National Infant Screening for Hearing Program in India: Necessity, Significance and Justification

Abstract

Hearing impairment is one of the most prevalent disorder in children and adults worldwide, which not only interferes with the acquisition, development and maintenance of speech and language skills but also adversely deprive the auditory nervous system for future learning. It can have long term harmful effect on educational, social, emotional and cognitive skills in young children; restrict the vocational options and employment opportunities in adults; and can cause isolation, loneliness and depression in older adults, if remain undetected and intervened at the earliest. However, early identification and intervention is known to greatly reverse the ill effects and improve the quality of life of children and adults with hearing impairment. Current clinical means and methods to identify and intervene hearing loss are convenient, cost effective, reasonably accurate beneficial and evidenced based, can be easily employed nation-wide for early identification and intervention of hearing loss. This paper attempts to convince medical colleagues, public health care experts and policy makers by justifying the hearing, as public health issue and relevance of medical screening criteria for hearing. It also discusses the preferred model of hearing screening and intervention strategies in India.

Introduction

Hearing loss is the impairment of auditory system to hear environmental and speech sounds. Consequently, children with hearing impairment struggled with verbal communication and speech—language difficulties. Hearing impairment in neonates of mild to profound hearing loss bilaterally or unilaterally, hearing loss of varying degree above 1000 Hz or auditory deprivation, probably for few days, due to recurrent otitis media not only results in significant and long-term effect, although less well documented, reduced auditory input also adversely affects the developing central auditory nervous system which has harmful impact on acquisition of speech and language skills and speech perception abilities [1–4]. The permanent severe to profound hearing impairment in children have devastating and detrimental effect on development of biological functions including speech and language, [5–7] literacy, [5, 7] mental health [8], social and cognitive functioning [8, 9] educational achievement [10–12] employment and socio-economic opportunity [13], and may continue to plaque these individuals for the life time. However, the impact of hearing impairment is rescindable through institution of effective early identification and intervention programs.

Burden of Hearing Impairment

The World Health Organization defines a disabled person is anyone who has “a problem in body function or structure, an activity limitation, has a difficulty in executing a task or action; with a participation restriction” [14]. Accordingly, the World Health Organization [15], estimates around 466 million people worldwide have disabling hearing impairment (41 dB or greater in the better ear in adults (≥ 15 years) and greater than 30 dB in the better ear in children (≤ 14 years) averaged at octave frequencies 0.5, 1, 2, 4 kHz) including 34 million children, among them approximately 7.5 million children are below the age of 5 years. The vast majority (at least 80%) among them reside in low- and middle-income countries (LMICs) [15, 16]. The globally estimated prevalence of sensorineural hearing loss is 1.368 in every 1,000 live births [17]. Niskar et al. found 14.9% of children with either low frequency or high frequency hearing loss in a hospital-based survey [18]. Pascolini and Smith reported that bilateral severe to profound hearing loss affect more than 10 infants in every 1000 live births in developing countries [19].

Population-based survey using WHO protocol reported the prevalence of 10.5% disabling hearing impairment in Indian population [20]. Prevalence of significant hearing impairment in school children (aged 8–14 years) in the villages of Vadamavanthal, Tamil Nadu found to be 30.9% [21]. Census of India (2011) reports that hearing impairment affects about 5.73 million and 1.98 million of the populations with various types of speech problems almost uniformly distributed around the country. There are 20.42 lakhs children aged 0–6 years are disabled, among them 23% children have hearing disability, 20% children aged 0–19 years have hearing disability and 9% multiple disabilities. Thus, one in every 100 children in the age group 0–6 years suffered from some type of disability [22]. Recent data from the sample registration survey of India (SRS: 2018), the children between the ages of 0 and 14 years made up 25.9% of the population [23]. Considering the demographic setting, socioeconomic condition, hygiene and health facilities it can be assumed that India is home to the largest child population with hearing disability in the world.

Unquestionably, it is a challenge to provide hearing devices, special education, vocational training and employment to this large population especially in absence any comprehensive, cohesive and coherent early identification and intervention program. The enormity of the problem can only be tackled if preventive strategies are employed and early identification and intervention strategies implemented at the earliest to utilize the available infrastructures to mainstream the children with hearing impairment in regular education, vocational training and employment. Hence an endeavour has been made through this paper to emphasize, firstly the need of National Infant Hearing Screening and secondly to provide justification for hearing screening by critically examining the general screening criteria of medical disorders. It has been found that that hearing is compatible with all screening criteria for medical disorders to warrant national infant hearing screening program to deal with the severe consequences of hearing loss in newborn and infants.

Need of Prevention and Screening Hearing Impairment

The negative consequences of hearing impairment are ameliorable if prevention of hearing loss and hearing screening strategies are instituted at earliest. The World Health Organization (2016) estimates that in developed countries, 49% and in developing countries about 70% of the childhood hearing loss is preventable [24]. Hearing loss caused by meningitis, rubella, ear infection and glue ear etc. can be prevented through good hygiene and, in some cases, immunisations in developing countries. For adults, it was estimated that 37% of hearing loss is due to preventable causes, primarily noise-induced and ototoxicity. WHO [24] reported that “adult-onset hearing loss ranked 15th most leading cause amongst the Global Burden of Disease (GBD)". The undetected and untreated hearing impairment has adverse ramification and substantial impact on psychological, socioeconomic and well-being of persons with disabling hearing impairment, the family, and the community [25, 26].

For instance, Gaffney et al. estimated that the lifetime educational cost of hearing loss at $115,600 per child [27]. Further, persons with hearing disabilities are more often found to be unemployed or belong to a lower economic stratum than people with other disabilities, and the income for the hearing-impaired population is 40–45% lower than for the hearing population. The literature has indicated that children who identified and received intervention before 6 months of age achieved better language outcomes by 3 years of age and can be integrated with regular schooling than those who received later intervention [28]. Thus, early identification reduces the recurring cost for specialised education and need for other specialised program later in life [29]. The economic burden of hearing loss costs about $33.3 billion including estimated financial costs of hearing loss as $15.9 billion and lost wellbeing as $17.4 billion in Australian population [30]. Thus, prevention and early identification is valuable and cost effective. Hence, it can be said that preventive strategies can reduce the prevalence and minimize the impact of hearing loss significantly if early identification and intervention strategies are instituted in our country.

