Otology & Neurotology 35:407Y413 Ó 2014, Otology & Neurotology, Inc.
A New Comprehensive Cochlear Implant Questionnaire for Measuring Quality of Life After Sequential Bilateral Cochlear Implantation *Nancy King, †Edmund A. Nahm, ‡Penny Liberatos, ‡Qiuhu Shi, and *‡Ana H. Kim *New York Eye and Ear Infirmary, Department of Otolaryngology, New York, New York; ÞUniversity of Medicine and Dentistry of New Jersey, Newark, New Jersey; and þNew York Medical College, Valhalla, New York, U.S.A.
Objective: To develop a comprehensive cochlear implant questionnaire (CCIQ) as a tool for assessing changes in quality of life (QoL) after receiving a second cochlear implant (CI2) and to correlate the QoL with speech perception changes after CI2. Study Design: Retrospective case series with planned data collection. Setting: Academic cochlear implant center. Patients: Ninety-eight English-speaking adults who received CI2 between 2000 and 2011. Intervention: CCIQ is a 28-item, 5-point Likert-scale questionnaire that assesses the physical and psychosocial benefits of CI2. Main Outcome Measures: Test-retest reliability and Cronbach’s alpha internal consistency were used to assess the reliability of the CCIQ. Speech perception was tested using CNC and HINT. Results: Fifty-four patients completed the CCIQ, and 26 were retested. Respondents reported a subjective improvement in all domains. Test-retest reliability was satisfactory, with 64% of
items achieving an intraclass correlation coefficient of greater than 0.6. Internal consistency reliability was excellent for the overall measure and was satisfactory for 6 of 9 subdomains. Speech perception data were available for 22 patients. Average CNC scores improved 13 T 16%, and HINT scores improved 42 T 16%. No statistically significant correlation was found between QoL scores and audiometric data or duration of CI2 use. Conclusion: Our preliminary data indicate that this CCIQ is a promising tool in assessing QoL specific to CI2 patients. Overall, patients reported improved QoL, independent of speech perception scores. Further refinements of the questionnaire with larger patient numbers are needed to strengthen the CCIQ. Key Words: Bilateral cochlear implantationVQuality of lifeVSpeech perception.
Cochlear implantation (CI) is a widely accepted treatment for severe-to-profound sensorineural hearing loss (SNHL). Unilateral CI (CI1) has provided significant benefits to patients, improving sound and speech perception among other gains. However, CI1 users continue to experience the pitfalls of monaural hearing and have difficulty in everyday listening conditions, especially when localizing sound and understanding speech in a noisy environmentVthe ‘‘cocktail party phenomenon.’’ (1) The objective benefits of bilateral cochlear implantation (CI2) are well described in the literature. Binaural loudness summation is the perception that environmental signals are louder when perceived by both ears as opposed
to one. Binaural squelch is a central processing effect in which multiple signals are separated based on each ear receiving slightly different inputs, allowing the brain to focus and ‘‘hear’’ the target signal more clearly while eliminating others as ‘‘noise.’’ Head shadow occurs when the speech source originates from the side of the unaided ear with a competing noise presented to the aided ear. Reduction of the head shadow phenomenon is seen immediately after CI2, resulting in a 4- to 7-dB boost (2Y4). Lastly, CI2 can improve sound localization when compared with unilateral CI. Overall, the benefits of summation, squelch, and elimination of head shadow effect are experienced by CI2 patients as improvements in localization, speech perception in quiet, and speech perception in noise. However, the growing burden on our health-care system demands Class I-II evidence-based data demonstrating the benefits of CI2. In addition, current objective measures are limited, with only a few studies showing that objective improvements translate to significant improvements in
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Address correspondence and reprint requests to Ana H. Kim, M.D., New York Eye and Ear Infirmary, Department of Otolaryngology, 310 East 14th Street, New York, NY 10003; E-mail: [email protected] The authors disclose no conflicts of interest. Supplemental digital content is available in the text.
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quality of life (QoL) (5,6). Health-related QoL (HRQoL) provides patients, clinicians, and policy makers with a subjective assessment of the impact of disease and treatment on physical, psychological, and social functioning/ well-being (7). The majority of the HRQoL studies performed on CI recipients thus far have used generic instruments, such as the health utilities index (HUI) or the Medical Outcome Study Short Form (SF36), which are designed for versatility and use with multiple types of medical interventions (8Y10). Bichey and Miyamoto found a favorable cost-utility ratio and improved quality of life in bilateral CI recipients in their study with 23 patients when compared with unilateral CI users.11 Additional studies on both objective and subjective benefits of CI2 have been limited by small sample size or have focused on children (11Y14). Some have created QoL instruments tailored to the CI population that have good reliability and some evidence of validity (15Y17). Notably, Hinderink et al. developed the Nijmegen Cochlear Implant Questionnaire (NCIQ), which has been shown to be a reliable instrument for detecting QoL changes in CI1 users (18). The cochlear implant function index (CIFI), created by Coelho et al., appears to show good psychometric properties but focuses exclusively on assessing hearing function for CI patients in 6 settings (19). Both the NCIQ and CIFI were validated on CI1 patients and do not include items addressing the major advantages that CI2 offers. Furthermore, the psychological and social changes in QoL after receiving CI2 have yet to be investigated. A recent systematic review conducted by Lammers et al. demonstrated that the current literature on QoL/cost-utility of CI2 is sparse and ambiguous (20). To date, a validated QoL instrument specific to CI2 users is not available. The purpose of this study was twofold: 1) to develop a comprehensive cochlear implant questionnaire (CCIQ) specific to changes in QoL after receiving CI2, and 2) correlate speech perception changes after CI2 with QoL outcomes. MATERIALS AND METHODS Development of CCIQ QoL Adhering to most conceptualizations of HRQoL, which divide their questions into 3 main domainsVphysical, psychological, and social, we initially divided ours into the same 3 domains. The physical domain was renamed hearing and balance to more accurately describe its content in relation to bilateral cochlear implantation. Subdomains were created within the hearing and balance and social domains: speech perception in quiet, speech perception in noise, localization, vestibular effects, music, and general in the hearing and balance domain; and social interactions and activity in the social domain. Items should be easy to read and in nonmedical English, be phrased similarly, begin with ‘‘Since receiving my last implantI’’ to prompt participants to compare their current CI2 state with their previous state, adhere to a 5-point Likert scale, be ordered randomly, and include some negatively phrased items to reduce response bias. In addition, the CCIQ should be no more than 2 pages.
