Educationally significant hearing loss has been reported in 10% to 15% of children with congenita... more Educationally significant hearing loss has been reported in 10% to 15% of children with congenital toxoplasmosis. As part of a pilot study to assess feasibility and safety of prolonged therapy for congenital toxoplasmosis, 30 congenially infected infants and children were evaluated for auditory function. Serial testing, beginning within 2 months of birth, was performed. Availability of auditory brainstem response (ABR) testing made evaluation at an earlier age than previously possible. Six (20%) of the 30 infants had mild to moderate conductive type hearing loss associated with otitis media. No infant or child had sensorineural hearing loss. The better outcome we observed compared to previous reports of a 15% to 26% incidence of sensorineural hearing loss and 10% to 15% incidence of educationally significant, bilateral hearing impairment may be related to early initiation and/or prolonged institution of antimicrobial therapy. Continued followup to exclude progressive hearing impairm...
Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section, 1987
Auditory middle latency responses (MLRs) have been recorded in 217 patients ranging in age from 6... more Auditory middle latency responses (MLRs) have been recorded in 217 patients ranging in age from 6 days to 20 years. The probability of obtaining MLR components Na and Pa was higher with a high-pass filter setting of 15 Hz, 12 dB/octave as compared to 3 Hz, 6 dB/octave. This effect was found at all ages tested. Age-related latency effects were apparent with 3 Hz but not 15 Hz filtering.
Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section, 1984
The multiple problems associated with hydrocephalus put patients with this disorder at risk for h... more The multiple problems associated with hydrocephalus put patients with this disorder at risk for hearing loss and brain-stem damage. As a measure of both hearing and brain-stem dysfunction (Starr and Achor 1975; Davis 1976; Galambos and Hecox 1977), auditory brain-stem response (ABR) is a valuable diagnostic tool for use in these patients, especially infants and neonates. We became interested in studying the ABRs of hydrocephalic patients when it became apparent from our clinical experience that the incidence of ABR abnormalities suggesting clinically unsuspected brain-stem dysfunction was unusually high in this group. The intent of this investigation was to delineate the incidence and nature of ABR abnormalities in hydrocephalic patients. Methods ABR and clinical findings were examined in 40 patients (80 ears) with confirmed hydrocephalus. Twenty-nine patients were less than 3 years old; 9 patients were between 3 and 11 years old; 2 patients were adults. Follow-up testing was conducted in 9 patients several months after the initial test date. Auditory brain-stem responses were obtained by averaging a differentially recorded EEG signal (GI: vertex; G2: ipsilateral mastoid; ground: forehead). The averaging computer recorded 20 msec
Earlier studies have shown that infants with untreated congenital toxoplasmosis and generalized o... more Earlier studies have shown that infants with untreated congenital toxoplasmosis and generalized or neurologic abnormalities at presentation almost uniformly develop mental retardation, seizures, and spasticity. Children with untreated subclinical disease at birth have developed seizures, significant cognitive and motor deficits, and diminution in cognitive function over time. To determine neurologic, cognitive, and motor outcomes for children with congenital toxoplasmosis who were treated for approximately 1 year with pyrimethamine and sulfadiazine. Systematic, prospective, and longitudinal neurologic, cognitive, and motor evaluations were performed for 36 individuals with congenital toxoplasmosis. These infants were born between December 1981 and January 1991 and were treated with pyrimethamine and sulfadiazine for approximately 1 year beginning in the first months of life. Compliance with medications was documented. These individuals were evaluated in a standardized manner in a si...
This article is being reprinted from the September 1996 issue because it may have been inadverten... more This article is being reprinted from the September 1996 issue because it may have been inadvertently omitted from several copies of THE JOURNAL.
Interpretation of auditory brain stem response (ABR) findings can be problematic in cases where w... more Interpretation of auditory brain stem response (ABR) findings can be problematic in cases where waves III and V are absent. Such findings can be attributed to profound hearing loss, brain stem neuropathology, or both. Over a 3‐year period, 48 patients with no known brain stem damage and on whom audiologic data were available were found to have no response by ABR or absent waves III and V. Severe to profound hearing loss was documented in 38 cases, audiometric data were equivocal in 3 cases, and 7 patients showed pure tone sensitivity ranging from normal hearing to moderate impairment. Thus 15% had better hearing sensitivity than might have been expected from their ABR findings. Each of these patients also exhibited abnormal acoustic reflex findings. We report the electrophysiological (ABR, MLR, acoustic reflex}, medical (history, neurological, EEG, CT scan) and behavioral (audiometric, speech and language, learning disabilities, psychological) data which characterize this group of p...
