Quantitative Sensory Testing (QST): Difference between revisions
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=== Complementary Tests === | === Complementary Tests === | ||
Temporal summation | |||
Apply rapidly repeated mechanical stimuli to a painful region - if TS is present it will result in an increased pain perception indicating central sensitisation<ref name=":2" /> | |||
'''2-point discrimination''' | '''2-point discrimination''' | ||
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!'''Condition''' | !'''Condition''' | ||
!'''QST findings''' | !'''QST findings''' | ||
!'''Implication''' | |||
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|'' | |''Chronic low back pain'' | ||
| | |Increased sensitivity (decreased threshold) to heat and pressure; Temporal summation | ||
|Identifies peripheral and central sensitisation (TS present) components | |||
|- | |- | ||
|''Lower limb fractures'' | |''Lower limb fractures'' | ||
|Decreased sensitivity (elevated threshold) | |Decreased sensitivity (elevated threshold) to touch and warmth | ||
|Peripheral nerve injury which can affect limb function and balance | |||
|- | |- | ||
|''Knee OA'' | |''Knee OA'' | ||
|Increased sensitivity (lowered | |Increased sensitivity (lowered pressure/cold pain thresholds); Temporal summation (TS) | ||
|Identifies peripheral and central sensitisation (distal sites affected and TS) components if present and can predict surgery outcomes | |||
|} | |} | ||
[[File:QST.jpg|frameless|600x600px]] | |||
== Summary == | == Summary == | ||
QST can be a very | QST can be a very valuable clinical tool in patients with chronic pain by assisting to characterise pain experiences. It provides information about potential underlying mechanisms contributing to pain, therefore incorporating QST may improve the ability to implement individualised treatment plans based on underlying mechanisms<ref name=":2" />. | ||
== Resources == | == Resources == | ||
Revision as of 17:41, 22 August 2023
This article or area is currently under construction and may only be partially complete. Please come back soon to see the finished work! (22/08/2023)
Original Editor - Melissa Coetsee
Top Contributors - Melissa Coetsee and Carina Therese Magtibay
Introduction[edit | edit source]
Quantitative sensory testing (QST) is a systematic psychophysical test method used to measure sensory thresholds for pain, touch, vibration, and temperature sensations.[1]It quantifies individual sensory perceptions using direct patient feedback. It tests for sensory loss (hypoesthesia, hypoalgesia) and sensory gain (hyperesthesia, hyperalgesia, allodynia)[2]. Sophisticated computerised equipment is often used in clinical trials, but hand-held tools are also available for clinical use[1].
Clinical Application[edit | edit source]
QST can be used to evaluate any condition that affects sensory function - it may help with diagnosis and disease monitoring. QST can be very useful to identify underlying contributing pain mechanisms and pathophysiology, which can assist with targeted intervention strategies[2][3]. It is best to compare results with normative values, and it is best conducted early after onset of a condition.
Conditions for which QST can be useful include[2][3]:
- Neuropathic pain
- Polyneuropathy (diabetic, HIV-related, chemotherapy-related)
- Postherpetic neuralgia
- Complex regional pain syndrome (CRPS)
- Chronic low back pain
- Knee osteoarthritis
Procedure and Components[edit | edit source]
To perform QST, a patient is stimulated with quantified sensory stimuli and based on patient feedback, perception thresholds are identified for the following sensory functions: light touch, pressure, vibration, thermal sensations, heat and cold pain. This way A-delta fibres (small diameter myelinated) and C-fibres (unmyelinated) are assessed.
- Vibration
- Cold
- Heat
Interpretation[edit | edit source]
| Underlying mechanism | QST finding |
|---|---|
| Hypoesthesia (sensory loss) | Elevated sensory thresholds |
| Allodynia and hyperalgesia | Lowered sensory thresholds |
| Peripheral sensitisation | Heat hyperalgesia (lowered hot pain threshold) |
| Central sensitisation | Static mechanical hyperalgesia or dynamic mechanical allodynia; temporal summation (repeated mechanical and thermal stimuli causes increased pain) |
| Polyneuropathy | All thresholds elevated |
| Small fibre neuropathy | Vibration thresholds are normal, but others elevated |
Limitations[edit | edit source]
- QST abnormalities are present in non neuropathic pain, making it difficult to use QST as a definitive tool for identifying neuropathic pain[1]
- Abnormal findings are not specific for peripheral nerve dysfunction, as central nervous system disorders will also alter sensory thresholds[1]
- It is a subjective psychophysical test, entirely dependent on patient alertness, motivation and willingness to supply accurate feedback. There is large intra- and interindividual variation[1]
Complementary Tests[edit | edit source]
Temporal summation
Apply rapidly repeated mechanical stimuli to a painful region - if TS is present it will result in an increased pain perception indicating central sensitisation[2]
2-point discrimination
Conditional pain modulation test (CPM)
CPM tests the function of central pain inhibition. Involves applying a noxious stimulus (thermal or mechanical) to a region remote from the painful site - if descending inhibitory control is functioning properly, the initial source of pain will be less intense during the application of the remote stimulus. [2]*****
Specific Conditions[edit | edit source]
The table below summarises QST findings for specific conditions, as identified in research studies[2]:
| Condition | QST findings | Implication |
|---|---|---|
| Chronic low back pain | Increased sensitivity (decreased threshold) to heat and pressure; Temporal summation | Identifies peripheral and central sensitisation (TS present) components |
| Lower limb fractures | Decreased sensitivity (elevated threshold) to touch and warmth | Peripheral nerve injury which can affect limb function and balance |
| Knee OA | Increased sensitivity (lowered pressure/cold pain thresholds); Temporal summation (TS) | Identifies peripheral and central sensitisation (distal sites affected and TS) components if present and can predict surgery outcomes |
Summary[edit | edit source]
QST can be a very valuable clinical tool in patients with chronic pain by assisting to characterise pain experiences. It provides information about potential underlying mechanisms contributing to pain, therefore incorporating QST may improve the ability to implement individualised treatment plans based on underlying mechanisms[2].
Resources[edit | edit source]
- Quantitative Sensory Testing - standardised full procedure
or
- numbered list
- x
References[edit | edit source]
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Horowitz SH. Neuropathic pain: is the emperor wearing clothes. Current Therapy in Pain, WB Saunders. 2009:9-14.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Weaver KR, Griffioen MA, Klinedinst NJ, Galik E, Duarte AC, Colloca L, Resnick B, Dorsey SG, Renn CL. Quantitative sensory testing across chronic pain conditions and use in special populations. Frontiers in Pain Research. 2022 Jan 28;2:779068.
- ↑ 3.0 3.1 Mucke M, Cuhls H, Radbruch L, Baron R, Maier C, Tolle T, Treede RD, Rolke R. Quantitative sensory testing (QST). English version. Schmerz. 2016;35:153-60.