Items were then developed for each domain and subdomain based on literature review and interviews with our institution’s CI team (surgeons, audiologists, and speech pathologists). Some items were adapted from CI-related questionnaires and revised in accordance with the above criteria. The following 5-point response scale indicating the degree to which the statement was true was used: (1) never, (2) rarely, (3) sometimes, (4) usually, and (5) always. No subdomains were used for the psychological domain because of the variety of topics included and limitations in the CCIQ length. In total, the CCIQ (see Appendix, Supplemental Digital Content 1, http://links.lww.com/MAO/A186) includes 28 questions: hearing and balance (16 items), psychological (4 items), and social (8 items) that focus on the perceived benefits and pitfalls of CI2.
Study Population and Procedures Our CI database includes all patients who have received implants at Beth Israel Medical Center, Manhattan Eye & Ear Infirmary, and New York Eye & Ear Infirmary (NYEEI), now collectively known as the Ear Institute of NYEEI. Approximately 2,000 cochlear implantations were performed from 1979 to 2012, with approximately 10% of these being bilateral. Only English-speaking adults were included. The CCIQ was administered either by mail or in person when attending routine CI appointments. To assess the test-retest reliability of the CCIQ, the questionnaire was readministered to respondents 6 weeks later. NYEEI institutional review board approval was obtained before the study.
Speech Perception Test CNC and HINT tests were administered at 50 dB HL. Any patients who had incomplete audiometric results were excluded. As speech perception testing beyond 50 dB was inconsistently administered to patients, only patients with pre and post CI2 results for CNC or HINT tested at 50 dB were included.
Statistical Analysis Scores from negatively phrased questions were reversed using the formula: absolute value of (score, 6). Thus, higher CCIQ scores indicate an improvement in QoL with 3 (‘‘sometimes’’ on the Likert scale) representing a ‘‘neutral’’ response as this would indicate that a particular attribute is inconsistently or equivocally experienced. Scores for each domain, subdomain, and overall were summed and divided by the number of completed items. Test-retest reliability was assessed by readministering the CCIQ 6 weeks after initial administration and comparing the 2 CCIQ administrations via the intraclass correlation coefficient (ICC). The ICC uses a scale from 0 to 1, with numbers closer to 1 indicating a higher degree of reliability. The internal consistency (extent to which items measure the same trait) was measured using Cronbach’s alpha, also a scale of 0 to 1, with values closer to 1 indicating good reliability. To assess the relationship between subjective and objective measures, scores for all domains and subdomains were correlated with audiometric tests and duration of CI2 use using the Spearman correlation.
RESULTS CCIQ was mailed to 91 patients, with 47 responding by mail (51.6%). CCIQ was administered to 7 patients in person during their routine CI mapping appointments. Retest CCIQ’s were mailed to all 54 respondents with
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A NEW CCIQ FOR MEASURING QOL 26 retest respondents. Audiometric data were available in 22 of these 54 respondents. Study summary is illustrated in Figure 1. Patient demographics and respondent stats are presented in Table 1. Mean CCIQ scores (Fig. 2) show subjective improvement in all domainsVhearing and balance, psychological, and social, with mean scores of 3.53 T 1.34, 4.13 T 1.20, and 3.68 T 1.23, respectively. Higher scores indicate a greater degree of improvement in QoL relative to the respondent’s previous state with CI1. Within the hearing and balance domain, respondents as a group reported subjective improvement in all subdomains with the exception of speech perception in noise. Overall, the CCIQ showed satisfactory test-retest reliability at 0.62 (Table 2). The hearing and balance domain items (64% of CCIQ items) had the highest test-retest reliability at 0.73. The psychological and social domains were considerably less at 0.31 and 0.57, respectively. Cronbach’s alpha for each subdomain, domain, and the overall questionnaire are also presented in Table 2. The internal consistency for the CCIQ as a whole was excellent at 0.87. Two of the 3 domains, hearing and balance and social, representing 85% of the questions (24 of 28 items), achieved good internal consistency of 0.79 and 0.73, respectively. The psychological domain showed the least adequate internal consistency with an alpha of 0.52. Average CNC and HINT scores improved by 13 T 16% and 42 T 16%, respectively, after CI2. These improvements were correlated with the average hearing and balance, psychological, and social domain scores using Spearman’s correlation. Spearman’s correlation did not reveal any significant relationships between speech perception and QoL.
FIG. 1.
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When respondents were stratified by duration of CI2 use, 5 patients have had CI2 for less than 1 year, 36 patients have used CI2 for 1 to 5 years, and 13 patients greater than 5 years. Although no statistically significant correlation was found between duration of CI2 use and QoL, there was an upward trend in QoL for CI2 users between 1 and 5 years, then a slight downward trend by those who have used CI2 greater than 5 years (Fig. 3).