Follow-up brainstem care unit of infants screened by auditory response in the neonatal intensive ... more Follow-up brainstem care unit of infants screened by auditory response in the neonatal intensive Auditory brainstem response screening at 40 attd 60 dB was conducted in 100 infants in the neonatal intensive care unit to determine initial failure rate and prevalence of abnormality on follow-up. Of our N1CU population, 20 % failed one or both of the screening levels: 9 % failed at 60 dB in both ears, and 11% failed at 40 dB in one or both ears. On follow-up, half of the 60 dB failure group were found to have sensorineural or conductive impairment and represent the 2% to 4% prevalence of serious otologic-audiologic problems generally found in an N1CU population. Subsequent improvement (reversal) of the retest ABR records of the remaining infants in the 60 dB failure group was thought to be related to neural changes in the brainstem associated with recovery from hypoxic episodes. A transient or reversible conductive deficit appeared to account for the majority of failures at 40 dB. We recommend the screening protocol be expanded to include thresholdand latency measures in infants who fail the initial screening. The transient nature of many ABR abnormalities makes postdischarge ABR, otologic, audiologie, and neurologic examinations mandatory before any inferences are made about hearing loss or neurodevelopmental disorders.
Although the clinical use of the middle latency response (MLR) in adults is fairly straightforwar... more Although the clinical use of the middle latency response (MLR) in adults is fairly straightforward, its use is complicated by maturational changes that continue throughout the first decade of life. In order to telescope the time period of this long developmental course, we have approached the study of MLR maturation using the gerbil as an animal model. The course of MLR obtained over the temporal lobe development was characterized in the Monogolian gerbil ranging in age from 10 days to 3 months of life. The adult gerbil MLR consists of two positive peaks (A and C) at 11 and 25 ms, respectively, and a negative component (B) at 16 ms. These components emerge in a systematic fashion as a function of age. The present work supports a strong age effect of increased MLR detectability in the gerbil, similar to findings reported for humans. Wave A was infrequently detected in young animals, but when present, it occurred at adult latencies. The latency of waves B and C decreased systematically with age. The amplitude of all components increased with age, similar to findings in humans. The fact that adult-like thresholds were obtained shortly after birth indicates that when present, MLRs may be a good index of hearing threshold. Effects of stimulating across a wide range of intensities were described. The gerbil model appears appropriate for the study of development of the central auditory system function.
Auditory brainstem response (ABR) results with 82 severely developmentally delayed infants and ch... more Auditory brainstem response (ABR) results with 82 severely developmentally delayed infants and children suspected of being both deaf and blind are reported. Of the 79 children on whom acceptable ABR data were obtained, 34 or 43.0% had ABR thresholds in the normal-hearing range; 16 or 20.3% in the mild-to-moderate loss range; and 3 or 3.8% in the severe loss category. Twenty-six or 32.9% produced no ABR to clicks at a maximum intensity of 90 dB HL. On the basis of established audiological and neurological diagnostic criteria, 3 children showed neurological abnormality by ABR. We conclude that the hearing status of a high percentage of otherwise untestable children can be determined by ABR, that a significant number of infants and children who appear deaf are in fact not hearing impaired, and that the occurrence of brainstem neuropathology in this population is limited.
Two leading causes of hearing loss in infants and young children have been bacterial meningitis d... more Two leading causes of hearing loss in infants and young children have been bacterial meningitis due to Haemophilus influenzae Type b (Hib) and congenital toxoplasmosis. In this two-part review, we describe the essential nature and incidence of these two diseases and how the availability of a Hib vaccine effective and safe with infants as young as 2 mo of age; the prospect of universal immunization against Hib disease; the introduction of cephalosporin antibiotic and corticosteroid treatment; and the use of early and prolonged antimicrobial therapy with children with congenital toxoplasmosis promises significant reduction, if not complete eradication, of hearing loss in infants and toddlers attributable to Hib bacterial meningitis and congenital toxoplasmosis. As a result, there may be up to a third fewer children under the age of five with severe hearing impairment annually in the United States.
