- Email: [email protected]
Change of acoustic reflectivity with age
80
Clinical and laboratory observations
week of life. For all other ears on which multiple measurable recordings were obtained, the change in ear canal di: ameter caused by pneumatic stimulation steadily decreased with age. No visible deviation from resting diameter was appreciated in any patient after 56 days of age. These results suggest that after 2 months of age the air-pressure changes introduced during tympanometry do not cause visible motion of the ear canal walls at the speculum depths used in this study. Although ear canal wall mobility and complexity of tympanometric type decrease with age, they may not be related in individual subjects. O u r data demonstrate that on six occasions during the first 31 days of life, pressure pulses of • 250 to 300 daPa did not result in visible distension of the ear canal walls, and yet multiple peaks were found in the admittance tympanograms at 226 Hz. At that frequency, no correlation was found in the first week of life between tympanometric complexity and ear canal wall mobility. These results suggest that factors other than canal wall distensibility are responsible for the unusual tympanometric shapes, with multiple peaks, that have been found in neonates. In addition, the model of Vanhuyse et al. 9 and multifrequency tympanometric data from adults indicate that multipeaked patterns may occur in the middle ears of normal adults. It is possible that the patterns we observed were due to differences in neonatal middle, rather than external, ears. Anatomic development of the dimensions of the middle ear space or unresolved mesenchyme in the infant middle ear may contribute the these differences, l~ ll Attrition was high in our study, and the infants were less cooperative as they grew older. Therefore a limited number of interpretable video recordings were obtained between 103 and 133 days of age. Further investigation with a separate population of 4-month-old infants appears warranted. We conclude that a progressive decline in neonatal auditory canal wall distensibility was demonstrated in response to pressures of the magnitude used during tympanometry. No change in resting canal diameter was observed by 56 days of life, and complex tympanograms with multiple
The Journal of Pediatrics July 1990
peaks were obtained at 226 Hz in the absence of ear canal wall motion. The data suggest that, by 2 months of age, values of aural acoustic admittance obtained from tympanograms are unaffected by ear canal wall movement and may provide Clinically useful estimates of the input admittance at the tympanic membrane. These findings are consistent with previous reports that tympanometry may have diagnostic Usefulness in young infants and underscore the need for additional research to validate this procedure in babies less than 7 months of age. 12, 13 We thank Jon Birck, of the Virtual Corporation, and Dr. Charles Reiners. REFERENCES 1. Paradise JL. Editorial retrospective:tympanometry. N Engl J Med .1982;307:1074-6. 2. Keith RW. Middle ear function in neonates. Arch Otolaryngol 1975;101:376-9. 3. Joint Committee on Infant Hearing. Position statement 1982. Pediatrics 1982;70:496-7. 4. Paradise JL. Otitis media in infants and children. Pediatrics 1980;65:917-43. 5. Teele DW, Teele J. Detection of middle ear effusionby acoustic reflectometry. J PEDIATR1984;104:832-8. 6. Cavanaugh RM. Pneumatic otoscopy in healthy full-term infants. Pediatrics 1987;79:520-3. 7. Paradise JL, Smith CG, Bluestone CD. Tympanometric detection of middle ear effusionin infants and young children. Pediatrics 1976;58:198-210. 8. Cavanaugh RM. Pediatricians and the pneumatic otoscope: are we playing it by ear? Pediatrics 1989;84:362-4. 9. Vanhuyse V, Creten W, Van Camp K. On the W notching of tympanograms. Scand Audiol 1975;4:45-50. 10. Eby TL, Nadol JB. Postnatal growth of the human temporal bone. Ann Otol Rhinol Laryngol 1986;95:356-64. 11. Paparella MM, Shea D, Meyerhoff WL, et al. Silent otitis media. Laryngoscope 1980;90:1089-98. 12. Groothuis JR, Sell SH, Wright PF, et al. Otitis media in infancy: tympanometric findings. Pediatrics 1979;63:435-42. 13. Marchant CD, McMillan PM, Shurin PA, et al. Objective diagnosis of otitis media in early infancy by tympanometry and ipsilateral acoustic reflex thresholds. J PEDIATR 1986;109: 590-5.