The concept of early identification is not new, but it is yet to gain strong foothold in India. Nikam and Dharmaraj attempted infant hearing screening way back in 1971[31]. Basavaraj et al. carried out hearing screening in Bangalore [32] AYJNIHH Mumbai (1985) conducted 3 years project on screening pre-school children for early identification and intervention of hearing loss using high risk register (H.R.R) approach [33, 34]. In 2005 AYJNIHH now AYJNISHD, Mumbai conducted SHIP Project (Screening Hearing in Paediatrics) in neonates and infants using behavioural and electrophysiological methods. Hearing screening of NICU admitted neonates are under way at Wadia Children Hospital, Mumbai and AIIMS, New Delhi. The effectiveness of above techniques to identify hearing loss has not been reported in our literature. However, western literature reveals that 50% of hearing-impaired children are likely to be missed out in H.R.R. and N.I.C.U. approaches. Moreover, application of these approaches requires a team of specialised professionals and time to record risk indicators, making these process expensive [2].

In such circumstances it is believed that National Infant Screening for Hearing regardless of presence or absence of risk indicator is the most suited approach for early detection of hearing loss. However, there are no comprehensive early identification and intervention protocol is available in our country. There are sporadic reports of hearing screening are being conducted across the country in speech and hearing clinics, maternity and tertiary hospitals in absence of any comprehensive early identification protocol. Probably for this reason often there is no reported data available and if available, there are great variations in reported findings within country. This warrants serous attention, as WHO [35] reports that inconsistent approach to newborn and infant hearing screening and issues such as quality control, screening methods, follow-up, and cost effectiveness need to be thoroughly discussed and reviewed. Quality assurance issues in particular, are vital to successful newborn and infant hearing screening and related interventions. In some settings it is estimated that the poor training and performance of screeners renders up to 80% of screening useless and ineffective [35]^.

Furthermore despite the fact, hearing deficiency having medical connotation, yet it has been failed to attract required attention of medical professionals, health agencies administrators and policy makers as compared to other medical diseases leading to disabling conditions, that have attracted many national programs, like national program for control of blindness, national iodine deficiency disorder control program, national mental health program, child survival and safe motherhood program, universal immunisation and pulse polio immunisation program etc. Though, India launched the National Programme for Prevention and Control of Deafness-2006. This programme is currently operational in over 60 districts of the country and its aim is to identify babies with bilateral severe-profound hearing losses by 6 months of age and initiate rehabilitation by 9 months of age [36]. But, the results of the program is insufficient and outcome has not been reported adequately. Thus, there is a strong enough evidence to convince our medical colleagues and health administrators to plan and implement the national infant screening for hearing program.

Significance of Newborn Hearing Screening

There is an appreciable agreement among health care professionals to recognize the hearing loss in infants at earliest so that timely and appropriate otologic, audiologic-habitation and family centred program can be instituted to take the full advantage of the plasticity of developing sensory system i.e., maximum utilization of critical period of 0–3 years. The early identified and intervened child enjoys normal speech and language development, cognitive, social, and emotional growth and academic achievement. Theoretical arguments on auditory and cognitive plasticity have suggested that earlier auditory stimulation is better for developing the individual child’s auditory and cognitive potential [37]. Infant hearing screening yields improved benefits, infants whose hearing loss is identified before 6 months of age have significantly better language abilities compared to those whose hearing loss was identified later [37–39]

The early intervention i.e., hearing aid fitting and supportive services before the age of 6 months enables infants to develop and maintain normal language skills on a par with their cognitive development whereas for infants identified after 6 months of age exhibit persistent language delay of two to four years [37, 40]. Davis and Hind reported that the age of first hearing aid fitting was a significant predictor of verbal and non-verbal reasoning as well as overall IQ, age at diagnosis was a significant forecaster of working memory and the cognitive performance was quality of life indicator of children with moderate to severe permanent hearing loss [41]. Yoshinaga-Itano [42] provided the most important and compelling benefits associated with early identification as summarized below.

• Children with hearing loss born in hospitals with Universal Newborn Hearing Screening (UNHS) had an 80% probability of having language development within the normal range of development.

• Children with hearing loss born in hospitals with UNHS were 2.6 times more likely than children with hearing loss born in hospitals without UNHS i.e. (non-screening) of having language development within the normal range of development.

• 76% of children with hearing loss in the screened group had language quotients that were 70 or greater—whilst only 32% of the non-screened group had language quotients of 70 or greater.

• Early-identified children in the screened group had a 10-point discrepancy between their language and cognitive quotients—whilst later-identified children in the non-screened group displayed a 35-point discrepancy.

• The vocabulary of children at the 75th percentile of the non-screened group contained fewer words than that of the children at the 25th percentile of the screened group.

• The 75^th percentile of the screened group had speech that was “always or almost always understandable”—whilst the 75th percentile of the non-screened group had speech that was “hard to understand”.

• Early-identified children-maintained language development in the same vein as their non-verbal cognitive symbolic play development, while later-identified children demonstrated a greater than 20-point discrepancy between their non-verbal cognitive development and their language development.

• Children with additional disabilities who were identified early and provided with immediate early intervention services also had symbolic play quotients that were similar to their language quotients—whilst children with additional disabilities who were identified later displayed significant discrepancies between their cognitive and language quotients.

• Early-identified children with hearing loss had significantly higher personal-social skill development than children whose hearing losses were identified later.

• The first six months of life appear to be a particularly sensitive period in early language development as young children identified with hearing loss and placed in intervention by 6 months of age present with significantly higher language development than later-identified children with hearing loss.

It is also important to note that Universal Newborn Hearing Screening (UNHS) programmes have succeeded in lowering the early identification age of children with hearing loss. This has provided the opportunity for timely intervention so that access may be gained to the benefits of early auditory stimulation. UNHS programme has decreased the mean age at which hearing loss was detected from 20 months (prior to implementing UNHS) to 5.7 months (by year four) [43]^. The Hawaii UNHS programme reduced the average ages of identification and amplification from 12 and 16 months to 3 and 7 months respectively [44]. In Colorado, the average age for hearing aid fitting is 5 weeks [45]. These research outcomes provide evidence that hearing screening programmes reduce the age of hearing loss identification, lower the age of intervention initiation, and produce significantly improved outcomes for both the child and his/her family. Thus, above literature clearly demonstrating the significant benefits of infant hearing screening programmes toward early identification and intervention (which provide infants with an opportunity to reach optimal outcomes) to justify its role as an important part of neonatal care.

