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Auditory Deprivation
Auris·Nasus·Larynx (Tokyo) 12 (Suppl. J) S 36-S 37, 1985
AUDITORY DEPRIVATION Robert J. RUBEN, M.D. Departments of Otolaryngology and Pediatrics, Albert Einstein College of Medicine of Yeshiva, Montefiore Medical Center, New York, New York, U.S.A.
External sensory stimuli cause physical change within the central nervous systems of all animals. Auditory stimuli are consistent with this general biological law. An effect of the change brought about in the central nervous system by auditory stimuli is that of sharpening the responsivity of the organism to respond to auditory stimuli which are of special significance for the particular animal. This has been shown in a number of different species. Some examples of this are the patterning of bird songs, the warning call of the mother duck, etc. (RUBEN and RAPIN, 1980). Studies of the effect of auditory stimuli in man have been consistent with that which has been observed in other animals. The studies which have shown the initial responsivity of infants to unique speech sounds and then, after a few months of isolation from the sounds, the infants acquired an inability to respond to the sound (KUHL, 1976). This and other studies illustrate the generality of the biological phenomena of the sharpening of the central nervous system by auditory stimuli. Auditory deprivation is a special case of the general phenomena of the moulding of the central nervous system by auditory stimuli. The deprivation can be brought about by either a defective transformer, a conductive hearing loss and/or a defective transducer, a sensorineural hearing loss or due to the lack of appropriate sound stimulus. There is a literature concerning the experimental work which has been done in the area of auditory deprivation (RUBEN, 1980; RUBEN and RAPIN, 1980, 1981). This work has shown that there are anatomical, physiological and behavioral effects from the deprivations. The most
marked anatomical changes occur when the inner ear is removed from the embryonic chick. This severe "deprivation" causes profound changes within the structure of the auditory nuclei of the brain stem and the mid brain of the chick. Fortunately, this form of deprivation is rare in man. However, there is the probability that late embryonic or early fetal "deafness" will result in severe changes in the brain stem and mid brain nuclei in man. This has an obvious implication in habilitation in that the changes in the central nervous system may make the acquisition of meaning for auditory stimuli different than if the central nervous system was not affected. Hearing losses which are less than severe also affect the central nervous system (WEBSTER and WEBSTER, 1977; WEBSTER, 1983). These conductive losses, which have been experimentally induced in the young mouse, have resulted in decreases in the size of the cells and a diminution in the dendritic processes (WEBSTER, 1985) of cells of the auditory nuclei in the brain stem and the mid brain. Electrophysiological changes have occurred from various types of auditory deprivations. These have included decreased amplitude of the cortical auditory evoked potentials in the rat, changes in the pattern of two tone inhibition in the inferior colliclus of the rat; a change in the firing patterns of single cells in the inferior colliclus of the rat dependent upon their exposure to a unique sound (RUBEN and RAPIN, 1980). Behavioral changes following auditory deprivations have been documented in a number of species. These include elevations of threshold for auditory stimuli; lack of responsivity to stimuli which have been deprived, i.e., stimuli which occur as new to
Panel
Audiological Aspects of OME
the organism after the animal has reached the adult state; changes in preference or reactivity to stimuli other than auditory; etc. The pattern which emerges from these studies is that the animal's ability to respond to different auditory stimuli is greater in the late fetal and early infancy than it is in the adult. The anatomical, physiological and behavioral effects of auditory deprivation are all more apparent the earlier that they occur. There are no studies which correlate these three domains of observation, anatomical, physiological and behavioral with each other. Auditory deprivation in man should follow the same general patterns as found in all other animals. There is not yet evidence of the anatomical or physiological effects of moderate auditory deprivation in man, as these effects have not been looked for in a systematic fashion. The behavioral effects of auditory deprivation in man are well documented. These include the lack of speech and language development in the profound to severely hearing impaired child, the deficits in language in the less than profoundly deaf child (RUBEN et al., 1982) and the multitude of effects found consequent to the intermittent modest deprivations which occur in association with otitis media with effusion (RUBEN, 1984). These effects are complex in that they are dependent on more than just the intermittent variable amounts of auditory deprivation. There are significant interactions with the intelligence of the child, the social and economic status of the child, the time of the deprivation and the qualitative nature of the deprivation. There is a biological continuum of the plasticity of the developing central nervous system. Auditory deprivation in man is a special example of the general phenomena of sensory plasticity. The effects of auditory deprivations in man are deliterious, especially in the areas of language, cognition based on language, socialization, and speech. These deleterious effects in man should have their basis in anatomical changes in the
