Quantitative sensory testing

Quantitative sensory testing (QST) is a panel of diagnostic tests used to assess somatosensory function, in the context of research and as a supplemental tool in the diagnosis of somatosensory disorders, including pain insensitivity, painless and painful neuropathy. The panel of tests examine a broad range of different sensations, including hot, cold, touch, vibration. It has both positive and negative tests (can test for increased or reduced sensitivity). QST reflects a formalisation of existing neurological tests into a standardised battery designed to detect subtle changes in sensory function. Large datasets representing normal responses to sensory tests have been established to quantitate deviation from the mean and allow comparison with normal patients. It is thought that a detailed evaluation of somatosensory function may be useful in identifying subtypes of pain and as a potential tool to identify asymptomatic neuropathy, which may represent up to 50% of total people with neuropathy (or loss of the nerve fibres). In clinical use, it is often combined with other tests such as clinical electrophysiology. In research settings it is increasingly applied in combination with advanced imaging such as fMRI, epidermis "nerve" biopsies and microneurography to classify subtypes of painful disorders.