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Home : Child Health : Health Surveillance and Epidemiology : Maternal and Infant Health : Publications : Early Hearing : Chapter I
 

Early Hearing and Communication Development

Chapter I: Introduction

Purpose

Author: Sharon Bartholomew

The Canadian Working Group on Childhood Hearing (CWGCH) has prepared this document as an evidence-based resource on early hearing and communication development (EHCD). The evidence is reviewed and presented here for the reader by subject. The final chapter draws conclusions where possible and briefly addresses the broader context that needs to be taken into account in the development of programs.

The intention of the CWGCH is that this resource document will be useful for individuals in jurisdictions in Canada who are making EHCD policy and programming decisions. Overall, the desired outcome for this document is to enhance EHCD programs and services for children.

The document has several purposes. It will:

  • lead to an increase in the use of evidence-based knowledge on newborn hearing screening, diagnostic testing and early intervention
  • serve as a dissemination vehicle for current evidence on early hearing and communication development
  • encourage evidence-based approaches in support of best practices
  • make a statement on conclusions that will summarize the evidence
  • lead to the lowering of the age of initiation of intervention and improve long-term outcomes for children with hearing impairment

The target audience for this document includes:

  • advocates for children with hearing impairment
  • decision makers at all levels (bureaucrats and politicians)
  • health professionals (audiologists, speech and language pathologists, otolaryngologists, paediatricians, neonatologists, family practitioners, etc.)
  • educators of health professionals
  • researchers in the field of hearing impairments
  • opinion leaders

Approach

The CWGCH was established in September 2000 by the Health Surveillance and Epidemiology Division in the Public Health Agency of Canada (formerly the Population and Public Health Branch of Health Canada). It was established in response to a growing interest in the field of EHCD.

Membership on the Working Group included: representatives of national professional associations; consumers/parents; and individual experts in otolaryngology, audiology, speech-language pathology, nursing, child health and public health from across Canada. The multidisciplinary nature of the Working Group is critical to the success of this document. All of the relevant disciplines impacted by EHCD were included on the CWGCH, so that this resource document will be as relevant as possible to a broad range of individuals and professions.

In order to produce this report, critical and systematic reviews were conducted in the following areas:

  1. Screening Justification (Burden of Target Disorder)
  2. Diagnostic Methods/Technology
  3. Amplification
  4. Assessment Techniques
  5. Medical Management
  6. Communication Development Options

These reviews were not done as formal systematic reviews,1 apart from that on communication development options. However, they were completed by experts in the field using common time periods (1966-2002) and a variety of electronic databases, gray literature and manual searching of relevant journals. The term "critical reviews" was used instead of either "narrative reviews" or "systematic reviews." The individual reviews were agreed upon by the group before being finalized. The full reviews were summarized for this document and the complete English versions can be obtained through the Maternal and Infant Health Section, Health Surveillance and Epidemiology Division, Public Health Agency of Canada.

Consultations

In order for this document to be as relevant as possible to its target audience, consultations were held on a draft version. These consultations were held across Canada over a period of six months during 2003. The invitees to the consultations included representatives from provincial/territorial governments, professionals, researchers, educators and consumer groups. The feedback from these consultations was very valuable and has been incorporated into this report.

Terminology Used in this Report

The readers should be advised that some of the terminology used in this document may be different than what has been in common use before. This was a conscious decision by the CWGCH to more accurately reflect the work currently being done in the field. Some examples of changes in terminology include:

New Term/Phrase Replacing
  • early hearing and communication development
  • early hearing detection and intervention
  • hearing and communication development options
  • interventions

While the term "early hearing detection and intervention" (EHDI) is popular, especially in the United States, it has significant limitations. The term "intervention" is non-specific and may be seen as inappropriate in a context that emphasizes a family-centred process aimed at early and maximal development of hearing function and communication function.