In addition, interestingly, there are other clinically important reasons that necessitates for hearing screening. The concept of identifying hearing loss before it is clinically apparent is an appealing health promotion and consideration, early identification provides baseline on which subsequent evaluation can be made and compared. Also, medical and surgical treatment can be initiated to control and prevent conductive and progressive hearing loss. Moreover, it provides basis for auditory diagnosis and selection of necessary amplification, and timely information to parents, provides base for process of acceptance of hearing impairment that improves parent readiness to initiate family centred program [46]. Furthermore, early identification and intervention is also guaranteed by RPWD Act (2016) [47]. These significances the urgency of planning and implementation of National Infant Screening for Hearing (NISH) in India. However, with regard to medical screening principals, there are many questions for hearing screening that needs to be answered to convince the various stake holders of Infant Screening for Hearing. To achieve, we have evaluated and justified hearing impairment as a medical disorder below to match with disorder-related screening principles practiced by the medical fraternity.

Justification for National Infant Screening for Hearing

According to the World Health Organization [48], screening is a "medical investigation that does not arise from a patient’s request for advice for specific complains. The term covers all types of examination and does not refer to their speed or accuracy. "Screening is a process by which individuals are identified who may have disease or disorders that are otherwise undetected" and which many have "findings of asymptomatic cases" [49]. Screening is a process of applying certain rapid, accurate, valid, simple tests and procedures to generally a large population to identify individual with high probability of having target condition from the individuals who probably don’t have the disorder, with less commitment of time, cost and inconvenience, who are then given diagnostic tests and if necessary, treatment. When considering an appropriate screening program Wilson and Jungner [50] recommend the following ten basic principles that screening program should observe to be effective:

1. "The condition to be screened for should be an important health problem

2. There should be an accepted treatment for cases identified

3. Facilities for diagnosis and treatment should be available

4. There should be a recognizable latent (early, asymptomatic) stage in the condition

5. There should be a suitable test to employ in screening

6. The test should be acceptable to the population

7. The natural history of the condition should be understood

8. There should be an agreed policy on whom to treat as patients

9. The cost of case-finding (including diagnosis and treatment of those diagnosed) should be non-wastefully balanced in relation to expenditure on medical care as a whole

10. Case-finding should be an ongoing process and not a ‘one-off’ project."

The above criteria’s have been construed in detail with relevant studies and data wherever available and conceivably to provide evidences for the principles of hearing screening as a societal responsibility and to assess current practice in the developed world as a background to considering neonatal hearing screening in the developing countries like India.

The Condition to be Screened for Should be an Important Health Problem

For this principal, there are two important disease or disorder related factors that can be considered. Firstly, the occurrence of disorder should be sufficiently frequent and secondly the disorder should have long term severe impact on the sufferer.

1. Occurrence of disorder should be sufficiently frequent

The incidence and prevalence rate of hearing impairment in India is quite alarming. The National Sample Survey (NSS) 58th round (2002) surveyed disability in Indian households and found that hearing disability was 2nd most common cause of disability and top most cause of sensory deficit. In urban areas, loss was 9% of all disability and in rural areas, it was 10% [51]. More recent studies have estimated a bilateral permanent newborn and infant hearing loss of 1.5 to 6 per 1000 live births [52]. As per the Census of India (2011) reports that hearing impairment affects about 5.73 million and 1.98 million of the populations with various types of speech problems. 20.42 lakhs children aged 0–6 years are disabled, among them 23% children have hearing disability, 20% children aged 0–19 years have hearing disability and 9% multiple disabilities.

Further, according to recent data from the sample registration survey of India (SRS: 2018) the children between the ages of 0 and 14 years made up 25.9% of the population [23]. Hence, it can be said that India is home for, if not highest, but at least the largest number of children with hearing impairment. Unfortunately, up to present time no comprehensive nationwide census of prevalence of hearing loss in newborn or infant exist. Surprisingly, prevalence of hearing loss as per Planning Commission of India and RPWD Act (2016) is awaited in our country. Though, there is big contrast in the different statistical surveys and estimated prevalence of hearing impairment in our country due various reasons like the purpose and methodology adopted in different statistical surveys. However, irrespective of purpose and methodological variations, considering the demographic setting, socioeconomic condition, hygiene and health facilities, it is for sure that the prevalence of hearing impairment in newborns and infants is more frequent and sufficiently high in our country to justify hearing screening.

• b)The disorder should have serious and/or long-term Consequences:

Hearing impairment has substantial and long-term impact on psychological and economic well-being of the affected person, the family, and the community [25, 26]. As per Census of India, 4.01million (61%) out of 6.58 million disabled children aged 5–19 years are attending educational institution and only 60% of those who attend school complete class 10. There are about 75 million children of primary school age who are out of school, among them “one-third are children with disabilities.” Further, only 2 per cent of the PWDs were enrolled in any vocational course (India Social Development Report—2016). Further, the lifetime educational cost of hearing loss at $115,600 per child [27]. Further, persons with speech disabilities are more often found to be unemployed or belong to a lower economic stratum than people with other disabilities, and the income for the hearing-impaired population is 40–45% lower than for the hearing population. There are 17.1 million unemployed disabled, among them about 46% are in the age group 15–59 years, 31% in the age group 0–14 years and 23% are 60 + years. One in every two disabled non-workers is dependent on their respective families, among those with disability in hearing 38.7% are dependents and 32.5% are students, persons with disability in speech, 33.5% are dependents while 37.2% are students. There are 41.72% are never married and 10.29% of them are widowed [22]. Thus, hearing impairment has severe and long-term consequences to warrant for hearing screening.

There Should be an Accepted Treatment for Cases Identified

The primary purpose of hearing screening is prevention and early identification of disease symptoms, if early identification fails at an earlier stage, there could be severe ramification and late identification will be disadvantageous. Thus, this matter has been deliberated into three dimensions.