DISCUSSION The purpose of this study was to present a newly developed CCIQ that would accurately reflect QoL changes in sequential CI2 recipients. Previous HRQoL questionnaires were designed for generic health interventions, and other CI-specific questionnaires did not focus on the unique aspects of the CI2 population. Our CCIQ is an important preliminary step toward achieving a definitive questionnaire tailored to the subjective benefits of CI2. The benefit of CI2 is reflected in the fact that most subjects do not regret receiving it (51 of 54 answered ‘‘Never’’ or ‘‘Rarely’’ to the statement ‘‘There are times I regret getting my last implant’’). This is in accordance with prior CI2 QoL studies using generic QoL questionnaires (11,17, 21). Our CCIQ demonstrated that patients overall experienced improved QoL metrics in all 3 domains. The hearing and balance domain contained the subdomain with the greatest gain (vestibular effectsVaverage score, 4.67 T 0.09) and the lowest gain (speech perception in noiseVaverage score, 2.83 T 0.15) (Fig. 2). Only a small number of patients had vestibular symptoms after CI2 that were qualitatively worse than those experienced after CI1.
Methodology flowchart. Otology & Neurotology, Vol. 35, No. 3, 2014
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TABLE 1.
Characteristics
Demographic and clinical characteristics Total Retested Respondents with respondents respondents audiometric data (n = 54) (n = 26) (n = 22)
Sex Male 23 (43%) 10 (28%) Female 31 (57%) 16 (62%) Current mean age T SD 52 T 17 52 T 15 (years) Mean duration of 11 T 14 10 T 12 HL before first CI T SD (yr) Mean duration of 8.74 T 4.56 8.42 T 4.16 CI1 usage (yr) Mean duration of 2.92 T 1.93 2.81 T 1.73 CI2 usage (yr) Presumed etiology Unknown 36 (67%) 21 (81%) Congenital 5 (9%) 1 (4%) Measles 2 (4%) 1 (4%) Meningitis 2 (4%) 1 (4%) Otosclerosis/ 2 (4%) V stapedectomy Ototoxic medications 3 (6%) 1 (4%) Noise exposure 1 (2%) V Scarlet fever 1 (2%) V Norrie’s disease 1 (2%) 1 (4%) Usher’s syndrome 1 (2%) V
10 (45%) 12 (55%) 54 T 16 10 T 15 7.61 T 2.89 2.70 T 1.51 18 (81%) V V V V 1 (5%) V 1 (5%) 1 (5%) 1 (5%)
Our patients showed the least satisfaction with speech perception in noise. As speech perception in noise is known to be a skill that improves with time and increased CI2 use,
FIG. 2.
the low average may be a reflection of the short duration of CI2 use with almost 10% of our subjects utilizing their CI2 for less than 1 year. Laske et al. postulated that with time, patients become so used to their first implant that it becomes difficult to become accustomed to CI2 even if it’s on the better hearing ear (21). They found that the ear implanted first remained the better ear in 73% of the CI2 patient group. Literature suggests that implantation as early as possible after a diagnosis of deafness and minimal interval between implants leads to best hearing results (22Y24). Average duration of deafness in our study ranged from 10.5 T 13.6 years before initial implantation to an average interval of 4.4 T 4.1 years between implants. Our subjects showed the most satisfaction within the psychological and social domains, with scores of 4.13 T 0.09 and 3.68 T 0.09, respectively. This is consistent with previous studies showing additional benefit of CI2 on patient’s psychological and social QoL (11, 12, 21). Preliminary data does not show a correlation between CCIQ scores and audiometric data. This is likely limited by our small group of patients with sufficient audiometric data. Interestingly, of the 22 patients with complete sets of audiometric data, the highest scorers in all three QoL domains also had the least improvement in speech perception testing. It has been hypothesized that a subject’s perceived improvement in QoL from CI is not directly linked to objective measures such as audiometric data (15). Previous studies have also shown that prelingually deafened adults report substantial benefits in QoL
Mean CCIQ scores.
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A NEW CCIQ FOR MEASURING QOL TABLE 2.
Item analysis of domains
Test-retest Internal Internal consistency of reliabilitya consistencyb domain if item deleted Physical domain
0.73
0.79
Speech perception in quiet Q1 Q21 Speech perception in noise Q3 Q15 Localization Q9 Q14 Q20 Vestibular effects Q27 Q28 Music Q7 Q19 General Q5 Q6 Q13 Q25 Q26 Psychological domain
0.63
0.79
Q4 Q11 Q18 Q24 Social domain
0.77 0.77 0.62
0.74 0.77 0.76
0.77
0.77 0.78 0.78 0.79
0.64
0.81 0.79 0.80
0.87
0.78 0.78 0.78
0.76
0.54 0.79 0.78 0.78 0.77 0.80
0.31
0.52 0.65 0.52 0.26 0.25
0.57
Social interactions Q2 Q8 Q12 Q22 Functioning Q10 Q16 Q17 Q23
0.64
CCIQ Composite
0.62
0.73 0.53 0.73 0.74 0.72 0.70
0.50
0.70 0.67 0.73 0.71 0.64 0.87
a
Intraclass correlation coefficient of 0.6 or greater considered satisfactory for test-retest reliability. b Cronbach’s >-coefficient of 0.7 or greater considered sufficient for purpose of group comparisons.
improvements despite only moderate gains in hearing ability (25). Other studies on postlingually deafened adults also did not find a strong correlation between audiometric results and QoL after CI2 (12, 18, 21). These findings suggest that the current standards of measuring CI success predominantly by audiometric performance may not provide a complete picture and should include subjective measures using tools like this CCIQ. The lack of larger scale studies on the correlation between audiometric improvements and QoL highlights the need for further research in this area and emphasizes the necessity of a questionnaire such as the CCIQ that can accurately and reliably assess QoL in CI2 recipients.
