Validation of the Swedish version of the LittlEARS® Auditory Questionnaire in children with normal hearing – a longitudinal study
Anna Persson, Carmela Miniscalco ORCID Icon, Anette Lohmander ORCID Icon & Traci Flynn ORCID Icon
Received 04 Apr 2019, Accepted 15 May 2019, Published online: 01 Jun 2019
Download citation  https://doi.org/10.1080/14992027.2019.1621397 
Abstract
Objective: To externally validate the Swedish version of the LittlEARS® Auditory Questionnaire (LEAQ) in children with normal hearing followed longitudinally, and to examine to what extent the LEAQ correlates to other measures of auditory and language development.

Design: The Swedish version of the LEAQ was completed every other month over a 2-year period and correlated with the Parents’ Evaluation of Aural/Oral Performance of Children (PEACH) and McArthur-Bates Communicative Development Inventory (CDI) to examine overlapping areas of development. Normative curve was derived through linear mixed models and the effect of time investigated with repeated measures ANOVA.

Study sample: Parents of 25 typically developing children with normal hearing (13 girls, 12 boys).

Results: The norm curve of the Swedish LEAQ showed a similar equation as the original German version and the effect of time was significant. Correlations between LEAQ and CDI were moderate to high, and between LEAQ and PEACH weak or non-existing.

Conclusion: The Swedish version of the LEAQ is a reliable tool in accordance with the original version. However, results indicate that this questionnaire to a large extent measures language skill rather than audition specifically.

Keywords: Parental questionnaire, auditory development, normative assessments, language development
Introduction
The prevalence rate of children who are born deaf and/or hard of hearing (DHH) is 1–3/1000 births (Mehl and Thomson 1998 Mehl, A. L., and V. Thomson. 1998. “Newborn Hearing Screening: The Great Omission.” Pediatrics 101 (1): E4. doi:10.1542/peds.101.1.e4.
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; Berninger and Westling 2011). Early hearing amplification is considered to facilitate the speech and language development in children who are DHH (Yoshinaga-Itano, Coulter, and Thomson 2001 Yoshinaga-Itano, C., D. Coulter, and V. Thomson. 2001. “Developmental Outcomes of Children with Hearing Loss Born in Colorado Hospitals with and without Universal Newborn Hearing Screening Programs.” Seminars in Neonatology 6 (6): 521–529. doi:10.1053/siny.2001.0075.
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). However, this group of children continue to experience delays in their auditory skill development (McCreery et al. 2015 McCreery, R. W., E. Walker, M. Spratford, J. Oleson, R. Bentler, L. Holte, and P. Roush. 2015. “Speech Recognition and Parent-Ratings from Auditory Development Questionnaires in Children Who Are Hard of Hearing.” Ear and Hearing 36 (0 1): 60S–75S. doi: 10.1097/AUD.0000000000000213.
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) and display large individual variability in terms of spoken language outcomes (Ching et al. 2013 Ching, T. Y. C., H. Dillon, V. Marnane, S. Hou, J. Day, M. Seeto, K. Crowe., et al. 2013. “Outcomes of Early- and Late-Identified Children at 3 Years of Age: Findings from a Prospective Population-Based Study.” Ear and Hearing 34 (5): 535–552. doi:10.1097/AUD.0b013e3182857718.
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). Early monitoring and evaluation of auditory development has been shown useful for predicting longitudinal speech and language outcomes (Ching 2015 Ching, T. 2015. “Is Early Intervention Effective in Improving Spoken Language Outcomes of Children with Congenital Hearing Loss?” American Journal of Audiology 24 (3): 345–348. doi:10.1044/2015_AJA-15-0007.
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). The tools that are used to monitor and evaluate development, like parental questionnaires, are typically available in English. There is a lack of these tools in other languages, especially in languages with few speakers (e.g. Swedish). To be able to implement tools and use tools clinically for all children who are DHH, there is a need to translate and validate tools into more languages.

