DICHOTIC-LISTENING, EVENT-RELATED POTENTIALS, AND INTERHEMISPHERIC-TRANSFER IN THE ELDERLY

Objective: To determine the basis for the large, age-related asymmetri es in dichotic listening performance scores reported by Jerger et al. (1994). Design: Behavioral and electrophysiologic responses to dichoti c listening tasks in both verbal and nonverbal paradigms were obtained in four groups of subjects: young adults with normal hearing, elderly persons with presbyacusis, elderly persons with presbyacusis and mark ed dichotic deficits, and patients with lesions of the corpus callosum . Results: In comparison with the young group the two elderly groups s howed an increasing left-ear deficit on the verbal task, and an increa sing right-ear deficit on the nonverbal paradigm. The pattern of resul ts obtained in the elderly persons with marked dichotic deficits was s imilar to the pattern of results in the group with callosal lesions. C onclusions: With age, there may be a significant loss of efficiency of interhemispheric transfer of auditory information through the corpus callosum. Such age-related deficit might have important implications f or the effective use of binaural information by elderly persons.