| 1. Introduction |
Otitis media with effusion (OME), or “glue or effusion ear,” has been defined as serous to thick fluid in the middle ear without symptoms of acute infection that can cause temporary hearing loss.1-3
Otitis media with effusion is considered a common cause of vestibular impairment and movement disorganization in pediatrics.4 However, there are a small number of studies on the relationship between vestibular hypofunction and OME in pediatrics.4
Chronic OME has been identified as one of the main causes of balance instability and vertigo in pediatrics.5, 6
Rosenfeld et al 2 suggested that persistent fluid in the middle ear, originating from OME, could lead to reduced mobility of the tympanic membrane and negatively affect sound conduction. Approximately 25% of chronic OME episodes lasting more than three months negatively affect hearing, vestibular function, behavior, school performance, and quality of life.2
Many researchers have evaluated the effect of OME on postural stability in children; However, none of these studies analyzed changes in postural stability depending on the functional status of the middle ear.6. Middle ear dysfunction includes partial or complete blockage of the Eustachian tube that contributes to chronic ear infections and failure to effectively regulate ear pressure. 7
Recent research shows that during recurrent episodes of OME, children have abnormal balance and vestibular hypofunction.8 Because OME is the most common disease in pediatrics, it is important to examine their postural stability, vestibular system, and motor function both during presence and absence of episodes to know if the child is at risk of having these problems.8
The main reason parents of children with OME consult an otolaryngologist is hearing loss, which is the most common complication of OME.9 Williamson3 determined that 91% of children between the ages of two months and two years will experience an episode of OME, and 52% of them will have a mid-bilateral effusion.3
Risk factors that have been described in case-control studies include daycare attendance, age six years or younger, exposure to passive smoking, repeated upper respiratory tract infections, and a significant number of siblings.3
Robb and Williamson1 reported that there is a bimodal peak of incidence in children between two and five years of age, and that OME episodes resolve spontaneously within three months in approximately half of cases. The vestibular, visual, and proprioceptive systems are the primary components that provide postural stability.5 When one of the three postural stability systems becomes dysfunctional, vestibular compensatory efforts increase.5
Structural complications in children with middle ear effusion are present in the tympanic membrane and ossicular chain of the ear.10 Reddy 11 reported that lack of ventilation of the Eustachian tube plays an important role in the development of OME. Eustachian tube dysfunction is the lack of its ability to adequately perform the minimum of its functions, which are hearing protection, ventilation of the middle ear, and mucociliary clearance of the middle ear.
Impaired pressure regulation and ventilation of the middle ear due to Eustachian tube obstruction leads to increased negative pressure in the middle ear. The angle and length of the Eustachian tube are more horizontal and shorter in babies than in adults. The angle becomes more vertical and longer with age as children grow, and these developmental changes are greatest between the ages of three to four years.12 Takasaki et al.12 reported that there was no statistical difference between the angle and Eustachian tube length in infants with and without OME.
Rosenfeld et al2 reported that 90% of children have OME before school age and have, on average, one episode per year. This shows how common this disease is in pediatrics and is why it is now called “early childhood occupational risk.”2
Postural stability and balance are important components for functional and purposeful movement.13 The mechanism of how OME affects postural stability has been explained as subsequent changes in the ion channels of the kinocilia and stereocilia due to the transfer of ions through of the semipermeable membrane that affects balance.5 This transfer changes the normal chemical composition of the endolymph and perilymph within the inner ear, which can affect balance.5 Children learn by interacting and exploring their environment.13
Casselbrant et al14 suggested that children with OME who had vestibular hypofunction may rely solely on the visual and proprioceptive systems to support postural stability. Postural sway in children with OME is greater than in children without OME when responding to a visually moving object.14 To identify the importance of the vestibular system in the management of OME in pediatrics, more studies are needed.14
Postural stability and the vestibular system in children with recurrent OME may or may not completely improve once the disease resolves.9 To avoid complications in the child’s sensory integration development, early intervention should be considered.9
Current OME clinical practice guidelines strongly recommend insertion of a tympanostomy tube to treat children with OME lasting three months or longer.2 This procedure involves placing a surgical tube through a myringotomy incision to ventilate middle ear pressure.15 It is the most common outpatient surgery performed in the United States, with 667,000 children under the age of 15 undergoing the surgery annually15
The objectives of this study were to examine the effect of multiple ear infections on pediatric postural stability and visual overdependence.
It was hypothesized that postural stability would be worse in children with a history of multiple ear infections compared to children without such a history and children with a history of multiple ear infections would be more visually dependent on maintaining postural stability than those that they don’t have them.
| 2. Methods |
Forty children aged 10 to 12 years with and without a history of multiple ear infections and/or tympanostomy tubes before the age of five were recruited for this study from the local community.
Based on parental self-report to a single question, participants were divided into two groups (18 participants with a history of tympanostomy tubes and/or 3 or more ear infections before age five and 22 participants with no history of tympanostomy tubes and/or 3 or more ear infections before age five. tympanostomy and 0-2 ear infections before the age of five).
