Dichotic Training in Children with Auditory Processing Disorder

International Journal of Pediatric Otorhinolaryngology 110 (2018) 114–117

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International Journal of Pediatric Otorhinolaryngology

journal homepage: www.elsevier.com/locate/ijporl

Dichotic training in children with auditory processing disorder T ∗ Maryam Delphia, Farzaneh Zamiri Abdollahib, a Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran b Audiology Department, Tehran University of Medical Sciences, Tehran, Iran

ARTICLE INFO ABSTRACT

Keywords: Objectives: Several test batteries have been suggested for auditory processing disorder (APD) diagnosis. One of Dichotic listening the important tests is dichotic listening tests. Significant ear asymmetry (usually right ear advantage) can be Auditory training indicative of (APD). Two main trainings have been suggested for dichotic listening disorders: Differential Auditory processing Interaural Intensity Difference (DIID) and Dichotic Offset Training (DOT). The aim of the present study was comparing the efficacy of these two trainings in resolving dichotic listening disorders. Methods: 12 children in the age range of 8 to 9 years old with APD were included (mean age 8.41 years old ± 0.51). They all had abnormal right ear advantage based on established age-appropriate norms for Farsi dichotic digit test. Then subjects were randomly divided into two groups (each contained 6 subjects): group 1 received DIID training (8.33 years old ± 0.51) and group 2 received DOT training (8.50 years old ± 0.54). Results: Both trainings were effective in improvement of dichotic listening. There was a significant difference between two trainings with respect to the length of treatment (P-value≤0.001). DOT needed more training sessions (12.83 ± 0.98 sessions) than DIID (21.16 ± 0.75 sessions) to achieve the same amount of performance improvement. Conclusion: Based on the present study it can be assumed that DOT might be a good replacement for DIID training in cases that DIID is not applicable and DIID candidacy conditions are not met. To generalize the results, studies with larger sample sizes are recommended.

1. Introduction can also help determining language dominant hemisphere. Corpus callosum is important for inter-hemispheric transfer in dichotic lis- Central auditory processing disorder (APD) is defined as a deficit in tening [9,10]. A variety of stimuli can be used for dichotic testing in- auditory performances such as sound localization and lateralization, cluding syllables, digits, words or sentences [11]. Test interpretation is auditory temporal processing, auditory discrimination, auditory per- based on individual ear score and ear advantage. Ear advantage is the formance in presence of noise, or comprehension of degraded signals difference between the score of two ears in a given dichotic listening [1]. Therefore, this term can refer to a wide variety of auditory func- task [12–14]. In children usually, right ear score is higher than the left tional deficits [2]. One of the complaints of these patients is listening ear and it shows that left brain hemisphere is language dominant. This difficulty in noisy environments which can lead to academic failure in phenomenon is called REA (Right Ear Advantage). REA has an age-re- children and can affect the quality of life in elderly [1,3,4]. lated norm and if it is outside the established norm, it is interpreted as Several test batteries have been suggested for APD diagnosis (e.g. abnormal interaural asymmetry [14–16]. Stimuli presented to the left Buffalo model, Bellis-Ferre Model and MAPA (multiple auditory pro- ear have to pass through corpus callosum and reach to left hemisphere cessing assessments)) [5–7]. One of the important test that is included which is language dominant brain hemisphere in most people. With age in almost all of the APD test batteries, is dichotic listening tests. The ear asymmetry (REA) decreases and in 11–12-year-old children, REA is dichotic hearing is a condition in which different auditory stimuli are similar to adults [16,17]. Dichotic listening maturation is highly related presented simultaneously to each ear [8]. In psychological studies di- to corpus callosum maturation (myelination) which occurs by age of 10. chotic listening has been used for evaluation of divided (binaural in- Corpus callosum maturation facilitate inter-hemispheric transfer and tegration) and selective attention (binaural separation). In the former, leads to decrement in the ear asymmetry [18]. listener must attend to both ears (free recall) and in the latter listener Significant ear asymmetry (usually REA) can be indicative of APD. must attend to only one ear (focused or directed recall). Dichotic tests Deborah Moncrieff suggested that when there is a significant interaural