Research aimed at quantifying the benefits a hearing aid user might expect from noise suppression... more Research aimed at quantifying the benefits a hearing aid user might expect from noise suppression hearing aids purported to improve hearing in the presence of background noise have yielded widely varying results. We suggest this may in part be due to the inappropriate use of experimental approaches based on group design and inferential statistical analysis. Included in this paper is our rationale for employing a single-subject experimental design to investigate subject performance with two commercially available hearing-aid noise suppression systems. Preliminary results with two subjects indicate that both the Siemens Automatic Signal Processing (ASP) and Zeta Noise Blocker (ZNB) noise suppression systems markedly improve listener scores on the low predictability sentence material of the SPIN Test. We conclude these two noise suppression systems may improve performance as the listening situation becomes contextually more difficult, and that single-subject experimental designs could be a valuable addition to applied behavioral research with hearing aids.
The 1982 Position Statement by the Joint Committee on Infant Hearing recommends that infants at r... more The 1982 Position Statement by the Joint Committee on Infant Hearing recommends that infants at risk for hearing impairment be screened by 3 mos of age and that the diagnostic process be completed and habilitation begun by 6 mos of age. How close to this ideal actual practice comes in an urban setting is the subject of this study. Data on 88 infants referred to a hospital-based parent-infant program were retrospectively examined to determine the occurrence of risk factors and at what ages: (1) hearing loss was first suspected, (2) hearing loss was diagnosed, and (3) habilitation was initiated. Results indicate that over one-quarter of all hearing-impaired infants will not manifest any of the risk factors proposed in the 1982 Position Statement and that regardless of whether the infant graduates from a neonatal intensive care unit or well-baby nursery, the median age for enrollment in a parent-infant program is a year or more later than the 1982 recommendation.
Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were re... more Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were referred to our study group. A uniform approach to evaluation and therapy was developed and is described herein along with the clinical characteristics of these infants and children. In addition, case histories that illustrate especially important clinical features or previously undescribed findings are presented. Factors that contributed to the more severe disabilities included delayed diagnosis and initiation of therapy; prolonged, concomitant neonatal hypoxia and hypoglycemia; profound visual impairment; and prolonged, uncorrected increased intracranial pressure with hydrocephalus and compression of the brain. Years after therapy was discontinued, three children developed new retinal lesions (without loss of visual acuity when therapy for Toxoplasma gondii was initiated promptly), and three children experienced a new onset of afebrile seizures. Most remarkable were the normal developmental, neurological, and ophthalmologic findings at the early follow-up evaluations of many--but not all--of the treated children despite severe manifestations, such as substantial systemic disease, hydrocephalus, microcephalus, multiple intracranial calcifications, and extensive macular destruction detected at birth. These favorable outcomes contrast markedly with outcomes reported previously for children with congenital toxoplasmosis who were untreated or treated for only 1 month.
Congenital transmission of Toxoplasma gondii from a mother who was apparently immunologically com... more Congenital transmission of Toxoplasma gondii from a mother who was apparently immunologically competent and who had toxoplasmic lymphadenitis 2 months before conception is described. Since no T. gondii-specific serological data were available for this mother from the time her lymph node biopsy specimen was obtained, the specimen was studied by polymerase chain reaction (PCR) to determine whether the T. gondii B1 gene was present. The predictive diagnostic value of histologic findings previously considered to be classic signs of T. gondii lymphadenitis also was studied. This was done by correlation of serological tests diagnostic of acute acquired T. gondii infection and presence of characteristic findings in biopsy specimens from persons without known immunocompromise. Both PCR and review of the characteristic features of her lymph node biopsy specimen confirmed the diagnosis of preconceptual infection in the mother. We also discuss two other cases in which apparently immunologically competent mothers with preconceptually acquired infection transmitted this parasite to their fetuses.
Archives of Otolaryngology - Head and Neck Surgery, 1983
Auditory brainstem response (ABR) was used to assess possible hearing loss in 60 patients recover... more Auditory brainstem response (ABR) was used to assess possible hearing loss in 60 patients recovering from bacterial meningitis. The ABR results were consistent with either unilateral or bilateral hearing loss in 35% of the cases tested. Of these, 15% were conductive-type hearing loss. Twelve percent had sensorineural hearing losses and normal brainstem function. The remaining 8% had elevated ABR thresholds coincident with findings suggestive of neuropathology of the auditory brainstem pathways. A case of reversible sensorineural hearing loss was documented. Various clinical and demographic factors were examined to determine their predictive value with regard to hearing loss. As expected, otitis media occurred significantly with conductive hearing loss. Type of pathogen (Streptococcus pneumoniae) and hospitalization greater than two weeks were significantly correlated with sensorineural hearing loss. As meningitis typically affects young children who are difficult to test with conventional audiometry, ABR provides an effective means of testing hearing in this population.
