Newborns Hearing And Ocular Diseases Simultaneous Screening Program & Audiovisual (A-V) Neural Function Integration Mechanism

Both anatomically and physiologically, hearing and vision are closely related. The brain, by temporally and spatially integrating the senses of hearing and sight and other senses, maintains the continuity of cognition and behaviors, and anatomically and functionally balance and coordinate separate cerebral activities. Clinically, visual and auditory disorders are commonly seen in many diseases and syndromes and deaf children tend to have visual problems as compared with normal kids. Hearing loss and visual impairments are two important causes of developmental disabilities among infants. Hearing and ocular conditions, if undetected or untreated, can have substantial long-term implications for the quality of life of the child and the family and can be a burden on public health resources. According to an estimate of WHO, 1.5 million children worldwide are blind. Two-third of these cases (1.0 million) is in developing countries. In developing countries, 30% to 72% of childhood blindness is avoidable. Children with severe and profound hearing loss account for 1/800 of all newborns. At the mean time, deaf children are heavily reliant on the sense of vision to develop efficient communication skills and explore the world around them. Any ophthalmic disorder may thus negatively impact on this process, especially if it is not identified in the early years of their life. These disorders may be correctable (such as myopia) or curable (such as cataract), and their early identification is of the utmost importance for their development of their language (spoken or sign, or both) and social cognition.The close relations (anatomical, physiological and clinical) between hearing and vision make it a necessity to study their functional interactions and integration. The vision and hearing processes and their integration, however, are complicated. The The vision and hearing functions can, to some degree, be temporally and spatially integrated. Some studies examined and explained the mechanism of spatial integration, but the temporal integration of auditory and visual information in brain has not been clearly elucidated.This study, by employing the technique of synchronous auditory and visual evoked potential, examined the neuro-biological features of integration of visual and auditory senses. Meanwhile, going beyond the newborn hearing screening, a multi-discipline study on the basis of newborn audiology was conducted and a new public health program---Newborn Simultaneous Vision and Hearing Screening---was put forward. The study also examined the change in hearing loss over time among newborns and infants and the high risk factors of hearing loss in Shandong Province. The combination of vision and hearing screening in newborns will greatly contribute to the control of newborn hearing loss (NHL) in China.PartⅠA Preliminary Study on Integration Mechanism of Auditory and Visual Neural Function by Using Synchronous Auditory and Visual Evoked PotentialObjective: To explore the electrophysiological properties of integration of auditory-visual neural functions by using the technique of synchronous auditory and visual evoked potential.Methods: By using technique of synchronous auditory and visual evoked potential and routine auditory brain-stem response (ABR) technique, 10 normal adult subjects (20 eyes and 20 ears) and 14 infants (aged from 3 to 4 month, 28 eyes and 28 ears) were studied. First, the different properties of auditory brainstem response (ABR) in auditory -visual synchronous program and non-synchronous program were explored.Then, under the program of auditory -visual synchronous evoked potential , unimodal (A or V) and simultaneous bimodal (A-V) stimuli were presented and we detected two aspects :( (1) the ABR changes in the synchronous procedures before and after the presentation of flash stimuli and (2) the features in flash visual evoked potential (fVEP) were examined. Results: (1) As compared with routine ABR, the synchronous procedure (with or without fVEP test) were stable. Though the latencies of ABR waves of synchronous procedure were longer than those of routine one, no changes was found between interwaves. This feature was not influenced by the addition of fVEP test. (2) With synchronous procedure, under 70 dB nHL click stimulation, when light stimuli were given, significant differences in the interwave latencies betweenⅢ-Ⅴof ABR were observed, while, the click stimuli under 30, 50 dB nHL did not cause any significant change in wave latencies and interwave latencies (P<0.05). (3) In terms of effect of sound stimuli on the fVEP, our study showed that sound stimuli of different intensities did not significantly affect the latencies of N1, P1 and N2 waves of fVEP and N1-P1 and P1-N2 amplitude (P>0.05). The sound stimuli of high, medium and low intensities did not change the length of latencies and amplitude of fVEP. Conclusion The stability of the parameters of visual evoked potential reflects the stability of electric field of the visual evoked potential. Under sound stimuli