Measures of auditory and early language development
Hearing sensitivity results from electrophysiological assessments typically serve as the starting point for establishing the need for intervention with hearing amplification. Once the need is established, behavioural information is gathered to ensure appropriate fitting of amplification. It can be challenging to obtain consistent behavioural responses from infants and toddlers. Therefore, subjective standardised measures of functional listening skills can aid in evaluating the effectiveness of early intervention with hearing amplification. These subjective measures include parental questionnaires based on observations in real-life settings which have been suggested to complement the objective measures (Katz et al. 2009 Katz, J., L. Medwetsky, R. Burkard, and H. Linda. 2009. Handbook of Clinical Audiology. 6th ed. Philadelphia: Lippincott Williams & Wilkins.
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Each listening stage is important for building efficient auditory pathways and there is an abundance of “auditory checklists” available in clinical practice that cover the stages of detection, discrimination, identification and understanding at different levels of development. There are, however, a limited number of tools with normative data available for the paediatric population. The LittlEARS® Auditory Questionnaire (LEAQ) is one such tool with normative data which is often used in clinics and research to evaluate the auditory development as observed in real-life settings of infants and toddlers who are deaf and/or hard of hearing. The LEAQ consists of 35 questions which are answered with “yes” or “no” and the total number of “yes” becomes the total score. It was developed in 2003, intended for children aged birth to 2 years of age following cochlear implantation (Coninx, Weichbold, and Tsiakpini 2003 Coninx, F., V. Weichbold, and L. Tsiakpini. 2003. The LittlEARS® Auditory Questionnaire. Innsbruck, Austria: MED-EL GmbH.
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) and has been translated into more than 20 languages (Coninx et al. 2009 Coninx, F., V. Weichbold, L. Tsiakpini, E. Autrique, G. Bescond, L. Tamas, A. Compernol., et al. 2009. “Validation of the LittlEARS® Auditory Questionnaire in Children with Normal Hearing.” International Journal of Pediatric Otorhinolaryngology 73 (12): 1761–1768. doi:10.1016/j.ijporl.2009.09.036.
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). The creators of the LEAQ recommend individual validation for each new language (Weichbold et al. 2005 Weichbold, V., L. Tsiakpini, F. Coninx, and P. D'Haese. 2005.“Development of a parent questionnaire for assessment of auditory behaviour of infants up to two years of age.” Laryngorhinootologie 84 (5): 328–334. doi:10.1055/s-2004-826232.
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) due to possible cultural differences (Wang et al. 2013 Wang, L., X. Sun, W. Liang, J. Chen, and W. Zheng. 2013. “Validation of the Mandarin Version of the LittlEARS® Auditory Questionnaire.” International Journal of Pediatric Otorhinolaryngology 77 (8): 1350–1354. doi:10.1016/j.ijporl.2013.05.033.
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; Geal-Dor et al. 2011 Geal-Dor, M., R. Jbarah, S. Meilijson, C. Adelman, and H. Levi. 2011. “The Hebrew and the Arabic Version of the LittlEARS(R) auditory Questionnaire for the Assessment of Auditory Development: Results in Normal Hearing Children and Children with Cochlear Implants.” International Journal of Pediatric Otorhinolaryngology 75 (10): 1327–1332. doi:10.1016/j.ijporl.2011.07.030.
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). In critical reviews of audiological outcome measures for infants and toddlers who are DHH, the LEAQ has been highly rated in terms of formal evaluation and received top scores on most psychometric characteristics (Bagatto et al. 2011 Bagatto, M. P., S. T. Moodie, R. C. Seewald, D. J. Bartlett, and S. D. Scollie. 2011. “A Critical Review of Audiological Outcome Measures for Infants and Children.” Trends in Amplification 15 (1): 23–33. doi:10.1177/1084713811412056.
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). However, information about characteristics like ceiling/floor effects as well as information about responsiveness have been described as unavailable (Gan et al. 2018 Gan, R. W. C., M. Daniel, M. Ridley, and J. G. Barry. 2018. “Quality of Questionnaires for the Assessment of Otitis Media with Effusion in Children.” Clinical Otolaryngology: Official Journal of Ent-UK ; Official Journal of Netherlands Society for Oto-Rhino-Laryngology &Amp; Cervico-Facial Surgery 43 (2): 572–583. doi:10.1111/coa.13026.
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). Although the LEAQ has mainly been used in the monitoring of children who are DHH and have cochlear implants, there are data available on children with conventional hearing aids (Bagatto et al. 2010 Bagatto, M., S. D. Scollie, M. Hyde, and R. Seewald. 2010. “Protocol for the Provision of Amplification within the Ontario Infant Hearing Program.” International Journal of Audiology 49 (sup1): S70–S79. doi:10.3109/14992020903080751.
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). As the LEAQ was created to monitor auditory development of children who received cochlear implants, it has been questioned if it is sensitive enough to capture the delays in children with milder degrees of hearing loss (McCreery et al. 2015 McCreery, R. W., E. Walker, M. Spratford, J. Oleson, R. Bentler, L. Holte, and P. Roush. 2015. “Speech Recognition and Parent-Ratings from Auditory Development Questionnaires in Children Who Are Hard of Hearing.” Ear and Hearing 36 (0 1): 60S–75S. doi: 10.1097/AUD.0000000000000213.
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For a measure to be responsive, it must be reliable and include multiple items dealing with aspects of the construct that are likely to change, and the scoring of the items must allow for improvement (Roach 2006 Roach, K. E. 2006. “Measurement of Health Outcomes: Reliability, Validity and Responsiveness.” Journal of Prosthetics and Orthotics 18 (6): P8–P12. doi:10.1097/00008526-200601001-00003
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). Previous validations of the LEAQ have shown high reliability with increasing scores with time (Coninx et al. 2009 Coninx, F., V. Weichbold, L. Tsiakpini, E. Autrique, G. Bescond, L. Tamas, A. Compernol., et al. 2009. “Validation of the LittlEARS® Auditory Questionnaire in Children with Normal Hearing.” International Journal of Pediatric Otorhinolaryngology 73 (12): 1761–1768. doi:10.1016/j.ijporl.2009.09.036.
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). The LEAQ contains several questions monitoring “pre-verbal development” (MED-EL Corporation 2011 MED-EL Corporation. 2011. LittlEARS® Auditory Questionnaire, Manual. Innsbruck, Austria: MED-EL Medical Electronics.
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) which makes it challenging to evaluate the construct of auditory behaviour per se. Validations comparing the LEAQ against other gold-standard measures of auditory development are sparse.

