There is converging evidence that aging causes a progressive decline in the central processing of speech and that this decline is greater for left-ear than for right-ear input. In the present paper we investigated, by means of a dichotic sentence identification paradigm, some parameters of the 'leftear effect." We analyzed the clinical records of 366 individuals, 203 males and 163 females, to whom the Dichotic Sentence Identification (DSI) Test had been administered as part of routine audiometric assessment. Subjects ranged in age from B to 91 yr.The DSI test was always carried out in two modes: free report (FR) and directed report (DR). In the FR mode the subject reported what was heard in both ears. In the DR mode the subject reported only what was heard in one precued ear. In half of the trials the right ear was precued, in the other half the left ear was precued. Findings confirm a progressively larger righkar advantage, or left-ear deficit, with increasing age. We'document this effect in both the FR and DR modes, then demonstrate that the effects cannot be attributed to interaural asymmetries in threshold sensitivity. Comparison of male and female data suggest a gender difference in the effect of age on the left-ear deficit. Males show a larger effect then females in both modes of test administration. Finally, we propose a model of dichotic listening performance that attempts to explain ear asymmetry as the linear combination of an auditory/structural component and a task-relatedhognitive component. We then show how these hypothetical components change with age in the present sample. (Ear BE Hearing 1994;15;274-286)It has long been recognized that the right ear enjoys an advantage over the left ear in the processing of dichotic speech and speech-like signals [For recent comprehensive reviews see Hugdahl (1988) and Hellige (199311. This right-ear advantage (REX) in dichotic listening is customarily explained by the hypothesis that the right ear enjoys privileged access to the left hemisphere, the hemisphere dominant for the processing of speech (e.g., Zaidel, 1983).There is conflicting evidence on whether the REA changes with age. Borod and Goodglass (19801, Gelfand, Hoffman, Waltzman, and Viper (19801, and Martini et al. (1988) found no age effect on the REA. On the other hand, Horning (19721, Clark and Knowles (1973), and Johnson et al. (1979) all reported an increase in the REA in elderly subjects.More recently Jerger, Stach, Johnson, Loiselle, and Jerger (1990) studied the effect of increasing age on performance in a dichotic sentence-identification paradigm. They found that age-related decrease in performance was greater for the left ear than for the right ear. Finally, Jerger and Jordan (1992) compared young and elderly listeners on a dichotic, sound-field, cued-listening task. The REA was substantially larger in the elderly group than in the young adults. Interestingly, there have also been reports of an REA in monaural tasks involving difficult listening. Investigators have demonstrated greater declin...

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Results affirm the significant impact of amplification on the quality of life of elderly persons. The strong preference for the conventional hearing aid in everyday use undoubtedly reflects the fact that elderly users usually are not willing to endure the difficulties associated with the use of remote-microphone systems.