Pain measurement and registration in non-verbal patients · 2015-08-28 · How this relates to pain ๏ Pain is not caused by nociception ๏ because you can be in pain when there

Morten Høgh MSc Pain: Science & Society

Specialist Physical Therapist in Musculoskeletal Physiotherapy (COMT), Specialist Physical Therapist in Sports Physiotherapy (RISPT)

Affiliations: Center for Neuroplasticity and Pain (CNAP) Aalborg University - www.videnomsmerter.dk - FysioDanmark Aarhus/Fysiocenter

Disclosure: I receive fee for authorship of ‘Smertebogen’

Pain measurement and registration in non-verbal patients

http://www.videnomsmerter.dk

“If color was a sense, then red is pain. But how would you determine the color and the nuances if not by asking the patient”.

The Biopsychosocial Model๏ Biochemical reactions do not translate directly into an illness

๏ Biological derangements do not shed light on the meaning of the symptoms in the patient

๏ Finding biology and treating patients require different skill sets

๏ Adopting a sick role does not require any biological derangement

๏ The success of biological treatments are influenced by

• Psychosocial factors (including placebo/nocebo)

• Adherence to treatment (therapeutic alliance)

• Patients are influenced by their clinicians - and visaversa

Engel (1977/1980) Borrell-Carrio et al. (2004)

Nociception

Pain experience

Adapted from Hume (1748)

Causation

if… then

Correlation

oftenif…

Pattern (in theory)

if… ?

then maybe

adapted from ‘An Enquiry Concerning Human Understanding’ by David Hume (1748)

“When two things occur at the same time or within the same place we

tend to believe that they are causal”

Nociception?

Pain experience

Adapted from Hume (1748)

How this relates to pain๏ Pain is not caused by nociception

๏ because you can be in pain when there is no nociception

๏ Nociception does not cause pain ๏ because you can have an injury and not feel it

๏ Pain correlate with nociception ๏ experimental pain depends on a relationship between pain and nociception

๏ We have many excellent theories (patterns) regarding the relationship between pain and nociception (neurophysiology) ๏ i.e. sensitisation and descending signals

๏ But current theories only seem to work if the stimulus is nociception ๏ current theories are insufficient at explaining pain without nociception

What causes pain?๏ No one knows!

๏ But we know that tissue damage alone should not be a theory for pain because it wrongly implies that ๏ pain is causally related to tissue damage = tissue-damage-repair is the only

sensible solution (and everything else is ‘psychogenic’ or ‘covering up’)

๏ pain (and all it correlates with) must go away if the tissue is healed

๏ more pain must mean more damage or be a sign of insufficient healing

๏ there must be undiscovered tissue damage if pain continues

๏ Clinical implications ๏ Understand the patient (‘patient-centred’)

๏ Focus on what pain does rather than what it is

๏ Understand mechanisms that may explain hyperalgesia (rule in/rule out)

Pain will most likely always:๏ Attract you attention

๏ Be aversive or unpleasant

๏ Be experienced in your body (including phantoms)

๏ Motivate you to get away from it by ๏ learning from the situation you are in (find patterns)

๏ behave adequately according to the context you are in (social)

๏ prioritise behaviours, thoughts and actions that are believed to be pain relieving

๏ Influence your well-being, mood and communication

๏ Reflect changes that you need to pay attention to

VA

S

100

Days Weeks Months Years

Is all pain equal?Acute vs. Chronic Pain

Acute pain๏ Intense and highly motivating

๏ ‘Get away and learn to avoid it’

๏ Usually acknowledged by society and peers ๏ ‘I have had it myself’ and ‘don’t worry you will get over it’ responses

๏ Usually highly predictive ๏ ‘Give it a day or two and come back if it hasn’t changed, or if it gets worse’

๏ More obstructive than worrying for most people ๏ ‘…but it’s just bad timing. I really don’t have time for this right now’

๏ Usually very responsive to treatments (any kind) ๏ Why do you think that most treatments don’t show significant effect after 6-12

weeks (regarding NSLBP - check out Artus et al. 2010 and 2014)

๏ But acute pain does not have to correlate with nociception

Normal (acute?) pain

It hurts!!!

I must remember to brush my teeth

Like the last time…

I guess there must be bacteria in my teeth

Chronic pain๏ Exhaustive and discouraging ๏ Unacknowledged by society and peers and HCPs ๏ Unpredictable stimulus-response (e.g. movement:pain) ๏ All absorbing: Is there a future? ๏ Often associated with mood changes and stress ๏ Loneliness: Social support becomes much more necessary

๏ ‘who will believe me’, ‘what can I believe’, ‘who should I trust’??

๏ Life quality: The pain sensation becomes less of a problem than the effect on life

๏ Cure does occur but no treatment is known to be curative

Complex It hurts

Should I be scared!