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The CCIQ proved to have test-retest reliability overall, especially in the hearing and balance domain, which accounts for the largest proportion of the questionnaire. Although the psychological and social domains had relatively low test-retest reliability, these areas are also the most sensitive to changes over time. The psychological and social domains have historically been difficult to measure through QoL studies because of the interplay between inherent personality traits and the impact of a medical intervention on these factors. Designing questions to directly measure the effect of a specific medical intervention on behavior influenced by personal traits is difficult. As this is a preliminary study, the psychological and social domain questions will be redesigned to address these issues in the future. The internal consistency for the CCIQ overall was excellent, indicating that the questions are likely measuring the same underlying constructVQoL with CI2. The hearing and balance and social domains showed adequate internal consistency. The psychological domain was the area with the lowest level of internal consistency. It was also the smallest domain, containing only 4 questions. These questions will need to be carefully reviewed for content and clarity with possible addition of questions. For example, an analysis on how to improve the CCIQ showed that excluding question 2 in the psychological domain would increase the alpha for the domain from 0.55 to 0.67, indicating that this question may need to be replaced or modified (Table 2). Two subdomains did not reach the threshold value of 0.7 for internal consistency. The general subdomain within the hearing and balance domain measured at 0.53, which is expected as the questions in this category vary in subject matter and are not intended to measure any underlying construct. The social interactions subdomain within the social domain also had a value of only 0.54. This subdomain naturally encompasses aspects that may be affected by CI, such as the role of a speech processor in social activities, and aspects that may be inherent to the subject’s personality, such as willingness to speak to strangers. The diversity of questions in this subdomain may reflect the low internal consistency score. Questions may need to be reworded to better reflect the effects of the CI2 as opposed to inherent personal characteristics. Another consideration is that the Social Interactions subdomain measures activities that develop over a period as the patient adapts to the social benefits that CI brings, such as participating more in group discussions. As our patient population ranges from subjects who have used the CI2 from 2 months to 6 years, the responses to this particular subdomain are likely to vary widely in relation to the amount of time they have used CI2. Although these 2 subdomains did not independently meet criteria for internal consistency, it is important to note that this did not affect their respective hearing and balance and socia domains from meeting internal consistency criteria overall. No statistically significant correlation was found between QoL scores and duration of CI2 use, likely because of small sample size (only 5 patients fell into the G1 year Otology & Neurotology, Vol. 35, No. 3, 2014
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FIG. 3.
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Mean CCIQ scores by subdomains categorized by duration of CI2 use.
of CI2 use group). We observed, however, an upward trend across all domains between 1 and 5 years of CI2, suggesting that the ideal timing for administering the CCIQ may lie within this time frame (Fig. 3). Less than a year may be too short a time to accurately assess QoL because many benefits of a CI2 require time to develop, and greater than 5 years post CI2 may lead to recall bias. As the correlation analysis is based on a small sample size, these results should be interpreted with caution. Overall, the CCIQ is a short, easy-to-administer test that represents an important first step in the development of a reliable questionnaire that accurately measures QoL in sequential CI2 recipients. Although the results from this preliminary pilot study show that this CCIQ is a reliable and consistent tool, we have identified areas needing improvement in the next version, such as in the psychological and social domainV2 domains that have historically been difficult to measure accurately. Small modifications can also be made within the psychological domain to improve its internal consistency. This study is limited by its retrospective nature and sample size. Another potential confounding factor is the possible response difference between those who answered a mailed questionnaire and those who answered the questionnaire in person. Seven patients fell into this category. Future plans include administering a modified version of the CCIQ in a consistent manner prospectively to a larger group of CI2 patients, pre- and post-CI1 and CI2, and correlating it to a larger set of audiometric data. In addition, the next version will be administered concurrently against a validated QoL instrument to establish its validity. CONCLUSION An accurate QoL measure is important in quantifying the subjective impact of CI2 on patients’ lives. This information can aid potential cochlear implant users, clinicians,
and policy makers to make informed decisions on health care that influence the future of cochlear implantation. Our preliminary data indicate that this CCIQ is a promising tool in assessing QoL specific to CI2 patients. Acknowledgments: The authors thank the Ear Institute audiologists (Megan Kumley), speech therapist (Liz Ying), otologists (Drs. George Alexiades, Ronald Hoffman, Christopher Linstrom, and Simon Parisier), and Lorie Singer (CI coordinator) who have contributed their effort, time, and patient data.
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A NEW CCIQ FOR MEASURING QOL 12. Summerfield AQ, Barton GR, Toner J, et al. Self-reported benefits from successive bilateral cochlear implantation in post-lingually deafened adults: randomized controlled trial. Int J Audiol 2006;45:S99. 13. Bond M, Mealing S, Anderson R, et al. The effectiveness and costeffectiveness of cochlear implants for severe to profound deafness in children and adults: a systematic review and economic model. Health Technol Assess 2009;13:1Y330. 14. Summerfield AQ, Marshall DH, Bellenger H, et al. Estimates of the cost-effectiveness of pediatric bilateral cochlear implantation. Ear Hear 2010;31:611Y24. 15. Hinderink JB, Krabbe PFM, van den Broek P. Development and application of a health-related quality-of-life instrument for adults with cochlear implants: The Nijmegen Cochlear Implant Questionnaire. Otolaryngol Head Neck Surg 2000;123:756Y65. 16. Damen GW, Beynon AJ, Krabbe PF, et al. Cochlear implantation and quality of life in postlingually deaf adults: Long-term follow-up. Otolaryngol Head Neck Surg 2007;136:597Y604. 17. Cohen SM, Labadie RF, Dietrich MS, et al. Quality of life in hearing-impaired adults: the role of cochlear implants and hearing aids. Otolaryngol Head Neck Surg 2004;131:413Y22. 18. Olze H, Grabel S, Haupt H, et al. Extra benefit of a second cochlear implant with respect to health-related quality of life and tinnitus. Otol Neurotol 2012;33:1169Y75.