To date, most of the validation studies of the LEAQ have used a cross-sectional design. These studies have predominantly had data from children at a single point in time, with normal hearing collected via parental report. The cross-sectional designs have often included many participants and made it challenging to investigate the developmental trajectory over time, which is an important intent of this questionnaire. The LEAQ was also investigated with a longitudinal design on a group of children following cochlear implantation (Obrycka et al. 2017 Obrycka, A., A. Lorens, J.-L. Padilla García, A. Piotrowska, and H. Skarzynski. 2017. “Validation of the LittlEARS Auditory Questionnaire in Cochlear Implanted Infants and Toddlers.” International Journal of Pediatric Otorhinolaryngology 93: 107–116. doi:10.1016/j.ijporl.2016.12.024.
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). Results of which indicated that higher scores were associated with early implantation and longer hearing aid usage than before implantation. The study of Obrycka et al. (2017 Obrycka, A., A. Lorens, J.-L. Padilla García, A. Piotrowska, and H. Skarzynski. 2017. “Validation of the LittlEARS Auditory Questionnaire in Cochlear Implanted Infants and Toddlers.” International Journal of Pediatric Otorhinolaryngology 93: 107–116. doi:10.1016/j.ijporl.2016.12.024.
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) demonstrated new evidence of discriminative validity of the LEAQ.

Another questionnaire focussing on auditory behaviour is the Parent’s Evaluation of Aural/Oral Performance in Children (PEACH). The PEACH was created to evaluate the effectiveness of amplification for children who are DHH (Ching and Hill 2007 Ching, T. Y. C., and M. Hill. 2007. “The Parents´ Evaluation of Aural/Oral Performance of Children (PEACH) Scale: Normative Data.” Journal of American Academy of Audiology 18: 221–237.
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). The PEACH consists of 13 questions which parents are asked to observe how their child has reacted in different listening situations during the last week and rate the frequency of behaviour using a 5-point rating scale ranging from “never” to “always”. Outcomes of the PEACH before the age of 2 years have been found to be a significant predictor of language development at 3 or through 5 years of age in children with congenital hearing impairment (Ching 2015 Ching, T. 2015. “Is Early Intervention Effective in Improving Spoken Language Outcomes of Children with Congenital Hearing Loss?” American Journal of Audiology 24 (3): 345–348. doi:10.1044/2015_AJA-15-0007.
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). Although the PEACH can be used with the paediatric population, researchers have cautioned interpreting results in children younger than 24 months of age (Bagatto et al. 2016 Bagatto, M., S. Moodie, C. Brown, A. Malandrino, F. Richert, D. Clench, S. Scollie., et al. 2016. “Prescribing and Verifying Hearing Aids Applying the American Academy of Audiology Pediatric Amplification Guideline: Protocols and Outcomes from the Ontario Infant Hearing Program.” Journal of the American Academy of Audiology 27 (3): 188–203. doi:10.3766/jaaa.15051.
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). As a guideline, it has been suggested to use the LEAQ until the age of 18 months or when a total score of 28 is reached. When this occurs, the PEACH should be used (Bagatto et al. 2011 Bagatto, M. P., S. T. Moodie, R. C. Seewald, D. J. Bartlett, and S. D. Scollie. 2011. “A Critical Review of Audiological Outcome Measures for Infants and Children.” Trends in Amplification 15 (1): 23–33. doi:10.1177/1084713811412056.
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). The PEACH was recently validated in Swedish (Brännström et al. 2014 Brännström, K. J., J. Ludvigsson, D. Morris, and T. Ibertsson. 2014. “Clinical Note: Validation of the Swedish Version of the Parents’ Evaluation of Aural/Oral Performance of Children (PEACH) Rating Scale for Normal Hearing Infants and Children.” Hearing, Balance and Communication 12 (2): 88–93. doi:10.3109/21695717.2014.903030.
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), but there is still a lack of an instrument to monitor the earliest auditory, speech and language development of Swedish children. The LEAQ could compliment the Swedish version of the PEACH for children between the ages of birth to 18 months.

