12/4/2023 0 Comments Isham 2000 dichotic listeningTwo procedures are followed: In one, the listener reports the numbers for the sentences heard in each ear (Free Report). After the presentation of each pair of sentences, the listener must report the number of the sentence or sentences heard. In the actual test a numbered list of the test sentences is placed before the listener. Each sentence is chosen at random from a pool of six sentences, originally selected from a larger pool of synthetic seven-word sentences, and carefully matched for duration. In the DSI test two different seven-word synthetic sentences are presented simultaneously to the two ears of the listener. It was purposely designed to be less challenging, and therefore less affected by the high-frequency losses so common in elderly persons. The DSI test was specifically developed to minimize such peripheral hearing loss confounds. Even a moderate degree of sensorineural hearing loss, especially in the high-frequency range above 1000 Hz, impacts performance on tests like Consonant-Vowel (CV) syllables and Dichotic Digits quite aside from cognitive and/or central auditory processing problems. One of the principal factors motivating the development of a dichotic sentence test was to diminish the contaminating effect of high-frequency SNHL on the speech recognition performance of elderly persons.Peripherally-based hearing sensitivity loss, a common characteristic of the aging auditory system, is difficult to control as the audiologist seeks to understand the possible cognitive and central auditory dimensions underlying an abnormally large REA/LED. 2 They are essentially meaningless sentences, but, surprisingly, often resemble reasonable sequences of English words. The speech test materials of the DSI Test are synthetically fashioned sentences, originally constructed by concatenating individual word triplets according to the rules governing third-order approximations to English syntax. The Dichotic Sentence Identification (DSI) Test In the present study we employed the Dichotic Sentence Identification Test (DSI) in both reporting modes. Then the procedure is repeated for the other ear. In the directed report mode, the listener is pre-instructed to report only the items heard in one of the two ears. In the free report mode, the listener is instructed to report both items in any order. In both modes, two different test items are presented to the two ears simultaneously. 1ĭichotic tests can be administered in two reporting modes, free report and directed report. Of particular interest is the finding of an abnormally large right-ear advantage (REA), or, more properly, an abnormally large left-ear disadvantage (LED), reported to be associated with auditory processing disorder (APD). Dichotic tests have a long history in the audiological evaluation of elderly persons. In this article we show how a test assessing dichotic listening might differentiate among simple sensorineural hearing loss (SNHL), SNHL plus cognitive decline, and SNHL plus auditory processing deficit in elderly listeners. The third factor, however, decline in the processing of auditory information in areas and pathways of the brain, has remained elusive. Degree of cognitive decline, especially memory, attention, and speed of mental processing, can be assessed by a number of psychological tests. The typical signature is a bilaterally-symmetrical sensorineural loss, increasing gradually with frequency. We use the pure-tone audiogram to assess the first factor by measuring pure-tone threshold loss across the audiometric frequency change. There are three principal causes:ġ) Loss in peripheral hearing sensitivity,Ģ) Decline in overall cognitive function, andģ) Deficit in central auditory processing. This article shows how the Dichotic Sentence Identification (DSI) Test can help differentiate between simple SNHL and those hearing losses involving cognitive decline or auditory processing disorder (APD) in older adults.Īs we grow older, successful listening-especially in noisy environments-becomes ever more challenging. Sensorineural hearing loss (SNHL) is often accompanied by a decline in cognitive function and/or deficits in central auditory processing. It is well known that a patient’s audiometric configuration does not, and cannot, always describe the true impact of a hearing loss. Research | March 2019 Hearing Review Toward differentiation between SNHL, SNHL with cognitive decline, and SNHL with APD
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