S 37
central nervous system. As these effects appear to be permanent, there every effort must be made to prevent them. Contemporary society is dependent upon verbal communication and language with a verbal basis. The societal members who have deficits in these domains from their auditory deprivations as infants and/or toddlers will be disadvantaged. The society which does not prevent or cure these effects, in this world of language and communication, will be handicapped. The optimization of auditory responsivity should ensure the more efficient use of the population's cognitive endowment. References KUHL, P. K.: Speech perception in early infancy: the acquisition of speech sound categories. In Hearing and Davis: Essays Honoring Hallowell Davis (Hirsch, S. K., Eldridge, D. H., Hirsch, 1. J., and Silverman, S. R., eds.), pp. 265-276, Washington University Press, St. Louis, 1976. RUBEN, R. J.: A review of transneuronal changes of the auditory central nervous system as a consequence of auditory defects. Int. J. Pediatr. Otorhinolaryngol. 1: 269-277, 1980. RUBEN, R. J.: An inquiry into the minimal amount of auditory deprivation which results in a cognitive effect in man. Acta Otolaryngol. (Stockh.) suppl. 414: 157-164, 1984. RUBEN, R. J., LEVINE, R., FISHMAN, G., BALDINGER, E., FELDMAN, W., SILVER, M., STEIN, M., UMANO, H., and KRUGER, B.: The moderate to severe sensorineural hearing impaired child: An analysis of etiology, intervention and outcome. Laryngoscope 92: 38-46, 1982. RUBEN, R. J., and RAPIN, 1.: Plasticity of the developing auditory system. Ann. Otol. Rhinol. Laryngol. 89: 303-311, 1980. RUBEN, R. J., and RAPIN, 1.: Theoretical issues in the development of audition. In Developmental Disabilities: Theory, Assessment and Intervention (Lewis, M., and Taft, L., eds.), Sp Medical and Scientific Books, pp. 63-78, 1981. WEBSTER, D. B.: A critical period during postnatal auditory development of mice. Int. J. Pediatr. Otorhinolaryngol. 6: 107-118, 1983. WEBSTER, D. B.: Personal communication, 1985. WEBSTER, D. B., and WEBSTER, M.: Neonatal sound deprivation affects brainstem auditory nuclei. Arch. Otolaryngol. 103: 392-396, 1977.
AUDITORY DEPRIVATION Robert J. RUBEN, M.D. Departments of Otolaryngology and Pediatrics, Albert Einstein College of Medicine of Yeshiva, Montefiore Medical Center, New York, New York, U.S.A.
External sensory stimuli cause physical change within the central nervous systems of all animals. Auditory stimuli are consistent with this general biological law. An effect of the change brought about in the central nervous system by auditory stimuli is that of sharpening the responsivity of the organism to respond to auditory stimuli which are of special significance for the particular animal. This has been shown in a number of different species. Some examples of this are the patterning of bird songs, the warning call of the mother duck, etc. (RUBEN and RAPIN, 1980). Studies of the effect of auditory stimuli in man have been consistent with that which has been observed in other animals. The studies which have shown the initial responsivity of infants to unique speech sounds and then, after a few months of isolation from the sounds, the infants acquired an inability to respond to the sound (KUHL, 1976). This and other studies illustrate the generality of the biological phenomena of the sharpening of the central nervous system by auditory stimuli. Auditory deprivation is a special case of the general phenomena of the moulding of the central nervous system by auditory stimuli. The deprivation can be brought about by either a defective transformer, a conductive hearing loss and/or a defective transducer, a sensorineural hearing loss or due to the lack of appropriate sound stimulus. There is a literature concerning the experimental work which has been done in the area of auditory deprivation (RUBEN, 1980; RUBEN and RAPIN, 1980, 1981). This work has shown that there are anatomical, physiological and behavioral effects from the deprivations. The most
