Brain plasticity and hand function

Abstract: The aim of this thesis was to investigate the effects of cortical reorganisational changes following experimental deafferentation and peripheral nerve injury and apply the concept of brain plasticity to enhance sensory re-education following peripheral nerve injury and repair in the hand.

In the first two papers the effects on hand function of contralateral deafferentation was investigated. Tourniquet induced anaesthesia (paper I) resulted in significant improvement in perception of touch, tactile discrimination, and grip strength in the opposite hand during anaesthesia. In order to investigate the effects of contralateral deafferentation with the pain factor eliminated, 100 patients, operated on in axillary plexus anaesthesia, were investigated (paper II). Axillary plexus anaesthesia also resulted in rapid, significant improvement in sensibility in the contralateral hand.

In paper III selective ipsilateral cutaneous anaesthesia of the forearm resulted in rapid significant improvement in ipsilateral hand function.

In the last two studies previous findings were applied on patients with median or ulnar nerve injuries. Tourniquet induced anaesthesia (paper IV) of the healthy hand results in significant rapid improvement in sensibility in nerve-injured hands. Repeated ipsilateral cutaneous anaesthesia (paper V) in combination with intensive sensory re-education resulted in improved hand function in nerve injured hands lasting at least 4 weeks after the last episode of anaesthesia.

In conclusion, hand function in both healthy persons and patients with median or ulnar nerve injuries can be improved by using the concept of brain plasticity. These findings have a potential clinical application in sensory re-education following nerve repair in the hand.