Evoked Fields After Median and Ulnar Stimulation

This study is directed at the (central and / or peripheral) mechanisms of pain and the cortical changes (plasticity) due to chronic non-malignant pain in two groups of patients and one healthy volunteer group.

The aim of the study is further to evaluate cortical processes by MEG (and fMRI, if feasible) to quantify and qualify the responses, localise the generators and study the effects of a pain therapy.

To search for patterns that may result in diagnostic criteria and have an indicative value for the treatment and the monitoring of the effects.

Finally the study not only intends to support clinical diagnosis but also to provide tools to monitor treatment and support the choice (algorithm) between SCS and SAN. An algorithm, facilitating decision making between these two treatments, will be promoted. It should also provide a clinical decision tool for the use of SAN

Inclusion criteria

CRPS I:

• (Absolute) functio laesa, secondary pain and cold sensations
• (Relative) abnormal skin colour, allodynia, hyperalgesia, hyperpathia, hyperhydrosis,oedema, increased nail growth, increased hair growth. (At least 4 need to be present).

CRPS II:

• All the previous but evidence of traumatic peripheral nerve injury.

Exclusion criteria

• General condition
• Pregnancy
• Technical implants (pacemaker, SCS: disturbs MEG)