1. Preventive measures and/or effective treatment for disorder must be available

Of all the criteria that a screening test should fulfil, the ability to prevent and treat the condition adequately, when not apparent or whenever discovered, is perhaps the most important and appealing. The primary aim of the screening must be to prevent the disorder to occur and when disorder cannot be prevented, harm to the patient should be avoided at all costs (the primum non nocere of Hippocrates) and effective treatment must be provided. Fortunately, majority of hearing loss are preventable and curable. The negative consequences of unpreventable hearing loss can be minimized with appropriate treatment modalities which are safe, efficient, effective and clinically proven. There are some specific treatments modalities exist that can be administered to an individual with hearing loss such as medical, surgical and audiologic-habilitation [52]. Hearing loss resulting from autoimmune disorders such as otitis media may be treated through the use of appropriate medications, such as corticosteroids or antibiotics. The ear canal obstruction, blockages by matter such as excess cerumen, benign growths or tumours may be addressed through removal of the foreign object(s).

Similarly, where hearing loss is caused by fluid build-up in the middle ear, fluid can be drained through a surgical incision, known as a myringotomy, and further fluid build-up prevented with the insertion of a tympanostomy tube, to keep the middle ear aerated. The outer and middle ear anatomical and structural deformities may be corrected surgically. Congenital and/or medically and surgically incurable hearing loss may be compensated through the use of the amplification devices. Hearing aids can help individuals with hearing loss by amplifying sound at listener’s ears and facilitating improved social communication. The state of art hearing aids is available, are more sophisticated, stylist and smaller, that can be tailored to different severities and configurations of hearing loss and can address cosmetic concerns. In order to ensure that amplification is as natural and responsive as possible, hearing aids are customised to a person’s particular pattern of hearing loss (e.g., selective amplification of relevant frequencies). Hearing aids are prescribed depending on severity of hearing loss, listening goals, and other specific medical and social circumstances. With invent of computerised probe mike real ear measurement, Selection, evaluation and fitting of hearing aid in newborns and children have become easier and objective.

Cochlear implant is an FDA approved hearing prosthesis which has improved the communication and quality of life of acceptable number of persons with disabilities and families. Cochlear implant is a medical device which is surgically implanted into the cochlea, and worn with an external sound processor. A cochlear implant provides signals to the brain by converting sound to electrical signals that directly stimulate the auditory nerve via multiple electrodes. Unlike hearing aids, cochlear implants simulate the auditory nerve in the inner ear directly. It is best suited to individuals with severe degree of hearing loss or for individuals who do not benefit from conventional hearing aids, but have an intact auditory nerve. Bone conduction and middle ear implants are surgically implanted to overcome a conductive hearing loss that cannot be treated through medication, surgery and hearing aids. Similar to the cochlear implant, an external sound processor converts sound energy into mechanical energy, and directly stimulates the middle ear and inner ear.

Government of India provides behind the ear digital hearing aids at subsidized rate under ADIP Scheme (Revised-2014) to hearing disable persons as per RPwD Act 2016. Most recently, Cochlear Implant and Speech-Language therapy are being provided free of cost to children with severe to profound hearing loss up to the age of 12 years under ADIP Scheme (Revised-2014) [53]. Similar facilities are also available under Rashtriya Bal Swasthya Karyakram (RBSK-2013) launched by ministry of health and family welfare. It is an initiative aimed at screening over 27 crore children from 0–18 years for 4 Ds: Defects at birth, diseases, deficiencies and development delays including disabilities. Children diagnosed with illnesses shall receive follow up including surgeries at tertiary level, free of cost under National Rural Health Mission (NRHM). Child Health Screening and Early Intervention Services under NRHM, covers 30 identified health conditions for early detection and free treatment and management [54].

• b)The disorder must respond to appropriate intervention and its effects on individuals can be reduced and minimised

The direct relevance of screening program is to provide effective treatment so that the sufferings of individuals with hearing impairment can be alleviated and minimised. The greater value of screening may lie in identification of mild to moderate hearing losses that are amenable to treatment. Furthermore, Otitis media with effusion, bacterial and viral diseases can be prevented and treated at Primary Health Centres. In the longitudinal study of 10 years Markides [55] (1986) reported that children identified with hearing loss between 0–6 month of age with immediate audio-logical and family centred program have achieved significantly higher developmental function than those with delayed identification, in terms of increased receptive/expressive vocabulary and language. They acquired a greater number of vowels and consonants and had good speech Intelligibility.

• iii)There should be advantage of early identification and disadvantage of late identification

Hearing screening has many merits. Empirical studies have demonstrated that multiple aspects of children and families’ life are benefited in short and long term [28, 29]. Children with early-identified hearing loss who receive appropriate early intervention, demonstrated significantly better language, speech, social and emotional development than late identified children. They had language development similar to their non-verbal cognitive development and their language development was maintained in the low average range throughout first five years of life. Furthermore, early intervention resulted in better speech intelligibility, better personal-social development, less parental concern and stress. Four-fifth of the identified neonates with hearing loss born in hospital with no other secondary disability had language development in the low average range through 1–5 years of life. When these statistics were compared with late identified children wherein one in every five children had language development commensurable with normal hearing child [56].

A population-based, prospective, the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study directly compared the outcomes of children with hearing loss who received early or later intervention (National Acoustics Laboratories, 2018). The study included approximately 470 children with hearing loss born between 2002 and 2007. The study provided world-first evidence of the benefits at 5 years of age of early hearing-aid fitting by 6 months or cochlear implantation by 12 months of age combined with educational intervention for language development of children. The study found that on average, children fitted with hearing aids before 6 months of age had higher language scores than those fitted later. For children with severe or profound hearing loss, those who received a cochlear implant before 12 months of age had significantly higher language scores than those who received a cochlear implant at an older age 13 months [57]. These reports suggest that early identified children tend to have better communication skills that leads to better academic performance, better carrier opportunity, psycho-social adaptation, better life quality and increased life time earning as compared to late identified children.

Facilities for Diagnosis and Treatment Should be Available

India has very impressive infrastructure for disseminating primary health care and rehabilitation services. The Ministry of Social Justice and Empowerment, Department of Empowerment of Persons with Disabilities (Divyangjan), has established nine National Institutes which are engaged in Human Resources Development, delivery of rehabilitation services to the persons with disabilities, dissemination of information and documentation and Research and Development in the field of disability. There are 19 Composite Regional Centres so far have been established for Persons with Disabilities in various states to provide both preventive and promotional aspects of rehabilitation like education, health, employment and vocational training, research and manpower development. For providing comprehensive services to children with disabilities and capacity building, Currently, 262 District Disability Rehabilitation Centers (DDRCs) are operational in various districts of the country [58].

