Tactile sensation Apply a gentle touch with fingers, cotton wisp, fine hairbrush or von Frey hairs to the skin of the body region which you want to examine. Ask the patient to close his/her eyes and say ‘yes’ when touched. Compare sensation in different body regions ▸ Patients with tactile hypaesthesia report reduced sensation in the affected body region compared with the corresponding normal one ▸ Patients with mechanical allodynia report pain in response to light touch (static mechanical allodynia) or gentle brushing (dynamic mechanical allodynia) | |
Thermal sensation Tubes or vials of warm and cold water can be used but this is usually not much practical. The Lindblom thermoroller is not widely present. Use the handle of the reflex hammer or the tuning fork, which is normally perceived as cold, and the palm of your hand, which is normally perceived as warm, to test thermal sensation. Ask the patient to close his/her eyes and identify when touched with warm or cold stimuli. Compare sensation in different body regions ▸ Patients with thermal hypaesthesia report reduced cold and/or warm sensation ▸ Patients with thermal hyperalgesia report that the thermal stimulus is discomforting or painful | |
Sensation to punctate stimuli Apply a punctate stimulus with a pin or with the sharp end of a broken wooden cotton tip. Ask the patient to identify ‘sharp or dull’ with his/her eyes closed ▸ Patients with punctate hypaesthesia report non-punctate touch-like sensation in response to the punctate stimulus ▸ Patients with punctate hyperalgesia report sharp pain in response to the punctate stimulus | |
Vibratory sensation (pallaesthesia) Place a vibrating low-frequency (128 Hz) tuning fork over a bone salience. Ask the patient to report whether he/she feels vibration and then to report when it stops. You can measure the minimal threshold for vibration sensation, in case the tuning fork is graduated, or compare different body regions ▸ Patients with hypopallaesthesia report decreased vibration sensation | |
Temporal summation of pain (wind up) (optional) Apply first a single punctate stimulus and then a series of 5/10 of the same punctate stimuli. Ask the patient to rate pain/discomfort intensity to the single stimulus and to the series of stimuli; compare two body regions ▸ Patients with enhanced wind-up report increased ratio between the series of stimuli and the single stimulus |
NP, neuropathic pain.