human research tools

Question 1

what are the different variations of human experimental pain for mechanical, thermal, electrical and chemical

Answer 1

• mechanical = touch using von frey, pressure using algometer of cuff
• thermal = thermorde, laser, cold pressor
• electrical = patch, needle electrodes
• chemical = topical, injection

Question 2

what happens to the stimulus response curve in presence of analgesia and allodynia

Answer 2

moves to the right with analgesia becasue increase detection and tolerance threshold
moves to left with allodynia = more pain (hyperalgesia) decreases threshold and allodynia = lowering detection threshold

Question 3

describe von frey as a mechinal example

Answer 3

for superficial somatic pain
the thick/stiff filaments are for pinprick pain and punctate hyperalgesia (AD)
tests threshold or response frequency = allodynia (AB)

Question 4

dscribe cuff algometry as a mechanical example

Answer 4

for deep somatic muscle pain
competer controlled cuff (C fibre)
rising to pain threshold and tolerance
assess hyperalgesia

Question 5

describe thermode as a thermal example

Answer 5

thermode on skin (c fibre)
starts at 34C (non-noxious)
increase, record pain threshold and tolerance temperatures

Question 6

describe cold pressor test as a thermal example

Answer 6

deep somatic pain in vessels
hand in cold water, pain threshold and tolderance
can identify hyperalgesia
can be paired with second test (conditioned pain modulation) to reveal variability in diffuse noxious inhibitroy controls

Question 7

describe what conditioned pain mpdulation requires nad what is tests

Answer 7

• requires test stimulus and conditioning stimulus
• tests both without each other
• and measures difference in test stimulus pain for the net effect of descending pain pathways

Question 8

how can painful cutaneous electrical stimulation (PCES) be used

Answer 8

• electrodes on skin
• stimulates conditions targeted to noci fibres AD, C
• increase in steps
• pain detection and tolerance thresholds
• bypasses nociceptors

Question 9

describe the UVB cutaneous inflammatory model

Answer 9

• induce skin erythema (neurogenic inflammation) by UVB irradiation
• difference in thermal, pressure of mechanical pain between uvb and untreated skinn
• hyperalgesia (peripheral sensitation)
• more localised than capsaicin

Question 10

describe capsaicin as a chemical example of testing hyperalgesia and allodynia

Answer 10

• skin, muscle, viscera
• thermal and mechanical hyperalgesia through AD, C and silent nociceptor sensitisation
• mechanical AB fibre, allodynia - central senitisation
• test analgesiscs for pain with peripheral or central sens components eg neuropathic pain

Question 11

what is the endo-cap model

Answer 11

dual-stimulus clinical model
inject capsaicin into forearm (TRPV1)
predose low dose endotoxin (TLR4) for innat immune priming
- measure area of allodynia (brush), punctate hyperalgesia (fon frey) flare (visual)

Question 12

how can we quantify clinical pain

Answer 12

one dimnesional pain scales = simple, efficicent, widely used etc
multidimenstional pain measurement tools = wider experience ef mcgill pain questionnaie