Change of acoustic reflectivity with age Jerome T, Combs, MD
Submitted for publication Aug. 23, 1989; accepted Jan. 4, 1990. Reprint requests: Jerome T. Combs, MD, 50 South Main St., Wallingford, CT 06492. 9/22/19198
Acoustic reflectometry has been introduced as a noninvasive, sonar technique capable of giving objective information about the likelihood of middle ear effusion, a The sensitivity and specificity of this method of middle ear evalu-
Volume 117 Number 1, Part I
Clinical and laboratory observations
81
Figure. Histogram showing in mean acoustic reflectivity with age in normal ears (SD and SEM are noted for each age group). Number at bottom of each age-group column is number of ears analyzed in each age group. See text for statement of statistical analysis of data.
See related article, p. 77. ation have been the subject of a number of studies, 1-6 recently summarized.7 All clinical evaluations have included infants, children, and adolescents together. Implicit in grouping patients without regard to age is the assumption that acoustic reflectivity is independent of age. It seems unlikely that acoustic reflectivity does not change from infancy to adulthood. The tympanic membrane in a term infant is of roughly adult size, with a diameter of about 9 mm, 8 but is positioned very obliquely and assumes a more vertical alignment in early infancy. The thickness of the tympanic membrane also changes with maturation. The compliance of the tympanic membrane to sound pressure, as measured by immittanee testing, increases from infancy to childhood. Additionally, the external ear canal elongates from approximately 1 em in infancy to 2.5 cm in the adult; the volume increases fourfold, from 0.5 to 2.0 cc. It appears difficult to predict the direction of change in acoustic reflectivity with age but unlikely that there is no change at all. A protocol was devised to evaluate the possibility that the value of acoustic reflectivity in normal ears is age dependent. METHODS All patients more than 6 months of age who were seen during a 1-month period in a solo primary care pediatric practice were considered for inclusion in the study.
For all patients, a history was taken and physical examination, tympanometry with the MicroTymp middle-ear analyzer9 (Welch Allyn, Inc., Skaneateles Falls, N.Y.), and acoustic reflectometry with recorder 1~ (ENT Medical Devices Inc., Wareham, Mass.) were performed. Tympanometry was done sequentially until at least two concordant findings were obtained for each ear. Acoustic reflectometry was done in triplicate. Patients with a history or physical findings of otitis media or with abnormal tympanograms (B or C curves) were excluded from the study. Ears with tympanostomy tubes and those impacted with wax were also excluded from analysis. Tympanograms and tracings from acoustic reflectometry were taped to index cards with notations regarding the age and gender of the patients. Each patient or parent was informed that the data were being collected as part of a clinical study, and the data were filed for subsequent analysis. At the end of the study period, the cards were grouped in arbitrary age divisions to provide a minimum of 40 ears in each category. A two-tailed t test was used to calculate whether there was a statistically significant difference in the mean refleetivity of one age group from the preceding one. RESULTS Data from a total of 530 ears that were normal by history, physical examination, and tympanometry were available for analysis (Figure). The male/female ratio was 258 to 281. There was a progressive increase in mean acoustic reflectivity from approximately 2 units in normal infants to
82
Clinical and laboratory observations
