Cortical evoked potentials (CAEP) with speech and noise stimuli in young adults and adults over 50 years of age

CAEP are not only a useful tool for objective measurement of hearing thresholds for complex stimuli, but they also allow gaining information on the integrity of the thalamo-cortical auditory pathway. As a part of the aging process, morphological and functional changes of the cochlea, the auditory nerve and the central auditory pathway will lead to the development of a slowly progressive hearing loss. To evaluate such changes, the latencies and morphology of the CAEP after different syllable and noise stimuli were investigated in normal-hearing young adults and adults older than 50 years.

61 adults were examined; 41 with age average of 28 2/12 years and 20 with age average of 55 6/12 years. Normal hearing was confirmed by measurement of otoacoustic emissions. CAEP were recorded with three speech stimuli Ba (600 Hz), Ga (2000 Hz), Sa (6500 Hz) and three in frequency matched narrowband noises (low: 70-1000 Hz, mid: 1-3 kHz, high: 3-6 kHz) presented by loudspeakers at 60dB SPL. CAEP showed an excellent identifiability (94-100%) for all stimuli. Changing the stimulus did not result in statistically significant differences in latency within a group. The mean Latency of P2 was observed to increases with increasing age. The Mann-Whitney U test showed a statistically significant difference in P2 latency in the over-50 group compared to the under-50 group with the low and high noise. P1 latency did not show comparable findings. The increase in latency of the later component of the CAEP in normal hearing subjects over 50 years of age, suggests a degenerative process in the auditory pathway that occurs even prior to the onset of hearing loss. This change may lead to impairment of speech discrimination abilities, especially in difficult listening situations (cocktail party effect).

Publication History

Article published online:
24 May 2022