|Year : 2020 | Volume
| Issue : 4 | Page : 371-376
Transient-evoked otoacoustic emission findings in children (1–12 years) with cerebral palsy in Kano, Nigeria
Yasir Nuhu Jibril1, Auwal Adamu1, Rabiu Ibrahim Jalo2, Zubaida Ladan Farouk3, Abubakar Danjuma Salisu4, Onyekwere George B. Nwaorgu5
1 Department of Otorhinolaryngology, Aminu Kano Teaching Hospital, Bayero University, Kano, Nigeria
2 Department of Community Medicine, Aminu Kano Teaching Hospital / Bayero University, Kano, Nigeria
3 Department of Pediatrics, Aminu Kano Teaching Hospital / Bayero University, Kano, Nigeria
4 Department of Otorhinolaryngology, Aminu Kano Teaching Hospital / Bayero University, Kano, Nigeria
5 Department of Otorhinolaryngology, University College Hospital / University of Ibadan, Ibadan, Nigeria
|Date of Submission||29-Jul-2020|
|Date of Decision||25-Aug-2020|
|Date of Acceptance||12-Oct-2020|
|Date of Web Publication||04-Nov-2020|
Dr. Yasir Nuhu Jibril
Department of Otorhinolaryngology, Aminu Kano Teaching Hospital, Kano
Source of Support: None, Conflict of Interest: None
Background: Children with cerebral palsy (CP) suffer from multiple problems and potential disabilities. These range from musculoskeletal problems, mental retardation, epilepsy, ophthalmologic and hearing impairment among others. Consequences of hearing loss include problems with speech and language development. Early detection in this difficult-to-test population may prevent these consequences of hearing loss. An otoacoustic emission assessment is useful in this regard. This study assessed transient-evoked otoacoustic emissions (TEOAEs) in children with CP. Materials and Methods: The study population were children with CP who presented at the paediatric neurology clinic during the study period. An equal number of control population matched for age and sex were also recruited using simple random sampling. An interviewer-administered questionnaire was used to obtain relevant clinical information. All participants selected underwent a detailed ear, nose and throat examination and TEOAE testing. Results: There were 330 participants in this study, categorised into CP cases (165) and non-CP controls (165). The age range of the participants was 1–12 years, with a mean age of 4.44 ± 2.92 among CP patients and 4.47 ± 2.90 among the controls. The male-to-female ratio was 2:1. TEOAEs were 'failed' in 83.6% of the CP patients and in 28.5% of the controls. This study found a statistically significant difference in 'failed' TEOAE result between the CP patients and the controls (P = 0.0001). Conclusion: This study found a high prevalence of 'failed' TEOAEs in children with CP in Kano.
Keywords: Cerebral palsy, children, hearing assessment, otoacoustic emission
|How to cite this article:|
Jibril YN, Adamu A, Jalo RI, Farouk ZL, Salisu AD, B. Nwaorgu OG. Transient-evoked otoacoustic emission findings in children (1–12 years) with cerebral palsy in Kano, Nigeria. Niger Postgrad Med J 2020;27:371-6
|How to cite this URL:|
Jibril YN, Adamu A, Jalo RI, Farouk ZL, Salisu AD, B. Nwaorgu OG. Transient-evoked otoacoustic emission findings in children (1–12 years) with cerebral palsy in Kano, Nigeria. Niger Postgrad Med J [serial online] 2020 [cited 2021 Jan 28];27:371-6. Available from: https://www.npmj.org/text.asp?2020/27/4/371/299911
| Introduction|| |
Cerebral palsy (CP) is the most commonly occurring physical disability in childhood. It is a heterogeneous group of permanent, non-progressive motor disorders of movement and posture caused by chronic brain injuries that originate in the neonatal, perinatal or postnatal period. In addition, children with CP suffer from other multiple problems and potential disabilities such as mental retardation, epilepsy, feeding difficulties and visual and hearing impairments. The presence of these disabilities contributes to the poor quality of life suffered by these patients, which may include poor speech and language development. As a result of these potential problems associated with CP, the American Academy of Neurology practise guidelines recommend that all children with CP are assessed for hearing impairments and for speech and language disorders among other things.
