Level A tests Level B test Level C tests
Assessment This test is used to determine the response of the slowly
adapting larger myelinated fibbers (A-a)
Assesses the quickly adapting large myelinated (A-a) fibbers These tests assess the small myelinated A-d and C fibbers
Test name Two-point discrimination test [39,40] Brush stroke direction
[39,40]
Contact detection/
light touch [39]
Thermal testing
[40]
Sharp blunt discrimination [41] Pin prick test [42]
Description Two pointed, but not sharp, tips of a calliper touch the skin simultaneously with light pressure while the patient’s eyes are closed. The separation of the two points are gradually reduced from 20 mm at the chin and 10 mm at the lips to the moment where the patient can feel one point only. The minimum separation at which two points can be report is recorded. The sensory modalities for these receptors are vibration, touch and flutter. Moving stimuli is delivered with a soft brush at a fairly constant velocity (2 - 3 cm/s). Ten, two interval forced choice trials are then delivered to verify that the direction of motion is identified correctly. The contact detection threshold, the minimum force of contact against the skin that is felt, is measured with the use of a monofilament mounted onto end of a plastic handle. Perception of warmth is attributed to the integrity of A-d fibbers and cold to C fibbers. Two small glass tubes containing water at 50°C (warm) and 15°C (cold) were used. The report of each stimulus i.e. cold versus hot is record. This is done by touching the test area randomly with a sharp or a blunt head of the mechanical probe. A rubber stopper is centred at the end of the dental probe so that when the tip is pressed to the skin, a constant degree of skin indentation was cause. Consisted of repeating ten touches with an explorer tip on the chin skin and perform how many times the patient accused the contact.