Objectives: Our study aimed at investigating the effect of repetitive recordings on somatosensory evoked potentials (SEPs) related to spatial attention in a population of healthy elderly subjects.
Methods: Fifteen healthy elderly subjects were tested for six consecutive days using a somatosensory oddball paradigm, in which target stimuli were applied above the elbow and the non-target stimuli on the ipsilateral shoulder. Brain electrical activity was recorded from six scalp electrodes (Fz, Cz, F3, F4, T3 and T4).
Results: The N140 response to target stimuli showed a significantly decreased amplitude across the sessions with the lowest value during the fourth day of recording and with a partial recovery at the sixth day. On the contrary, the amplitude of the N140 response to non-target stimuli and that of the P300 potential to target stimuli were not significantly modified.
Conclusions: The significant amplitude reduction of the N140 potential in target, but not in non-target recordings across sessions, suggests that the voluntarily oriented attention is reduced by stimulus repetition, while the automatic attention is not.