marked anatomical changes occur when the inner ear is removed from the embryonic chick. This severe "deprivation" causes profound changes within the structure of the auditory nuclei of the brain stem and the mid brain of the chick. Fortunately, this form of deprivation is rare in man. However, there is the probability that late embryonic or early fetal "deafness" will result in severe changes in the brain stem and mid brain nuclei in man. This has an obvious implication in habilitation in that the changes in the central nervous system may make the acquisition of meaning for auditory stimuli different than if the central nervous system was not affected. Hearing losses which are less than severe also affect the central nervous system (WEBSTER and WEBSTER, 1977; WEBSTER, 1983). These conductive losses, which have been experimentally induced in the young mouse, have resulted in decreases in the size of the cells and a diminution in the dendritic processes (WEBSTER, 1985) of cells of the auditory nuclei in the brain stem and the mid brain. Electrophysiological changes have occurred from various types of auditory deprivations. These have included decreased amplitude of the cortical auditory evoked potentials in the rat, changes in the pattern of two tone inhibition in the inferior colliclus of the rat; a change in the firing patterns of single cells in the inferior colliclus of the rat dependent upon their exposure to a unique sound (RUBEN and RAPIN, 1980). Behavioral changes following auditory deprivations have been documented in a number of species. These include elevations of threshold for auditory stimuli; lack of responsivity to stimuli which have been deprived, i.e., stimuli which occur as new to
Panel
Audiological Aspects of OME
the organism after the animal has reached the adult state; changes in preference or reactivity to stimuli other than auditory; etc. The pattern which emerges from these studies is that the animal's ability to respond to different auditory stimuli is greater in the late fetal and early infancy than it is in the adult. The anatomical, physiological and behavioral effects of auditory deprivation are all more apparent the earlier that they occur. There are no studies which correlate these three domains of observation, anatomical, physiological and behavioral with each other. Auditory deprivation in man should follow the same general patterns as found in all other animals. There is not yet evidence of the anatomical or physiological effects of moderate auditory deprivation in man, as these effects have not been looked for in a systematic fashion. The behavioral effects of auditory deprivation in man are well documented. These include the lack of speech and language development in the profound to severely hearing impaired child, the deficits in language in the less than profoundly deaf child (RUBEN et al., 1982) and the multitude of effects found consequent to the intermittent modest deprivations which occur in association with otitis media with effusion (RUBEN, 1984). These effects are complex in that they are dependent on more than just the intermittent variable amounts of auditory deprivation. There are significant interactions with the intelligence of the child, the social and economic status of the child, the time of the deprivation and the qualitative nature of the deprivation. There is a biological continuum of the plasticity of the developing central nervous system. Auditory deprivation in man is a special example of the general phenomena of sensory plasticity. The effects of auditory deprivations in man are deliterious, especially in the areas of language, cognition based on language, socialization, and speech. These deleterious effects in man should have their basis in anatomical changes in the
S 37
central nervous system. As these effects appear to be permanent, there every effort must be made to prevent them. Contemporary society is dependent upon verbal communication and language with a verbal basis. The societal members who have deficits in these domains from their auditory deprivations as infants and/or toddlers will be disadvantaged. The society which does not prevent or cure these effects, in this world of language and communication, will be handicapped. The optimization of auditory responsivity should ensure the more efficient use of the population's cognitive endowment. References KUHL, P. K.: Speech perception in early infancy: the acquisition of speech sound categories. In Hearing and Davis: Essays Honoring Hallowell Davis (Hirsch, S. K., Eldridge, D. H., Hirsch, 1. J., and Silverman, S. R., eds.), pp. 265-276, Washington University Press, St. Louis, 1976. RUBEN, R. J.: A review of transneuronal changes of the auditory central nervous system as a consequence of auditory defects. Int. J. Pediatr. Otorhinolaryngol. 1: 269-277, 1980. RUBEN, R. J.: An inquiry into the minimal amount of auditory deprivation which results in a cognitive effect in man. Acta Otolaryngol. (Stockh.) suppl. 414: 157-164, 1984. RUBEN, R. J., LEVINE, R., FISHMAN, G., BALDINGER, E., FELDMAN, W., SILVER, M., STEIN, M., UMANO, H., and KRUGER, B.: The moderate to severe sensorineural hearing impaired child: An analysis of etiology, intervention and outcome. Laryngoscope 92: 38-46, 1982. RUBEN, R. J., and RAPIN, 1.: Plasticity of the developing auditory system. Ann. Otol. Rhinol. Laryngol. 89: 303-311, 1980. RUBEN, R. J., and RAPIN, 1.: Theoretical issues in the development of audition. In Developmental Disabilities: Theory, Assessment and Intervention (Lewis, M., and Taft, L., eds.), Sp Medical and Scientific Books, pp. 63-78, 1981. WEBSTER, D. B.: A critical period during postnatal auditory development of mice. Int. J. Pediatr. Otorhinolaryngol. 6: 107-118, 1983. WEBSTER, D. B.: Personal communication, 1985. WEBSTER, D. B., and WEBSTER, M.: Neonatal sound deprivation affects brainstem auditory nuclei. Arch. Otolaryngol. 103: 392-396, 1977.