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19. Coelho DH, Hammerschlag PE, Bat-Chava Y, Kohan D. Psychometric validity of the Cochlear Implant Function Index (CIFI): a quality of life assessment tool for adult cochlear implant users. Cochlear Implants Int 2009;10:70Y83. 20. Lammers MJ, Grolman W, Smulders YE, et al. The cost-utility of bilateral cochlear implantation: a systematic review. Laryngoscope 2011;121:2604Y9. 21. Laske RD, Veraguth, D, Dillier N, et al. Subjective and objective results after bilateral cochlear implantation in adults. Otol Neurotol 2009;30:313Y8. 22. Ramsden R, Greenham P, O’Driscoll M, et al. Evaluation of bilaterally implanted adult subjects with the nucleus 24 cochlear implant system. Otol Neurotol 2005;26:988Y98. 23. Peters BR, Litovsky R, Parkinson A, et al. Importance of age and postimplantation experience on speech perception measures in children with sequential bilateral cochlear implants. Otol Neurotol 2007;28:479Y85. 24. Papsin BC, Gordon KA. Bilateral cochlear implants should be the standard for children with bilateral sensorineural deafness. Curr Opin Otolaryngol Head Neck Surg 2008;16:69Y74. 25. Hinderink JB, Mens LHM, Brokx JPL, et al. Performance of prelingually and postlingually deaf patients using single channel or multichannel cochlear implants. Laryngoscope 1995;105:618Y22.
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A New Comprehensive Cochlear Implant Questionnaire for Measuring Quality of Life After Sequential Bilateral Cochlear Implantation *Nancy King, †Edmund A. Nahm, ‡Penny Liberatos, ‡Qiuhu Shi, and *‡Ana H. Kim *New York Eye and Ear Infirmary, Department of Otolaryngology, New York, New York; ÞUniversity of Medicine and Dentistry of New Jersey, Newark, New Jersey; and þNew York Medical College, Valhalla, New York, U.S.A.
Objective: To develop a comprehensive cochlear implant questionnaire (CCIQ) as a tool for assessing changes in quality of life (QoL) after receiving a second cochlear implant (CI2) and to correlate the QoL with speech perception changes after CI2. Study Design: Retrospective case series with planned data collection. Setting: Academic cochlear implant center. Patients: Ninety-eight English-speaking adults who received CI2 between 2000 and 2011. Intervention: CCIQ is a 28-item, 5-point Likert-scale questionnaire that assesses the physical and psychosocial benefits of CI2. Main Outcome Measures: Test-retest reliability and Cronbach’s alpha internal consistency were used to assess the reliability of the CCIQ. Speech perception was tested using CNC and HINT. Results: Fifty-four patients completed the CCIQ, and 26 were retested. Respondents reported a subjective improvement in all domains. Test-retest reliability was satisfactory, with 64% of
items achieving an intraclass correlation coefficient of greater than 0.6. Internal consistency reliability was excellent for the overall measure and was satisfactory for 6 of 9 subdomains. Speech perception data were available for 22 patients. Average CNC scores improved 13 T 16%, and HINT scores improved 42 T 16%. No statistically significant correlation was found between QoL scores and audiometric data or duration of CI2 use. Conclusion: Our preliminary data indicate that this CCIQ is a promising tool in assessing QoL specific to CI2 patients. Overall, patients reported improved QoL, independent of speech perception scores. Further refinements of the questionnaire with larger patient numbers are needed to strengthen the CCIQ. Key Words: Bilateral cochlear implantationVQuality of lifeVSpeech perception.
Cochlear implantation (CI) is a widely accepted treatment for severe-to-profound sensorineural hearing loss (SNHL). Unilateral CI (CI1) has provided significant benefits to patients, improving sound and speech perception among other gains. However, CI1 users continue to experience the pitfalls of monaural hearing and have difficulty in everyday listening conditions, especially when localizing sound and understanding speech in a noisy environmentVthe ‘‘cocktail party phenomenon.’’ (1) The objective benefits of bilateral cochlear implantation (CI2) are well described in the literature. Binaural loudness summation is the perception that environmental signals are louder when perceived by both ears as opposed
to one. Binaural squelch is a central processing effect in which multiple signals are separated based on each ear receiving slightly different inputs, allowing the brain to focus and ‘‘hear’’ the target signal more clearly while eliminating others as ‘‘noise.’’ Head shadow occurs when the speech source originates from the side of the unaided ear with a competing noise presented to the aided ear. Reduction of the head shadow phenomenon is seen immediately after CI2, resulting in a 4- to 7-dB boost (2Y4). Lastly, CI2 can improve sound localization when compared with unilateral CI. Overall, the benefits of summation, squelch, and elimination of head shadow effect are experienced by CI2 patients as improvements in localization, speech perception in quiet, and speech perception in noise. However, the growing burden on our health-care system demands Class I-II evidence-based data demonstrating the benefits of CI2. In addition, current objective measures are limited, with only a few studies showing that objective improvements translate to significant improvements in
Otol Neurotol 35:407Y413, 2014.
Address correspondence and reprint requests to Ana H. Kim, M.D., New York Eye and Ear Infirmary, Department of Otolaryngology, 310 East 14th Street, New York, NY 10003; E-mail: [email protected] The authors disclose no conflicts of interest. Supplemental digital content is available in the text.
