecting medically important heart-beat fluctuations? How should clinicians understand the relationship between symptoms as reported by the patient, and underlying physiological processes? These are complex and multifaceted issues, requiring nimble clinicians who integrate scientific knowledge as well as intuition about what the patient is experiencing bodily. Clinicans develop knowledge of their own bodies through life, and then are required to learn complex anatomical, physiological, and etiological concepts they will use to interpret their patient’s symptom reports. What patients have to say about what is happening in their bodies must be taken seriously, but not necessarily believed. The interrelated problems of how clinicians interpret patient verbal reports, reason about the relation between these reports compared to measurements and scientific models, and then make judgments about the patient’s accuracy in knowing about their own bodies are topics well worth honing in on, and to my knowledge, not throughly explored from a neurophenomenological perspective.

These acts of clinician cognition concerning their patient’s symptoms are framed by an evolving social and professional context. Modern medicine, like the Roman god Janus, stands two-faced, towards healing as an art, but also towards scientific models of disease. In the current era, what is known as “evidence-based medicine” requires an important shift in how clinicians operate, from historically rather unfettered individual judgments in some contexts, to increasingly accepting consensus-developed guidelines formulated from reviews of previous findings. Clinicans who have with great effort developed the ability to intuit diagnoses may have to defend their familiar constructs, criteria, heuristics, and practices if these are not bolstered by peer-reviewed studies, randomized clinical trials, systematic reviews, Bayesian statistical approaches to clinical problem solving, meta-analysis of previous data, and effectiveness metrics. Medical organizations can mandate “best practices” of patient care, “gold standards” of cost-effectiveness for ordering certain tests, references to efficacy criteria that must be satisfied before a program of treatment is established, and more. This ongoing process is transforming medicine, requiring that the traditional art of diagnosis based on years of education and experience be integrated with operationalized definitions, committee-approved metrics, and greater formalization, thus constraining individual opinion and practices in favor of organization-mandated standard operating procedures. Can symptoms based on an individual’s embodied experience be given proper attention in this brave new world of medicine?

I hope that more researchers would address the clinical aspects of neurophenomenology. This is a relatively new and undeveloped area. While William James and Erwin Straus were clinicians, as is Antonio Damasio, other pioneers such as Maurice Merleau-Ponty and Francisco Varela backgrounded medical concerns somewhat (however, if you are unaware of Varela’s haunting work at the end of his life “Intimate Distances -Fragments for a Phenomenology of Organ Transplantation“, it is a must-read.) Shawn Gallagher has made an excellent synthesis of philosophy and clinical studies in “How the Body Shapes the Mind“, a work that bears greater attention from the small community of neurophenomenology researchers.

For my part, I shall focus in on a particular area, palpitations, where changes towards operationalizing and standardizing the definition of “clinically significant” symptoms are occurring, with the aim of modeling the relationship between patient symptom reports and “significant” arrhythmias as revealed on ECG measurements. I will especially focus on how the predictive utility and accuracy of the reports can be operationalized, and attempt to represent for one domain how patients’ verbalization of their phenomenological state can be “mapped” onto measurements of cardiac rhythm abnormalities.

How to operationalize the “body-knowledge” construct so it can be analyzed and measured

I started using the term “body-knowledge” a few years back as a way to label the extent to which people can accurately report symptoms or interior sensations. It is not as of 2010 a popular term. The earliest citation of the term I know of is from a clinical neurology paper by Sirigu, Grafman, Bressler, and Sunderland, (1991): Multiple representations contribute to body knowledge processing: Evidence from a case of autotopagnosia

“Body knowledge” does quite not have the same meaning as “embodied cognition”, “body image”,”body schema”, “interoception”, “visceral perception”, or even “body cognition”, though there is considerable overlap. I typically use the concept body-knowledge to emphasize the verbal reporting of internal states. My epistemology teacher years ago taught me a great idea:

To know something, you have to know that you know it, and to know that you know it, you have to be able to say it.

I wouldn’t defend that as the end-all be-all theory of knowledge, but it works as a heuristic at the least. For now, I use “body-knowledge” to refer to how well people can know and verbally report on what is happening to their physiological states.