In terms of measures of early communication and language development in Sweden, one of the most frequently used measures is the MacArthur-Bates Communicative Developmental Inventory (CDI) (Fenson et al. 1993 Fenson, L., V. Marchman, D. Thal, P. Dale, J. Reznick, and E. Bates. 1993. The MacArthur-Bates Communicative Development Inventories: User´s Guide and Technical Manual. San Diego: Singular.
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). It was adapted to Swedish (SECDI-I and II) in 2000 by Berglund and Eriksson (2000a Berglund, E., and M. Eriksson. 2000a. “Communicative Development in Swedish Children 16-28 Months Old: The Swedish Early Communicative Development Inventory – Words and Sentences.” Scandinavian Journal of Psychology 41 (2): 133–144. doi:10.1111/1467-9450.00181.
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, 2000b Berglund, E., and M. Eriksson. 2000b. “Reliability and Content Validity of a New Instrument for Assessment of Communicative Skills and Language Abilities in Young Swedish Children.” Logopedic Phoniatrics Vocology 25 (4): 176–185. doi:10.1080/140154300750067557.
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). The SECDI can be used from the age of 8 months, which is after children who are DHH are diagnosed. But, another instrument is needed to monitor the early development up to 8 months of age. The LEAQ could potentially cover this need. The idea of monitoring the early development of communicative and auditory development in children with the LEAQ was investigated by Rauhamäki et al. (2014 Rauhamäki, T., E. Lonka, J. Lipsanen, and M. Laakso. 2014. “Assessment of Early Auditory Development of Very Young Finnish Children with LittlEARS® Auditory Questionnaire and McArthur Communicative Developmental Inventories.” International Journal of Pediatric Otorhinolaryngology 78 (12): 2089–2096. doi:10.1016/j.ijporl.2014.09.010.
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). They compared an abridged version of the Finnish CDI to the LEAQ and concluded that these instruments covered the most important milestones in preverbal development. The study recommended that the LEAQ could be implemented in the Child Health Care Centres (CHCs) in Finland for all DHH children. The authors suggested that it could detect hearing problems in children between the Newborn Hearing Screening (NHS) and their national hearing screening at 4 years of age (Rauhamäki et al. 2014 Rauhamäki, T., E. Lonka, J. Lipsanen, and M. Laakso. 2014. “Assessment of Early Auditory Development of Very Young Finnish Children with LittlEARS® Auditory Questionnaire and McArthur Communicative Developmental Inventories.” International Journal of Pediatric Otorhinolaryngology 78 (12): 2089–2096. doi:10.1016/j.ijporl.2014.09.010.
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).

Results on LEAQ have also been linked to receptive language skills. In a longitudinal study, examining the effects of variability in children’s auditory experience with the LEAQ and PEACH, the authors found receptive language to be positively associated with parents’ ratings on both the LEAQ and the PEACH (McCreery et al. 2015 McCreery, R. W., E. Walker, M. Spratford, J. Oleson, R. Bentler, L. Holte, and P. Roush. 2015. “Speech Recognition and Parent-Ratings from Auditory Development Questionnaires in Children Who Are Hard of Hearing.” Ear and Hearing 36 (0 1): 60S–75S. doi: 10.1097/AUD.0000000000000213.
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). However, as the early development of audition, communication and language are closely intertwined, these results question the ability of the different questionnaires to monitor each construct separately. By face validity, the first part of the LEAQ includes questions about detection, localisation and reactions to sound; whereas, the latter part asks questions about word and/or sentence identification and vocalisation/speech production. In contrast, the final eight questions of the LEAQ focus on auditory behaviours above 18 months, e.g. at an age where responses by nature become more language dependent. This indicates that the LEAQ may evaluate auditory behaviour separated from language components more strongly in the first 12 months but not after the age of 18 months.

Although the LEAQ seems to be clinically feasible and monitors the auditory development of the youngest age group over time, there are few studies that have confirmed this with a longitudinal study design. Therefore, an overall aim of this study was to contribute to previous validations of the LEAQ with this perspective. A more specific aim was to collect normative data on the Swedish translated version of the LEAQ. Furthermore, the LEAQ has not yet been evaluated against another validated and normed measure or parental questionnaire (Bagatto et al. 2011 Bagatto, M. P., S. T. Moodie, R. C. Seewald, D. J. Bartlett, and S. D. Scollie. 2011. “A Critical Review of Audiological Outcome Measures for Infants and Children.” Trends in Amplification 15 (1): 23–33. doi:10.1177/1084713811412056.
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), which could contribute to questions around convergent validity of the tool. Therefore, a final aim of this study was to examine to what extent the Swedish version of the LEAQ correlates to other validated measures of early development (i.e. SECDI and PEACH).

Materials and methods
Participants
Children born full-term with normal hearing, and normal speech and language development and without additional disabilities were invited to participate in the study. Children were excluded if they did not have at least one parent who was a native speaker of Swedish and spoke it with the child. Thirty children (15 girls and 15 boys) were recruited through two Child Health Care Centres in Stockholm, Sweden, and entered the study between the ages of 11 and 134 days (mean = 62.9 days). To control for normal hearing, all children passed the NHS and screening (MADSEN Astera2, GN Otometrics A/S Denmark), performed by a paediatric audiologist, (screening level 20dBHL at 250, 500, 1000, 2000, 4000 Hz) at 10, 18 and 24 months. (American Speech-Language-Hearing Association 1997). Most of the children listened via headphones (Radioear DD45, USA) or a free-field setting (Bose Model 101 Music Monitor, USA), not allowing ear specific hearing sensitivity.

The onset of canonical babbling (CB) no later than 10 months of age is a strong predictor of future speech and language development that is documented to be robust (Nathani, Oller, and Neal 2007 Nathani, S., D. K. Oller, and A. R. Neal. 2007. “On the Robustness of Vocal Development: An Examination of Infants with Moderate-to-Severe Hearing Loss and Additional Risk Factors.” Journal of Speech, Language, and Hearing Research 50 (6): 1425–1444. doi:10.1044/1092-4388(2007/099).
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). To control for early speech and language development, the children had to demonstrate CB at 10 months to be included in the study. All participants were observed independently by two experienced speech and language pathologists according to a standardised manner from audio and video recorded natural play with a caregiver for ∼40 min (Lohmander et al. 2017 Lohmander, A., K. Holm, S. Eriksson, and M. Lieberman. 2017. “Observation Method Identifies That a Lack of Canonical Babbling Can Indicate Future Speech and Language Problems.” Acta Paediatrica 106 (6): 935–943. doi:10.1111/apa.13816.
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). Four children were excluded due to lack of CB and one child left the study at 13 months due to relocation. Due to these five exclusions, the study group finally consisted of 25 participants with demographic data provided in Table 1.