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quality of life (QoL) (5,6). Health-related QoL (HRQoL) provides patients, clinicians, and policy makers with a subjective assessment of the impact of disease and treatment on physical, psychological, and social functioning/ well-being (7). The majority of the HRQoL studies performed on CI recipients thus far have used generic instruments, such as the health utilities index (HUI) or the Medical Outcome Study Short Form (SF36), which are designed for versatility and use with multiple types of medical interventions (8Y10). Bichey and Miyamoto found a favorable cost-utility ratio and improved quality of life in bilateral CI recipients in their study with 23 patients when compared with unilateral CI users.11 Additional studies on both objective and subjective benefits of CI2 have been limited by small sample size or have focused on children (11Y14). Some have created QoL instruments tailored to the CI population that have good reliability and some evidence of validity (15Y17). Notably, Hinderink et al. developed the Nijmegen Cochlear Implant Questionnaire (NCIQ), which has been shown to be a reliable instrument for detecting QoL changes in CI1 users (18). The cochlear implant function index (CIFI), created by Coelho et al., appears to show good psychometric properties but focuses exclusively on assessing hearing function for CI patients in 6 settings (19). Both the NCIQ and CIFI were validated on CI1 patients and do not include items addressing the major advantages that CI2 offers. Furthermore, the psychological and social changes in QoL after receiving CI2 have yet to be investigated. A recent systematic review conducted by Lammers et al. demonstrated that the current literature on QoL/cost-utility of CI2 is sparse and ambiguous (20). To date, a validated QoL instrument specific to CI2 users is not available. The purpose of this study was twofold: 1) to develop a comprehensive cochlear implant questionnaire (CCIQ) specific to changes in QoL after receiving CI2, and 2) correlate speech perception changes after CI2 with QoL outcomes. MATERIALS AND METHODS Development of CCIQ QoL Adhering to most conceptualizations of HRQoL, which divide their questions into 3 main domainsVphysical, psychological, and social, we initially divided ours into the same 3 domains. The physical domain was renamed hearing and balance to more accurately describe its content in relation to bilateral cochlear implantation. Subdomains were created within the hearing and balance and social domains: speech perception in quiet, speech perception in noise, localization, vestibular effects, music, and general in the hearing and balance domain; and social interactions and activity in the social domain. Items should be easy to read and in nonmedical English, be phrased similarly, begin with ‘‘Since receiving my last implantI’’ to prompt participants to compare their current CI2 state with their previous state, adhere to a 5-point Likert scale, be ordered randomly, and include some negatively phrased items to reduce response bias. In addition, the CCIQ should be no more than 2 pages.
Items were then developed for each domain and subdomain based on literature review and interviews with our institution’s CI team (surgeons, audiologists, and speech pathologists). Some items were adapted from CI-related questionnaires and revised in accordance with the above criteria. The following 5-point response scale indicating the degree to which the statement was true was used: (1) never, (2) rarely, (3) sometimes, (4) usually, and (5) always. No subdomains were used for the psychological domain because of the variety of topics included and limitations in the CCIQ length. In total, the CCIQ (see Appendix, Supplemental Digital Content 1, http://links.lww.com/MAO/A186) includes 28 questions: hearing and balance (16 items), psychological (4 items), and social (8 items) that focus on the perceived benefits and pitfalls of CI2.
Study Population and Procedures Our CI database includes all patients who have received implants at Beth Israel Medical Center, Manhattan Eye & Ear Infirmary, and New York Eye & Ear Infirmary (NYEEI), now collectively known as the Ear Institute of NYEEI. Approximately 2,000 cochlear implantations were performed from 1979 to 2012, with approximately 10% of these being bilateral. Only English-speaking adults were included. The CCIQ was administered either by mail or in person when attending routine CI appointments. To assess the test-retest reliability of the CCIQ, the questionnaire was readministered to respondents 6 weeks later. NYEEI institutional review board approval was obtained before the study.
Speech Perception Test CNC and HINT tests were administered at 50 dB HL. Any patients who had incomplete audiometric results were excluded. As speech perception testing beyond 50 dB was inconsistently administered to patients, only patients with pre and post CI2 results for CNC or HINT tested at 50 dB were included.
Statistical Analysis Scores from negatively phrased questions were reversed using the formula: absolute value of (score, 6). Thus, higher CCIQ scores indicate an improvement in QoL with 3 (‘‘sometimes’’ on the Likert scale) representing a ‘‘neutral’’ response as this would indicate that a particular attribute is inconsistently or equivocally experienced. Scores for each domain, subdomain, and overall were summed and divided by the number of completed items. Test-retest reliability was assessed by readministering the CCIQ 6 weeks after initial administration and comparing the 2 CCIQ administrations via the intraclass correlation coefficient (ICC). The ICC uses a scale from 0 to 1, with numbers closer to 1 indicating a higher degree of reliability. The internal consistency (extent to which items measure the same trait) was measured using Cronbach’s alpha, also a scale of 0 to 1, with values closer to 1 indicating good reliability. To assess the relationship between subjective and objective measures, scores for all domains and subdomains were correlated with audiometric tests and duration of CI2 use using the Spearman correlation.
RESULTS CCIQ was mailed to 91 patients, with 47 responding by mail (51.6%). CCIQ was administered to 7 patients in person during their routine CI mapping appointments. Retest CCIQ’s were mailed to all 54 respondents with
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A NEW CCIQ FOR MEASURING QOL 26 retest respondents. Audiometric data were available in 22 of these 54 respondents. Study summary is illustrated in Figure 1. Patient demographics and respondent stats are presented in Table 1. Mean CCIQ scores (Fig. 2) show subjective improvement in all domainsVhearing and balance, psychological, and social, with mean scores of 3.53 T 1.34, 4.13 T 1.20, and 3.68 T 1.23, respectively. Higher scores indicate a greater degree of improvement in QoL relative to the respondent’s previous state with CI1. Within the hearing and balance domain, respondents as a group reported subjective improvement in all subdomains with the exception of speech perception in noise. Overall, the CCIQ showed satisfactory test-retest reliability at 0.62 (Table 2). The hearing and balance domain items (64% of CCIQ items) had the highest test-retest reliability at 0.73. The psychological and social domains were considerably less at 0.31 and 0.57, respectively. Cronbach’s alpha for each subdomain, domain, and the overall questionnaire are also presented in Table 2. The internal consistency for the CCIQ as a whole was excellent at 0.87. Two of the 3 domains, hearing and balance and social, representing 85% of the questions (24 of 28 items), achieved good internal consistency of 0.79 and 0.73, respectively. The psychological domain showed the least adequate internal consistency with an alpha of 0.52. Average CNC and HINT scores improved by 13 T 16% and 42 T 16%, respectively, after CI2. These improvements were correlated with the average hearing and balance, psychological, and social domain scores using Spearman’s correlation. Spearman’s correlation did not reveal any significant relationships between speech perception and QoL.
