Altered Central Processing and PENS Therapy

In the presence of nociceptive pain, pain messages travel from the periphery via C-fibres (fibres that respond to broad range of painful stimuli) to the dorsal horn at Rexed Lamina 1 & 2 and from there via the spinal thalamic tract to terminate in the sensory cortex.

Therefore in these circumstances it is possible to stimulate peripheral inhibitory fibres via Transcutaneous Electrical Nerve Stimulation (TENS) and cause a reduction of pain to the affected body area. In the case of peripheral neuropathic pain a subset of patients have increased pain in the presence of TENS therapy.

In this group of patients C-fibre termination at Rexed Lamina 1 & 2 ceases as a result of peripheral nerve damage and is replaced at Rexed Lamina 1 & 2 by Aß-fibres.

In a patient with neuropathic pain the Aß-fibres projecting into Rexed Lamina 1 & 2 cause an exaggerated nociceptive response to what are normally innocuous stimuli. These patients are frequently most likely to benefit from PENS therapy.