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Introduction
Cleft lip and palate are a common facial deformity that may involve cleft lip, lip and palate, or palate only [1]. A cleft palate specifically is a congenital abnormality affecting the secondary palate, which may be unilateral, bilateral, complete, or incomplete [2, 3]. Children with cleft palate frequently experience hearing problems, including otitis media, which is characterized by fluid accumulation in the middle ear leading to an ear infection. This occurs due to abnormal functioning of the tensor veli palatini and levator veli muscles, which causes a lack of ventilation in the middle ear cavity and subsequent fluid buildup. These conditions usually manifest within the first six months of life in children with cleft palate [4, 5]. The objective of treating children with cleft lip and palate is to achieve normal speech, eating, teeth, aesthetic appearance, psychological function, and hearing [5, 6]. Cleft lip surgery is typically conducted at approximately three months of age, while cleft palate surgery is performed around six months of age [5, 6].
Tympanometry is the most reliable method for assessing middle ear conditions in children with cleft palate, as confirmed by exploratory surgery. Tympanometry has a sensitivity of 95.6% and specificity of 59.6% in diagnosing middle ear diseases in these children [7]. Single-frequency tympanometry using a 226 Hz tone probe is more effective at identifying injuries related to middle ear stiffness, whereas a high-frequency tone probe, such as 1000 Hz or 678 Hz is more effective at identifying injuries related to mass [8]. Broadband reflectance can be used for infants with small ears and narrow canals because it has fewer probe-sealing problems. Compared to high-frequency tympanometry, it is also more sensitive to middle ear disorders [9]. Wideband tympanometry is a novel method for assessing impedance, admittance, absorption, and reflectance of the middle ear. It provides more diagnostic information than conventional methods without requiring additional measures and takes the same amount of time as conventional tympanometry. This technique involves recording several tympanograms over a wide frequency range from 250 Hz to 8000 Hz using a wideband click stimulus. In addition to the information available in conventional methods, this technique also provides additional information, such as a graph of sound energy absorption, resonance frequency (RF), and average tympanogram. Studies have revealed that the amount of middle ear energy absorbance is lower at frequencies below 1000 Hz and above 4000 Hz [9]. Since conventional tympanometry findings have low sensitivity and do not exhibit significant changes after surgery [10, 11]; accordingly, this study investigates the middle ear condition of individuals with cleft palate before and after surgery using the wideband tympanometry.

Materials and Methods
The research utilized a longitudinal approach with repeated assessments, employing a descriptive-analytical design. The study participants included individuals with cleft lips who sought medical care at Ali-Asghar Hospital and Hazrat-e-Fatemeh Hospital in Tehran City, Iran. The study employed a non-random sampling technique to select participants based on the availability and willingness of their parents to participate. The sample size was established using G*Power software and data from a previous study conducted by Hunter et al. (2008) [12]. A total of 14 participants (8 boys and 6 girls) were determined to be necessary with a power of 0.8 and a significance level of 0.05. 
The inclusion criteria were confirmation of cleft palate by an ear, nose, and throat doctor or plastic surgeon expert, scheduling of cleft palate repair surgery for the child, and an age range of 4 months to 2 years. Meanwhile, the exclusion criteria were parental unwillingness to continue cooperation and the presence of acute otitis media identified after the initial evaluation.
The Titan Wideband Tympanometry device (Interacoustics, Denmark) was used to record wideband tympanometric responses. Additionally, a questionnaire was administered to gather personal and contextual information. The first assessment was conducted before the cleft palate surgery, while the second evaluation took place approximately one month after the surgery to evaluate changes in wideband tympanometry findings. 
The study evaluated various variables, including middle ear pressure, middle ear absorption percentage, external ear canal volume, admittance at five frequencies (226 Hz, 678 Hz, 800 Hz, 1000 Hz, and resonance frequency), tympanogram width at five frequencies, and middle ear pressure at five frequencies [13, 14]. Non-parametric Wilcoxon tests were used to compare the variables due to the small sample size and non-normal distribution of the data. The SPSS software, version 23 was used for data analysis.