To analytically probe this construct, I started looking very deeply at a particular domain: symptom reporting about cardiovascular processes. I have found some useful results from earlier studies that serve as a guide to help approximate how accurate people are when they feel and report palpitations: their heart is racing, they feel irregular beats, heart thumping or pounding, skipped beats, and so forth. Evidently a fair amount of the time people suffering from panic disorder or anxiety “cognize” otherwise benign sensations and report heart problems, and such false positives adds a great deal of expense to the healthcare system.

Symptom report accuracy is a largely unexplored area for the young field of neurophenomenology: how much of what is happening inside our bodies is accessible to our minds? Very little of the existing neurophenomenology literature deals with these issues.

How can the “body-knowledge accuracy” construct be operationalized, analyzed and measured? For the particular domain of palpitations reporting, here are some useful core metrics:

From ‘The Validity of Bodily Symptoms in Medical Outpatients,” (Barsky, 2000) Chapter 19 in The Science of Self Report (Stone, A, ed): -When patients complaining of palpitations undergo 24-hour, ambulatory, electrocardiographic monitoring, 39% to 85% manifest some rhythm disturbance; the vast majority of these arrhythmias are benign, clinically insignificant, and do not merit treatment). Although as many as 75% of these patients with arrhythmias report their presenting symptom during monitoring; in only about 15% of cases do these symptom reports coincide with their arrhythmias.

From Barsky, Ahern, Delamater, Clancy & Bailey (1997): -145 consecutive outpatients referred to an ambulatory electrocardiography (Holter) laboratory for evaluation of palpitations were accrued, along with a comparison sample of 70 nonpatient volunteers who had no cardiac symptoms and no history of cardiac disease. A symptom was considered accurate when it followed within 30 seconds after any demonstrated arrhythmia.

-average positive predictive value (PPV)… is equal to the number of reported symptoms that were preceded by an arrhythmia divided by the total number of symptoms reported (true positives / [true positives + false positives]).

-Ninety-nine palpitation patients (68%) reported at least one palpitation during monitoring. Among those patients who were symptomatic, the mean number of diary symptoms reported in 24 hours was 3.7. The mean PPV for all symptom reports among palpitation patients was 0.399, compared with a mean PPV = .118 for the nonpatient volunteer sample (p = .01).

-the palpitation descriptors most likely to be accompanied by electrocardiographic abnormalities are heart stopping, fluttering, and irregular heartbeat. The least predictive descriptive terms used by the patients were racing and pounding.

-34% of the symptomatic palpitation patients and 11% of the asymptomatic comparison subjects were classified as accurate reporters

How accurate are people at knowing what is happening inside their bodies?

Were people utterly inaccurate at judging their body state and reporting on it, clinical medicine would be deprived of a critical tool.  Evidence has accumulated that in certain circumstances, some people are evidently able to access information about the physiological processes inside of their bodies, and to report on it.  Experiments seem to demonstrate that some people are relatively accurate perceivers of symptoms or physiological state (Jones and Hollandsworth, 1981), (Adam, 1998), and that subjects can be ranked into good or poor estimators of internal state; for instance, with perceivers of heart rate (Schandry, 1981).

When we are actually aware of specific processes inside our bodies and can state this verbally, it would seem that in some fashion unconscious information (or unconscious “information”) has generated or has been transformed into knowledge. However, there is contradictory evidence about accuracy of symptom perception: how good people really are at perceiving various physiological states, and how accurate symptom-reports or other verbal-reports actually are. Many studies have yielded data consistent with the idea that people are not particularly good at accurately reporting on their symptoms or physiological states (Pennebaker, 1982). It is worth pointing out the assertion that people are generally inaccurate about knowing about physiological processes in their bodies reformulates the principle that humans lack epistemological privilege concerning introspective or verbally reported data. In considering the question: are we are likely to be in error when we report on the contents of what is in our minds, or not, it is critical to appreciate the persuasive interpretation of experiments written up in papers such as “Telling More than We Can Know” by the psychologists Robert Nisbett and Timothy Wilson (1977), which seems to show how introspection-based retroactive judgments can are in error.  This category of research typically features subjects placed in circumstances where their choices are influenced by variables controlled by experimenters, and who give explanations for their choosing that display incorrect “folk psychological” constructions. Nisbett and Wilson’s analysis can properly interpreted as to cast doubt on the ability of people to know the causes of our behavior and “higher order” information-processing, and can be summed up with their statement that people may possess “little ability to report accurately on their cognitive processes” (p. 246).