Table 1. Demographic data of the 25 participants and their parents.

CSVDisplay Table
The study was approved by the Regional Ethical Review Board in Stockholm (Ref no 2014/1:7 and 2014/1162-31/1) and parents gave written consent.

Materials and procedure
A longitudinal prospective design was used to control for predictability of scores over time. To investigate the content of the LEAQ, the Swedish version was correlated to other standardised measures of functional hearing and communication, and language development (see below). The parents were reminded, either via text message or email (chosen preference) one day before the target dates and/or if the responses were delayed more than one week.

The LEAQ (Weichbold et al. 2005 Weichbold, V., L. Tsiakpini, F. Coninx, and P. D'Haese. 2005.“Development of a parent questionnaire for assessment of auditory behaviour of infants up to two years of age.” Laryngorhinootologie 84 (5): 328–334. doi:10.1055/s-2004-826232.
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) was created to evaluate and monitor auditory development over time and consist of 35 questions. It has a hierarchal structure from early to later development asking if young children respond to acoustic and linguistic stimuli in the areas of reception, understanding and to (and with own) vocalisations. Parents are asked to respond if a behaviour is present (“yes”) or absent (“no”). In children under 12 months, parents are instructed to stop if they have six consecutive “no-responses”. The total score is the sum of all questions answered with “yes”. The LEAQ was forward-backward translated into Swedish in 2011 [Persson and Rasmussen for MED-EL (Persson and Rasmussen 2011 Persson, A., and P. Rasmussen. 2011. Translation and Adaptation of the LittlEARS® Auditory Questionnaire. Stockholm: Karolinska University Hospital.
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)] and used in a pilot study by an audiology student, evaluating item and scale properties with a cross-sectional design (Khan 2012 Khan, A. 2012. “Validation of LittlEARS® questionnaire.” Bachelor thesis at the Department of Audiology, Karolinska Institutet.
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). In the current study, the first LEAQ (Swedish version) was completed at study entry by the parent in person together with the first author, making it possible for parents to ask questions. The parents then received the LEAQ in paper format to complete at home and return with a pre-stamped envelope every two months until the child turned 24 months. As the LEAQ has expected values for each age month, the goal was to collect questionnaires spanning the entire age range of 0–24 months. Due to the long period of data collection, it was considered too burdensome for parents to respond every month. Moreover, many data points to close in time could lead to potential response bias. As the LEAQ was completed every second month and that the age of the children varied at study entry, the total number of participants for each age month also varied. A total of 299 LEAQ questionnaires for the 25 children were collected with a distribution between 5 and 21 questionnaires for each age span between 0 < 1 and 23 < 24 months (see Table 2). The first author scored all sheets, which were cross-checked by a teacher of the deaf experienced with the LEAQ before data were inputted into IBM SPSS Statistics 23 for analysis. The cross-check led to a change of 19 out of 299 questionnaires. Changes were due to deviations from scoring according to the instruction criteria, and four changes were due to written comments from parents that affected the interpretation of the score. The calculations of chronological age were within ±4 days of each month.

Table 2. Completed LEAQ questionnaires by age category of the participants (n = 25). The total number of questionnaires = 299, including 10–13 per participant over time.

CSVDisplay Table
The PEACH (Ching and Hill 2007 Ching, T. Y. C., and M. Hill. 2007. “The Parents´ Evaluation of Aural/Oral Performance of Children (PEACH) Scale: Normative Data.” Journal of American Academy of Audiology 18: 221–237.
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) consists of 13 questions. The initial two questions about hearing technology were removed, as this study included children with normal hearing. This questionnaire asks parents to observe and rate how often their child has reacted in different listening situations during the last week via a five-point Likert scale. The Swedish version of the PEACH (Brännström et al. 2014 Brännström, K. J., J. Ludvigsson, D. Morris, and T. Ibertsson. 2014. “Clinical Note: Validation of the Swedish Version of the Parents’ Evaluation of Aural/Oral Performance of Children (PEACH) Rating Scale for Normal Hearing Infants and Children.” Hearing, Balance and Communication 12 (2): 88–93. doi:10.3109/21695717.2014.903030.
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) was given in paper format at the hearing screening visits at 18 and 24 months, and parents were asked to complete and return with a pre-stamped envelope. All participants returned their PEACH forms at 18 and 24 months within 0–3 weeks past target date. The total score from the PEACH questionnaires was calculated by the first author and then cross-checked by an experienced paediatric audiologist. One, out of 50 scores differed by two points due to a miscalculation of the total score and was adjusted before analysis.