Educationally significant hearing loss has been reported in 10% to 15% of children with congenita... more Educationally significant hearing loss has been reported in 10% to 15% of children with congenital toxoplasmosis. As part of a pilot study to assess feasibility and safety of prolonged therapy for congenital toxoplasmosis, 30 congenially infected infants and children were evaluated for auditory function. Serial testing, beginning within 2 months of birth, was performed. Availability of auditory brainstem response (ABR) testing made evaluation at an earlier age than previously possible. Six (20%) of the 30 infants had mild to moderate conductive type hearing loss associated with otitis media. No infant or child had sensorineural hearing loss. The better outcome we observed compared to previous reports of a 15% to 26% incidence of sensorineural hearing loss and 10% to 15% incidence of educationally significant, bilateral hearing impairment may be related to early initiation and/or prolonged institution of antimicrobial therapy. Continued followup to exclude progressive hearing impairm...
Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section, 1987
Auditory middle latency responses (MLRs) have been recorded in 217 patients ranging in age from 6... more Auditory middle latency responses (MLRs) have been recorded in 217 patients ranging in age from 6 days to 20 years. The probability of obtaining MLR components Na and Pa was higher with a high-pass filter setting of 15 Hz, 12 dB/octave as compared to 3 Hz, 6 dB/octave. This effect was found at all ages tested. Age-related latency effects were apparent with 3 Hz but not 15 Hz filtering.
Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section, 1984
The multiple problems associated with hydrocephalus put patients with this disorder at risk for h... more The multiple problems associated with hydrocephalus put patients with this disorder at risk for hearing loss and brain-stem damage. As a measure of both hearing and brain-stem dysfunction (Starr and Achor 1975; Davis 1976; Galambos and Hecox 1977), auditory brain-stem response (ABR) is a valuable diagnostic tool for use in these patients, especially infants and neonates. We became interested in studying the ABRs of hydrocephalic patients when it became apparent from our clinical experience that the incidence of ABR abnormalities suggesting clinically unsuspected brain-stem dysfunction was unusually high in this group. The intent of this investigation was to delineate the incidence and nature of ABR abnormalities in hydrocephalic patients. Methods ABR and clinical findings were examined in 40 patients (80 ears) with confirmed hydrocephalus. Twenty-nine patients were less than 3 years old; 9 patients were between 3 and 11 years old; 2 patients were adults. Follow-up testing was conducted in 9 patients several months after the initial test date. Auditory brain-stem responses were obtained by averaging a differentially recorded EEG signal (GI: vertex; G2: ipsilateral mastoid; ground: forehead). The averaging computer recorded 20 msec
Earlier studies have shown that infants with untreated congenital toxoplasmosis and generalized o... more Earlier studies have shown that infants with untreated congenital toxoplasmosis and generalized or neurologic abnormalities at presentation almost uniformly develop mental retardation, seizures, and spasticity. Children with untreated subclinical disease at birth have developed seizures, significant cognitive and motor deficits, and diminution in cognitive function over time. To determine neurologic, cognitive, and motor outcomes for children with congenital toxoplasmosis who were treated for approximately 1 year with pyrimethamine and sulfadiazine. Systematic, prospective, and longitudinal neurologic, cognitive, and motor evaluations were performed for 36 individuals with congenital toxoplasmosis. These infants were born between December 1981 and January 1991 and were treated with pyrimethamine and sulfadiazine for approximately 1 year beginning in the first months of life. Compliance with medications was documented. These individuals were evaluated in a standardized manner in a si...
This article is being reprinted from the September 1996 issue because it may have been inadverten... more This article is being reprinted from the September 1996 issue because it may have been inadvertently omitted from several copies of THE JOURNAL.
Interpretation of auditory brain stem response (ABR) findings can be problematic in cases where w... more Interpretation of auditory brain stem response (ABR) findings can be problematic in cases where waves III and V are absent. Such findings can be attributed to profound hearing loss, brain stem neuropathology, or both. Over a 3‐year period, 48 patients with no known brain stem damage and on whom audiologic data were available were found to have no response by ABR or absent waves III and V. Severe to profound hearing loss was documented in 38 cases, audiometric data were equivocal in 3 cases, and 7 patients showed pure tone sensitivity ranging from normal hearing to moderate impairment. Thus 15% had better hearing sensitivity than might have been expected from their ABR findings. Each of these patients also exhibited abnormal acoustic reflex findings. We report the electrophysiological (ABR, MLR, acoustic reflex}, medical (history, neurological, EEG, CT scan) and behavioral (audiometric, speech and language, learning disabilities, psychological) data which characterize this group of p...