approximately 4 units in healthy older adolescents. The difference between mean reflectivity in the 6-monthold to 2-year-old group and the 2- to 4-year-old category was significant (p <0.01). A further increase in reflectivity from the 2- to 4-year-old group to the 4- to 6-year-old category was demonstrated (p <0.001). N o significant change in reflectivity with increased age occurred from 6 to 16 years. A modest increase was seen in patients older than 16 years of age (p <0.001). The oldest patient was 21 years of age; no data were collected for adults. In each age group there was a relatively wide range of values for acoustic reflectivity. However, no normal ear had a value of more than 5.7 in this small sample. DISCUSSION The results of this evaluation suggest that it may not be appropriate to group patients without regard to age in future studies of acoustic reflectometry. The grouping of data from infants, toddlers, children, and adolescents in earlier studies 1-7 may help to explain why the accuracy of this technology has been reported to range very widely in various population samples. Obviously, small study populations may be very disparate if age is not regarded as an important factor. This consideration might also help explain why some authors have concluded that a reflectivity of 6 is a reasonable cutoff point and others have recommended a value of 4 or 5 to distinguish normal from abnormal ears. The data presented here suggest that patient age is a statistically important issue in deciding which value of acoustic reflectivity is to be accepted as indicative of an abnormal
The Journal of Pediatrics July 1990 tympanic membrane. The wide range of normal reflectivity in all age groups indicates that serial observations of individual patients may be the most meaningful way of apply. ing this technology when medical and surgical management decisions are made. REFERENCES
1. Teele DW, Teele J. Detection of middle ear effusion by acoustic reflectometry. J PEDIATR 1984;104:832-8. 2. Lampe RM, Weir MR, Spiev J, Rhodes MF. Acoustic reflectometry in the detection of middle ear effusion. Pediatrics 1985;76;75-8. 3. Schwartz DM, Schwartz RH. Validity of acoustic reflectornetry in detecting middle ear effusions. Pediatrics 1987;79:73% 42. 4. Avery CA, Gates GA, Prihoda TJ. Efficacy of acoustic reflectometry in detecting middle ear effusion. Ann Otol Rhinol Laryngol 1986;95:472-6. 5. Bihrer K, Wallh G, Schuster L. The acoustic reflectometer as screening device: comparison. Ear Hear 1985;6:307-14. 6. Oyiborhoro J, Olaniyan S, Newman C. Efficacy of acoustic otoscopy in detecting middle ear effusion in children. Laryngoscope 1987;97:495-8. 7. Lampe RM, Schwartz RH. Diagnostic value of acoustic reflectometry in children with acute otitis media. Pediatr Infect Dis 1989;8:59-61. 8. Birney J, Barcz D, Jafek BW. Developmental anatomy and physiology of the ear. In: Balkany T J, Pashley NRT, eds. Clinical pediatric otolaryngology. St Louis: CV Mosby, 1986:79. 9. Wazen J J, Ferraro JA, Hughes R. Clinical evaluation of a portable, cordless, hand-held middle ear analyzer. Otolaryngology 1988;99:348-50. 10. Combs JT. Precision of acoustic reflectometry with recorder in acute otitis media. Pediatr Infect Dis J 1988;7:329-30.
Totally implantable vascular access devices in cystic fibrosis: A four-year experience with fifty-eight patients J a n B. Morris, MD, M a r i a E. O c c h i o n e r o , RN, M i c h a e l W. L. G a u d e r e r , MD, R o b e r t C. Stern, MD, a n d C a r l F. D o e r s h u k , MD From the Division of Pediatric Surgery, Department of Surgery and the Cystic Fibrosis Center, and the Division of Pulmonary Medicine, Department of Pediatrics, Rainbow Babies and Childrens Hospital of the University Hospitals of Cleveland, Case Western Reserve University School of Medicine, Cleveland, Ohio Supported in part by grant No. DK 27651 from the National Institutes of Health and by grants from the Cystic Fibrosis Foundation and United Way Services of Greater Cleveland. Submitted for publication Nov. 2, 1989; accepted Jan. 24, 1990. Reprint requests: Michael W. L. Gauderer, MD, Chief, Division of Pediatric Surgery, Rainbow Babies and Childrens Hospital, 2101 Adelbert Rd., Cleveland, OH 44106. 9/22/19665
The totally implantable vascular access device has emerged as an effective means of intermittent, central venous access for therapeutic infusions.1 The T I V A D consists of a subcutaneously placed reservoir attached to a Silastic catheter placed in a central vein. Much of the information on T I V A D efficacy concerns adult 25 and pediatric 6,7 patients with cancer requiring long-term intravenous chemotherapy. We
Clinical and laboratory observations