The SECDI-I (Berglund and Eriksson 2000a Berglund, E., and M. Eriksson. 2000a. “Communicative Development in Swedish Children 16-28 Months Old: The Swedish Early Communicative Development Inventory – Words and Sentences.” Scandinavian Journal of Psychology 41 (2): 133–144. doi:10.1111/1467-9450.00181.
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) was given in paper-format at the babbling observation and hearing screening at 10 months of age, and the SECDI-II (Berglund and Eriksson 2000b Berglund, E., and M. Eriksson. 2000b. “Reliability and Content Validity of a New Instrument for Assessment of Communicative Skills and Language Abilities in Young Swedish Children.” Logopedic Phoniatrics Vocology 25 (4): 176–185. doi:10.1080/140154300750067557.
[Taylor & Francis Online], , [Google Scholar]
) was given at 18 and 24 months of age when the participants came for hearing screening on-site. Parents were asked to complete the questionnaire and return with a pre-stamped envelope. All participants returned their SECDI inventories at 10, 18 and 24 months within 0–3 weeks past target date.

The SECDI vocabulary data from 10, 18 and 24 months of age were scored by an undergraduate student in linguistics and cross-checked by the first author. The SECDI contains over 600 items and discussion for consensus on interpretation occurred. For example, in cases where the caregiver had scored out the target word and provided a synonym or replaced it with the word in their second language, a score of zero was given. For three children, answers to some pages of the inventory were missing at 10 months. It is unclear whether these scores represented the child’s actual development or if the caregivers forgot to cross all pages or were unaware of this.

Analyses
To investigate the effect of time on the total scores, the ANOVA for repeated measures was used. As the participants had provided questionnaires every second month (uneven n = 15, even n = 10) two age months were combined and analysed as ten different time points from 2–3 months up to 22–24 months (the final timepoint combined 3 age months). To determine if there were any timepoints that were significantly different, pairwise tests and correlations were performed. Since all participants did not complete the questionnaire at each age month, a linear regression mixed model was performed to compensate for missing values and create a growth curve based on predicted scores over time. To examine the correlation between LEAQ and other instruments, LEAQ total scores of each participant at 10, 18 and 24 months of age were compared with the total scores on the vocabulary section of the SECD-I and II at 10, 18 and 24 months, and total score on the PEACH at 18 and 24 months. These calculations were performed with Pearson correlation analyses. All data were analysed using IBM SPSS Statistics 23 for Windows 18.0 software (Armonk, NY), except the normative curve which was calculated in Statistica 13.0 Software (Tulsa, OK).

Results
Effect of time
Before the repeated measures ANOVA was performed, data were checked to investigate if the required assumptions were met. The data conformed to the assumptions that the dependent variable was measured at a continuous level, and the same subjects were represented at all time points when grouped into two age-months. As the data set included several levels, the risk of violated sphericity was elevated and therefore checked through the Maulchy’s test with a value of 0.389 assuming that sphericity was violated. There was also reason to believe that the assumption of normal distribution would be somewhat affected due to the limited number of participants. Although not significant, there were six individual outliers (one at 6–7 months, one at 18–19 months and four at 22–24 months) that may have questioned the assumption of normality. However, all 25 participants were included in the final analysis of the repeated measures ANOVA (Figure 1). A repeated measures ANOVA with a Greenhouse-Geisser correction determined that mean LEAQ score differed statistically significantly between time points (F(3.894, 93.467)=368.304, p < 0.0005). Pairwise comparisons between all time points were significant (p = 0.0005) and a significant difference was seen between time point 1 and time point 10 (p = 0.000). The mean scores on the LEAQ increased for every time point and therefore, it was concluded that the scores increase with age over time from birth to 24 months of age.

Figure 1. Results from the repeated measures ANOVA with 25 participants divided into groups of two age months from 2–3 months, 4–5 months and so on to 22–24 months.


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Normative data
Parents of 25 children completed 10–13 questionnaires over the time period of two years. Most of the total scores at each administration were within the 95% confidence intervals of the predicted scores (Figure 2). The majority of the participants reached a ceiling effect around 18–20 months of age and by 24 months of age, all participants but a couple seem to have reached the total score. The coefficient determination for the model shows that ∼90% of the variance in the total scores can be explained by age (R2=0.899). The Swedish norm curve (quadratic model) had the following equation: 1.0026 + 2.1543×x − 0.0298×x2 which is similar to the German version with the equation: 2.0651 + 2.2175×x − 0.0376×x2.

Figure 2. LittlEars validation data from Swedish normal hearing children and the German derived-norm curve. The solid line shows the Swedish normative curve derived through mixed regression model with random intercept and random slope (age) with a quadratic trend with the equation of = 1.0026 + 2.1543×x − 0.0298×x2. The bold dotted line shows the original German normative curve with the equation of = 2.0651 + 2.2175×x − 0.376×x2. The dotted black lines display the upper and lower confidence intervals of the Swedish sample. The circles represent the raw data of the 299 questionnaires of the 25 participants.


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Predicted growth curve
The linear regression mixed model showed individual growth curves among the 25 participants, all with scores increasing over time (Figure 3). In the first 3 age months, the predicted scores of the participants were somewhat higher in the children who entered the study after 3 months compared to those who completed the LEAQ before. With this predictive model, two participants did not seem to follow the exact same pattern as the others, showing lower scores from 16–20 months of age where the rest of the group started to hit ceiling effect.

Figure 3. Predicted scores development over time of each participant estimated with mixed regression model (n = 25).


