Several studies have reported that children with severe and/or profound hearing loss (HL) may substantially benefit from using a cochlear implant (CI), together with proper auditory rehabilitation. These children have greater likelihood of acquiring oral language1 and being integrated in regular schools2, extending their chances of participating in activities and being part of the world of sounds3.

To perform activities and participate in the auditory world means to communicate and, consequently, communication is directly related to socializing, since social interactions occur by means of verbal communication4. The social aspect is one of the most important parts of a child's global development; it integrates the meaning of “quality of life”, as well as other issues associated with functionality, physical and mental well-being4. Therefore, if the CI provides for hearing and language development and, consequently, the development of communication skills, such progress, because of CI use, would bring quality of life improvements for children with hearing loss.

However, although the CI can usually improve the quality of life (QL) of children, there is but a very limited number of studies in our field investigating such aspects5. This is a surprising finding, since hearing interference has been well documented, especially in regards of social performance, self-esteem and acceptance at school6; and these issues are even more relevant in children with severe and/or profound hearing loss7.

Studies in this field evaluate aspects which are more associated with auditory, language and speech performance, school type, and analyze the cost-effectiveness of the CI treatment1,3,8,9. More attention has been given to the measures carried through in image/behavior clinic/laboratory than the collection of information at the level of CI user's functionality or other significant factors associated with their bio-psycho-social development10.

Concerning the progresses achieved in the field of Audiology, especially with the pediatric population using CI, healthcare professionals must consider that the factors affecting the results are so numerous, and only one part of them can be investigated by means of tests or other instruments used in clinical routine11. Moreover, a detailed investigation concerning other aspects of life is not only relevant for the parents and physicians, but also for setting up healthcare policies12, allowing for proper resource assignments to take care of the different social needs, service programs and specific interventions for this population13.

Thus, to measure health-related quality of life (HRQL), which is a unique and personal perception of physical, mental and social well-being in diverse situations and activities9, it is important to evaluate the multidimensional impact of hearing loss and cochlear implant use in the life of children, complementing the results of the clinical measures14.

But, specifically in the pediatric population, to measure the HRQL is not an easy task. Numerous methodological issues permeate this type of evaluation, and to measure the state of health of a child requires choices concerning which health aspects are relevant, which preferences are of interest (child, parents, professors, doctors, etc.), the values that must be used, and an entire series of other contextual and psychometric issues that must be tended to15.

The challenge is in putting it within a comprehensive concept which HRQL aspects are important for the child, and how such aspects may progress during his/ her development are determining factors in this type of assessment. For example, HRQL domains for a 5 year girl who is starting school can be different from those for an 18 year old who is just starting to drive. This fact directly reflects the choice of instrument to be used, since it must identify and evaluate all the relevant factors for the population being studied. Moreover, most of the time, HRQL questionnaires for children are frequently filled up by the parents or care-givers and studies have shown a poor correlation between the scores from the parents and the child vis-à-vis mental and social aspects, and a better correlation concerning physical domains16. Thus, the interpretation of the HRQL results must take into consideration the questionnaire's respondent and, when possible, the evaluation of the parents and that of the child must be done together17.

Having all these issues associated with the measure of quality of life in children and trying to guide the bibliography survey with high scientific evidence, we carried through a systematic revision of the literature in order to pinpoint quality of life of children with cochlear implants, and find out which are the main aspects assessed in this population and factors associated with quality-of-life measuring.

As an essential principle of evidence-based studies, the investigated issue in this study was: “Which are the main quality of life aspects assessed in children using CI and the factors related with its results?”.

The search strategy used in the bibliographical revision was oriented by the combination of seven keywords indexed in the DecS (health keywords) in Portuguese and English, employing the keywords in groups with at least two keywords (Chart 1).

Chart 1.

Search strategies in the data bases.

(0.14MB).

The chosen scientific databases for the search were: LILACS, MedLine, SciELO, Cochrane Library, PubMed, Embase, Institute for Scientific Information (ISI) and Science Direct. For the purposes of this study, we considered the publications produced during the period from january of 2000 through september of 2011, and the last manual search was carried out in electronic databases in september of 2011.

