HypothesisCortical origin of pathological pain
Section snippets
Hypothesis
How might this centre be involved in pathological pain? Let us assume that the unilateral right cortical centre monitoring incongruence of sensation (CIS), proposed by Ramachandran from his experiments on patients with left neglect,20 is the one shown in the functional imaging studies. The CIS is strongly influenced by unilateral vestibular stimulation,20, 21 and if vestibular and proprioceptive sensation of balance and body displacement are incongruent with vision, we feel nausea. In an
Testing the hypothesis
Evidence to support the hypothesis includes preliminary reports that watching a virtual image of a phantom limb move in synchrony with motor commands may relieve phantom-limb pain,8 and that exercises to restore normal sensory cortical maps may relieve RSI16 or focal hand dystonia in musicians.17 Extending the design of these exercises to emphasise visual monitoring of movements should increase their effectiveness.
Pharmacological agents that act centrally to relieve motion sickness, for example
Therapy
How may these observations be useful in the design of therapy? Relief of early symptoms might be achieved with centrally acting pharmacological agents that give prophylaxis for motion sickness. Restoring a normal sensory cortical map by daily exercises, in which individual fingers are vibrated or asynchronously moved through wide excursions under close visual monitoring, might reverse the symptoms of RSI, and so might learning to read braille.22 Typists susceptible to RSI might be advised to
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