The term "early hearing and communication development" (EHCD), on the other hand, emphasizes the primary goal of enhancing development of communication function, which may include oral language, visual language and speech. It also connotes accelerated development of hearing ability, which is a desired outcome of early detection of hearing impairment. The ability to hear is of value in itself as well as by virtue of its intermediary role in communication development. The term also accentuates the positive (as does the carefully chosen "early hearing detection" component of EHDI), and also emphasizes the ultimate purpose of the program activity, rather than the necessary but not sufficient components of it, such as detection of hearing impairment.

The CWGCH would also like to clearly define how the term "universal newborn hearing screening" (UNHS) is being used in this document. UNHS refers specifically to population-wide screening, and not to EHCD as a whole.

The term "hearing impairment" has been chosen for use in this document rather than "hearing loss." Although the term hearing loss has become more popular in North America, the CWGCH believes that for this document hearing impairment is more appropriate and more consistent with the World Health Organization (WHO) International Classification of Functioning, Disability and Health (ICF).2

Guiding Principles

The CWGCH is committed to the following guiding principles:

(i) National Role

The CWGCH will provide leadership in the development and dissemination of a resource document on early hearing and communication development (EHCD) in Canada. This report will be a reference for individuals in all provinces and territories in Canada who wish to develop their own EHCD program or policy.

(ii) Evidence-Based Approach

The CWGCH will take an evidence-based approach to the development of the resource document for EHCD. This approach involves the systematic and critical review of currently available research and program information on childhood hearing.

(iii) Family-Centred Approach

The CWGCH endorses an integrated approach to families, reflecting an understanding of the physical, emotional, mental and psychosocial aspects of hearing and communication development (HCD) options for children with hearing impairment and their families.

(iv) Partnership and Collaboration

The CWGCH is a partnership with various stakeholders, including federal, provincial and territorial governments; professional associations; consumers/parents; and national and international experts in otolaryngology, audiology, speech-language pathology, nursing, child health and public health. This report on EHCD is a result of collaboration among all stakeholders to build on experiences, create linkages and provide opportunities for further capacity building and promotion of best practices in HCD.

(v) International Classification of Functioning

The CWGCH believes that it is important that the WHO's ICF be used to guide the terminology in clinical practice, research and programming. The ICF offers a conceptual framework for information that is applicable to personal health care. This includes prevention, health promotion and the improvement of participation by removing or mitigating societal hindrances and encouraging the provision of social supports and facilitators.

The ICF, which was published in 2001, succeeds the International Classification of Impairments, Disabilities and Handicaps (ICIDH). It has progressed from describing the consequences or outcomes of chronic disease to a classification of human functioning and disability.

The four main aims of the ICF are to:

  1. Provide a scientific basis for understanding and studying health and health-related states, outcomes and determinants.
  2. Establish a common language for describing health and health-related states in order to improve communication between different users, such as health care workers, researchers, policy makers and the public, including people with disabilities.
  3. Permit comparison of data across countries, health care disciplines, services and time.
  4. Provide a systematic coding scheme for health information systems.2

Principles and Practices of Screening

The basic purpose of screening is to detect individuals who are at risk for a condition by applying a test to all asymptomatic persons in a population. The goal of screening is to improve the outcome in affected individuals.

In order for a screening program to be justified it should meet certain criteria. A classic example of these criteria is presented in the WHO document Principles and Practices of Screening for Disease, 1968.3

The definition of screening used by the WHO comes from a conference on chronic illness held in 1951 where screening was defined as "the presumptive identification of unrecognized disease or defect by the application of tests, examinations, or other procedures which can be applied rapidly." The document goes on to point out that screening tests sort out apparently well persons who probably have a condition from those who probably do not. A screening test is not intended to be diagnostic. Persons with positive or suspicious findings must be referred to physicians or other specialists for diagnosis and necessary treatment.4

Principles and Practices of Screening for Disease3 describes the aims of early detection as: discovering and managing conditions which occur in the presence of pathological change, but which have not so far reached a stage at which medical aid is sought spontaneously; and achieving more per unit expenditure by saving the time of highly trained professionals, since part of the work can be performed by less highly trained personnel who are able to carry out screening tests.