week of life. For all other ears on which multiple measurable recordings were obtained, the change in ear canal di: ameter caused by pneumatic stimulation steadily decreased with age. No visible deviation from resting diameter was appreciated in any patient after 56 days of age. These results suggest that after 2 months of age the air-pressure changes introduced during tympanometry do not cause visible motion of the ear canal walls at the speculum depths used in this study. Although ear canal wall mobility and complexity of tympanometric type decrease with age, they may not be related in individual subjects. O u r data demonstrate that on six occasions during the first 31 days of life, pressure pulses of • 250 to 300 daPa did not result in visible distension of the ear canal walls, and yet multiple peaks were found in the admittance tympanograms at 226 Hz. At that frequency, no correlation was found in the first week of life between tympanometric complexity and ear canal wall mobility. These results suggest that factors other than canal wall distensibility are responsible for the unusual tympanometric shapes, with multiple peaks, that have been found in neonates. In addition, the model of Vanhuyse et al. 9 and multifrequency tympanometric data from adults indicate that multipeaked patterns may occur in the middle ears of normal adults. It is possible that the patterns we observed were due to differences in neonatal middle, rather than external, ears. Anatomic development of the dimensions of the middle ear space or unresolved mesenchyme in the infant middle ear may contribute the these differences, l~ ll Attrition was high in our study, and the infants were less cooperative as they grew older. Therefore a limited number of interpretable video recordings were obtained between 103 and 133 days of age. Further investigation with a separate population of 4-month-old infants appears warranted. We conclude that a progressive decline in neonatal auditory canal wall distensibility was demonstrated in response to pressures of the magnitude used during tympanometry. No change in resting canal diameter was observed by 56 days of life, and complex tympanograms with multiple
The Journal of Pediatrics July 1990
peaks were obtained at 226 Hz in the absence of ear canal wall motion. The data suggest that, by 2 months of age, values of aural acoustic admittance obtained from tympanograms are unaffected by ear canal wall movement and may provide Clinically useful estimates of the input admittance at the tympanic membrane. These findings are consistent with previous reports that tympanometry may have diagnostic Usefulness in young infants and underscore the need for additional research to validate this procedure in babies less than 7 months of age. 12, 13 We thank Jon Birck, of the Virtual Corporation, and Dr. Charles Reiners. REFERENCES 1. Paradise JL. Editorial retrospective:tympanometry. N Engl J Med .1982;307:1074-6. 2. Keith RW. Middle ear function in neonates. Arch Otolaryngol 1975;101:376-9. 3. Joint Committee on Infant Hearing. Position statement 1982. Pediatrics 1982;70:496-7. 4. Paradise JL. Otitis media in infants and children. Pediatrics 1980;65:917-43. 5. Teele DW, Teele J. Detection of middle ear effusionby acoustic reflectometry. J PEDIATR1984;104:832-8. 6. Cavanaugh RM. Pneumatic otoscopy in healthy full-term infants. Pediatrics 1987;79:520-3. 7. Paradise JL, Smith CG, Bluestone CD. Tympanometric detection of middle ear effusionin infants and young children. Pediatrics 1976;58:198-210. 8. Cavanaugh RM. Pediatricians and the pneumatic otoscope: are we playing it by ear? Pediatrics 1989;84:362-4. 9. Vanhuyse V, Creten W, Van Camp K. On the W notching of tympanograms. Scand Audiol 1975;4:45-50. 10. Eby TL, Nadol JB. Postnatal growth of the human temporal bone. Ann Otol Rhinol Laryngol 1986;95:356-64. 11. Paparella MM, Shea D, Meyerhoff WL, et al. Silent otitis media. Laryngoscope 1980;90:1089-98. 12. Groothuis JR, Sell SH, Wright PF, et al. Otitis media in infancy: tympanometric findings. Pediatrics 1979;63:435-42. 13. Marchant CD, McMillan PM, Shurin PA, et al. Objective diagnosis of otitis media in early infancy by tympanometry and ipsilateral acoustic reflex thresholds. J PEDIATR 1986;109: 590-5.
