James Jerger

Speech Understanding in the Elderly

Both auditory and cognitive status were determined in 130 elderly persons, in the age range from 51 to 91 years. Data were analyzed from the standpoint of the congruence of auditory and cognitive deficits. The prevalence of central auditory processing disorder was 50%, and the prevalence of cognitive deficit was 41%. Findings in the two areas were congruent, however, in only 63% of the total sample. Central auditory status was abnormal in the presence of normal cognitive function in 23% of subjects. Central auditory status was normal in the presence of cognitive deficit in 14% of subjects. In general, results did not support the hypothesis that decline in speech understanding in the elderly can be explained as the consequence of concomitant cognitive decline.

Some effects of aging on central auditory processing.

Seniors often have more difficulty understanding speech than younger adults, particularly in noisy environments. While loss in peripheral hearing sensitivity explains many of the listening problems of elderly persons, age-related declines in general cognitive skill and central auditory processing also appear to contribute. In this article, we focus primarily on the effects of age on central auditory mechanisms. To this end, we review research examining a central locus for deficits in temporal processing and summarize behavioral and event-related potential findings from our laboratorys research on the effects of aging on dichotic listening performance. Results show that age-related deficits in interhemispheric information processing may underlie some of the listening problems among seniors. We also discuss implications for clinical audiological rehabilitative efforts in this population.

Correlational analysis of speech audiometric scores, hearing loss, age, and cognitive abilities in the elderly.

A battery of speech audiometric measures and a battery of neuropsychological measures were administered to 200 elderly individuals with varying degrees of pure-tone sensitivity loss. Results were analyzed from the standpoint of the extent to which variation in speech audiometric scores could be predicted by knowledge of pure-tone hearing level, age, and cognitive status. For the four monotic test procedures (PB, SPIN-Low, SPIN-High, and SSI) degree of hearing loss bore the strongest relation to speech recognition score. Cognitive status accounted for little of the variance in any of these four speech audiometric scores. In the case of the single dichotic test procedure (DSI), both degree of hearing loss and speed of mental processing, as measured by the Digit Symbol subtest of the WAIS-R, accounted for significant variance. Finally, age accounted for significant unique variance only in the SSI score.

Effects of age and gender on dichotic sentence identification.

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 “left ear 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 right-ear 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-related/cognitive component. We then show how these hypothetical components change with age in the present sample.

Auditory dysfunction in traumatic brain injury.

Effective communication is essential for successful rehabilitation, especially in patients with traumatic brain injury (TBI). The authors examined the prevalence and characteristics of auditory dysfunction in patients with TBI who were admitted to a Department of Veterans Affairs TBI inpatient unit before and after the onset of Operation Iraqi Freedom (OIF). In order to delineate the characteristics of the auditory manifestations of patients who had sustained blast-related (BR) TBI, we reviewed the medical records of 252 patients with TBI and categorized them according to admission date, either before (Group I, n = 102) or after (Group II, n = 150) the onset of OIF. We subdivided Group II into non-blast-related (NBR) and BR TBI; no subjects in Group I had BR TBI. We found that admissions for TBI have increased 47% since the onset of OIF. In Group I, 28% of patients with TBI complained of hearing loss and 11% reported tinnitus. In Group II-NBR (n = 108), 44% complained of hearing loss and 18% reported tinnitus. In Group II-BR (n = 42), 62% complained of hearing loss and 38% reported tinnitus. Sensorineural loss was the most prevalent type of hearing loss in Group II-BR patients. In light of the high prevalence of hearing loss and tinnitus in this growing population of returning soldiers, we need to develop and implement strategies for diagnosis and management of these conditions.

Hearing impairment in older adults: new concepts.

OBJECTIVE: To review present information about the epidemiology, etiologies, pathogenesis, evaluation, and quality of life aspects of hearing loss and to present an approach to rehabilitation for hearing loss in older adults.

Interactions of age, gender, and sensorineural hearing loss on ABR latency

The interactive effects of gender, age, and degree of sensorineural hearing loss on the absolute latency of wave V of the auditory brain stem response were analyzed in 325 subjects with cochlear loss. Norms based on these data were then applied to an analysis of the wave V latencies of 87 subjects with retrocochlear loss. Results in the cochlear group revealed interactions between gender and age and between gender and degree of hearing loss. The interactive effect between gender and degree of loss was observed for wave V, but not for waves III or I. Separate gender norms for absolute wave V latency, based on empirical boundaries encompassing 99% of the cochlear group, resulted in a 90% correct identification rate in the 87 subjects with retrocochlear lesion.

Development of a dichotic sentence identification test for hearing-impaired adults

Third-order synthetic sentences were aligned to make them suitable for dichotic presentation. These dichotic sentence materials were then administered to 14 normal listeners and 48 hearing-impaired subjects to determine the influence of peripheral hearing loss on test performance. Results suggest that the Dichotic Sentence Identification test is resistant to the influence of peripheral hearing loss until the pure-tone average of 500, 1000, and 2000 Hz exceeds approximately 50 dB. Beyond this level, degree of peripheral hearing loss limits its value for detecting central auditory disorder. Data are also provided on six persons with either confirmed or suspected lesions involving retrocochlear structures.

Dichotic listening, event-related potentials, and interhemispheric transfer in the elderly

Objective To determine the basis for the large, age-related asymmetries in dichotic listening performance scores reported by Jerger et al. (1994). Design Behavioral and electrophysiologic responses to dichotic 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 marked dichotic deficits, and patients with lesions of the corpus callosum. Results In comparison with the young group the two elderly groups showed an increasing left-ear deficit on the verbal task, and an increasing right-ear deficit on the nonverbal paradigm. The pattern of results obtained in the elderly persons with marked dichotic deficits was similar to the pattern of results in the group with callosal lesions. Conclusions 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 for the effective use of binaural information by elderly persons.

Effect of sleep on the auditory steady state evoked potential.

The effects of both natural and sedated sleep on the auditory steady state evoked potential (SSEP) were evaluated in nine normal-hearing subjects. Both absolute amplitude and phase variability measures were obtained by Fourier analysis of successive samples of the averaged SSEP waveform. Amplitude decreased significantly in the sleeping state but phase variability was not substantially altered. Because it does not seem to be affected by sleep, phase variability of the SSEP is suggested as a potentially useful technique for predicting threshold sensitivity.