Hearing impairment occurs more frequently among children with CP than in the general population, since several risk factors in infants with CP were documented to be the same risk factors for the development of hearing impairment. The frequency of hearing impairment among CP patients reported from different parts of the world ranges from 4% to 13% in studies,,, from the United States of America and Europe, 26.2% in Jordan, 15.6% in Uganda and 24.4% and 11.9% from studies conducted in Nigeria.
Various audiological tests including both behavioural and physiological methods have been used to assess hearing in CP patients. The American Academy of Neurology practise guidelines recommend that audiometric assessment for children with global developmental delay can include behavioural audiometry or brainstem auditory-evoked response testing when feasible. The report also suggested that transient-evoked otoacoustic emission (TEOAE) testing should be an alternative when other audiometric tests are not feasible.
Pure-tone audiometry (PTA) is one of the common methods of assessment of hearing loss. However, it might not be possible in patients with CP because it is a subjective test that requires an input from the patients. The age of the patients and background neurocognitive problems of CP children are also barriers to the use of PTA in this group of patients. On the other hand, TEOAE is an objective test which is difficult to manipulate by the patient. It was reported to be more sensitive than PTA in early detection of cochlear damage. Therefore, this study assessed the TEOAE findings among children 1–12 years with CP in Kano, Nigeria.
| Materials and Methods|| |
This was a cross sectional descriptive study conducted at the Paediatrics Neurology Clinic and Otorhinolaryngology Clinic of Aminu Kano Teaching Hospital, (AKTH), Kano. Ethical clearance was obtained from the Research and Ethics Committee of the hospital (protocol number: NHREC/21/08/2008/AKTH/EC/2160 dated 28th December 2017). Informed consent was obtained from the parents of study participants before enrolment into the study. The study population were children with CP 1–12 years of age who are on follow-up in the Paediatrics Neurology Clinic of AKTH. An equal number of the control group matched for age and sex were selected from among children at day care attendance and from school children in the same locality with the hospital. Patients excluded from the study were those with history suggestive of ototoxicity, excessive noise exposure, ear disease, ear surgery, head injury, sickle cell anaemia or diabetes mellitus. The study's sample size was calculated using the Fisher's formula for descriptive studies: n = Z2pq/d2 where n = minimum sample size required, Z = 1.96, the standard normal deviate obtained from Z-table, P = 11.9% (0.119) prevalence of hearing impairment in children with CP obtained from a study conducted in Kano,q = complementary probability, P = 1 − P = 1 − 0.119 = 0.881 and d = 0.05 degree of precision at 95% confidence interval (CI). Thus: n = 3.8416 × 0.119 × 0.881/0.05 × 0.05 = 161. This was increased by 10% (16) to cover for attrition. The sample size required was 177. An equal number (177) of age- and gender-matched controls were also required. The total sample was 354. Participants were selected using simple random sampling until the required sample size was reached. The study was conducted over a period of 1 year (April 2018–March 2019). An interviewer-administered questionnaire, specifically designed for the study, was used to collect sociodemographic and relevant clinical information. All study participants underwent detailed ear, nose and throat examinations. Those with ear wax were de-waxed appropriately. Those with gross pathological findings in the ear such as ear discharge and ear deformity were excluded from the study.
The procedure of TEOAE was conducted according to the American Academy of Audiology guideline, using a calibrated otoacoustic emission (OAE) machine, which was a brand of Sentiero advanced hardware OAE machine (manufactured by Guymark Path Medical Solutions, Germany, serial no. 300232, and last calibration in March 2018). With the patient sitting comfortably on a chair (or held by the caregiver in a sitting position among the younger population), the TEOAEs were measured by placing the ear probe component of the machine in the outer part of the ear canal making a tight seal, which present a series of very brief acoustic stimuli in the form of clicks to the ear tested. The result produced, which was digitised and processed by the machine, was displayed on the screen of the machine as a valid or invalid response. A valid response was considered a 'pass', whereas an invalid response was considered as a 'fail assessment'. These tests were conducted individually for each ear, and the findings were recorded on the questionnaire. The tests were conducted in a quiet room in order to obtain an appropriate response and to prevent artefacts, with an ambient noise level of between 33 and 39 dB, which is within the tolerable limit of ambient noise level as recommended by Kemp et al. who found that TEOAE recordings become problematic only when noise levels exceeded 45 dBA.