There are 3907 ICDS projects covering nearly 70% of country’s community development blocks and 260 urban slum pockets. The population coverage through Anganwadi worker is approximately 1000 in Urban and Rural area, and 700 in tribal/hilly belts [58]. Following the launch of the National Programme for Prevention and Control of Deafness in 2006, infant hearing screening protocol, combining both institution-based and community-based modalities have been developed. This programme is operational in approximately 65 districts across the country. Moreover, under ADIP Scheme (Revised-2014), Ministry of social justice and empowerment provides binaural hearing aids yearly to school infants and school going children or monaural cochlear implant to children with hearing impairment up to age 12 years at subsidise rate of 0% on family income basis through its institutions and recognise agencies. The mapping of cochlear Implant, speech—language or auditory verbal is also provided at free of cost for three years post implantation.

Rural health services are facilitated by 1, 31,900 Health Sub Centres, each for every 5000 population in plain and 3000 population in tribal areas. There are 21,693 Primary Health Centres, for 30,000 populations in plain and 20,000 populations in tribal/hilly areas. There is 2385 upgraded Community Health Centre to cover 80,000 to 1.20-lakh populations. Each of these centres has gramsevikas, anganwadi workers, multipurpose workers, health workers, viklangbandhus and nurses etc. [59]. The Artificial Limbs Manufacturing Corporation (ALIMCO) has provided about 42 lakhs of assistive device to PwDs across the country. The National Handicapped Finance and Development Corporation (NHFDC) extends financial support for education, self-employment and entrepreneurship to Persons with Disabilities. It provides financial assistance up to 25.0 lakh for setting up income generating activities to PwDs at 5–8% p.a. interest rate (1% rebate for women PwDs and 0.5% rebate for VH/HH/MR PwDs). Education loan for pursuing higher education i.e., graduation, post-graduation and other professional courses approved by UGC/Government/AICTE etc. up to Rs.20.0 lakh for courses abroad. Rs.10.0 lakh within India at 4% interest rate (0.5% rebate on interest to women beneficiaries) [58].

There Should be a Recognizable Latent (Early, Asymptomatic) Stage in the Condition

In order to hearing screening to be effective to detect and treat disease at an early stage there must clearly be a reasonable period in the natural history of the condition during which symptoms are either not present or at any rate not clamant. There is, in fact, a latent stage in many chronic diseases that can be recognized including the disease-causing hearing impairment. Though, hearing impairment is often silent and considered as invisible disability that affects the person without any signal or warning. But hearing impairment is behaviourally visible in the affected persons as hearing has linkages to development and maintenance of almost all biological functions. There is recognizable latent phase in hearing impairment such as delay in oral language development, poor socialization, inability to attend name call and inattentiveness etc. in young children. There is precursor stage in many disease conditions leading to hearing disability and has certain recognizable presymptomatic state. For example, potentially damaging noise exposure, ototoxic drug, endolymphatic hydrops and retro cochlear pathologies have warning signals of temporary threshold shift, recruitment, fluctuating hearing loss, fullness of ear, tinnitus nausea and vertigo etc. Thus, there is recognizable latent (early, asymptomatic) stage in the hearing impairment condition.

There Should be a Suitable Test or Examination to Employ in Screening i.e., the Disorder Can be Diagnosed on Clinically Established Sign and Symptoms

The sign and symptoms of auditory deficit and otologic pathology can be clinically established in newborn and infants. In developing countries like India, the predominant method of detecting hearing loss in children is through parental suspicion by reason of the child’s inappropriate development, or lack of response to sound that occurs at a mean age of 9 months to 22 months [59], Gopal et al. [60] Mukari et al. [61] Olusanya et al. [62] whereas in developing countries early detection of hearing loss is done through reliable, valid, easy to apply, and safe hearing screening methods. According to McPherson and Olusanya (2008) a hearing screening is considered valid, "if it detects the majority of subjects with the target disorder (high sensitivity) and excludes most subjects without the disorder (high specificity) and if a positive test indicates the presence of the disorder (high positive predictive value)" [63].

There are two objective screening tests available for use in infants, otoacoustic emissions (OAEs) and auditory brainstem response (ABRs) Table 1 summarises hearing screening approaches and their rationale]. These electrophysiological methods are efficient, cost effective and accurate for identifying disabling degree of hearing loss. An OAE is an electrophysiologic measure of the integrity of the outer hair cells in the cochlea. There are two main types of OAEs, transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs). This test is relatively quick, non-invasive, and does not require the sleep or sedation [64]. The OAE screener results in either a pass or fail result, making it easy to read without requiring the screener to have audiological expertise. Furthermore, OAEs have a high sensitivity (> 9) and specificity (> 96%) based on a two-stage screening [65], [66]. The limitation of OAEs include its sensitivity to conductive hearing loss, which may occur within the first few days of life due to a vernix plug in an infant’s ear canal, does not detect auditory neuropathy, and DPOAEs may miss mild hearing loss.

Table 1.

summarises hearing screening approaches and their rationale

[64]

Screening apporach	Screening rationale
a) Auditory Brainstem Response	It is objective measurement of auditory system It provides ear specific information It is independent of subject’s state (sleeping, awake) It doesn’t require sound booth for evaluation ABR is independent of cerebral status ABR has a valuable contribution to cross check principle AABR and innovative analysis is cost effective
b) Otoacoustic emission	Normal OAE is recorded in normal cochlea OAE can be recorded reliably from newborn OAE is abnormal even in person with mild hearing loss Even nursing staff can perform it OAE recording require relatively brief time OAE provide frequency specific information Helps in identifying Auditory neuropathy along with ABR

ABR is an electrophysiologic measure of the function of cranial nerve eight and the auditory pathway in the brainstem. Three electrodes are placed on the scalp in order to record electrical responses from auditory stimuli. ABR is method of choice for hearing screening less than 5 months age ASHA (1991), as it does not require child participation and measurement can be done when the baby is sleeping (without sedation), sedated, or in a quiet state]. ABR recordings are correlated with the degree of hearing loss, for click ABR this range is from 1 to 4 k Hz within 10 to 15 dB HL. The screening version of ABR, or automated ABR (AABR), is designed to produce a simple pass or fail result. AABR has high sensitivity (> 90%), high specificity (> 96%) and low positive predictive value (19%) (Vohr et al. [51]; Watkin [67]) Therefore, it is recommended that hearing screening programs utilize a two-stage screening protocol that is made up of TEOAEs and AABR. Combined, these two tests have the most favorable combination of specificity, sensitivity, acceptability and high coverage in hospitals with a wide range of birth rates (Kennedy et al. [68] Vohr et al. [51]). One advantage of OAE and AABR is that they are able to identify auditory neuropathy; however, the disadvantage is that they may miss mild sensorineural or exclusively low frequency hearing loss.