However, I assert that this valuable critique of retrospective judgments has been improperly extrapolated to support a broad skepticism about introspection, what I shall call the “received view” or the “overly skeptical view”, which I might sum-up as the belief that introspective data should generally be regarded with skepticism. As has been noted by careful researchers on introspection, (Schwitzgebel, 2006), this more general rejection of introspection certainly goes beyond what Nisbett and Wilson argued: while they do indeed assert that the evidence of numerous studies shows people are poor at using verbal report-based introspection to the cognitive process behind our judging and deciding, they do not support a general disdain for introspective data. Rather, they state that instead of arguing that introspective reports should simply be discredited, while people do not have introspective access to the cognitive processes, they do have such access to the contents of their cognitions. For instance, Nisbett and Wilson (pg. 255) state that introspection can yield forms of knowledge: knowledge about cognitive content, as an everyday person:

“…knows what his current sensations are and what almost all psychologists and philosophers would assert to be “knowledge” at least quantitatively superior to that of observers concerning his emotions, evaluations, and plans”

Furthermore, the “received view” that introspective reports are to be generally regarded with suspicion is in tension with the clinical use of patient introspection, as well as the high accuracy ratings sometimes displayed in experiments where subjects are asked to evaluate their own physiology. Therefore, while showing appropriate regard for data suggesting limits on introspective access to cognitive information (indeed I will suggest that models of body-knowledge should account for this data), I will nonetheless highlight certain clinical and experimental data that support the following assertion, which  contradicts the view that introspective data should be generally regarded with skepticism:

There exist cognitive processes that allow people to access internal body-state or physiological information in a way that enables fairly, or even highly, accurate verbal reports.  Insofar as this is true, people evidently have some degree of epistemologically privileged access to internal body state or interoceptive information. This relative privilege allows for knowledge of the body, as distinct from mere beliefs.

However, if this is true, some accounting of to what degree or how true it is, with which mitigating conditions, and with what reference to underlying cognitive and neurophysiological mechanisms would be necessary.  For that matter, even if true, demarcating the explanatory power of this principle relative to data adequately explained by the “received view” or “overly skeptical view” is of critical importance. It may be that only special or rare abilities are at issue here, and that the people who have privileged access to their internal physiological information are outliers.

more on the status of introspection in psychology and in neuroscience

An index of the status of introspection within psychology comes from Medin, Markman, and Ross (2004) in the textbook Cognitive Psychology, which notes (pg.20) that:

“Although introspection is not an infallible window to the mind, psychological research is leading to principles that suggest when verbal reports are likely to accurately reflect thinking”

These perspectives all can be said to implicitly or explicitly challenge what I shall call the “received view” or the “overly skeptical view”, which is an interpretation of the Nisbett and Wilson work that goes beyond what those authors’ famous paper actually said. While it is the case that the “Telling More than we can Know” Nisbett and Wilson paper argued persuasively that introspection-based reports of subjects asked to retrospect on the causes of their behavior are generally not accurate, these authors made a point of not dismissing the value of introspection and verbal reporting on the contents of cognition one is aware of , such as sensation or perception and “private facts”. But the “received view” of their research all too often neglects or ignores the more nuanced and balanced view about introspection of the authors, as well as that of other cognitive scientists who carefully investigated the issues involved, such as Anders Ericsson and Herbert Simon (1993).   This is an important concept: see Eric Schwitzgebel’s excellent take on the “Nisbett-Wilson myth“.

What is the most important concept to take away from the controversies about introspection? Probably it is that insofar as researchers want to be able to take advantage of all possible tools and data sources to make sense of the complex, enigmatic processes characterizing body knowledge, they should follow the example set by many physicians and some experimentalists, and be willing to get data by asking subjects or patients for their observations on body state. But here I will go one step further, and assert that the accuracy, or lack of accuracy, of verbal report data relative to other data, can serve as that which must be explained by a comprehensive and robust model of personal or self-reportable knowledge of the body. Doing so would require experiments where verbally reported data might be compared to, and possibly integrated with, data from external sources, such as from brain measurement: “neurophenomenology” in operationalized form.

One such effort came from a trio of researchers interested in assessing whether introspective data on pain had measurable neural correlates (Coghill, McHaffie, Yen, 2003, pg. 8538):

“Using psychophysical ratings to define pain sensitivity and functional magnetic resonance imaging to assess brain activity, we found that highly sensitive individuals exhibited more frequent and more robust pain-induced activation of the primary somatosensory cortex, anterior cingulate cortex, and prefrontal cortex than did insensitive individuals. By identifying objective neural correlates of subjective differences, these findings validate the utility of introspection and subjective reporting as a means of communicating a first-person experience”

This forward-looking research in effect turns behaviorism on its head: instead of verbal reports being rejected or at best tolerated within the overall context of strict objectivity, the very phenomenon the model seeks to explain is “subjective”!

Verbal report data: psychologists may be skeptical, but clinicians are more practical

Cognitive neuroscience and psychology needs to account for  verbal report data from people about their body states. In perceptual psychology and psychophysics experiments, in cognitive studies of human problem-solving, in clinical trials of drug efficacy and safety, in phenomenological-psychological investigations into the thematics of body experience, researchers routinely ask subjects or patients to answer questions. This is so common that its significance is perhaps under-appreciated. Science, at least in a narrow sense,  is conventionally understood to be based on objectively observable facts, not subjective opinions. But certain phenomena can not only be observed from the outside, as part of a system, but can also be reported on by people from the inside, as perceived or experiential events.

This regular use of the human self-reporting capacity is more remarkable in the light of intellectual history.  “Orthodox” cognitive science developed in the era of behaviorist dominance, and inherited certain skepticism about the trustworthiness of verbal reports, which are viewed as being sources of data, but not “privileged.” This stance indicates a rejection of older philosophical and psychological traditions that emphasized the use of introspection. Nonetheless, even in the time of behaviorist hegemony, psychologists still asked subjects questions in perception experiments, and clinicians have always used patient assessments to gain insight (Nahmias, 2002). While certain path-breaking cognitive scientists and psychologists explored the nature of introspection, and worked out the circumstances in which verbal reports could be authoritative and true accounts of aspects of cognitive processes (Erickson and Simon, 1991), (Ericsson, Chase, and Simon, 1979), the results of other widely cited experiments have been interpreted to denigrate introspective data, especially that of Nisbett and Wilson’s (1977) “Telling More than we can know” paper. Their research has been interpreted to indicate, for instance, that subjects made demonstrably inaccurate judgments about their underlying mental states because human beings apparently have little or no direct introspective access to the underlying cognitive processes of the mind (pg. 233):

“The accuracy of subjective reports is so poor as to suggest that any introspective access that may exist is not sufficient to produce generally correct or reliable reports.”

The interpretation of their data featured assertions that are now influential:  subjects lack  introspective access to the causal relationship between stimuli controlled by the experimenter and the verbal reports they produce. They are unable to accurately report which stimuli affected their responses. Rather, these verbal reports of effects of stimuli are based on unvalidated belief (such as naïve “folk psychological” theories about the causal connections between the stimuli and their response). Furthermore, if the reports on stimulus-response relationships are correct, it is because their naïve theories happen to be correct, and not because introspection gave them any privileged access to information. The upshot can be summarized as: subjects in situations with variables controlled by scientists make introspective judgments about why they behave in a particular manner or think a certain way, they state this explanation verbally to an experimenter, who can show the explanation to be false: (pg. 243)

“In order to test subject ability to report influences on their associative behavior, we had 81 male introductory psychology students memorize a list of word pairs. Some of these word pairs were intended to generate associative processes that would elicit certain target words in a word association task to be performed at a later point in the experiment. For example, subjects memorized the word pair “ocean-moon” with the expectation that when they were later asked to name a detergent, they would be more likely to give the target “Tide” than would subjects who had not previously been exposed to the word pairs….Immediately following the word association task, subjects were asked in open-ended form why they thought they had given each of their responses in the word association task. Despite the fact that nearly all subjects could recall nearly all of the words pairs, subjects almost never mentioned a word pair cue as a reason for giving a particular target response. Instead subjects focused on some distinctive feature of the target (“Tide is the best-known detergent”), some personal meaning of it (“My mother uses tide”), or an affective reaction to it (“I like the Tide box”).