Follow-up brainstem care unit of infants screened by auditory response in the neonatal intensive ... more Follow-up brainstem care unit of infants screened by auditory response in the neonatal intensive Auditory brainstem response screening at 40 attd 60 dB was conducted in 100 infants in the neonatal intensive care unit to determine initial failure rate and prevalence of abnormality on follow-up. Of our N1CU population, 20 % failed one or both of the screening levels: 9 % failed at 60 dB in both ears, and 11% failed at 40 dB in one or both ears. On follow-up, half of the 60 dB failure group were found to have sensorineural or conductive impairment and represent the 2% to 4% prevalence of serious otologic-audiologic problems generally found in an N1CU population. Subsequent improvement (reversal) of the retest ABR records of the remaining infants in the 60 dB failure group was thought to be related to neural changes in the brainstem associated with recovery from hypoxic episodes. A transient or reversible conductive deficit appeared to account for the majority of failures at 40 dB. We recommend the screening protocol be expanded to include thresholdand latency measures in infants who fail the initial screening. The transient nature of many ABR abnormalities makes postdischarge ABR, otologic, audiologie, and neurologic examinations mandatory before any inferences are made about hearing loss or neurodevelopmental disorders.
Although the clinical use of the middle latency response (MLR) in adults is fairly straightforwar... more Although the clinical use of the middle latency response (MLR) in adults is fairly straightforward, its use is complicated by maturational changes that continue throughout the first decade of life. In order to telescope the time period of this long developmental course, we have approached the study of MLR maturation using the gerbil as an animal model. The course of MLR obtained over the temporal lobe development was characterized in the Monogolian gerbil ranging in age from 10 days to 3 months of life. The adult gerbil MLR consists of two positive peaks (A and C) at 11 and 25 ms, respectively, and a negative component (B) at 16 ms. These components emerge in a systematic fashion as a function of age. The present work supports a strong age effect of increased MLR detectability in the gerbil, similar to findings reported for humans. Wave A was infrequently detected in young animals, but when present, it occurred at adult latencies. The latency of waves B and C decreased systematically with age. The amplitude of all components increased with age, similar to findings in humans. The fact that adult-like thresholds were obtained shortly after birth indicates that when present, MLRs may be a good index of hearing threshold. Effects of stimulating across a wide range of intensities were described. The gerbil model appears appropriate for the study of development of the central auditory system function.
Auditory brainstem response (ABR) results with 82 severely developmentally delayed infants and ch... more Auditory brainstem response (ABR) results with 82 severely developmentally delayed infants and children suspected of being both deaf and blind are reported. Of the 79 children on whom acceptable ABR data were obtained, 34 or 43.0% had ABR thresholds in the normal-hearing range; 16 or 20.3% in the mild-to-moderate loss range; and 3 or 3.8% in the severe loss category. Twenty-six or 32.9% produced no ABR to clicks at a maximum intensity of 90 dB HL. On the basis of established audiological and neurological diagnostic criteria, 3 children showed neurological abnormality by ABR. We conclude that the hearing status of a high percentage of otherwise untestable children can be determined by ABR, that a significant number of infants and children who appear deaf are in fact not hearing impaired, and that the occurrence of brainstem neuropathology in this population is limited.
Two leading causes of hearing loss in infants and young children have been bacterial meningitis d... more Two leading causes of hearing loss in infants and young children have been bacterial meningitis due to Haemophilus influenzae Type b (Hib) and congenital toxoplasmosis. In this two-part review, we describe the essential nature and incidence of these two diseases and how the availability of a Hib vaccine effective and safe with infants as young as 2 mo of age; the prospect of universal immunization against Hib disease; the introduction of cephalosporin antibiotic and corticosteroid treatment; and the use of early and prolonged antimicrobial therapy with children with congenital toxoplasmosis promises significant reduction, if not complete eradication, of hearing loss in infants and toddlers attributable to Hib bacterial meningitis and congenital toxoplasmosis. As a result, there may be up to a third fewer children under the age of five with severe hearing impairment annually in the United States.