The Test Should be Acceptable to the Population

Clearly a test or series of tests must be acceptable to the population to which it is offered. Acceptability is, of course, related to the nature of the risk and to the way in which the ground is prepared previously by health education. The parental anxiety is an important factor that can potentially interfere with maternal infant attachment and cause abnormal parenting behaviour and communication. Watkin et al. reported that 96% parents of severely deaf children indicated that they would have wanted neonatal identification and a small portion (only 4%) indicated that they would have preferred to have waited because of the anxieties related to hearing screening results [69]. Watkin et al. investigated 288 mothers whose babies had received a neonatal screen, and found that less than 1% were very anxious by the neonatal screening [70]. However, Watkin concluded that parental anxiety to hearing screening is very small and manageable [71]. Clemens et al. in a study of 5010 infants report that 90% of the mothers indicated universal newborn hearing screening (UNHS) to be a “good” idea [72]. Similarly, Hergils and Hergils indicated that 95% of the parents had a positive attitude towards neonatal hearing screening in Sweden [73].

Yoshinaga-Itano reports that neonatal identification of hearing loss does not result in greater parental stress than later identification when the intervention programme contains a comprehensive counselling content [42]. In a study of 184 parents of children with hearing loss, He reported that the parents of early-identified children were not more likely to present with stress than parents of late-identified children. Vohr et al. (2001) reported that 88–89% of mothers indicated none or very less anxiety to hearing screening [51]. The reports are uniform in their conclusions that parental anxiety due to screening programmes is negligible and does not differ significantly from that of parents whose infant did not receive screening. In addition to this, parents of children with hearing loss demonstrate emotional availability similar to parents of children with normal hearing [42]. The study also indicated that resolution of grief by families with early-identified children occurs faster than for families with later-identified children, as long as their children develop strong language and communication skills [42]. Yoshinaga-Itano reported that there has been no evidence that newborn hearing screening causes parental harm [45]^.

McPherson and Olusanya (2008) [63] inscribe, "evidence from ongoing infant hearing screening programs has shown that hearing screening tests are acceptable to parents because they are not invasive, painless and quick to administer. They are currently employed in developed countries and in a growing number of developing countries." They also recommended that the two-stage screening protocol be performed on newborns prior to hospital discharge in order to decrease the number of infants lost to follow-up care.

The Natural History of the Condition, Including Development from Latent to Declared Disease, Should be Adequately Understood

Normal auditory integrity within the early years of life is essential for quality development of the child. Hearing loss of any degree results in substantial and long-term damages in all spheres of human life. Table 2 provides comprehensive impact of degree of hearing loss on speech and language development, psychosocial maturation and academic difficulties in infants and children.

Table 2.

Impact of degree of hearing loss on speech and language development, psychosocial maturation and academic difficulties [1, 2, 29]

Degree of hearing loss	Communication abilities	Psychosocial maturation	Educational difficulties
00–15 dBHL	May have difficulty in discriminating speech in presence of noise	Child may be unaware of sub conventional cues and may be viewed as awkward	May miss instructions in class, depending upon configuration of loss
16–25 dBHL	Misses unvoiced consonants. (p, s, f, ch, t, h etc.). Mild auditory dysfunction in language learning	May miss portion of fast paced peer interaction. May be fatigued than peers due to listening efforts	Child can miss up to 10% of speech when teaching more than 3″ and class is noisy
26-40dBHL	Mild auditory dysfunction in language learning and language retardation	Child may lose selective hearing that affects child’s self-esteem and attention	May miss 50% of class discussion when teacher is not facing the child
41–55 dBHL	Delayed and defective syntax, limited words, imperfect speech and voice quality	Increasing impact on self-esteem. Socialisation and communication are affected with normal peers. Child may judge as retarded	May judged as slow learner. Special educational support may be needed especially in primary grade
56–70 dBHL	Defective syntax, limited vocabulary and poor speech intelligibility	Poor self-esteem and social maturity. Avoids group discussion. Inattention	Special educational support for language skills may be required
71–90 dBHL	Severe delays in speech and language. Speech can deteriorate if hearing loss is post lingual	Child prefers only hearing-impaired as friends. This improves self-esteem and sense of cultural Identity	May need fulltime special school with emphasis on auditory language skills
> 91 dBHL	May rely primarily on visual avenues for communication	Shows temper tantrum and aggressiveness. Child selects his association	Requires fulltime special school and selection of learning mode
Unilateral hearing loss	Difficulty in localisation on affected side. Poor speech discrimination in presence of noise	Fatigue due to efforts in hearing, inattentive and frustrated. Loss of concentration	Scholastic backwardness. Poor at dictation if face of teacher’s is not available

There are other factors too, like onset, type, configuration of hearing loss and associated neurological deficits that have cascading effect on academics and cognitive setbacks in infants and children

There Should be an Agreed Policy on Whom to Treat as Patients

There should be an agreed policy on screening hearing impairment and the further diagnostic investigation of individuals with a positive test result and on the choices available to those individuals. The implementation of newborn hearing screening programmes has led to the development and refinement of screening principles, general screening philosophy and criteria for the population to be screened (ASHA, 1997) [74]. It is therefore logical to answer the question “what type and degree of hearing loss to screen for. In other words, the specified or targeted condition needs to be defined for identification and intervention for hearing impairment [75]. Davis et al. suggested that the target hearing loss to be screened for should be selected based on the basis it proves to be a significant health problem for the population [65] Thus, to resolve this issue to some extent, the Rights of PERSONS WITH DISABILITIES ACT (RPWD Act, 2016) defined the hearing impairment and set a benchmark disability i.e., 40% hearing disability in the better ear as a disability in a person.