Results
To investigate the impact of surgery on middle ear function, the study utilized the Wilcoxon signed-rank test. The results, as presented in Table 1, demonstrated significant differences between pre- and post-surgery values for middle ear pressure, resonance frequency, and absorption percentage.


The study found that middle ear pressure significantly decreased after surgery, with a mean difference of -89.50 (w=231917.50, P<0.001). Resonance frequency also showed a significant increase, with a mean difference of 887.46 (w=0.00, P<0.001). Similarly, the absorption percentage significantly increased after surgery, with a mean difference of 38.14 (w=1773.00, P<0.001). However, no significant difference was observed in ear canal volume before and after surgery (mean difference=0.00, w=154047.00, P=0.73). These findings highlight the substantial impact of surgery on middle ear function, specifically changes in middle ear pressure, resonance frequency, and absorption percentage. 
Table 2 presents a detailed comparison of admittance, tympanogram width, and middle ear pressure before and after cleft palate repair at five different frequencies.


The results provide a clear understanding of the impact of surgical intervention on middle ear function. The study found a significant improvement in admittance at all frequencies after cleft palate repair. The mean admittance values notably increased, ranging from 0.32 to 0.36, compared to the preoperative values (P<0.001). Similarly, resonance frequency demonstrated a significant increase in admittance, indicating improved middle ear compliance and resonance characteristics (P<0.001). Also, a significant reduction in tympanogram width at all evaluated frequencies after cleft palate repair was observed. The mean differences ranged from -151.03 to -185.60, indicating a narrower range of pressure variation in the middle ear post-surgery (P<0.001). This reduction suggests improved middle ear stability and a more precise pressure regulation system. Cleft palate repair surgery also resulted in a meaningful increase in middle ear pressure across all frequencies, with mean differences ranging from 45.74 to 103.10 (P<0.001). This suggests that the surgery led to improved middle ear function and better regulation of pressure between ambient and middle ear pressure. 

Discussion
This study examines middle ear function in pediatric patients with cleft palate and lip before and after surgical intervention, using wideband tympanometry. The results showed significant impairment in middle ear function before surgery, as indicated by all measured parameters. Wideband tympanometry demonstrated higher sensitivity for identifying middle ear pathology at lower frequencies (226 Hz) compared to conventional tympanometry. This was due to its more comprehensive analysis of the middle ear, which covers a wider range of frequencies, distinguishing it from the limited low-frequency measurement of traditional tympanometry. Overall, these findings underscore the efficacy of wideband tympanometry in evaluating middle ear function in children with cleft palate and lip, both before and after surgical intervention. Moreover, the study identified a postoperative increase in resonant frequency, denoting improved energy transmission, particularly at higher frequencies. These observations concur with previous research, such as the work by Wimmer et al. (2010), emphasizing the diagnostic relevance of high-frequency tympanometry for accurate assessment of increased energy transmission or resonance [8].
Additionally, average acoustic admittance at frequencies of 226 Hz, 678 Hz, 800 Hz, and 1000 Hz, along with resonance frequency and pre-and post-operative resonant frequencies, were examined. The results showed an overall increase in acoustic admittance at all five frequencies following surgery, indicating improved middle ear function. These findings are consistent with a previous study by Tunçbilek et al. (2003) on a group of 50 children with cleft palate, which observed a reduction in middle ear pathologies, including type B and C tympanograms, accompanied by decreased acoustic admittance [15]. The study suggests that regular postoperative evaluations of middle ear function and auditory status are important for individuals with cleft palate.
Furthermore, tympanogram width at frequencies of 226 Hz, 678 Hz, 800 Hz, and 1000 Hz, and resonance frequency along with pre-and post-operative resonant frequencies, were compared. Tympanogram width represents the interval between two pressure points at which the tympanogram reaches 50% of its peak admittance. The results indicated a reduced tympanogram width at all five frequencies following surgery, suggesting a sharper peak and improved middle ear conditions. This finding supports the significance of early management in children with cleft palate, as emphasized by Robinson et al. (1992), which includes the timely insertion of ventilation tubes to ensure adequate hearing and contribute to a narrower peak and diminished tympanogram width [10].
Moreover, the average peak pressure in the middle ear at frequencies of 226 Hz, 678 Hz, 800 Hz, and 1000 Hz, and resonance frequency were compared before and after surgery. The results showed a negative reduction in peak pressure at all five frequencies, indicating improved middle ear function post-surgery. These findings are consistent with previous research by Keefe et al. (2012) which demonstrated that wideband tympanometry is more sensitive than 226 Hz tympanometry in predicting negative middle ear pressure and subsequent hearing loss [16]. Additionally, cleft palate closure through surgery can result in a reduction in middle ear pathologies, negative middle ear pressure, and auditory disorders, thereby mitigating the detrimental effects associated with the condition [17]. Overall, these findings underscore the importance of timely and effective surgical intervention for individuals with cleft palate to improve middle ear function and reduce related complications.