Change of acoustic reflectivity with age Jerome T, Combs, MD
Submitted for publication Aug. 23, 1989; accepted Jan. 4, 1990. Reprint requests: Jerome T. Combs, MD, 50 South Main St., Wallingford, CT 06492. 9/22/19198
Acoustic reflectometry has been introduced as a noninvasive, sonar technique capable of giving objective information about the likelihood of middle ear effusion, a The sensitivity and specificity of this method of middle ear evalu-
Volume 117 Number 1, Part I
Clinical and laboratory observations
81
Figure. Histogram showing in mean acoustic reflectivity with age in normal ears (SD and SEM are noted for each age group). Number at bottom of each age-group column is number of ears analyzed in each age group. See text for statement of statistical analysis of data.
See related article, p. 77. ation have been the subject of a number of studies, 1-6 recently summarized.7 All clinical evaluations have included infants, children, and adolescents together. Implicit in grouping patients without regard to age is the assumption that acoustic reflectivity is independent of age. It seems unlikely that acoustic reflectivity does not change from infancy to adulthood. The tympanic membrane in a term infant is of roughly adult size, with a diameter of about 9 mm, 8 but is positioned very obliquely and assumes a more vertical alignment in early infancy. The thickness of the tympanic membrane also changes with maturation. The compliance of the tympanic membrane to sound pressure, as measured by immittanee testing, increases from infancy to childhood. Additionally, the external ear canal elongates from approximately 1 em in infancy to 2.5 cm in the adult; the volume increases fourfold, from 0.5 to 2.0 cc. It appears difficult to predict the direction of change in acoustic reflectivity with age but unlikely that there is no change at all. A protocol was devised to evaluate the possibility that the value of acoustic reflectivity in normal ears is age dependent. METHODS All patients more than 6 months of age who were seen during a 1-month period in a solo primary care pediatric practice were considered for inclusion in the study.
For all patients, a history was taken and physical examination, tympanometry with the MicroTymp middle-ear analyzer9 (Welch Allyn, Inc., Skaneateles Falls, N.Y.), and acoustic reflectometry with recorder 1~ (ENT Medical Devices Inc., Wareham, Mass.) were performed. Tympanometry was done sequentially until at least two concordant findings were obtained for each ear. Acoustic reflectometry was done in triplicate. Patients with a history or physical findings of otitis media or with abnormal tympanograms (B or C curves) were excluded from the study. Ears with tympanostomy tubes and those impacted with wax were also excluded from analysis. Tympanograms and tracings from acoustic reflectometry were taped to index cards with notations regarding the age and gender of the patients. Each patient or parent was informed that the data were being collected as part of a clinical study, and the data were filed for subsequent analysis. At the end of the study period, the cards were grouped in arbitrary age divisions to provide a minimum of 40 ears in each category. A two-tailed t test was used to calculate whether there was a statistically significant difference in the mean refleetivity of one age group from the preceding one. RESULTS Data from a total of 530 ears that were normal by history, physical examination, and tympanometry were available for analysis (Figure). The male/female ratio was 258 to 281. There was a progressive increase in mean acoustic reflectivity from approximately 2 units in normal infants to
82
Clinical and laboratory observations