Way back in 2006, Ministry of Social Justice and Empowerment, Government of India drafted National Policy 2006 for Persons with Disabilities to ensures equality, freedom, justice and dignity of all individuals and implicitly mandates an inclusive society for all including persons with disabilities enshrine in the Constitution of India. National Policy for Persons with Disabilities 2006 was formulated and brought out the with focus on Prevention of Disabilities and Rehabilitation Measures. The principal areas of intervention under the Policy are: Prevention, Early-detection and Intervention; Programmes of Rehabilitation; Human Resource Development; Education of Persons with Disabilities; Employment; Barrier free-environment; Social Protection; Research; Sports, Recreation and Cultural Activities. Department of Empowerment of Persons with Disabilities, Ministry of Social Justice and Empowerment is the nodal Department to coordinate all matters relating to implementation of the Policy. The Chief Commissioner for Persons with Disabilities at Central level and State Commissioners at the State level have been given the responsibility in implementation of the National Policy, apart from their respective statutory responsibilities.

The Cost of Case-Finding (Including Diagnosis and Treatment of Those Diagnosed) Should be Non-wastefully Balanced in Relation to Expenditure on Medical Care as a Whole

The screening cost are affected by several factors, such as capital costs, operating expenses, screening technique, follow-up costs, the number of babies for screening and assumptions regarding the prevalence of hearing loss [76]. Numerous studies have reported on the costs of neonatal hearing screening (NHS). Maxon et al. estimated costs per infant screened to be $26.05 [77]. A volunteer-based UNHS programme reported similar costs of $27.41 per infant screened [78]. Vohr et al. (2001) investigated the costs of screening by using three different protocols and reported similar results across protocols [52]. The estimated of costs were $28.69, $32.81 and $33.05 for TEOAE, AABR and two-step protocols respectively. Mehl and Thomson (1998) estimated the true cost for each infant screened to be $25, which includes labour cost, disposable supplies and remunerated capital equipment. The cost of screening per infant ranged from $18.30 when performed by supervised volunteers, to $25.60 when performed by a paid technician, and $33.30 when performed by an audiologist [79].

Kezirian et al. compared OAE and AABR screening protocol costs and subsequently estimated costs per screen to vary between $13 and $25. The most cost-effective screening was performed with OAE screening with an estimated total cost of $5100 per infant identified with congenital hearing loss. The study estimated costs for the AABR was $25, with a total cost of $9500 per infant identified with hearing loss. The principal finding was that an OAE/OAE protocol demonstrated the lowest cost and is the cost effective by a large margin [80]. The Colorado UNHS state wide programme reports a cost of approximately $9600 for identifying congenital hearing loss and $12,600 for identifying bilateral hearing loss [56]. Even though the cost of screening individual infants for other birth defects may be lower, the prevalence of hearing loss is much higher. This leads to cost comparisons indicating that costs for identifying hypothyroidism is similar to the cost for identifying hearing loss (at $10,000), and higher for cases of hemoglobinopathy ($23,000) and phenylketonuria ($40,000). Johnson et al. report similar cost comparisons [81]. The comparison of yields from various newborn-screening programs in Table 3 illustrates the relative status of hearing screening.

Table 3.

Illustrates relative status of hearing screening

Disease screened	Yields
Phynylketonuria Combined immunodeficiency disease Maple syrup urine disease Neonatal hyperthyroidism Neonatal hearing screening (HRR approach)	1 in 15,000 births 25 in 300,0000 births 1 in 300,000 live births 1 in 6000 live births 1 in 50 to 100 births

From: M.P. Downs and K.P. Gerkin: Early identification. In Lass et.al (eds.): Handbook of

Speech and Language Pathology and Audiology. Toronto, B.C. Becker inc.; 1988, pp1191

The case for early identification and intervention is also supported by long-term cost benefits for families and society. For every child who will not need special educational services, there will be an annual savings of more than $10,000 and for each child who will require a less intensive educational programme, annual savings may amount to $5000 [56]. According to Johnson et al., the annual cost for an infant with hearing loss in a regular classroom will be $3383 compared to $35,780 in residential programmes [81]. Yoshinaga-Itano and Gravel [56] report similar figures and state an annual cost difference of between $25,000 and $35,000 for education in the local educational agency and a residential school for the deaf respectively. It is also probable that the higher the educational outcomes for children with significant hearing loss, the more likely that they will become employed adults to their full potential and contributing to society [56]. The above literature revealed hearing screening justified on the grounds of long-term economic benefit for families and society, as well as significant improvement in quality of life for individuals and families [82]. The above statistics provide an important justification of hearing screening as a cost effective and accepted practice.

Case-Finding Should be an Ongoing Process and Not a ‘One-Off’ Project."

Hearing screening should be ongoing with organised follow up and case tracking process because late-onset hearing loss within the first year of life is not known [46]. Norton et al. estimated that only 2% of children with permanent hearing loss by 12 months of age had normal hearing at birth [83]. But, according to Davis et al., an estimated 10% of permanent childhood hearing loss is either progressive or late-onset [62]. In a recent multi-centre study among 81 children who were survivors of neonatal respiratory failure (with or without diaphragmatic hernia) and who passed neonatal hearing screening at the time of hospital discharge, a high incidence of sensorineural hearing loss was reported at 4 years of age. Altogether 53% of the children presented with sensorineural hearing loss, of whom 70% had hearing loss at the age of 2 and of these, 60% was progressive between 2 and 4 years of age [84].

According to the US Preventative Services Task Force (USPSTF)-2001, between 13 and 31% of infants referred for further diagnostic testing in existing Universal Newborn Hearing Screening (UNHS) programmes do not return for follow-up [85]. Data from the Colorado NHS project (1992 to 1999), which screened 148,240 newborns and identified 291 infants with congenital hearing loss, indicates a 76% documented follow-up rate for referred infants [86]. This is a significant increase from a follow-up rate of 48% during the first five years of screening. Nine of the participating hospitals were able to achieve a follow-up rate of 95% or more for infants failing the initial screening tests. Although reports indicate high follow-up return rates for established programmes, room for improvement still remains.

Universal Newborn Hearing Screening (UNHS) in Cochin was conducted to pick up hearing loss up to 30–35 dB at the Charge (cost) of Rs. 150/- per child (including repeat screen) as a one-time payment. By paying Rs.150, screen negative parents were happy that their child has normal hearing and screen-positive parents were relieved their child’s problem is detected early for effective management [87]. The survey also reported that 14% mothers exhibited anxiety to a positive screen. It is also reported that regardless of anxiety, 90% of all respondents were glad that their children had a hearing test and thought that universal hearing screening was a good idea. When the authors reiterated to the parents that the next level of testing is undertaken to rule out for good if there is hearing impairment or not. It was soothing for most parents. Therefore, the study concludes that anxiety is similar to any other screening tool that is used in medicine [87].

