Alterations in neural responses and pain perception in older adults during distraction

Abstract

[eng] Objective: Although it is acknowledged that pain may be modulated by cognitive factors, little is known about the effect of aging on these control processes. The present study investigated electroencephalographical correlates of pain processing and its cognitive modulation in healthy older individuals. Methods: For this purpose, the impact of distraction on pain was evaluated in 21 young (9 men; 20.71±2.30) and 20 older adults (10 men; 66,80±4,14). Participants received individually adjusted electrical pain stimuli in a high distraction condition (1-back task) and in a low distraction condition (simple letter response task). Pain-related evoked potentials and pain ratings were analysed. Results: Both groups rated pain as less intense (F(1,39)=13.954, p<.001) and less unpleasant (F(1,39)=10.111, p=.003) when it was experienced during the high rather than the low distraction condition. However, in comparison to younger participants, older adults gave higher unpleasantness ratings to painful stimulation (F(1,39)=4.233, p=.046), accompanied by attenuated neural responses (N1-P1 and P3 amplitudes), regardless of the distraction condition (respectively, F(1,38)=6.028, p=.019 and F(1,38)=6,669, p=.014). Conclusions: Older participants felt pain relief through distraction, like younger participants. However, we also found that aging may enhance affective aspects of pain perception. Finally, our results show that aging is characterized by reduced neural processing of painful stimuli. This phenomenon could be related to the increased vulnerability of older participants to develop chronic pain.