approximately 4 units in healthy older adolescents. The difference between mean reflectivity in the 6-monthold to 2-year-old group and the 2- to 4-year-old category was significant (p <0.01). A further increase in reflectivity from the 2- to 4-year-old group to the 4- to 6-year-old category was demonstrated (p <0.001). N o significant change in reflectivity with increased age occurred from 6 to 16 years. A modest increase was seen in patients older than 16 years of age (p <0.001). The oldest patient was 21 years of age; no data were collected for adults. In each age group there was a relatively wide range of values for acoustic reflectivity. However, no normal ear had a value of more than 5.7 in this small sample. DISCUSSION The results of this evaluation suggest that it may not be appropriate to group patients without regard to age in future studies of acoustic reflectometry. The grouping of data from infants, toddlers, children, and adolescents in earlier studies 1-7 may help to explain why the accuracy of this technology has been reported to range very widely in various population samples. Obviously, small study populations may be very disparate if age is not regarded as an important factor. This consideration might also help explain why some authors have concluded that a reflectivity of 6 is a reasonable cutoff point and others have recommended a value of 4 or 5 to distinguish normal from abnormal ears. The data presented here suggest that patient age is a statistically important issue in deciding which value of acoustic reflectivity is to be accepted as indicative of an abnormal
The Journal of Pediatrics July 1990 tympanic membrane. The wide range of normal reflectivity in all age groups indicates that serial observations of individual patients may be the most meaningful way of apply. ing this technology when medical and surgical management decisions are made. REFERENCES
1. Teele DW, Teele J. Detection of middle ear effusion by acoustic reflectometry. J PEDIATR 1984;104:832-8. 2. Lampe RM, Weir MR, Spiev J, Rhodes MF. Acoustic reflectometry in the detection of middle ear effusion. Pediatrics 1985;76;75-8. 3. Schwartz DM, Schwartz RH. Validity of acoustic reflectornetry in detecting middle ear effusions. Pediatrics 1987;79:73% 42. 4. Avery CA, Gates GA, Prihoda TJ. Efficacy of acoustic reflectometry in detecting middle ear effusion. Ann Otol Rhinol Laryngol 1986;95:472-6. 5. Bihrer K, Wallh G, Schuster L. The acoustic reflectometer as screening device: comparison. Ear Hear 1985;6:307-14. 6. Oyiborhoro J, Olaniyan S, Newman C. Efficacy of acoustic otoscopy in detecting middle ear effusion in children. Laryngoscope 1987;97:495-8. 7. Lampe RM, Schwartz RH. Diagnostic value of acoustic reflectometry in children with acute otitis media. Pediatr Infect Dis 1989;8:59-61. 8. Birney J, Barcz D, Jafek BW. Developmental anatomy and physiology of the ear. In: Balkany T J, Pashley NRT, eds. Clinical pediatric otolaryngology. St Louis: CV Mosby, 1986:79. 9. Wazen J J, Ferraro JA, Hughes R. Clinical evaluation of a portable, cordless, hand-held middle ear analyzer. Otolaryngology 1988;99:348-50. 10. Combs JT. Precision of acoustic reflectometry with recorder in acute otitis media. Pediatr Infect Dis J 1988;7:329-30.
Totally implantable vascular access devices in cystic fibrosis: A four-year experience with fifty-eight patients J a n B. Morris, MD, M a r i a E. O c c h i o n e r o , RN, M i c h a e l W. L. G a u d e r e r , MD, R o b e r t C. Stern, MD, a n d C a r l F. D o e r s h u k , MD From the Division of Pediatric Surgery, Department of Surgery and the Cystic Fibrosis Center, and the Division of Pulmonary Medicine, Department of Pediatrics, Rainbow Babies and Childrens Hospital of the University Hospitals of Cleveland, Case Western Reserve University School of Medicine, Cleveland, Ohio Supported in part by grant No. DK 27651 from the National Institutes of Health and by grants from the Cystic Fibrosis Foundation and United Way Services of Greater Cleveland. Submitted for publication Nov. 2, 1989; accepted Jan. 24, 1990. Reprint requests: Michael W. L. Gauderer, MD, Chief, Division of Pediatric Surgery, Rainbow Babies and Childrens Hospital, 2101 Adelbert Rd., Cleveland, OH 44106. 9/22/19665
The totally implantable vascular access device has emerged as an effective means of intermittent, central venous access for therapeutic infusions.1 The T I V A D consists of a subcutaneously placed reservoir attached to a Silastic catheter placed in a central vein. Much of the information on T I V A D efficacy concerns adult 25 and pediatric 6,7 patients with cancer requiring long-term intravenous chemotherapy. We