Test for light touch

Definition:
Light touch sensory testing evaluates the presence of a lesion affecting the peripheral nerve, posterior column, thalamus or sensory cortex.

Test procedure:
Perform the test with the patient either sitting or lying down, using a piece of cotton wool, cloth etc. to dab the skin rather than stroke it. Show the patient what you are going to do, asking them to indicate verbally when they feel a stimulus. General neurological screening would include random proximal and distal test locations; diagnostic investigation would involve dermatomal mapping and/or peripheral nerve distribution testing. Include sacral stimulation when considering bowel, bladder or lower limb symptoms.

Test findings:
A positive finding involves the inability to identify stimuli within a certain area of skin. The area should be carefully mapped in order to assist identification of relevant peripheral nerve or nerve root distribution. Sensory deficit may result from an ipsilateral lesion below the medulla, or a contralateral lesion above it.
Test procedure:

Perform the test with the patient either sitting or lying down, using a piece of cotton wool, cloth etc. to dab the skin rather than stroke it. Show the patient what you are going to do, asking them to indicate verbally when they feel a stimulus. General neurological screening would include random proximal and distal test locations; diagnostic investigation would involve dermatomal mapping and/or peripheral nerve distribution testing. Include sacral stimulation when considering bowel, bladder or lower limb symptoms.

Test findings:
A positive finding involves the inability to identify stimuli within a certain area of skin. The area should be carefully mapped in order to assist identification of relevant peripheral nerve or nerve root distribution. Sensory deficit may result from an ipsilateral lesion below the medulla, or a contralateral lesion above it.