The effect of aging on auditory components of event-related brain potentials

Objective: To describe auditory perceptual, pre-attentive, attention-related and cognitive processes along lifespan in normal people by a simple auditory oddball paradigm easily usable in clinical practice. Methods: ERPs were recorded in 72 normal subjects. Four blocks of tones were delivered (20% rare 2000 Hz and 80% frequent 1000 Hz). In the former two blocks, subjects performed a concomitant distracting visual search task (distracted condition); in the latter two blocks, they had to attend the occurrence of the rare tones (active condition). Latency and amplitude of ERPs were analyzed according to age, gender, educational level and repetition. Results: N100 amplitude was greater in active than in distracted condition. MMN amplitude decreased with age. N2b and P300 latencies increased with age, while their amplitudes decreased. Females produced greater P300 than males. In the elderly, P300 latency was found to be longer in the second block than in the first one. Conclusions: N100 and MMN were found to be less affected by age than N2b and P300. When repeated, P300 showed increased latency in elderly subjects. Significance: The protocol detected the higher influence of aging on late cognitive processes than on the perceptual and pre-attentive ones. Age-adjusted normative data were produced.