of different intensities, the changes of ABR parameters showed some patterns. Our results suggest that in the integration of visual and auditory inputs, the auditory and visual signals enter the brain in an orderly manner. There exists a temporal guidance of auditory signals by visual signals (which affects latencies), thereby maintain the homeostasis of internal milieu in terms of information processing.PartⅡClinical Application of Simultaneous Screening for Hearing and Ocular Diseases in NewbornsObjective: In this part, we explored the feasibility of simultaneous screening for hearing and ocular diseases in newborns and its clinical application, examined the hearing impairment and eye diseases in newbornsMethods: The universal newborn hearing screening (UNHS) was performed by using transient otoacoustic emission (TEOAE) in a baby-friendly nursery, and a two-stage screening protocol (including TEOAE stage and AABR [auto auditory brainstem response] stage) was carried out in a neonatal intensive care unit (NICU). At the same time, an eye disease screening was conducted. The re-screenings for hearing diseases and eye diseases were conducted simultaneously. If a newborn failed to pass the hearing re-screening test, with in 3 months after birth, she or he will be put on a diagnostic procedure, which included: (1) TEOAE, acoustic immitance, ABR, 40 Hz auditory event related potential (40 Hz AERP), behavioral audiometry ; (2) medical and imagological evaluations, follow-up and regular audiological and ophthalmological evaluations. If suspected cases of eye diseases were referred to pediatric ophthalmologists for definite diagnosis. The normal newborns were subjected to re-screening for eye-disease. The newborns who had received treatment in NICU were examined for screening and diagnostic purposes before being discharged (technique of synchronous auditory and visual evoked potential was conducted as required). And the cases that had positive sign and/or abnormal result of the ocular disease screening were referred for further examination by pediatric ophthalmologists.Results: A total of 16800 children were born in Jinan Maternal and Child Hospital from October 1, 2002 to April 30, 2005. Of these infants, 15398 cases (916.0‰) were subjected to simultaneous screening for hearing and eye diseases. Our results showed that the incidence of bilateral congenital sensorineural hearing loss (SNHL) among infants who received UNHS was 3.11‰(48/15398), and the incidence of unilateral SNHL was 2.27‰(35/15398). Among them, 4 cases of congenital SNHL were complicated with newborn eye diseases: including 1 case of profound SNHL (bilateral) and auditory neuropathy accompanied by congenital cataract (bilateral), 1 case of mild SNHL (bilateral) complicated with membrana pupillaris perseverans (left), 1 case of mild SNHL (bilateral) with retina vein dilatation (bilateral), and 1 case of mild SNHL (right) with accompanying bilateral persistent hyaloid artery. In all the 15398 newborns, 12 eye-related diseases and signs were detected (involving 1266 cases).Conclusion The hearing loss and ocular diseases/visual impairment is not uncommon in neonatal time and infancy. The simultaneous screening for newborn hearing and ocular diseases is not only feasible but also effective in the control of hearing loss and/or ocular disorders. Implementation of simultaneous screening for newborn hearing and ocular diseases entails (1) a well-established mechanisms of multli-discipline co-operation and (2) intensive work in neonate audiology and ophthalmology in clinical practice. The newborn screening for visual and auditory disease is the first step towards the simultaneous monitoring of eye disease, vision and hearing; hearing evaluation and eye disease monitoring should start at neonate stage and continue at every single stage of child health care and the means of evaluation should be in line with the age of juvenile development.PartⅢA Preliminary Study of Screening for Neonatal Ocular Diseases Objective: To explore the clinical strategies for the screening of newborn eye diseases and get information concerning the incidence of newborn ocular diseasesMethods: The newborns in a baby-friendly nursery were evaluated for screening 2 to 7 days after birth (including reaction to light sitimuli, external ocular examination and test for red reflex) and those with abnormalities were subjected to diagnostic examination. The newborns in NICU were subjected to screening 5 to 14 days after birth and they, together with those with high risk factors, received a comprehensive examination for screening and diagnostic purpose. The suspected cases were referred to department of ophthalmology for definite diagnosis.Results: Among the 15398 (916.0‰) who were enrolled the screening program, 12 kinds of eye diseases (involving 1266 cases) were detected, with a detection rate of 82.22%. Of these eye diseases, 7 were congenital ocular diseases, involving 809 cases (52.54‰) and including congenital ptosis (0.13‰), congenital corneal opacity (0.39‰), persistent pupillary membrane (47.02‰), congenital cataract (15 cases, 22 eyes involved, accounting for 