∗ Corresponding author. Rehabilitation school, Pich-e-Shemiran, Enghelab Street, Tehran, Iran. E-mail address: [email protected] (F. Zamiri Abdollahi). https://doi.org/10.1016/j.ijporl.2018.05.014 Received 30 March 2018; Received in revised form 8 May 2018; Accepted 9 May 2018 0165-5876/ © 2018 Elsevier B.V. All rights reserved. M. Delphi, F. Zamiri Abdollahi International Journal of Pediatric Otorhinolaryngology 110 (2018) 114–117 asymmetry in dichotic listening tasks, there is actually an amblyaudia ear asymmetry, the performance was considered normal. When there [19]. Difficulty in dichotic speech recognition skills has a significant was a 10% asymmetry or less, training was stopped and two weeks after correlation with poor speech recognition in adults and poor auditory training was completed, DDT was retested to make sure the outcome processing in the classroom in children [20]. was permanent. DDT was tested at the end of each session, too. Two main trainings has been suggested for dichotic listening disorders: Differential Interaural Intensity Difference (DIID) and Dichotic 2.3. DOT procedure Offset Training (DOT) [21,22]. DIID uses interaural intensity difference (IID) and DOT uses interaural time difference (ITD). The aim of the For DOT letters and CVs were used. Both materials were used during present study was comparing the efficacy of these two trainings in re- each session. The presentation was in the format of the staggered solving dichotic listening disorders. spondee word test (SSW test). Two letters and CVs were directed to the right ear and two letters and CVs to the left ear. There was an offset for 2. Method the presentation of letters and for the first phoneme of the CVs [21]. Items began in the right ear (left ear lag). Lagging the presentation to 2.1. Participants the poorer ear helps it to process signal better. The patient had to repeat all four items in the correct order [24]. 50 children with listening, spelling and reading problems were re- This training is similar in DIID II [25] and DOT [21,26]. DOT and ferred to the audiology clinic for auditory processing evaluations in DIID II have a common basic concept. The training started with com- November and December of 2017. Among these children, 12 children in peting items separated by 500 ms; gradually the offset was reduced by the age range of 8–9 years old were diagnosed as having APD (mean age 100 steps for subsequent conditions. When the patient was able to 8.41 years old ± 0.51). They had normal PTA (auditory perform the task with 80% accuracy or more at a specificoffset, the threshold ≤ 20 dB HL in 500 to 4000 Hz) in both ears; symmetric offset was decreased [21]. At the end of each session, DDT was eval- hearing thresholds (PTA difference ≤5 dBHL between two ears); uated. When there was a 10% asymmetry or less, training was stopped normal middle ear function (normal tympanogram); Wechsler IQ-chil- and two weeks after training was completed, DDT was retested to make dren score ≥85, monolingualism (Persian language); no history of sure the outcome was permanent. ADHD, seizures, behavioral or developmental disorders; not being on any central nervous system medications; having poor academic per- 3. Results formance; abnormal results (≥2 SDs from established norms) in dichotic digit test (DDT), pitch pattern sequence test (PPST) and mon- 12 children in the age range of 8–9 years old with APD were in- aural selective auditory attention test (mSAAT). MAPA study showed cluded (mean age 8.41 years old ± 0.51). Then subjects were randomly that DDT/PPS/mSAAT test battery can provide 90% sensitivity and divided into two groups: group 1 received DIID training (8.33 years 100% specificity in APD diagnosis [5]. All these tests are available in old ± 0.51) and group 2 received DOT training (8.50 years old ± 0.54). Farsi language with appropriate age-related norms [1,16]. The results of the DDT before training were compared between two All the subjects were diagnosed as having APD for the first time and groups by using U-Mann Whitney, as data did not show normal dis- they were not under any training program at the time. Then subjects tribution in K-S test of normality. There was not any significant dif- were randomly divided into two groups (each contained 6 subjects): ference between two groups (Table 1). As it is shown, there was a group 1 received DIID training (8.33 years old ± 0.51) and group 2 significant REA in all the cases. The results were compared with the received DOT training (8.50 years old ± 0.54). After the present study, age-appropriate norm in Farsi language [16]. they received comprehensive APD training. This comprehensive Graph 1 and 2 show the trend of dichotic listening improvement training included auditory attention and memory exercises, phonemic (based on DDT) for DIID and DOT trainings. Both training were effec- training program and noise desensitization training. The study protocol tive in improvement of dichotic listening. Table 2 summarizes the mean was approved by the Ethical Committee of Tehran University of number of the training sessions for DIID and DOT trainings. There was a Medical Sciences (TUMS) and written informed consent was obtained significant difference between the two trainings with respect to the from all parents prior to the start of the study. length of training based on using U-Mann Whitney test (P- value≤0.001). Table 3 shows patient characteristics and results in both 2.2. DIID procedure groups.