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Association between questionnaires
Scores on the LEAQ at 10, 18 and 24 months were correlated to scores on the SECDI at 10, 18 and 24 months, and the PEACH at 18 and 24 months. Moderate correlations were found between the LEAQ and SECDI at 10 months (r = 0.57, p < 0.01), at 18 months (r = 0.58, p < 0.01), and moderate to weak at 24 months (r = 0.42, p < 0.05). The correlation between the LEAQ and the PEACH was moderate to weak at 18 months (r = 0.46, p < 0.05) and non-existing at 24 months of age (r = 0.18).

Association between time points within the LEAQ
Pearson correlation analysis between the different time points revealed that there were moderate to strong correlations between the time points 1–4 (e.g. ages: 2–11 months) with values ranging from (r = 0.45 to 0.80, p < 0.01) but non-significant or very weak with the time points 6–10 (e.g. ages: 12–24 months) (r = 0.023–0.39). Time points 5–10 showed significant moderate to high correlations (r = 0.55–0.82, p= <0.01). The highest correlation was seen between time point 7 and time point 8 (e.g. ages: 16–19 months) (r = 0.82, p < 0.01). In the group of higher time points, time point 10 showed moderate correlations with time point 8 (r = 0.54) and 9 (r = 0.56) at the (p= <0.01 level) but also moderate correlations with time point 1–3 (r = 0.43–0.47, p < 0.5).

Discussion
With regards to the results from the repeated measure ANOVA, the effect of time was significant as the scores increased with each time point. Therefore, the Swedish version of the LEAQ seems able to evaluate auditory behaviour over time. However, the results from the performance of the repeated measures ANOVA should be taken with caution due to the limited number of participants, which makes the assumptions more sensitive to violation where minor outlying numbers may result in large effects. The sensitivity of having missing data in a small study sample was seen in the linear mixed model where the participants who did not have real scores in the first 3 months, had a higher starting point compared to those who did. In spite the limited number of participants, the curves from the different analyses showed similar patterns to a large extent which support the validity of the translation and adaptation of the original LEAQ version to Swedish (Weichbold et al. 2005 Weichbold, V., L. Tsiakpini, F. Coninx, and P. D'Haese. 2005.“Development of a parent questionnaire for assessment of auditory behaviour of infants up to two years of age.” Laryngorhinootologie 84 (5): 328–334. doi:10.1055/s-2004-826232.
[Crossref], [PubMed], [Web of Science ®], , [Google Scholar]
). The similar curves could be interpreted as auditory behaviour is robust and that the LEAQ is constructed to capture this development in a reliable way even in smaller study samples. Therefore, this longitudinal study supports the previous results from the cross-sectional study designs that the LEAQ is an appropriate tool to measure auditory behaviour over time.

When comparing the LEAQ scores in relation to the scores from the other assessments, the highest correlations were found between the LEAQ and the SECDI. These results are in line with the findings of Rauhamäki et al. (2014) and McCreery et al. (2015 McCreery, R. W., E. Walker, M. Spratford, J. Oleson, R. Bentler, L. Holte, and P. Roush. 2015. “Speech Recognition and Parent-Ratings from Auditory Development Questionnaires in Children Who Are Hard of Hearing.” Ear and Hearing 36 (0 1): 60S–75S. doi: 10.1097/AUD.0000000000000213.
[Crossref], [PubMed], , [Google Scholar]
) which also illustrate the correlation between the LEAQ and the SECDI. This association could raise the question if the LEAQ is specifically targeting audition compared to other questionnaires used in the paediatric population regarding communication and language (e.g. SECDI). If scores of individual children on different tools display strong associations, it might be explained by the weighting of many questions representing the same aspect of a construct, e.g. they are measuring the same thing.

The relation between the LEAQ and the PEACH showed a moderate correlation at 18 months but no correlation at 24 months. The difference in results between the two age categories may, therefore, be explained by the overlap of similar questions of the LEAQ and the PEACH are found around or below the age of 18 months of the LEAQ (e.g. questions 18 or below) but not above. The weak correlation at 18 months between the LEAQ and the PEACH became nonexistent at 24 months. As the results from the calculations of the normative curve as well as the repeated measures ANOVA showed, many of the participants hit ceiling effect on the LEAQ around 18–20 months of age. This effect could suggest that the LEAQ is not able to account for variability in the last 6 months of the questionnaire. As limited variability in the gathered data may reduce the power of statistics on correlations, this could be the case of the nonexistent correlations between the LEAQ and the PEACH at 24 months of age. Furthermore, both the LEAQ and PEACH have smaller scales with fewer items compared to the SECDI, but it may also be that the cluster of the responses at 18–20 months represents the natural limit of auditory behaviour.

By face validity, it was hypothesised that the first part of the LEAQ consisted of questions related to auditory behaviours that by nature would not be as language dependent. This was to some part confirmed by the significant moderate to strong correlations between the first 4 time points in contrast to the last 6 within the LEAQ. Individual variability acknowledged, the age around 10–12 months is often when children move from using their auditory experiences and beginning to understand and say their first words.