The study reported that the social, emotional and physical cost of the 162 cases of deafness detected cannot be quantified just with money. The screening has a futuristic and prophylactic utility; it creates awareness for the future among the profession and the lay public to look out for possibility of hearing impairment. The author also concluded that it is unreasonable to claim that most mothers pick up deafness in children before the age of 6 months on their own. Responses to conventional sound cues are crude and non-standardized and should never be resorted to, when we have better, non-invasive standardized procedures. Abraham K Paul [87] concluded that screening tool is not cost-effective in India does not stand to reason. The usefulness and cost-effectiveness of Newborn Hearing Screening procedure prompted the Ministry of Health and Family Welfare, Government of India to include Newborn Hearing Screening in ‘Rashtriya Bal Suraksha Karyakram’ 2013.

The Wilson and Jungner principles of screening which often represent the de facto starting point for inherently contentious and costly sets of decisions for screening the disorders. Fortunately, in every aspect the above discussions on principles of screening meets all the painstaking criterions and supplies the sufficient necessity, significance and justification for Implementation of National Infant Screening for Hearing Program in India. Health care professionals, screening experts and policy-makers from all parts of the world use these principles to guide screening decisions. But despite the popularity of these principles, screening decisions remain challenging. Recent controversies regarding screening for hearing screening in newborns highlight the persistent complexity of screening decisions and the intense scrutiny under which they are made. However, it our strong belief that these justifications will help our Health care professionals, medical professionals (especially otolaryngologists and paediatrician) and public health expert for successful implementation National Infant Screening for Hearing in our country.

Discussions and Conclusions

A substantial number of newborn babies suffer from congenital hearing loss, which causes severe damages to both infants and their families. Hence it is necessary to secure normal, social and holistic development of the child by detecting hearing loss at birth and providing remedial services at the earliest. Unfortunately, there is no dedicated national policy for early identification and intervention is available at yet in India. Therefore, undoubtedly, it is the biggest challenge to provide technological support, special education, vocational training and employment to this large population especially in absence any comprehensive, cohesive and coherent early identification and intervention program. Census of India (2011) reports that one in every 100 children in the age group 0–6 years suffered from some type of disability. There are more than 5 lakh children with hearing impairment in the age 0–6 years and only 5% of them have access to special schools in India. Paradoxically, at present only low paid unskilled or semi-skilled jobs are available to handful hearing impaired adults. Thus, enormity of the problem can only be tackled if available infrastructures are used to mainstream the hearing-impaired people in regular education, vocational training and employment by attending the hearing loss in time and instituting appropriate remedial measures.

The present paper has justified that hearing loss as a public health issue and highly compatible with all medical screening criteria. Most importantly hearing screening procedures are not only standardised but also advantageous and cost effective, as the child who receives early services requires less costly special education later and leads quality of life. Moreover, infant hearing screening program is one of the most acceptable screening procedures in the multitude of health screening program across the world. In spite, hearing Screening program is one of the most acceptable screening procedures across the world. However, its implementation approaches differ between countries in terms of health care systems and the availability of resources and personnel to implement hearing screening programmes. For this reason, different approaches to screen the hearing are implemented in different countries. Therefore, considering the demography, socioeconomic status and availability of infrastructure we must adopt the most suitable infant hearing screening program nationally.

Recommendations

Currently, some actions have been taken to prevent hearing loss in our country. These actions include: promotion of immunization against known causes of hearing loss (e.g., measles, mumps, and rubella); improved care of mothers before and during child delivery; and education on the use or misuse of ototoxic drugs. However, McPherson and Olusanya [63] reported that unfortunately the healthcare systems in the majority of developing countries such as India are unable to uphold these standards of care and hearing loss continue to inflict to large number of persons. Further, in absence decipherably available National Infant Screening for Hearing Program, hearing loss is often left undetected in all ages in our country. According to McPherson and Olusanya [63], hearing screenings are considered a high priority component of a hearing healthcare program in large due to the fact that early detection of hearing loss in infants can allow for prompt assessment, detection, and intervention of congenital and early onset hearing loss. Furthermore, research has shown the importance of early intervention during the critical period of speech and language development [37]. Thus, the true value of screening lies in detection of transient hearing losses that may dissipate with appropriate medical intervention and in identification of mild to moderate hearing losses that are amenable to treatment and if left unattended, may behave like severely hearing-impaired child.

The disorder related screening principles provide a strong foundation for National Infant Screening for Hearing (NISH) by indicating the burden of disorder, addressing the necessity for hearing screening due to the detrimental effect of late identification and the studied significance and benefits of early identification. The significantly improved disorder outcomes to effective-evidence based intervention provide adequate justification for National Infant Screening for Hearing Program in our country. We provide below here some recommendations and suggestions to plant and implement National Infant Screening for Hearing in India,

• National Infant Screening for Hearing Administration (NISHA) or National Task Force in three areas viz prevention, early identification and intervention should be constituted to Plan, Implement and Monitor the Program.

• National plan for the prevention and control of major avoidable causes of hearing loss in infants, and for early detection of hearing in newborns and infants.

• National Action Plan should be evolved to prevent hearing impairment at country level including the detection of hereditary factors, by genetic testing and counselling.

• Childhood immunization against the target diseases such as mumps, measles, rubella and (meningococcal) meningitis should accelerated and ensured.

• To create awareness, to provide advocacy and appropriate implementation of legislation for the proper management of particularly important causes of deafness and hearing impairment, such as otitis media, use of ototoxic drugs and harmful exposure to noise and music at workplace, festivals and celebrations.

• Dissemination of appropriate public information and education for hearing protection and conservation in particularly vulnerable or exposed population groups.

At present, it is high order for India to Implement National Infant Screening for Hearing (NISH) which is resource less but philosophically rich country to serve the people with disabilities (Divyangjan). Our national priorities and challenges are different than the developed and other countries. But there are ample of opportunities, man and material that can be purposefully utilized for Infant Screening for Hearing. Therefore, we are hopeful that one day we shall overcome all challenges and utilize all available resources and opportunities to plan and implement National Infant Screening for Hearing (NISH) in near future.

Funding

No funding received for the article.

Declarations

Confilct of interest

No conflict of interest.

Ethical Approval

Ethics approval is not applicable.