The 10 principles of early disease detection discussed in the WHO document are:

  1. The condition sought should be an important health problem.
  2. There should be an accepted treatment for patients with recognized disease.
  3. Facilities for diagnosis and treatment should be available.
  4. There should be a recognizable latent or early symptomatic stage.
  5. There should be a suitable test or examination.
  6. The test should be acceptable to the population.
  7. The natural history of the condition, including development from latent to declared disease, should be adequately understood.
  8. There should be an agreed upon policy on whom to treat as patients.
  9. The cost of case finding (including diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole.
  10. Case finding should be a continuing process and not a “once and for all project.”

The WHO principles have been used, in whole or in part, for justifying screening programs for many years. However, these principles have been seen to fall short in a few areas for today's health care situation. The National Screening Committee of the British National Health Service found it could improve on the WHO principles by including criteria around three issues: the adverse effects of screening; the opportunity costs associated with screening; and, instead of suggesting that there be an acceptable treatment, adding a statement about the strength of the evidence regarding the treatment (see Table 1).

Table 1: Criteria Developed by the National Screening Committee5
The Condition
  1. The condition should be an important health problem.
  2. The epidemiology and natural history of the condition, including development from latent to declared disease, should be adequately understood, and there should be a detectable risk factor, disease marker, latent period or early symptomatic stage.
  3. All the cost-effective primary prevention interventions should have been implemented as far as practicable.
The Test
  1. There should be a simple, safe, precise and validated screening test.
  2. The distribution of test values in the target population should be known and a suitable cut-off level defined and agreed.
  3. The test should be acceptable to the population.
  4. There should be an agreed policy on the further diagnostic investigation of individuals with a positive test result and on the choices available to those individuals.
The Treatment
  1. There should be an effective treatment or intervention for patients identified through early detection, with evidence of early treatment leading to better outcomes than late treatment.
  2. There should be agreed evidence-based policies covering which individuals should be offered treatment and the appropriate treatment to be offered.
  3. Clinical management of the condition and patient outcomes should be optimized by all health care providers prior to participation in a screening program.
The Screening Program
  1. There should be evidence from high-quality randomized controlled trials that the screening program is effective in reducing mortality or morbidity.
  2. There should be evidence that the complete screening program (test, diagnostic procedures, treatment/intervention) is clinically, socially and ethically acceptable to health professionals and the public.
  3. The benefit from the screening program should outweigh the physical and psychological harm (caused by the test, diagnostic procedures and treatment).
  4. The opportunity cost of the screening program (including testing, diagnosis and treatment) should be economically balanced in relation to expenditure on medical care as a whole.
  5. There should be a plan for managing and monitoring the screening program and an agreed set of quality assurance standards.
  6. Adequate staffing and facilities for testing, diagnosis, treatment and program management should be available prior to the commencement of the screening program.
  7. All other options for managing the condition should have been considered (e.g., improving treatment, providing other services).

Key References

  1. Egger M, Smith GD, Altman DG, editors. Systematic Reviews in Health Care. London: BMJ Publishing Group; 2001.
  2. World Health Organization. International Classification of Functioning, Disability and Health: ICF. Geneva: WHO; 2001.
  3. World Health Organization. Principles and Practices of Screening for Disease. Geneva: WHO; 1968.
  4. Commission on Chronic Illness. Chronic Illness in the United States: Volume 1. Prevention of chronic illness. Cambridge, MA: Harvard University Press; 1957. p. 45. (As cited in WHO's Principles and Practices of Screening for Disease, 1968.)
  5. Muir Gray JA. Evidence-based screening in the United Kingdom. Int J Technol Assess. 2001;17(3):400-8.

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