| dc.description | Three studies were carried out to investigate pain's effects on early attentional processes. Previous research has found that pain can disrupt attentional processing. The Mismatch negativity (MMN) event-related potential has been established as a hardwired index of early auditory pitch difference detection. It is elicited independent of active attentional focus but can be modulated by focused attention and attentional demand. In the present studies, participants' MMN was used to compare early attentional processing between no-pain and pain conditions. In Experiment 1, healthy volunteers' MMN was recorded using a passive auditory paradigm where auditory stimuli were presented during a simple visual task. Recordings were taken during no-pain, experimentally induced cold pressor pain, and experimentally induced ischemic pain conditions. No difference was found in MMN amplitude or latency between these conditions. In Experiment 2, MMN in another group of healthy volunteers was compared between no-pain and experimentally induced ischemic pain conditions using passive and active auditory attention paradigms. The attentional demand of the visual task in the passive condition was greater than in Experiment l. As well, the discrimination difficulty level of the auditory stimuli was also varied in both attention conditions. As in Experiment 1, no differences were found in MMN amplitude or latency between the pain conditions. The attentional demand of the auditory task did not affect pain's effects on MMN. Experiment 3 used the same auditory paradigms as Experiment 2. However, participants were individuals with intractable chronic pain. These participants were tested before and after receiving nerve block injections for their pain. Although pain did not affect MMN during the active auditory attention task, it did decrease MMN amplitude during the passive auditory task. The findings of these studies suggest that the nature and level of pain may be a key factor during cognitive processing of attentionally demanding tasks. | en_US |