The choice of papers followed inclusion criteria based on confining the subject matters to the objectives of this paper. The adopted criteria were:

• •

  Participants - Children with cochlear implants

• •

  Intervention - Cochlear implant

• •

  Measured outcomes - Quality of life by means of questionnaires

• •

  Time - Published in last the 11 years (2000-2011)

• •

  Language: Papers written in Portuguese, English and Spanish

• •

  Types of studies - Papers published in indexed journals with evidence levels 1a, 1b, 2a, 2b, 3a, 3b and 4, in accordance with the criteria proposed by the American Speech Language Hearing Association (ASHA)18 (Table 1).

  Table 1.

  Levels of scientific evidence according to criteria proposed by the ASHA18.

  Levels of evidence	Type of study
  1a	Systematic review or high-quality metanalysis of randomized controlled trials
  1b	High-quality randomized controlled trials
  2a	Systematic review or high-quality metanalysis of non-randomized controlled trials
  2b	High-quality non-randomized controlled trials
  3a	Systematic review of cohort studies
  3b	Individual cohort studies or low-quality randomized controlled trials
  4	Studies from clinical outcomes
  5a	Systematic review of a case-control study
  5b	Individual case-control study
  6	Series of cases
  7	Specialists’ opinion without overt critical assessment

We took off those studies carried out with special groups of children with cochlear implant and other disorders, such as cerebral paralysis, auditory neuropathy, syndromes, auditory nerve hypoplasia, internal component re-implant, bilateral implant and other complications.

The selection of the studies was made in three stages and guided by the above-established criteria. Initially, four revisers analyzed all the studies identified by the combinations of the keywords in all the databases proposed, by analyzing the study title, selecting the papers which gathered the pre-established eligibility criteria (1st stage). Following that, we checked to see if the abstracts had information available on the use of some quality-of-life assessment instrument in children (2nd stage). The cases in which the title or the abstract left margins for doubt we studied the entire texts (3rd stage) to later be deemed pertinent to the subject of study and then be reviewed. The main data for each paper retrieved was carefully collected by means of a standardized protocol for the present study.

A total of 2,937 papers were identified in all the databases. In a pre-selection of these citations, based on reading the titles and summaries of all studies found in the electronic search, we took 2,853 studies off, 84 papers were selected and read in their entirety (Flowchart 1).

Flowchart 1.

Number of studies identified and selected for inclusion in the systematic review and reasons for exclusion.

(0.08MB).

At the end, 10 papers met the inclusion criteria3,7,11,17,19-24. Of these 10 papers included in this revision, 8 were classified as cross-sectional studies3,11,19-24, one was characterized as a high quality non-randomized controlled trial7, classified as level 2b according to the ASHA criteria, and one was a systematic revision17 (Tables 2 and 3).

A systematic review is described on Table 2 with the authors’ names, the year of publication, the journal chosen for publication, type of study, the age group included in the papers examined by the authors, the search string, the inclusion criteria for selecting the studies and the results found.

This set of papers was submitted to data evaluation, and the relevant information from each paper (number of participating subjects, age upon CI, duration of use, mean age of the subjects, object of the study, questionnaires used and conclusion), as well as classification vis-à-vis the degree of recommendation, gathered in tables to facilitate consultation and access during the presentation and result discussion (Table 3).

The cochlear implant (CI) surgery impact on the children and adolescents with severe and/or profound hearing loss extends to beyond the improvement in hearing and language skills, and in speech production and perception. This impact also involves other aspects of the child's daily life, such as physical, psychological and social well-being19.

Considering the interest to investigate which were the main quality-of-life aspects described in the literature and to check which factors were associated with this measure in children and youngsters using CI, this study involved a systematic survey of the literature in this field.

The results showed a difference among the studies investigated, considering the age upon evaluation, age of surgery, CI use duration, and the instruments used to assess quality of life. These results were also found in the systematic review carried out by Lin & Niparko17.

From the qualitative analysis of the studies, it was possible to notice that the main aspects of quality of life raised in the studies selected for this systematic review were: physical well-being; emotional well-being; self-esteem; family; friends; school; satisfaction with the CI; social aspects; mobility; self-care; pain; telephone use; speech understanding; hearing environmental sounds; communication; self-sufficiency; use of the devices; attitudes of the others and self-confidence.

Thus, both aspects of health-related quality of life (physical, psychological and social well-being)20 and specific aspects of this population of CI users (family, friends, school, satisfaction with the CI, telephone use, speech understanding, listening to environmental sounds and use of the devices) were investigated.