Conclusion
The current study utilized wideband tympanometry to evaluate middle ear function in children with cleft palate and lip before and after surgery. The results highlighted compromised pre-operative middle ear function, with wideband tympanometry showing superior diagnostic capacity compared to conventional techniques and offering enhanced precision in evaluating middle ear function in this patient population. Furthermore, wideband tympanometry was found to be a feasible option for newborns with narrow and small ear canals and demonstrated higher sensitivity in diagnosing middle ear pathologies compared to high-frequency tympanometry. As such, this study suggests that wideband tympanometry has significant potential as an alternative tool in clinical practice for assessing middle ear function.

Study limitations and future research recommendations
This study encountered several limitations that may impact the generalizability of its findings. Firstly, the emergence of the COVID-19 pandemic restricted access to potential patients. The ban on intercity travel, the quarantine of cities, and the reluctance of individuals to leave their homes resulted in a smaller sample size than originally intended. This smaller sample size may impact the generalizability of the findings. Another limitation was that the hearing evaluations used in the study required a significant amount of time and effort from participants, which may have led to fatigue and decreased compliance. This limited the feasibility of examining other hearing evaluations.
Future studies could be conducted on a larger scale with a larger sample size and the inclusion of additional hearing tests that can provide further insights into the auditory system’s functioning. Additionally, periodic follow-up assessments of patients could be conducted to evaluate the success of the surgery and assess the function of the middle ear over time. This would provide a more comprehensive understanding of the long-term outcomes of the intervention and help identify any potential complications or issues that may arise with time. 

Ethical Considerations
Compliance with ethical guidelines
The study received ethical approval from the Ethics Committee of Iran University of Medical Sciences (Code: IR.IUMS.REC.1399.779). 

Funding
This study was extracted from the master's thesis of Atefeh Kazemi, approved by the Department of Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, and was supported by Iran University of Medical Sciences (No.: 0-1-6-19855).

Authors' contributions
Conceptualization: All authors; Data collection, writing the original draft: Atefeh Kazemi; Statistical analysis: Malihe Mazaher Yazdi; Project administration: Mohsen Ahadi and Abbas Kazemi Ashtiani; Study design, review and editing: Mohsen Ahadi: Malihe Mazaher Yazdi and Abbas Kazemi Ashtiani; Supervision: Mohsen Ahadi.

Conflict of interest
The authors declared no conflict of interest. 

Acknowledgments
The authors thank Nahid Jalilehvand, for her support and contribution in referring the patients. Her involvement was essential in allowing us to gather the required data. The authors express our gratitude to all those families who participated in the study. 
 

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