FIG. 1.
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When respondents were stratified by duration of CI2 use, 5 patients have had CI2 for less than 1 year, 36 patients have used CI2 for 1 to 5 years, and 13 patients greater than 5 years. Although no statistically significant correlation was found between duration of CI2 use and QoL, there was an upward trend in QoL for CI2 users between 1 and 5 years, then a slight downward trend by those who have used CI2 greater than 5 years (Fig. 3).
DISCUSSION The purpose of this study was to present a newly developed CCIQ that would accurately reflect QoL changes in sequential CI2 recipients. Previous HRQoL questionnaires were designed for generic health interventions, and other CI-specific questionnaires did not focus on the unique aspects of the CI2 population. Our CCIQ is an important preliminary step toward achieving a definitive questionnaire tailored to the subjective benefits of CI2. The benefit of CI2 is reflected in the fact that most subjects do not regret receiving it (51 of 54 answered ‘‘Never’’ or ‘‘Rarely’’ to the statement ‘‘There are times I regret getting my last implant’’). This is in accordance with prior CI2 QoL studies using generic QoL questionnaires (11,17, 21). Our CCIQ demonstrated that patients overall experienced improved QoL metrics in all 3 domains. The hearing and balance domain contained the subdomain with the greatest gain (vestibular effectsVaverage score, 4.67 T 0.09) and the lowest gain (speech perception in noiseVaverage score, 2.83 T 0.15) (Fig. 2). Only a small number of patients had vestibular symptoms after CI2 that were qualitatively worse than those experienced after CI1.
Methodology flowchart. Otology & Neurotology, Vol. 35, No. 3, 2014
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TABLE 1.
Characteristics
Demographic and clinical characteristics Total Retested Respondents with respondents respondents audiometric data (n = 54) (n = 26) (n = 22)
Sex Male 23 (43%) 10 (28%) Female 31 (57%) 16 (62%) Current mean age T SD 52 T 17 52 T 15 (years) Mean duration of 11 T 14 10 T 12 HL before first CI T SD (yr) Mean duration of 8.74 T 4.56 8.42 T 4.16 CI1 usage (yr) Mean duration of 2.92 T 1.93 2.81 T 1.73 CI2 usage (yr) Presumed etiology Unknown 36 (67%) 21 (81%) Congenital 5 (9%) 1 (4%) Measles 2 (4%) 1 (4%) Meningitis 2 (4%) 1 (4%) Otosclerosis/ 2 (4%) V stapedectomy Ototoxic medications 3 (6%) 1 (4%) Noise exposure 1 (2%) V Scarlet fever 1 (2%) V Norrie’s disease 1 (2%) 1 (4%) Usher’s syndrome 1 (2%) V
10 (45%) 12 (55%) 54 T 16 10 T 15 7.61 T 2.89 2.70 T 1.51 18 (81%) V V V V 1 (5%) V 1 (5%) 1 (5%) 1 (5%)
Our patients showed the least satisfaction with speech perception in noise. As speech perception in noise is known to be a skill that improves with time and increased CI2 use,
FIG. 2.
the low average may be a reflection of the short duration of CI2 use with almost 10% of our subjects utilizing their CI2 for less than 1 year. Laske et al. postulated that with time, patients become so used to their first implant that it becomes difficult to become accustomed to CI2 even if it’s on the better hearing ear (21). They found that the ear implanted first remained the better ear in 73% of the CI2 patient group. Literature suggests that implantation as early as possible after a diagnosis of deafness and minimal interval between implants leads to best hearing results (22Y24). Average duration of deafness in our study ranged from 10.5 T 13.6 years before initial implantation to an average interval of 4.4 T 4.1 years between implants. Our subjects showed the most satisfaction within the psychological and social domains, with scores of 4.13 T 0.09 and 3.68 T 0.09, respectively. This is consistent with previous studies showing additional benefit of CI2 on patient’s psychological and social QoL (11, 12, 21). Preliminary data does not show a correlation between CCIQ scores and audiometric data. This is likely limited by our small group of patients with sufficient audiometric data. Interestingly, of the 22 patients with complete sets of audiometric data, the highest scorers in all three QoL domains also had the least improvement in speech perception testing. It has been hypothesized that a subject’s perceived improvement in QoL from CI is not directly linked to objective measures such as audiometric data (15). Previous studies have also shown that prelingually deafened adults report substantial benefits in QoL
Mean CCIQ scores.
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A NEW CCIQ FOR MEASURING QOL TABLE 2.