Participants who had balance and gait disorders, seizure disorders, uncorrected visual impairments, and/or medications affecting balance were excluded. Parents of all participants signed the informed consent approved by the Loma Linda University Institutional Review Board prior to participation in the study, and the children then also read and signed the informed consent.
The Physical Activity Questionnaire for Children (PAQ C) was used to assess the general activity level of children.4 The PAQ-C was developed for primary school-aged children aged 8 to 14 years and is a nine-item questionnaire related with the memory of the child’s last seven days of physical activity.
The total score was calculated by taking the average of the 9 items. A score of 1 indicated low physical activity, while a score of 5 indicated a high level of physical activity for the child.16 Voss et al 17 reported that the PAQ-C is a valid and reliable tool used to assess physical activity. level of physical activity in healthy children of primary school age.
Postural stability was measured using three different assessment tools: the Bertec Balance Advantage Computerized Dynamic Posturography with Immersive Virtual Reality (CDP-IVR), the Pediatric Balance Scale (PBS), and the NeuroCom Computerized Dynamic Posturographic Stability Assessment Test. ® VSR ™ SPORT (SET). The CDP-IVR measured static postural stability by calculating participants’ center of gravity displacements in three conditions.18
Condition 1 measured baseline postural stability using a stable force plate with eyes open. Condition 2 measured postural stability on a stable force platform with eyes open and focusing on a virtual reality infinite tunnel. Condition 3 measures postural stability in an unenclosed location.
Each condition included three 20-s trials, and the average of the three trials was calculated for each condition. The CDP-IVR calculates postural stability and generates a balance score as follows: signals of participants’ effort to maintain balance were sampled and analyzed at 1000 Hertz, and the sway trajectory was calculated.
The testing protocol calculates the sway trajectory with balance scores quantified by how well the participants’ sway remains within the expected angular limits of stability during each test condition. The following formula was used to calculate the balance score: balance score ð ESÞ = ð½12: 5 degrees - ð the taMAX - the taMIN: / 12: 5 degrees∗. 100.
The ES uses 12.5° as the normal limit of the anterior-posterior roll angle range, taMAX is theta maximum and taMIN is theta minimum. The sway angle was calculated as follows: sway angle = arcsin ðCOGy / ð: 55 ∗ hÞÞ, where y is the anteroposterior axis of sway and h is the height of the participant in cm or inches.
The inverse sine of the center of gravity was divided by 55% of the subject’s height. Participants who exhibit little sway achieve balance scores close to 100, while participants who exhibit more sway achieve balance scores further from 100. 19
The PBS was used to assess balance in the participants. The PBS is a 14-item, criterion-referenced, non-computerized tool that measures static and dynamic functional balance of daily activities in children. 19, 20
PBS tasks include elements such as sit-to-stand, transfers, and 360-degree turns.19, 20 Yi et al21 reported that the PBS is a simple and valid tool that could be used in pediatric rehabilitation to examine functional balance and predict ability and motor capacity.
Furthermore, Chen et al22 reported that the PBS is a valid tool to examine functional balance in children with cerebral palsy. Franjoine et al 23 reported that the PBS is a reliable tool for assessing balance in school-aged children with mild to moderate motor impairments.
Postural stability was also measured using SET. The SET has good to excellent reliability for measuring postural stability (ICC = 0:93; 95% CI: 0.88, 0.95) with significant practice effects (p < 0:05). 24 Static postural stability was tested on a stable surface in three conditions.
• SET condition 1 measured postural stability with a narrow two-limb stance on a firm surface.
• SET Condition 2 measured postural stability with a single-limb stance on a firm surface.
• SET condition 3 measured postural stability with a tandem stance (dominant foot behind) on a firm surface.
• SET condition 4 measured postural stability with a narrow two-limb stance on an unstable surface.
• SET condition 5 measured postural stability with a single-limb stance on an unstable surface.
• SET condition 6 measured postural stability with a tandem stance (dominant foot behind) on an unstable surface.
In all conditions, participants closed their eyes and placed their hands on the iliac crests. The SET protocol quantifies center of gravity sway or postural stability as a weighted average of the six conditions.
| 3. Procedures |
Participants completed the PAQ-C. Before the postural stability test, participants removed their shoes and socks, followed by height and weight measurements. Participants put on a safety harness before measuring postural stability. Postural stability was measured using three different assessment tools. Postural stability was first measured using the CDP IVR in the three conditions described above.
The participant’s postural stability was then measured using the PBS. Each item ranged from 0 (unable to perform) to 4 (able to perform the task without difficulty independently according to instructions). Participants received verbal and visual instructions for each item. One trial was provided to each participant.
A second test was performed if the participant was unable to understand the verbal or visual instructions. Finally, postural stability was measured using the SET, which measured static postural stability on a stable surface in six conditions, including a two-limb stance, a single-limb stance, and a tandem stance (dominant foot behind).
In each condition, participants closed their eyes and placed their hands on their iliac crests. The same three conditions were repeated on a foam surface to test postural stability on an unstable surface.