Will it go away?

Does my dentist know what’s going on with me?

What am I doing wrong?

They don’t believe me!

I should have never…

Never again will I…

Brush my teeth? How?!?

It’s in my teeth

Attention

Genes

Imune system

Culture and social heritage

Expectations

Placebo

Nocebo

Nociception

PERCEPTION

and much more?

Friends, beliefs and knowledge

Experience

Adapted from Moseley (2007)

What is it in this person that make

her hurt in this context?

Butler & Moseley Explain Pain (2003)

Hierarchy of Pain Assessment Techniques

Self-report

Search for Potential Causes of Pain

Observe Patient Behaviors

Surrogate Reporting (family members, parents, caregivers) of Pain and Behavior/Activity Changes

Attempt an Analgesic Trial

Adapted from Herr et al Pain Manag Nurs. 2006;7(2):44-52

Pain is complex - always…

How effective the patient believes the

treatment is

How well the patient can work

and be social

Daily functions

Mood

Social support

StressSleep

NRS (0-10)NRS (0-100)

How are you today?๏ Mood changes (including depression and anxiety) ๏ Sleep disturbances ๏ Cardio-vascular fitness (including metabolic syndrome) ๏ Immune responses ๏ Muscular responses (muscle dysfunction, sarcopenia-like effects) ๏ Reduced self-confidence and meta-cognitive capacity ๏ Socio-economic deroute (job, marriage, parental role…) ๏ Perceived injustice and insufficient support (HCPs, spouse,

family, work…) ๏ Feeling guilty (medication abuse, not doing enough, receiving

passive treatments…)

Patient reports

0 1 2 3 4 5 6 7 8 9 10

Værst tænkeligesmerter

Ingensmerter

Milde s

merter

(1-3

)

Moder

ate sm

erter

(4-6

)

Volds

omme s

merter

(4-7

)

Ingen

smer

ter

(0)

Evaluation of the pain intensity

VAS

NRS

VRS

Faces Pain Scale

Anbefales til ældre uden eller

med mild demens

Pain drawing

Palpation

Patient Specific Functional Scale

Adapted from:Stratford, P. (1995). Assessing disability and change on individual patients: a report of a patient specific measure. Physiotherapy Canada.

Pain provoking functions (disablities)Describe the function:

How would you rate your best, worst and average pain?

Does pain stop you from this activity?

How does the pain react to accumulation of activity?

How long does it take for the pain to reach baseline again?

0-100 (NRS) - best and worse during this activity?

0 = cannot perform the task at all10 = can functionally perform with no restrictions/as before

#2: Search for potential causes of pain

Self-report





๏ Expectations

๏ Mood

๏ Sleep

๏ Social support

๏ Acceptance and understanding

๏ Health Care (providers, payers, law…)

๏ The attitudes of the dentists (and significant others)

๏ Genetics

๏ Tissue damage

๏ High threshold stimuli

๏ Sensitisation (LTP)

๏ Genetics?

๏ Cognition?

PAINNOCICEPTION

Nociceptive Withdrawl Reflex• ‘The Sherrington Reflex’

• Motor response to nociceptive (and other) stimuli

• No strong correlation with other nociceptive responses

The FLARE response

• axonal reflex

• not nociceptive specific

• possible correlation with skin irritants (including pain)

Peripheral terminal

Axon

Cell nucleus

Central terminal

Axon hillock

other neurons

Central neuron

Free nerve endings

Receptors

Acute tissue injury

Axonal reflex

Neural CellularVacular

Peptide exocitose

Proteins released from injured cells

Chemokines, bradykinin, serotonin, histamine,

neutrophils, macrophages

Destruction of bacteria and removal of debris

Vasodilation

Increased permability

Chemotaxis of neutrophils, macrophages, plasma, T-

Cells, mast cells etc.

Cytokine release

NGF/GDNF release from Schwannske Celler

CGRP Sub P

Vasocontriction

Is neuro imaging the answer we are looking for?

What’s causing the activity?

Legrain et al. (2011)

“The pain neuromatrix is dead and it is time for pain research to be more critical”

“Stimulus-specificity can be falsified”

Adapted from prof. Iannetti @ Wellcome Trust scientific congress,

Cambridge 2015

Salience rather than nociception?

Legrain et al. (2011)

Can pain be a conditioned

(learned) response?