Item analysis of domains
Test-retest Internal Internal consistency of reliabilitya consistencyb domain if item deleted Physical domain
0.73
0.79
Speech perception in quiet Q1 Q21 Speech perception in noise Q3 Q15 Localization Q9 Q14 Q20 Vestibular effects Q27 Q28 Music Q7 Q19 General Q5 Q6 Q13 Q25 Q26 Psychological domain
0.63
0.79
Q4 Q11 Q18 Q24 Social domain
0.77 0.77 0.62
0.74 0.77 0.76
0.77
0.77 0.78 0.78 0.79
0.64
0.81 0.79 0.80
0.87
0.78 0.78 0.78
0.76
0.54 0.79 0.78 0.78 0.77 0.80
0.31
0.52 0.65 0.52 0.26 0.25
0.57
Social interactions Q2 Q8 Q12 Q22 Functioning Q10 Q16 Q17 Q23
0.64
CCIQ Composite
0.62
0.73 0.53 0.73 0.74 0.72 0.70
0.50
0.70 0.67 0.73 0.71 0.64 0.87
a
Intraclass correlation coefficient of 0.6 or greater considered satisfactory for test-retest reliability. b Cronbach’s >-coefficient of 0.7 or greater considered sufficient for purpose of group comparisons.
improvements despite only moderate gains in hearing ability (25). Other studies on postlingually deafened adults also did not find a strong correlation between audiometric results and QoL after CI2 (12, 18, 21). These findings suggest that the current standards of measuring CI success predominantly by audiometric performance may not provide a complete picture and should include subjective measures using tools like this CCIQ. The lack of larger scale studies on the correlation between audiometric improvements and QoL highlights the need for further research in this area and emphasizes the necessity of a questionnaire such as the CCIQ that can accurately and reliably assess QoL in CI2 recipients.
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The CCIQ proved to have test-retest reliability overall, especially in the hearing and balance domain, which accounts for the largest proportion of the questionnaire. Although the psychological and social domains had relatively low test-retest reliability, these areas are also the most sensitive to changes over time. The psychological and social domains have historically been difficult to measure through QoL studies because of the interplay between inherent personality traits and the impact of a medical intervention on these factors. Designing questions to directly measure the effect of a specific medical intervention on behavior influenced by personal traits is difficult. As this is a preliminary study, the psychological and social domain questions will be redesigned to address these issues in the future. The internal consistency for the CCIQ overall was excellent, indicating that the questions are likely measuring the same underlying constructVQoL with CI2. The hearing and balance and social domains showed adequate internal consistency. The psychological domain was the area with the lowest level of internal consistency. It was also the smallest domain, containing only 4 questions. These questions will need to be carefully reviewed for content and clarity with possible addition of questions. For example, an analysis on how to improve the CCIQ showed that excluding question 2 in the psychological domain would increase the alpha for the domain from 0.55 to 0.67, indicating that this question may need to be replaced or modified (Table 2). Two subdomains did not reach the threshold value of 0.7 for internal consistency. The general subdomain within the hearing and balance domain measured at 0.53, which is expected as the questions in this category vary in subject matter and are not intended to measure any underlying construct. The social interactions subdomain within the social domain also had a value of only 0.54. This subdomain naturally encompasses aspects that may be affected by CI, such as the role of a speech processor in social activities, and aspects that may be inherent to the subject’s personality, such as willingness to speak to strangers. The diversity of questions in this subdomain may reflect the low internal consistency score. Questions may need to be reworded to better reflect the effects of the CI2 as opposed to inherent personal characteristics. Another consideration is that the Social Interactions subdomain measures activities that develop over a period as the patient adapts to the social benefits that CI brings, such as participating more in group discussions. As our patient population ranges from subjects who have used the CI2 from 2 months to 6 years, the responses to this particular subdomain are likely to vary widely in relation to the amount of time they have used CI2. Although these 2 subdomains did not independently meet criteria for internal consistency, it is important to note that this did not affect their respective hearing and balance and socia domains from meeting internal consistency criteria overall. No statistically significant correlation was found between QoL scores and duration of CI2 use, likely because of small sample size (only 5 patients fell into the G1 year Otology & Neurotology, Vol. 35, No. 3, 2014
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FIG. 3.
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Mean CCIQ scores by subdomains categorized by duration of CI2 use.
of CI2 use group). We observed, however, an upward trend across all domains between 1 and 5 years of CI2, suggesting that the ideal timing for administering the CCIQ may lie within this time frame (Fig. 3). Less than a year may be too short a time to accurately assess QoL because many benefits of a CI2 require time to develop, and greater than 5 years post CI2 may lead to recall bias. As the correlation analysis is based on a small sample size, these results should be interpreted with caution. Overall, the CCIQ is a short, easy-to-administer test that represents an important first step in the development of a reliable questionnaire that accurately measures QoL in sequential CI2 recipients. Although the results from this preliminary pilot study show that this CCIQ is a reliable and consistent tool, we have identified areas needing improvement in the next version, such as in the psychological and social domainV2 domains that have historically been difficult to measure accurately. Small modifications can also be made within the psychological domain to improve its internal consistency. This study is limited by its retrospective nature and sample size. Another potential confounding factor is the possible response difference between those who answered a mailed questionnaire and those who answered the questionnaire in person. Seven patients fell into this category. Future plans include administering a modified version of the CCIQ in a consistent manner prospectively to a larger group of CI2 patients, pre- and post-CI1 and CI2, and correlating it to a larger set of audiometric data. In addition, the next version will be administered concurrently against a validated QoL instrument to establish its validity. CONCLUSION An accurate QoL measure is important in quantifying the subjective impact of CI2 on patients’ lives. This information can aid potential cochlear implant users, clinicians,
and policy makers to make informed decisions on health care that influence the future of cochlear implantation. Our preliminary data indicate that this CCIQ is a promising tool in assessing QoL specific to CI2 patients. Acknowledgments: The authors thank the Ear Institute audiologists (Megan Kumley), speech therapist (Liz Ying), otologists (Drs. George Alexiades, Ronald Hoffman, Christopher Linstrom, and Simon Parisier), and Lorie Singer (CI coordinator) who have contributed their effort, time, and patient data.
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