0.97‰), persistent hyaloid artery (3.51‰), obstruction of nasolacrimal duct (0.46‰), lacrimal gland prolapse (0.07‰). Five diseases (involving 457 cases) detected were acquired ones, including neonatal conjunctivitis (25.39‰), vitreous haemorrhage (0.39‰), retinal haemorrhage (2.12‰), and neonatal dacryocystitis (1.49‰). Of 27 premature babies with body weight lower than 1500 g, 3 had retinopathy of prematurity (ROP, 6 eyes involed). Of 14306 normal newborns, 7 kinds of congenital diseases were detected in 717 cases, with a detection rate of 50.12‰and 4 kinds of acquired diseases were found in 417 cases with a detection rate of (29.15‰). In 1092 newborns who had received treatment in NICU, 5 kinds of congenital diseases were found in 92 cases, with the detection rate being 84.25‰and 5 kinds of acquired eye diseases were found in 40 cases, with a detection rate of (36.63‰). The detection rate of both the congenital and acquired diseases in the NICU group were higher than those in the group of normal newborns (P=0.000; P=0.016). The eye diseases whose detection rates in NICU group were higher than those of normal newborn group included congenital cataract (P=0.000), persistent hyaloid artery (P=0.000) and retinal hemorrhage (P=0.001). The detection rate of persistent pupillary membrane in the NICU group was lower than that in normal children group (P=0.01).Conclusion: The visual disorders were not uncommon in newborns and except for ROP that were all found in NICU group, the incidences of congenital cataract, persistent hyaloid artery, retinal hemorrhage were also high in the group. Early intervention is of great importance for the prevention and treatment of neonatal ocular diseases such as congenital cataract and ROP. The screening of newborn ocular diseases is not only feasible but also effective in the monitoring and control of the eye diseases in neonates.PartⅣChange of the Severity of Newborn/Infant Hearing Loss and Influencing FactorsObjective: To examine the change in hearing impairment level over time (ages) and after progression of diseases in order to get information for reducing the overall morbidity and slowing the progression of hearing loss.Methods: The newborns who failed to"pass"the hearing screening were routinely examined, with in the age of 3, by TEOAE, acoustic immitance, otoacoustic emission, ABR, 40 Hz auditory event related potential (40 Hz AERP), behavioral audiometry for audiological diagnosis and medical evaluation, and intervention plans were laid. For those with abnormalities identified and/or with high risk factors, a once-every-3-month audiological and medical evaluation was performed.Results: A long-term (6-48 months, 17.6±3.2 months) out-patient follow-up and repeated audiological evaluations in 110 newborns with hearing impairment showed that thought the hearing impairment in newborns might improve or deteriorate over time, in most of the cases (58.2%), their conditions remained unchanged, with the improvement rate of hearing impairment (29.1%) being higher than the deterioration rate (12.7%). The cases of mild and moderate hearing loss tended to experience changes. In groups of mild, moderate, severe and profound hearing loss, 79.2% (38/48), 72.7% (16/22), 53.3% (8/15) and 3.6%(1/28)79.2%, respectively, showed changes in hearing level ; in the group of conductive hearing loss and group of sensorineural hearing loss, 78.4% (40/51) and 39.0% (23/59) had change in hearing impairment level (p=0.000), and the change rate in the conductive hearing loss group was 2 times that in sensorineural hearing loss group. The hearing level changed in 55.5% (24/45) of the cases of unilateral hearing loss group and in 64.6 % ( 42/65) of the cases of bilateral hearing loss (P=0.448). No significant difference was found in the change rate between the groups of unilateral and bilateral hearing loss. With 64 ears with decreased ABR threshold (with hearing improvement), 6.3%, 28.1%, 65.6% of them had reduction by 30, 20, 10 dB nHL respectively. In 79.7% of the ears, the function of middle ear was improved. In 28 ears with hearing deterioration, 75%, 21.4%, 3.6% of them the ABR threshold increased by 10, 20, 40 dB nHL respectively and in 50% of the ears, the deterioration concerns the functions of middle ear.Conclusion: The change of hearing level in children with hearing loss was not uncommon in clinical practice and the change is both gradual and reversible. The functions of middle ear and neonatal diseases bear close relation with the change of hearing level in children with hearing loss. With either unilateral or bilateral hearing loss, the mild and moderate hearing loss is a border-line state which could develop toward improvement or deterioration, i.e., having high risk of developing progressive hearing loss (unilateral or bilateral), which requires dynamic monitoring and long-term preventive and therapeutic effort.PartⅤA Case-control Study on High-risk Factors for Newborn Hearing Loss in Seven Cities of Shandong ProvinceObjective: To investigate the high-risk factors for newborn unilateral or bilateral hearing loss and to provide information for preventing the development of hearing loss and delaying its progression.Methods: In 7 screening centers selected from 7 districts, a multi-center study was conducted. All the neonates who failed to pass the universal newborn hearing screening (UNHS) were referred to Jinan Newborn Hearing Screening and Rehabilitation Center. The basic features of the definitely diagnosed cases were statistically described and one-to-one pair-matched case-control method was employed. High-risk factors relating to the unilateral or bilateral hearing loss were evaluated by univariate and multivariate Logistic regression analysis. 