The data obtained were analysed using Statistical Products and Service Solution version 21 for windows (IBM Inc., Chicago, IL, USA). Data were summarised and presented as quantitative and qualitative variables. Quantitative variables were expressed as mean and standard deviation (SD). Qualitative variables were expressed as frequencies and percentages, and Chi-squared test was used to establish the association between categorical variables in which P = 0.05 or less was considered statistically significant. Logistic regression model analysis was used to establish true associations between categorical variables.
| Results|| |
Out of 354 participants, 330 (165 children with CP and 165 non-CP controls) successfully completed the study. The age range of the participants was 1–12 years, with a mean and SD of 4.44 ± 2.92 among the cases and 4.47 ± 2.90 among the control group. The sex distribution among children with CP was 111 males (67.3%) and 54 females (32.7%), whereas the control group was 99 males (60.0%) and 66 females (40.0%). The age and sex distribution showed matching in both the groups, as shown in [Table 1]
The relevant clinical history shown in [Table 2] revealed that majority of the children with CP (96.4%) were born at term. One hundred and two (61.8%) of them were diagnosed with CP at <1 year of age. The most common risk factor for developing CP was jaundice (39.2%), followed by birth asphyxia (37.5%), febrile illness (13.4%) and seizures (8.9%).
[Figure 1] shows the type of CP found in these patients. The most common type encountered was spastic 78 (47.3%), then mixed 50 (30.3%), hypotonic 16 (9.7%), dyskinetic 14 (8.5%) and ataxic 7 (4.2%).
TEOAEs were failed in the right ear in 135 (81.8%) and in 141 (85.5%) of the left ear, with only 30 (18.2%) and 24 (14.5%) ears passing the test in the right and left sides among the cases, respectively. Among the control group, 47 (28.5%) and 46 (27.9%) failed the test in the right and left ears, respectively. One hundred and eighteen (71.5%) passed the test in the right ear among the controls, whereas 119 (72.1%) passed the test in the left ear. The passed and failed results for both ears are also shown in [Table 3]. A sample of TEOAE result among patients with CP is shown in [Figure 2].
|Table 3: Transient-evoked otoacoustic emissions among cases and controls|
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The result of TEOAEs among children with CP revealed a 'pass' in 27 (16.4%) and a 'fail' in 138 (83.6%) cases. Among the control group, the TEOAE test showed a 'pass' in 118 (71.5%) and 'fail' in 47 (28.5%) children, as shown in [Table 4]. A statistically significant difference was found in TEOAE assessment finding between the cases and the control group (P = 0.0001).
|Table 4: Transient-evoked otoacoustic emission findings among cases and controls|
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[Table 5] shows the association between TEOAE results with sociodemographic and clinical variables. The following variables were found to be significant: age of the child (P = 0.001), admission into neonatal intensive care unit/special care baby unit (NICU/SCBU) (P = 0.030), age at CP diagnosis (P = 0.017) and history of hearing difficulty (0.001). Other factors recorded in [Table 5] were not statistically significant. The variables that were found to be significant at bivariate level of analysis were put into logistic regression model, and the result showed that age of the child (P = 0.036), admission into NICU/SCBU (P = 0.05) and history of hearing difficulty (P = 0.01) were significant predictors for 'fail' TEOAEs. Age at CP diagnosis was not significant predictors for 'fail' TEOAEs [Table 6].
|Table 5: Association between transient-evoked otoacoustic emission results with sociodemographic and clinical variables|
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|Table 6: Predictors of 'fail' transient-evoked otoacoustic emission results among children with cerebral palsy|
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| Discussion|| |
Hearing impairment has been shown to occur more frequently in children with CP than in the general population. In this study, nearly half of the guardians (46.7%) reported hearing difficulty in their children. This high prevalence of hearing loss reported among cases in this study differs significantly from findings of other studies,,,,,,, which revealed lower prevalence rates. These variations in the prevalence of hearing impairment reported most likely result from the differences in the age group of the population of children with CP studied and the type of CP encountered. While audiometry was used to establish hearing loss in few of the studies, quoted, the type of audiological test used in other studies,,,,,, has not been mentioned. It is possible that the hearing impairment reported in the studies was based on clinical observation or guardian reported, rather than due to audiological evaluation.