Research aimed at quantifying the benefits a hearing aid user might expect from noise suppression... more Research aimed at quantifying the benefits a hearing aid user might expect from noise suppression hearing aids purported to improve hearing in the presence of background noise have yielded widely varying results. We suggest this may in part be due to the inappropriate use of experimental approaches based on group design and inferential statistical analysis. Included in this paper is our rationale for employing a single-subject experimental design to investigate subject performance with two commercially available hearing-aid noise suppression systems. Preliminary results with two subjects indicate that both the Siemens Automatic Signal Processing (ASP) and Zeta Noise Blocker (ZNB) noise suppression systems markedly improve listener scores on the low predictability sentence material of the SPIN Test. We conclude these two noise suppression systems may improve performance as the listening situation becomes contextually more difficult, and that single-subject experimental designs could be a valuable addition to applied behavioral research with hearing aids.
The 1982 Position Statement by the Joint Committee on Infant Hearing recommends that infants at r... more The 1982 Position Statement by the Joint Committee on Infant Hearing recommends that infants at risk for hearing impairment be screened by 3 mos of age and that the diagnostic process be completed and habilitation begun by 6 mos of age. How close to this ideal actual practice comes in an urban setting is the subject of this study. Data on 88 infants referred to a hospital-based parent-infant program were retrospectively examined to determine the occurrence of risk factors and at what ages: (1) hearing loss was first suspected, (2) hearing loss was diagnosed, and (3) habilitation was initiated. Results indicate that over one-quarter of all hearing-impaired infants will not manifest any of the risk factors proposed in the 1982 Position Statement and that regardless of whether the infant graduates from a neonatal intensive care unit or well-baby nursery, the median age for enrollment in a parent-infant program is a year or more later than the 1982 recommendation.
Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were re... more Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were referred to our study group. A uniform approach to evaluation and therapy was developed and is described herein along with the clinical characteristics of these infants and children. In addition, case histories that illustrate especially important clinical features or previously undescribed findings are presented. Factors that contributed to the more severe disabilities included delayed diagnosis and initiation of therapy; prolonged, concomitant neonatal hypoxia and hypoglycemia; profound visual impairment; and prolonged, uncorrected increased intracranial pressure with hydrocephalus and compression of the brain. Years after therapy was discontinued, three children developed new retinal lesions (without loss of visual acuity when therapy for Toxoplasma gondii was initiated promptly), and three children experienced a new onset of afebrile seizures. Most remarkable were the normal developmental, neurological, and ophthalmologic findings at the early follow-up evaluations of many--but not all--of the treated children despite severe manifestations, such as substantial systemic disease, hydrocephalus, microcephalus, multiple intracranial calcifications, and extensive macular destruction detected at birth. These favorable outcomes contrast markedly with outcomes reported previously for children with congenital toxoplasmosis who were untreated or treated for only 1 month.
Congenital transmission of Toxoplasma gondii from a mother who was apparently immunologically com... more Congenital transmission of Toxoplasma gondii from a mother who was apparently immunologically competent and who had toxoplasmic lymphadenitis 2 months before conception is described. Since no T. gondii-specific serological data were available for this mother from the time her lymph node biopsy specimen was obtained, the specimen was studied by polymerase chain reaction (PCR) to determine whether the T. gondii B1 gene was present. The predictive diagnostic value of histologic findings previously considered to be classic signs of T. gondii lymphadenitis also was studied. This was done by correlation of serological tests diagnostic of acute acquired T. gondii infection and presence of characteristic findings in biopsy specimens from persons without known immunocompromise. Both PCR and review of the characteristic features of her lymph node biopsy specimen confirmed the diagnosis of preconceptual infection in the mother. We also discuss two other cases in which apparently immunologically competent mothers with preconceptually acquired infection transmitted this parasite to their fetuses.
Archives of Otolaryngology - Head and Neck Surgery, 1983
Auditory brainstem response (ABR) was used to assess possible hearing loss in 60 patients recover... more Auditory brainstem response (ABR) was used to assess possible hearing loss in 60 patients recovering from bacterial meningitis. The ABR results were consistent with either unilateral or bilateral hearing loss in 35% of the cases tested. Of these, 15% were conductive-type hearing loss. Twelve percent had sensorineural hearing losses and normal brainstem function. The remaining 8% had elevated ABR thresholds coincident with findings suggestive of neuropathology of the auditory brainstem pathways. A case of reversible sensorineural hearing loss was documented. Various clinical and demographic factors were examined to determine their predictive value with regard to hearing loss. As expected, otitis media occurred significantly with conductive hearing loss. Type of pathogen (Streptococcus pneumoniae) and hospitalization greater than two weeks were significantly correlated with sensorineural hearing loss. As meningitis typically affects young children who are difficult to test with conventional audiometry, ABR provides an effective means of testing hearing in this population.
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