After documenting that dichotic listening problem, a crossover 4. Discussion performance point was established by reducing the intensity of the stimuli presented to the better ear. For utilization of the DIID, there are This study was performed on 12 children with APD who suffered two conditions: performance in the poorer ear must be at normal or from dichotic listening problems. They all had abnormal REA. They near normal limits at the crossover level and intensity of the stimulus randomly received DIID or DOT trainings. Both trainings were effective presented to the better ear must not drop below the hearing threshold. and led to normal dichotic listening ability but DOT took more time to Once crossover point and candidacy for the procedure were estab- make the same amount of improvement in the dichotic listening task. ff lished, initial training began with an interaural intensity di erence Mean number of the training sessions for DIID was 12.83 ± 0.98 and (IID) that was 5 dB greater than the crossover point. The level at the for DOT was 21.16 ± 0.75. The training duration difference might be poorer ear was kept at 50 dB HL. Tasks that were used included: dichotic CV, dichotic sentences and dichotic story in music background. Table 1 During a session, patients were asked to attend to both ears (free recall), Results of the DDT in DIID and DOT groups before training. or attend to only one ear at a time (directed recall). Mean SD SE P-value There were 4 sessions per week, each session lasted for 30 min. The aim was reducing the IID. If performance in the poorer ear was ≥80%, Right DDT Group 1 91.66 4.08 1.66 0.72 then training continued at that specific IID for the entire week. If per- Group 2 90.83 3.76 1.53 formance was ≤80%, the IID was increased in 1 dB increments until the Left DDT Group 1 36.66 6.05 2.47 0.51 performance of the poorer ear reaches 80% or until the IID level returns Group 2 34.16 6.64 2.71 REA Group 1 55.00 4.47 1.82 0.59 to the starting level. The goal was improving performance to the normal Group 2 56.66 6.05 2.47 limit [23]. Based on the established norms, when there was only 10%

115 M. Delphi, F. Zamiri Abdollahi International Journal of Pediatric Otorhinolaryngology 110 (2018) 114–117

Graph 1. The trend of dichotic listening improvement in DIID training. attributable to the different underlying mechanisms in these two Table 2 trainings. DIID is based on interaural level difference and DOT is based Comparison of the number of training sessions in DIID and DOT training on interaural time difference. Presumably they activate different audi- groups. tory pathways in the brainstem. Mean SD SE P-value Studies showed that a dichotic deficit will usually manifest itself as a unilateral deficit on dichotic tasks [25] which is in agreement with the Training length (number of sessions) Group 1 12.83 0.98 0.40 ≤0.001 present study. The goal of the DIID is to increase the performance of the Group 2 21.16 0.75 0.30 poorer ear to reach the age-appropriate normal limit [25]. Musiek et al. (1979) studied patients with corpus callosum dysfunction and showed performance in the left ear. Following 6 weeks of training, performance that with decreasing the level of dichotic presentation in the better ear, on this test returned to the normal limits in both ears and subjects there is a crossover level at which poorer ear shows better dichotic showed academic performance improvement, as well [25]. performance than the better ear [27]. DIID rehabilitation is based on Effects of the DIID have also been investigated in the auditory this phenomenon. evoked potentials. Middle latency response (MLR) and binaural inter- Several studies have shown the DIID training can improve patients' action component (BIC) of MLR are potentially reliable responses to performance in behavioral dichotic tasks. Weihing and Musiek (2007) reflect effects of APD trainings objectively [1,29]. Schochat et al. in children with confirmed APD that had REA in DDT, showed that DIID (2010) used DIID as a part of auditory rehabilitation in 30 children with training led to the 10–15% left ear improvement [6]. Moncrieff and APD. They showed that Na-Pa amplitude at the C3 electrode increased Wertz (2008) conducted a similar study and shown performance im- in the APD group following training [29]. provement on DDT following training [28]. Musiek and Schochat In general, studies show that DIID is an efficient training for dichotic (1998) administered the DIID in a 15-year-old boy with learning dis- listening improvement but Musiek et al. (2008) mentioned that more abilities (LD) who had a low score in DDT in both ears with poorer

Graph 2. The trend of dichotic listening improvement in DOT training.

116 M. Delphi, F. Zamiri Abdollahi International Journal of Pediatric Otorhinolaryngology 110 (2018) 114–117

Table 3 Acknowledgment Patient characteristics and results.

subjects age sex DDT (%) REA Type of Training length The research team would like to thank the individuals who parti- training (number of cipated in the study and their parents. Right ear Left ear sessions) References 1 8 F 90 30 60 DIID 13 2 8 F 95 45 50 DIID 12 fi 3 8 F 85 30 55 DIID 12 [1] F.Z. Abdollahi, Y. Lot , A. Moosavi, E. Bakhshi, Binaural interaction component of 4 8 M 95 35 60 DIID 14 middle latency response in children suspected to central auditory processing disorder, Indian J. Otolaryngol. Head Neck Surg. (2017) 1–4. 5 9 F 95 40 55 DIID 14 [2] A.A. Ludwig, M. Fuchs, E. Kruse, B. Uhlig, S.A. Kotz, R. Rübsamen, Auditory pro- 6 9 M 90 40 50 DIID 12 cessing disorders with and without central auditory discrimination deficits, J. 7 8 F 90 30 60 DOT 21 Assoc. Res. Otolaryngol. 15 (3) (2014) 441–464. 8 9 F 95 30 65 DOT 22 [3] M. Delphi, M.-Y. Lotfi, A. Moossavi, E. Bakhshi, M. 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