331 cases (including 177 bilateral hearing loss cases and 154 unilateral hearing loss cases) who fully satisfied the matching requirements were included as subjectsResults: (1) With newborns with bilateral hearing loss, univariate Logistic regression identified 11 hearing loss-related risk factors: age of father, educational level of father, educational level of mother, parity, birth weight, genstation weeks, craniofacial anomalies, history of NICU care, neonatal diseases, family history of ear diseases, and family history of congenital hearing loss. Conditional Logistic regression analysis showed that neonatal bilateral hearing loss had 4 independent risk factors: parity (OR=16.285, 95% CI 3.379—78.481), neonatal diseases (OR=34.968,95% CI 2.720—449.534), family history of congenital hearing loss (OR=69.488,95% CI 4.417—1093.300) and birth weight (OR=0.241, 95% CI 0.090—0.648). The former 3 factors are promoting factors and the last one is protective factor. (2) With newborns with unilateral hearing loss, univariate Logistic regression found 8 hearing loss-related risk factors: profession of father, educational level of mother, profession of mother, parity, craniofacial anomalies, history of NICU care, neonatal diseases, family history of ear diseases. Conditional Logistic regression analysis revealed that neonatal unilateral hearing loss had 2 independent risk factors: parity (OR=9.789, 95% CI 2.270—42.173) and history of congenital hearing loss (OR=4.234, 95% CI 1.179—15.203) and they are all promoting factors.Conclusion: The multi-center case-controlled study of neonatal hearing loss in Shandong province showed that parity, neonatal disease, congenital hearing loss are promoting factors for bilateral hearing loss in newborns, the birth weight is a protective factor. The parity and family history of ear diseases are promoting factors of unilateral hearing loss and intervening measures should be taken with these cases.Characteristics and Innovations in the StudyThe study, for the first time, put forward a new public health care program, i.e., the"simultaneous screening of vision and hearing in neonates". It broadens the horizon of and brings opportunities for the clinical study on the branch of"ocular disorders in children with deafness and hearing loss"and the"audiovisual science/hearing loss-visual impairment". The simultaneous screening of vision and hearing has profound academic implications and potential market demand and its extensive application will bring immense social and economic benefits.The implementation of standardized, large-population eye disease screening and control program in newborns will lead to timely treatment of the disease at neonatal stage thereby preventing sight loss in newborns.Domestically, the study is of great importance in that (1) establishment of ear-hearing and eye-vision health care system for children will help to integrate the hearing disease screening and eye disease screening thereby promoting their healthy development; (2) successful collection of first-hand and complete data in relevant fields can provide information of the three-tier prevention program for juvenile eye diseases and hearing loss; (3) the first-time multi-center study about the risk factors of hearing loss not only identified the high-risk factors of bilateral hearing loss but also, for the first time in China, identified the high-risk factors of unilateral hearing loss, with intervening measures proposed; (4) by employing the technique of simultaneous visual and auditory evoked potentials, the study, for the first time, suggests that the visual and auditory signals enter brain in an orderly manner and the visual signals can provide temporal guidance for auditory signal (affecting latency), thereby achieving the homeostasis of internal environment in terms of information handling; (5) the study for the first time, points out that with either unilateral or bilateral hearing loss, the mild and moderate hearing loss is a border-line state which may develop towards recovery or deterioration, i.e., a dangerous state of developing unilateral or bilateral hearing loss that requires dynamic monitoring, preventive and therapeutic measures.To sum up, in this study, by combining advanced audiological tests, evaluation and rehabilitation techniques, hearing-care sciences, a standardized and scientific evaluation system was established. It provides information for reducing hearing loss and visual disorders and slowing their progression. It also provides clinical guidance for the future work of hearing and vision rehabilitation.