The LEAQ and SECDI showed moderate correlations but the LEAQ and PEACH did not, which could also suggest that the PEACH is measuring audition through language independent behaviours. As the interpretation of scores from the PEACH in infants below 24 months have been previously questioned (McCreery et al. 2015 McCreery, R. W., E. Walker, M. Spratford, J. Oleson, R. Bentler, L. Holte, and P. Roush. 2015. “Speech Recognition and Parent-Ratings from Auditory Development Questionnaires in Children Who Are Hard of Hearing.” Ear and Hearing 36 (0 1): 60S–75S. doi: 10.1097/AUD.0000000000000213.
[Crossref], [PubMed], , [Google Scholar]
), investigation of this tool regarding the effect of age in the paediatric population is encouraged. Furthermore, the LEAQ and the PEACH could be used simultaneously from the age of 18 months.

This study included a group of 25 children with highly educated parents, which may affect the credibility to generalise these findings to a larger population. Despite this limitation, the results on the LEAQ and PEACH showed similar results as previous studies (Coninx et al. 2009 Coninx, F., V. Weichbold, L. Tsiakpini, E. Autrique, G. Bescond, L. Tamas, A. Compernol., et al. 2009. “Validation of the LittlEARS® Auditory Questionnaire in Children with Normal Hearing.” International Journal of Pediatric Otorhinolaryngology 73 (12): 1761–1768. doi:10.1016/j.ijporl.2009.09.036.
[Crossref], [PubMed], [Web of Science ®], , [Google Scholar]
; Brännström et al. 2014 Brännström, K. J., J. Ludvigsson, D. Morris, and T. Ibertsson. 2014. “Clinical Note: Validation of the Swedish Version of the Parents’ Evaluation of Aural/Oral Performance of Children (PEACH) Rating Scale for Normal Hearing Infants and Children.” Hearing, Balance and Communication 12 (2): 88–93. doi:10.3109/21695717.2014.903030.
[Taylor & Francis Online], , [Google Scholar]
). The participants’ individual scores on the SECDI-I and II were distributed from the lower to higher end of the normative scale, thus being representative of a normal distribution of children 0–2 years of age. In terms of respondent burden, there was high compliance of the participants with no dropouts. This indicates that the LEAQ is not a burdensome questionnaire and therefore feasible to implement in the Swedish clinics of children who are DHH.

As the estimated total scores of the LEAQ over time were significant, the results from this study further strengthen previous validations that the LEAQ increases in difficulty with age and is appropriate for monitoring children’s development over time (Coninx et al. 2009 Coninx, F., V. Weichbold, L. Tsiakpini, E. Autrique, G. Bescond, L. Tamas, A. Compernol., et al. 2009. “Validation of the LittlEARS® Auditory Questionnaire in Children with Normal Hearing.” International Journal of Pediatric Otorhinolaryngology 73 (12): 1761–1768. doi:10.1016/j.ijporl.2009.09.036.
[Crossref], [PubMed], [Web of Science ®], , [Google Scholar]
). When comparing the LEAQ to the SECDI and the PEACH, results indicated that the LEAQ is to a moderate extent rich in linguistic content and evaluates a child’s response regarding early communication and language development, rather than auditory development specifically. This is particularly the case in the second half of the questionnaire as evidenced by the correlations with the PEACH and SECDI.

In summary, the results of this study support the findings from the previous pilot study of Swedish children (Khan 2012 Khan, A. 2012. “Validation of LittlEARS® questionnaire.” Bachelor thesis at the Department of Audiology, Karolinska Institutet.
 [Google Scholar]
). Due to the correlation between measures, the LEAQ is a useful tool in the early intervention for monitoring early auditory behaviour and language development, and suitable for multidisciplinary teamwork of audiologists, speech and language pathologists, and other professionals.

Conclusion
The similarity of the data from the Swedish and the original LEAQ makes the Swedish version a reliable tool to be used in the monitoring of early auditory behaviour of Swedish-speaking children. The correlations between the LEAQ/PEACH and SECDI, indicates that the early development of audition, communication, speech, receptive and expressive language are closely intertwined and may be challenging to measure as separate constructs. Therefore, the results on the LEAQ may convey a broader picture of a child’s overall development rather than just auditory.

As the LEAQ was originally created for monitoring auditory development of children who receive cochlear implants, future validations could include larger groups of children with various types and degrees of hearing loss to further examine the sensitivity and specificity of the instrument. Such studies would need to control for factors like age at hearing aid fitting, hearing aid use, and aided audibility of the hearing aids. In terms of future validations of the LEAQ, the authors recommend that the construct of audition could be further examined. Evaluating early development is important to ensure children are on the right trajectory. To design and provide appropriate services there is a need for a variety of tools to illustrate the complexity of the auditory, communicative and language abilities in children and how they affect each other. By collecting individual data from several early measures over time, more information behind the heterogeneity of the group of children who are DHH and how best to interpret the results from these questionnaires would need to be gathered.

Acknowledgments
The authors would like to thank the people who helped with the recruitment of the participant families and colleagues involved in data collection and cross-checking of data. Special thanks to participating parents and children. We would also like to thank Hörselforskningsfonden, Sunnerdahls Handikappfond, Tysta skolan, Wibelfonden and Jerringfonden for their financial support as well as Möllerström Medical for their provision of questionnaires for the study.

Declaration of interest
No potential conflict of interest was reported by the authors.

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