Auditory temporal processing in healthy aging: a magnetoencephalographic study.
BACKGROUND
Impaired speech perception is one of the major sequelae of aging. In addition to peripheral hearing loss, central deficits of auditory processing are supposed to contribute to the deterioration of speech perception in older individuals. To test the hypothesis that auditory temporal processing is compromised in aging, auditory evoked magnetic fields were recorded during stimulation with sequences of 4 rapidly recurring speech sounds in 28 healthy individuals aged 20 - 78 years.


RESULTS
The decrement of the N1m amplitude during rapid auditory stimulation was not significantly different between older and younger adults. The amplitudes of the middle-latency P1m wave and of the long-latency N1m, however, were significantly larger in older than in younger participants.


CONCLUSIONS
The results of the present study do not provide evidence for the hypothesis that auditory temporal processing, as measured by the decrement (short-term habituation) of the major auditory evoked component, the N1m wave, is impaired in aging. The differences between these magnetoencephalographic findings and previously published behavioral data might be explained by differences in the experimental setting between the present study and previous behavioral studies, in terms of speech rate, attention, and masking noise. Significantly larger amplitudes of the P1m and N1m waves suggest that the cortical processing of individual sounds differs between younger and older individuals. This result adds to the growing evidence that brain functions, such as sensory processing, motor control and cognitive processing, can change during healthy aging, presumably due to experience-dependent neuroplastic mechanisms.
Department of Neurology, Münster University Hospital, Albert-Schweitzer-Str. 33, 48149 Münster, Germany. peter.soros@gmail.com
Peter
P
Sörös
Inga K
IK
Teismann
Elisabeth
E
Manemann
Bernd
B
Lütkenhöner
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology; D013060:Speech / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult