PHANTOM SENSATIONS FOLLOWING ACUTE PAIN

In human amputees with painful phantom sensations, mislocalizations of tactile stimuli to the phantom increase with the amount of cortical r epresentational reorganization and the extent of phantom pain. A simil ar phenomenon was incidentally encountered in healthy subjects. For re asons unrelated to the question of mislocalization, we performed a stu dy involving the application of experimental acute pain to the hand fo llowed by non-noxious tactile stimulation of the ipsilateral lip. Duri ng lip stimulation, two out of six subjects spontaneously reported per ceiving an additional phantom-like sensation in the hand synchronously to the non-noxious lip stimulation. Similar, although more diffuse, p hantom sensations were observed in two out of seven additional subject s who were then tested specifically for this effect. The observation i s compatible with a pain-induced hyperresponsiveness of the cortical h and area to somatotopically adjacent inputs from the lip. This suggest s that, even in the absence of deafferentation, pain can lead to a rep resentational reorganization. (C) 1998 international Association for t he Study of Pain. Published by Elsevier Science B.V.