Test | Fibres tested | Which question(s) of the diagnostic algorithm can be answered? | Advantages | Disadvantages |
---|---|---|---|---|
Electrodiagnosis (EMG, ENG, reflex responses) | Aβ | 3, 4 | Available in most centres Define the pathology, topography, extension and prognosis of the lesion | Do not evaluate nociceptive fibres |
Somatosensory evoked potentials | Aβ | 3 | Define the level of the lesion in the CNS | Do not evaluate nociceptive pathways |
Quantitative sensory testing | Aβ, Aδ, C | 3 | Evaluates nociceptive fibres | Time-consuming |
Quantifies positive and negative signs | Cannot define the level of the lesion | |||
Study the whole somatosensory system | Requires patient's collaboration Available in few centres | |||
Laser evoked potentials | Aδ, C | 3 | Evaluate nociceptive fibres | Time-consuming |
Evaluate the nociceptive pathways | Cannot define the level of the lesion Available in few centres | |||
Skin biopsy | Aδ, C | 4 | Quantifies IENF density | Time-consuming and expensive |
Available in few centres | ||||
Imaging (US, CT, MRI) | – | 4 | Identify a pathological process in the peripheral and the central nervous systems | Do not explore nociceptive fibres and pathways |
Functional Imaging (fMRI, PET) | Aδ, C | 3 | Explores the pain matrix | Available in few centres |
Autonomic tests | C | 3 | Available in many centres | Do not evaluate nociceptive fibres |
Microneurography | Aβ, Aδ, C | 3, 4 | Allows direct recordings from peripheral axons | Time-consuming |
Quantifies positive sensory changes | Requires patient's collaboration | |||
Available in very few centres |
CNS, central nervous system; EMG, electromyography; ENG, electroneurography; fMRI, functional MRI; IENF, intraepidermal nerve fibres; NP, neuropathic pain; PET, positron-emission tomography; US, ultrasound.