Edwards RR et al. (2011)

Placebo mechanisms

Benedetti F (2010)

Fear and learning120 J. Zaman et al. / Neuroscience and Biobehavioral Reviews 51 (2015) 118–125

Fig. 1. Evolution of discrimination acuity and perception of bodily sensations during chronic pain. During acute pain fear learning can result in reduced perceptual discrim-ination, i.e., a reduced ability to discriminate between the CS and similar stimuli (more or less intense stimuli), in this example on the intensity dimension (left panel). Therelationship between discrimination acuity and physical distance between the CS and similar stimuli is represented by the gray ellipses. The ellipses represent compromisedacuity in discriminating between the CS and similar stimuli despite increased physical dissimilarity between stimuli. In addition to decrements in discrimination acuity withdisease progression, the perception of the CSs might also change. CSs can acquire US properties (right panel) and therefore shift on the axis in a non-linear fashion (expo-nential decay). As a consequence of this shift, discrimination impairments that previously applied to these interoceptive and proprioceptive stimuli, result in an impaireddiscrimination of painful and non-painful sensations. CS = conditioned stimulus; US = unconditioned stimulus.

developed an internet-delivered cognitive behavioral therapy pro-tocol that included an exposure procedure in which subjects aregradually exposed to irritable bowel syndrome (IBS) symptoms byengaging in various activities such as eating symptom provokingfoods or physical activities (Ljótsson et al., 2014, 2013, 2011). Therationale of these interventions is that persistence of avoidancebehavior results in the maintenance of fear responses, and interfer-ence with daily activities. In addition, there is emerging evidenceshowing fear learning or extinction deficits in chronic pain patients.Fibromyalgia patients displayed reduced contingency awarenessand safety learning compared to healthy controls in a differen-tial fear conditioning paradigm (Jenewein et al., 2013; Meulderset al., 2015). Schneider et al. (2004) showed elevated conditionedresponses during extinction in chronic back pain patients comparedto controls in addition to acquisition differences. Following pairingof a visual cue with a painful stimulus applied to the abdomen,IBS patients had higher skin conductance responses during extinc-tion compared to controls (Labus et al., 2013). Further support foraltered fear learning and extinction comes from studies on anxietydisorders which often co-occur with chronic pain (Bouton et al.,2001; Lissek et al., 2005; Mineka and Oehlberg, 2008).

1.3. Fear learning, perception and chronic pain

While acknowledging that behavior is an important and treat-able component of chronic pain, less scientific attention has beenpaid to how associative fear learning affects the perception of bodilysensations in general and pain perception in particular. Here, weargue that the effects of associative fear learning on the perceptionof bodily sensations, which may be mediated through perceptualdiscrimination (i.e., reduced discrimination acuity of bodily sen-sations), are especially relevant for contemporary chronic painmodels. Fear learning during acute pain is thought to impair one’sability to discriminate between bodily sensations (CSs) associatedwith pain (see Fig. 1). As a consequence of these learning processes,pain-related expectations arise in response to the CS (Vlaeyen andLinton, 2000, 2012), which bias perceptual decision-making towardpain (Wiech et al., 2014). The combination of these processes mayresult in a lower perceptual accuracy of pain-related sensations(Wiech et al., 2014). Note that perceptual accuracy and discrimina-tion are closely related but not identical, as the former is considered

to be an outcome, while the latter is a process that changes overthe course of the chronification process. Over time, the perceptionof interoceptive and proprioceptive stimuli associated with painchanges. The driving mechanism behind these changes remainsunclear but contemporary theories assign a critical role to anxietyand fear (Vlaeyen et al., 2012; Vlaeyen and Linton, 2012), as theyare thought to bias perception toward pain (Apkarian et al., 2011,2009). Thus, due to their association with pain these bodily sen-sations become aversive (De Houwer, 2007; De Peuter et al., 2011;Van Oudenhove and Aziz, 2013; Vlaeyen and Linton, 2000) and withtime elicit sensations of pain. As a consequence of this shift, discrim-ination impairments that previously applied to these interoceptiveand proprioceptive stimuli, result in an impaired discrimination ofpainful and non-painful sensations (see Fig. 1). Within this frame-work, the role of attentional process should be further explored,especially the concept of hypervigilance given its association withpain (Van Damme et al., 2006; Vlaeyen and Linton, 2000). Hyper-vigilance originates as a consequence of a heightened perceptionof threat and might bias pain perception, as the body is scanned forthreats (Crombez et al., 2005). This detection of potentially threat-ening stimuli could be at the expense of a more thorough processingof sensory input and might result in the misclassification of bodilysensations as painful.

2. Perceptual discrimination and chronic pain

Interoceptive stimuli are often complex constellations of fea-tures on multiple dimensions (e.g., modality, intensity, location,unpleasantness). Their representation consists of a graded pat-tern of activation across a range of units for multiple dimensionssimultaneously (McLaren and Mackintosh, 2000). Perceptual dis-crimination is the ability to distinguish stimuli that differ in at leastone dimension. In the context of chronic pain it can apply to the abil-ity to distinguish between different non-painful bodily sensations(CSs vs. similar stimuli, e.g., more or less intense stimuli), betweendifferent sensory qualities of pain (burning vs. pricking), or betweenpainful and non-painful bodily sensations.

