ABSTRACT
Evidence suggesting that aging is related to increasing suppression of the left ear
in the dichotic listening paradigm is reviewed. The effect has been demonstrated for
digits, words, sentences, and continuous discourse. It is present in both the free-recall
and the directed-attention modes, and it cannot be readily ascribed to age-related
increase in hearing sensitivity loss. It has been demonstrated both behaviorally,
in terms of accuracy scores and reaction times, and electrophysiologically, in terms
of the peak latency of the event-related potential recorded from scalp electrodes.
Moreover changing the to-be-attended speech feature from linguistic to nonlinguistic
can reverse the direction of the suppression effect. Taken as a whole these findings
suggest an age-related deficit in the interhemispheric transfer of auditory information
via the corpus callosum.
KEYWORD
Dichotic listening - aging - corpus callosum - event-related potentials - left ear
suppression