The influence of this research has had the practical effect of renewing suspicions among psychologists and other researchers about introspective data, even if such methods continue to be used (Jack and Roepstorff, 2003) and despite the balanced view of Nisbett and Wilson where introspection has some utility regarding “sensations and/or private facts”, which takes into consideration the longtime use of introspective data as a method in psychology. Cognitive scientists, psychologists, physicians, and others can adopt their pragmatic distinction between the contents of cognition, such as sensations and emotions which can indeed be known and verbally reported, and the underlying causes, the information-processing or cognitive processes, which remain epistemologically inscrutable to introspection.

Yet while clinical medicine often regards introspective data with caution, it nonetheless uses it pragmatically. For instance, the standard neuropsychology text Clinical Neuropsychology (Heilman and Valenstein, 2003) states (pg.5)

“at times, patients’ observations of their own mental state may not only be helpful but necessary.”

This implies that it is a standard clinical methodology to use introspective data, and that patients have some useful access to their own minds.

This data-collection method of asking subjects and patients for self-reports is routinely used, according to psychologist Arthur Stone (Stone, 2000) (pg. 297):

“In both clinical practice and in research, the primary method of obtaining information about physical symptomology is through self-reports. Every day, thousands upon thousands of health care providers ask their patients to describe how they are generally feeling and too discuss specific symptoms. Patients present their doctors with panoply of global states (“I feel lousy,” “I am fatigued,” “I don’t feel right”) to very concrete descriptions (“I have a sharp pain in my right knee that is worse on awakening”). Information from these interviews, along with various medical tests, provides the basis for treatment and for the evaluation of its efficacy. In medical research, information of the same sort is obtained with questionnaires and structured interviews. These data-collection methods may provide a more systematic way of gathering physical symptom information, but regardless of the mode of data collection, the information is self-reported. Thus, reports of physical symptoms may be considered the mainstay of medical practice and research”

the legacy of Cartesian “objectivity” makes it hard to understand patient verbal reports

Psychiatrist Allan Beveridge (2002) hones in on a facet of the patient-physician relationship relevant to neurophenomenology: the over-adoption in medicine of the scientific attitude of objectivity towards phenomena. While entirely appropriate in the many research contexts, this may make understanding the personal body-knowledge of the patient more difficult (pg. 101):

“In the mental state examination, a standard method of describing the clinical encounter is to contrast the patient’s supposedly ‘subjective’ account with the doctor’s ‘objective’ description. In this model, the doctor is granted a privileged position: the clinician’s perspective is taken to be superior to that of the patient. The doctor’s objective approach is considered neutral, scientific and representing the truth of the matter. In contrast, the patient’s subjective report is regarded as unreliable, distorted and potentially false. The lowly status of the subjective perspective is further emphasized by the frequent use of the accompanying prefix, merely. On reflection, this dichotomy is an extraordinary one. It is held that the doctor is an authority on the patient’s inner experiences. The doctor knows more about how the patient is thinking and feeling than the patient him-/herself”

This “scientific” medical stance towards patient subjective reporting is consistent with the Cartesian heritage of the sciences of the mind. The implications, hidden or unexamined commitments should be critically examined if the verbal reports about patient body-states are to be better grasped by science and medicine. To the extent cognitive science, psychology, neuroscience, and medical fields uncritically base their methodologies on unexamined premises, certain problems may appear just due to the very choices of what is considered “data”. The relegation of patient verbal reports to the category of “merely subjective” allows for Cartesian assumptions about cognition to create difficulties at the outset of any research project attempting to model personal knowledge of the body. It may be that the very categories of subject and object, or scientific knowledge vs. subjective or “folk psychological” naïve theories of the body, present foundational problems for understanding how neurophysiological processes relate to verbally reportable knowledge of the body. But as a practical matter, health care professionals must simply cope with patient statements as one more data source (Ersser and Atkins, 2000, pg. 68):