Data analysis was performed using SPSS version 24.0. A sample size of 42 subjects was estimated using an effect size (d = 0:90), a power of 0.80, and a significance level set at 0.05. General characteristics of participants were summarized using means and standard deviations for quantitative variables and counts and percentage ages for categorical variables.
The gender frequency distribution was compared between the two study groups using the chi-square test. Normality of continuous variables was examined using the Shapiro-Wilk test and box plots.
Mean age, BMI, and postural stability were compared during conditions one, two, and three, two-leg stance on stable and foam surfaces, single-leg stance on stable and foam surfaces, and tandem stance. on a stable surface using the independent t test.
The distribution of postural stability during a tandem stance on a foam surface and PBS scores were not approximately normal and therefore the Mann-Whitney test was used to examine differences in mean stability scores between the two groups. The level of significance was set at p ≤ 0:05.
| 4. Results |
Forty children (20 males and 20 females) with a mean age of 10:7 ± 0:8 years participated in this study. The study sample consisted of 18 children with a history of tympanostomy tubes and/or 3 or more ear infections and 22 children without a history of tympanostomy tubes and/or 0-2 ear infections. Baseline characteristics were similar between the two groups (p > 0:05).
There was no significant difference in mean postural stability in CDP-IVR at baseline, eyes open, eyes closed, and immersive virtual reality conditions. Furthermore, no significant differences were observed in mean postural stability on the SET during a two-leg stance on firm and unstable surfaces, a one-leg stance on firm and unstable surfaces, and a tandem stance on a firm surface (p > 0 :05).
A significant difference was found in the mean postural stability scores on the SET during tandem stance on an unstable surface between the two groups (median (minimum maximum) of 9.1 (1.4, 11.4) versus 5. 8 (1.7, 12.8), p = 0:04). Additionally, there was a significant difference in mean PBS scores between participants with and without ear infection (54 (47, 56) versus 56 (55, 56), p = 0:001).
| 5. Discussion |
The present study investigated the effects of chronic pediatric ear infections, before age five, on postural stability in children aged 10 to 12 years with a history of tympanostomy tubes and/or 3 or more ear infections compared to those without a history of tympanostomy tubes. and/or 0-2 ear infections by using CDP-IVR, SET and PBS.
Results determined that tandem stance in both the SET and PBS caused the greatest postural instability in children with a history of tympanostomy tubes and/or 3 or more ear infections. Additionally, tandem stance with eyes closed on an unstable surface was more challenging for children with a history of tympanic tubes and or more ear infections.
Casselbrant et al 8 reported that during recurrent episodes of OME, children have abnormal balance and vestibular hypofunction. Furthermore, postural stability and the vestibular system in children with recurrent OME may or may not completely improve once the OME episode resolves.9 The results of the present study support these findings and suggest that postural stability did not completely improve after of the OME resolution.
Casselbrant et al14 suggested that children with OME and vestibular hypofunction may rely solely on the visual and proprioceptive systems to support postural stability. They used a posture platform with a visual environment (EquiTest, NeuroCom, Inc.) in three conditions: no visual scene motion, scene motion at 0.10 Hz, and scene motion at 0.25 Hz to test the dependence of visual balance.
In the present study, there was no significant difference in mean postural stability during eyes closed or during immersive virtual reality conditions. The results suggest that children with OME do not exaggerate their visual system to compensate for their abnormal postural stability. This could be related to the fact that all participants were active as measured by the PAQ-C. However, children with a history of multiple ear infections who have lower activity levels may present differently. 25, 26
The CDP-IVR measures static postural stability by calculating participants’ center of gravity displacements in three conditions.18 The SET measures postural stability as sway speed in degrees per second under several different test conditions. 27
Participants assume a broader base of support during CDP-IVR compared to the SET protocol, which could be the reason for the different results between SET and CDP-IVR. In this study, there was no significant difference in mean postural stability during the eyes-closed or immersive virtual reality conditions of CDP IVR, but differences were found between groups during the SET protocol.
This study had some limitations. The study sample included few participants with a history of tympanostomy tubes. Additionally, group assignment was based on self-report. Additionally, blinding was not used during PBS, introducing the possibility of examiner bias.
Future investigators should consider recruiting children with a history of tympanostomy tubes, children with a history of multiple ear infections who have low activity levels, and having parents of participants provide medical records regarding history of tympanostomy tubes. thymus and ear infections. Additionally, participants in both groups were physically active.
Future researchers should consider recruiting participants with lower activity levels, as physical activity level may have a positive impact on postural stability in children with tubal and/or 3 or more ear infections before age five. years.
In conclusion , the results of this study suggest that children aged 10 to 12 years with a history of tympanostomy tubes and/or 3 or more ear infections before age five have decreased postural stability compared to children without a history of tympanostomy tubes and/or 0-2 ear infections.
The results suggest that alterations in postural stability persist even after resolution of ear infections in early childhood. Future studies should evaluate the effects of postural stability exercises in children with a history of tympanostomy tubes and/or 3 or more ear infections before age five.