Despite a few exceptions (Peters and Schmidt, 1992, 1991), themajority of the clinical studies point to an impaired perceptual dis-crimination in individuals suffering from chronic pain. Most studieshave investigated discrimination between non-painful bodily

Stress and pain

Stress-induced analgesiaFear/anxiety related pain (nocebo)

Stressor (e.g. context)

Pain(inhibition through

endogenous opioids)

Att

entio

n

Stressor(e.g. context)

Pain(via CCK)A

ttention

Adapted from Benedetti (2011) Oxford Press

Could pain be pain-reducing?

Modulation is all about balance

PRO-NOCICEPTIVE MECHANISMS

ANTI-NOCICEPTIVE MECHANISMS

Think about modulation as a way for the body to get just the right amount of response in any given situation. And remember that it is plastic!

Communication

Clinician

Care-taker Patient

The tool box

Skills needed in ‘BPS’ practice • patient-education (teaching)

• tools of motivation and negotiating

• awareness to non-verbal communications

• indirect data collection and influence via significant others

• task-specific qualifications (e.g. dental surgery)

E.M.P.A.T.H.Y.

Riess & Kraft-Todd, Academic Medicine, Vol. 89, No. 8 / August 2014

Eye

cont

act

Facial muscles

Posture

E.M.P.A.T.H.Y.


Aff

ecti

ve s

tate

s

E.M.P.A.T.H.Y.


Tone of your voice

E.M.P.A.T.H.Y.


Hea

ring

the

who

le p

atie

nt

and

seei

ng t

he c

onte

xt

E.M.P.A.T.H.Y.


(Your response)

affective vs

cognitive empathy!

#3: Observe patient behaviours

Self-report





Observations

• Grimassing

• Behaviour

• Verbalising

What signs would you look for in the face of a patient to support

your hypothesis of pain?

Bemærk musklerne omkring øjne, øjenbryn og næsen

Verbalising & behaviour• Sighing

• Moaning

• ‘Growling’ and ‘Grunting’

• Shouting

• Loud respirations or irregular respiration

• Asking for help or attention

• Agression (words, gestures or behaviour)

• Rigidity

• Tension

• Protective gestures or behaviors

• Rocking movement

• Reduced ROM or other (sudden) changes in mobility

#4: Surrogate reporting

Self-report





Possible data sources

• Significant others (spouse, partner, child/parent)

• Friends and other family

• Caregivers and GP

• Colleagues, neighboughs and business partners

Attention

Genes

Imune system

Culture and social heritage

Expectations

Placebo

Nocebo

Nociception

PERCEPTION

and much more?

Friends, beliefs and knowledge

Experience

Adapted from Moseley (2007)

Educate๏ Sharing knowledge that gives you confidence

in the benign nature of the condition ๏ Make sure the patient knows why you think it

is valid for them (not for ‘someone like them’) ๏ What’s wrong with me? ๏ What will happen to me? ๏ How do I explain this (once I buy it)

๏ Share and exercise explanations, diagnosis and narratives

๏ Focus on the role of the spouse/family if the patient is cognitively impaired

Hunter Integrated Pain Service and Hunter Urban Medicare Local thank our colleagues in Denmark at the Slagelse GenoptraeningsCenter and Morten Hoegh for their contribution to this work.

Understanding Complex Pain

NU

TR

ITIO

N A

ND

LIF

ESTYLE

MY

STORY

MOVEMENT AN

D FU

NC

TIO

N

M E D I C A L T R E A T MENTS

THOUGHTS AND

EMO

TION

S

How big

an impact

are pain

and mood

having on

my wel lbeing?

Is there still somethingwrong with my body?

Maybe my diet and lifestyle are contributing to a sensitized nervous system

Finding new meaning...has stress taken over my body?

Without movement I won’t do well

health

relationships

money

my past

pain

fear

acceptance

My management plan:

Watch YouTube video“Understanding pain and what to do about it in less than 5 minutes”

Information on

complex pain:

www.hnehealth.

nsw.gov.au/pain

Retrain yourbrain!

#5: Attempt analgesic trial

Self-report





Pharma• Local anesthetics

• Non-opioids

• Paracetamol

• NSAIDs

• Opioids

• Anti-depressants

• Anti-convulsants

Although mechanism-based

it will rely heavily on probability if you don’t have patient reports

www.videnomsmerter.dk

Thank you for your attention you may find pdf of the slides at:

[email protected]

mailto:[email protected]

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Pain measurement and registration in non-verbal patients · 2015-08-28 · How this relates to pain ๏ Pain is not caused by nociception ๏ because you can be in pain when there