“Clinical decisions involve information of a necessary type and quality. Professionals take account of both objective and subjective data during the clinical assessment process to decide on a patient’s health care need and care plan. The difficulty lies in professionals understanding how best to reconcile their objective perspective with that of the patient, when formulating clinical judgments”

Before a doctor revives technical training, he or she is a person with experiences of health and sickness. The verbal reports of patients are interpreted by professionals with their own history of embodiment. To what extent does their personal body knowledge consciously or unconsciously affect their clinical intuition about the accuracy of patient verbal reports? Does expert knowledge of the body gained from studying anatomy and physiology allow for better knowledge of one’s own body? Such questions point to our current rather murky understanding of embodied cognition, underscoring the need for models capturing richer, more subtle aspects of experience, cognition, and brain.

Jack and Roepstorff on introspection

From Trusting the Subject (2003), Anthony Jack and Andreas Roepstorff write:

“The unique challenge facing a science of consciousness is that that the best instrument available for measuring experience depends on cognitive processes internal to the subject. So just how much faith can we place in the capacity of the mind to understand itself? In principle, the construction of a maximally robust methodology for introspective evidence would require a detailed understanding of the operation of introspective processes — the processes that mediate the acquisition of introspective knowledge and underlie the production of introspective reports”

And:

“It is important to realize that no principled problem stands in the way of the scientific assessment of various types of introspective evidence. The testing of the reliability, consistency and validity of various types of introspective report measures lies well within the orbit of currently available methods. A measure may be called ‘reliable’ if it yields the same results when tested in multiple sessions over time (‘test–retest reliability’) and across individuals (a cousin of ‘inter-rater’ and ‘inter-observer’ reliability). Of course, subjects’ reports may differ, and so appear to be unreliable, simply because their internal mental processes and states vary. Thus it is critical to establish well controlled experimental conditions for eliciting reports. The considerable advances in behavioural science since the time of the Introspectionists offers experimenters considerable advantages in this regard (see Ericsson, this volume). Not only do these advances make it much more probable that experimenters can establish conditions under which introspective measures can be shown to be reliable, they also provide much greater insight into the behavioural and neural correlates of experiential phenomena.

A measure may be called ‘consistent’ when it can be shown that the results are not due to specific features of the measurement technique. Tests of consistency provide a means of checking that the observed effect is not due to a methodological artefact. Thus we might test the consistency of introspective  evidence by comparing immediate forced-choice button-press reports with retrospective and open-ended verbal reports. In this way we might establish, for instance: that the results of forced-choice button-press reports have not been influenced by variations in the criterion for response or by automatisation of response such that they no longer constitute true introspective reports; and that retrospective reports have not been distorted by forgetting or memory interference effects.

‘Validity’ is the most important factor to establish, yet it is also the most theoretically complex, and a particularly vexed issue in cognitive science. A measure is validated when it can be shown to accurately reflect the phenomenon it purports to measure. Validity is complex because scientific measures are often simultaneously interpreted as providing evidence for phenomena at a number of
different levels. A rough characterisation of three major sources of evidence in cognitive science might read as follows:

-Data from functional Magnetic Resonance Imaging (fMRI) serves most directly as evidence of cerebral blood flow (which has been validated), less directly as evidence for neural activity (which is in the process of being properly validated), and least directly as a means of identifying and localising specific cognitive functions (far from well validated).

– Behavioural measures (e.g. the averaging of reaction time measures over multiple trials) serve most directly as evidence for stable patterns of behaviour, less directly as a means of assessing information processing, and least directly as means of establishing the existence and operation of specific cognitive functions.

-Introspective reports serve most directly as evidence about the beliefs that subjects have about their own experience, less directly as evidence concerning the existence of experiential phenomena, and least directly as evidence concerning the operation of specific cognitive functions.