Although the generic instruments of health-related quality-of-life evaluation are much too general vis-à-vis the investigated aspects, which cannot enable the investigation of issues of particular interest for a given condition (for instance, telephone use), some studies currently show that these bear enough sensitivity, given the ample impact that the hearing loss has on the life of a child³. Another advantage of this type of instrument is the ability of being able to compare the multidimensional aspects that make it, in different groups of children20.

Moreover, currently few specific and standardized HRQL assessment tools are available for the pediatric population with hearing loss. It was only in December of 2011 that a tool intended for the assessment of quality of life in children with hearing loss was published, called “Hearing Environments and Reflections on Quality of Life (HEAR-QL)”25. This questionnaire was not translated into Portuguese until the final analysis of this study.

Thus, we recommend that these two types of assessment should be used in order to perform a HRQL assessment in children with hearing loss, as complementary to the clinical results. The two instruments are needed to completely understand the CI impact instead of compartmentalizing this intervention into an auditory phenomenon only20.

In relation to the analysis of the quality-of-life measure-related factors in children and youngsters with CI, one of the evaluated aspects was the child's age upon surgery. The qualitative analysis of the studies which ran this analysis made it possible to consider that children who were submitted to surgery in earlier ages make a more positive analysis of their quality of life.

Although each study evaluated children at different ages, research in this field show that children implanted earlier reach a better auditory perception, better, incidental language acquisition and better speech inteligibility1,8. The early development of these skills can improve the children's communication with their parents and at school, thus bringing about better social performances, reflected on quality of life assessments.

As to the duration of use, of the three studies that ran this analysis, two found a positive correlation between the total HRQL score and the duration of the CI use, and those children using it longer had a more positive assessment of their HRQL. This aspect has also has been relevant in the results obtained from children26. Children using it longer and more effective may have a better speech perception and intelligibility performances; and just like the age upon implantation, the more effective communication may bring about benefits for other aspects of life.

Thirty children using CI for a period of 10 to 14 years were assessed in a prospective and longitudinal study as to their speech perception and intelligibility. The results showed that 87% of the children used the implant effectively, and after 10 years of use, 60% could speak on the telephone, and 77% developed speech intelligibility near that of their normal hearing counterparts27.

Some studies7,20,21 found a significantly inverse correlation between the child's chronological age and the HRQL evaluation, in which the younger children made a more positive classification of their HRQL than the older children. The groups of children evaluated in these studies had ages varying between 4 and 16 years and, in the three studies, the younger children had been submitted to the CI surgery earlier than the older children, and these findings can be justified vis-à-vis quality of life.

This early identification and prevention of the hearing loss may have provided for a faster and more complete acceptance, recover of hearing and, consequently, of the CI in the lives of the younger children. That is, the CI use within the children's day-to-day activities enables them to embody the device as part of themselves, instead of being something that distinguished them from their normal-hearing colleagues7.

Both for children and their parents, the speech perception results were correlated with quality of life, and these findings may indicate that their perceptions regarding the well-being of the CI users are influenced by factors that go beyond hearing and communication capacity28. Moreover, today, advances in the CI hardware, software and speech processing technology have had a direct impact on the performance and success associated with speech understanding, and such factors should be always considered, since they may in such a way impact the QL results.

As to the differences in quality-of-life evaluations among children using the CI, their parents and children with hearing, the data did not allow for conclusions in relation to these comparisons.

In some fields, such as auditory rehabilitation - where the problems are of complex and intervention cannot be done in definitive groups (control group versus case group), it is possible to include in the systematic review those studies with limited methodological characteristics, at least for the methodological standards adopted by high scientific evidence studies29. Consequently, these studies could be susceptible to a restricted analysis, but they should not be discarded.

We must consider the different ages at which the surgery was carried out, and the duration of CI use in each study must be considered a limitation, given the well-established association between the development of hearing and language skills and these variables and, therefore, the heterogeneity of these factors may result in a population with broad results vis-à-vis language skills17.

Further studies must be done, using HRQL assessment tools which enable result comparison among clinics and countries, and which may lead to a better understanding of the criteria used to select candidates for the surgery, the needs for rehabilitating children with CI, besides enabling access to the clinics, allowing the children with CI to develop their true potential in all aspects of their lives.