On TEOAE testing, it was found that 83.6% of the individuals recorded a 'fail' assessment and required referral for further audiometric evaluation. It was also noted that a significant number (28.5%) among the control group also recorded a 'fail' assessment requiring referral. The finding is similar to that obtained in another study using distortion-product otoacoustic emissions, where the prevalence of failed assessment was seen in 83.3% of the cases. It is also closely related to that obtained from another study where the prevalence of 'failed' TEOAEs among children with CP was found to be 65% and also from finding in another study in children with auditory neuropathy with a prevalence of 'failed assessment' seen in 66.7% of the cases. However, it differs from other studies where the prevalence of failed TEOAEs was found to be 20% and 40%, respectively. Explanation to these differences may be as a result of varying study protocols or differences in sample size used. The high results of 'fail' TEOAE assessment in children with CP are due to the fact that the same factors that are known to cause cochlear hearing losses such as hypoxia, prematurity and central nervous system infections with the use of ototoxic agents are also being implicated in CP. The implication of this finding of high 'fail' rate of TEOAE, especially to those health caregivers who attend to children with CP but do not have access to OAE machine, is to have a high index of suspicion of the possibility of sensorineural hearing loss in any child with CP, especially in those with a severe form of the disease.
The study found a significant association between age of the patient, age at diagnosis of CP, admission into SCBU and guardian-reported hearing difficulty with 'failed' TEOAE assessment. When these variables were put into logistic regression analysis, only age of the child (adjusted odds ratio [AOR]: 3.84, 95% CI = 1.09–13.467), admission into SCBU (AOR = 3.168, 95% CI = 1.000–10.041) and history of guardian-reported difficulty (AOR = 6.450, 95% CI = 1.551–26.822) were found to be significant predictors for 'fail' TEOAEs. However, the study does not find a significant association between gender, place of delivery, gestational age at birth and presence of risk factors during neonatal period with TEOAE outcome.
Among the non-CP control group, the 'fail' assessment rate was found to be 28.5% which differs from the finding in another study where the prevalence of failure rate of OAEs in a follow-up study among children in an elementary school was found to be 70.4%. The finding also differs from another study conducted among school-age children where 94.8% of the ears recorded a 'pass' TEOAE assessment. The reason for the high 'failed' assessment among non-CP population from this study may include the presence of subclinical sensorineural hearing loss among some of the children in the control group as well as presence of conductive abnormalities, such as middle ear effusion, since the study was conducted among children some of whom do not have an optimal Eustachian tube function.
The strength of this study lies in the measurement of TEOAEs using a well-calibrated OAE machine of Sentiero Advanced Hardware Company among the population of randomly selected CP patients (that fulfilled the inclusion criteria) and matched controls. It is also important to emphasise that TEOAE is an objective measurement which is difficult to manipulate by the patient. However, one of the limitations of this study was inability to exclude patients with asymptomatic Eustachian dysfunction which can affect the findings of OAEs. OAEs are low-intensity sounds produced by outer hair cells of the cochlear and travel in a reverse direction from the inner ear through middle ear and tympanic membrane to the external ear canal where they are recorded. Once the patient has Eustachian dysfunction or middle ear effusion, the OAEs may not be recorded and/or may be absent.
| Conclusion|| |
This study found a high prevalence of 'fail' TEOAEs in children with CP compared to controls. Therefore, there is a need to include OAE testing as a routine in the evaluation and management of children with CP in our hospitals, especially where routine newborn hearing screening is not available.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]