Referred sensations following stroke

Referred sensations are recognized as phenomena experienced after amputation of a limb and have been used as proof of the consequences of changes in somatosensory body part representation in the adult brain. Such changes may accompany interruption of afferent sensory projections after subcortical stroke. This report describes some misplaced localization to touch in a subject 15 months after cerebral haemorrhage involving the posterior limb of the right internal capsule and lateral thalamus. The results revealed the occurrence of referred sensations, indicating some scrambling of the somatosensory representation of the affected limbs. While many stimuli were localized correctly, there were a number of stimuli applied to the hand and foot that were referred to more proximal limb segments. Stimuli to the upper arm were sometimes felt in more distal parts of the limb. Stimuli to the face were localized to the arm and not the hand. With the aim of determining consistency of findings, testing of the upper limb was carried out on four separate occasions. The subject had less referred sensations in each test, possibly indicating some change in his somatosensory representation that occurred with experience.