Quantitative Sensory Testing (QST)
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. 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 pain mechanisms and pathophysiology, which can assist with targeted intervention strategies[2]. 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]:
- Neuropathic pain
- Polyneuropathy (diabetic, HIV-related, chemotherapy-related)
- Postherpetic neuralgia
- Complex regional pain syndrome (CRPS)
- Chronic lower back pain
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 |
| Central sensitisation | Static mechanical hyperalgesia or dynamic mechanical allodynia |
| 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]
2-point discrimination
Evidence[edit | edit source]
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 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.
