Congenital cytomegalovirus (cCMV) is an important non-genetic cause of sensorineural hearing loss (SNHL) and is a major cause of neurodevelopmental delay.1,2 Vestibular hypofunction can result in gross motor delay, hypotonia, postural instability and lack of spatial awareness. Vestibular physiotherapy and safety advice may be indicated. Studies have shown that vestibular dysfunction is common in children with cCMV, both in children with and without sensorineural hearing loss.3 Routine screening for and appropriate management of vestibular hypofunction in all children with hearing loss is recommended by NICE-accredited guidelines issued by the British Association of Audiovestibular Physicians.4 An author5 recommended that children with cCMV with and without SNHL be tested for vestibular dysfunction. However, how and when to test vestibular function in children with cCMV is not part of the standard guidelines for the treatment of cCMV in the UK.
Shutterstock / Robert Kneschke. Hearing loss, balance, genetics.
Use of vestibular and balance tests used to assess children with cCMV. Hearing loss, balance, genetics.
Physician perceived obstacles to assessment of vestibular function in children with cCMV. Hearing loss, balance, genetics.
Most referrals to vestibular clinics are made by audiovestibular physicians and pediatricians. That’s why we invited audiovestibular physicians and paediatricians in audiology to participate in a national survey to document current practice in the UK.
MATERIALS & METHODS
An electronic survey asking for details of audiovestibular services and assessments in children with cCMV was designed and tested by four audiovestibular physicians. It was then revised with their feedback and emailed to all 100 members of the British Association of Pediatricians in Audiology and all 25 members of the British Association of Audiovestibular Physicians (BAAP) in the pediatric practice, with completion for three weeks in June 2019. No identifiable information was requested from the patient. Survey questions can be found in Appendix 1.
Twenty-one clinicians responded. This is about half of those with relevant clinics, as 25/50 members of BAAP have been trained in pediatrics and a minority of audiology pediatricians have had vestibular training.
19/21 clinicians reported assessing the vestibular system in children with cCMV: 16/19 performed clinical vestibular assessments in children with cCMV and SNHL, and 11/19 also performed clinical vestibular assessments in children with cCMV and normal hearing.
The most common time to perform vestibular assessments was when diagnosed with hearing impairment (42.1%) or when balance symptoms were reported (36.8%); however, clinicians reported assessing children of all ages. The clinical assessments most often used to assess general equilibrium function are shown in Figure 1 and include the Romberg test, gait assessment, hopping, tandem gait, and one-legged stance. The farmer test and the main thrust test, which specifically test vestibular function, have also been used extensively (see Figure 1). One doctor noted that he would avoid jumping testing in a severely disabled child with cCMV because it may not be safe.
Sixteen clinicians had access to quantitative vestibular function tests. The most commonly used tests were videonystagmography (4/16), the video head pulse test (vHIT) (3/16), and cervical vestibular evoked myogenic potentials (cVEMP) (3/16). Two clinicians used ocular vestibular evoked myogenic potentials (oVEMP), rotation tests, bithermic calorie tests, and mastoid vibrations. The percentage of clinician referrals for quantitative vestibular testing ranged between 0-100% of children with cCMV. Of the 13 clinicians who referred patients for quantitative vestibular testing, 10 (77%) had seen cases with confirmed vestibular dysfunction. A doctor reported that he had diagnosed cCMV in a child who presented primarily with imbalance, rather than hearing loss.
When asked to comment on the treatment of children with CMV and vestibular dysfunction, nearly 80% of respondents said they would refer children with vestibular dysfunction to physical therapy, and 63% said they would provide safety advice or advice regarding activities to promote vestibular balance / function. One respondent noted that they would make a referral for situational counseling, psychological assessment, and a full medical screen for detecting decompensation factors. Another respondent mentioned “tailor-made vestibular / sensory rehabilitation and, where appropriate, input from psychologists for stress management” as a management strategy for children with CMV and vestibular dysfunction.
Several barriers to the assessment of vestibular function were identified: children who were not healthy enough, hearing as a priority, and lack of training, awareness, testing facilities, and time in the clinic (Table 1). Doctors commented on the need for more specialized pediatric vestibular clinics that can be referred to in the UK, with reports that a service had recently been decommissioned.
Vestibular dysfunction in children with cCMV is common, 3 and may be even more common than SNHL. 6. pediatric vestibular clinics in the UK to refer children to.
In this survey, 75% of the treating clinicians regularly assessed children with SNHL and cCMV for vestibular dysfunction, yet the timing and study used varied from physician to physician. Doctors reported a number of obstacles to vestibular testing, including a lack of time, training, awareness, and resources. It is also recognized that children with cCMV with severe neurodevelopmental disorders may not be able to participate in or tolerate some of the assessments indicated to evaluate vestibular function.
Although pediatric vestibular medicine is included in the higher specialist audiovestibular medicine course, it remains a specialized and lesser known field. The UK has an estimated 50 audiovestibular counselors, about half of whom work in a pediatric setting, while there is little formal vestibular training for pediatricians working in audiology. There are only a handful of dedicated pediatric vestibular clinics in the UK.
It is therefore important that all clinicians working in pediatric audiology have access to training and equipment to diagnose vestibular disorders in children with hearing loss. Some tests, such as VEMPs, use equipment that audiology departments already have, and some testing equipment is relatively inexpensive, such as mastoid vibrators, video Frenzel glasses, and vHITs. These tests are relatively well tolerated and could be used more widely to increase access to vestibular tests. The Farmer Test (used up to 6 weeks) and the Head Pulse Test (used for any child who can fixate on a target) are nighttime tests of vestibular function that require no additional equipment and are easy to learn. They can be used as a screening tool in children with cCMV with balance problems and / or delay in gross motor milestones to guide referral for vestibular tests
This survey was limited by the small sample size. Therefore, no conclusions can be drawn on the prevalence of vestibular dysfunction in cCMV cases. It is possible that physicians who worked in the field and / or with relevant experience were more likely to respond, which may mean that an even smaller proportion of children with cCMV are referred for vestibular testing than reported in this study. cCMV itself, despite being the main non-genetic cause of deafness, is underdiagnosed, and not all children diagnosed with vestibular disorder will have tests for cCMV. The ability to retrospectively diagnose children with cCMV by retrieving stored dried blood stains from neonates is essential to diagnose individuals presenting outside the neonate with vestibular dysfunction, and studies for cCMV deserve consideration in future guidelines for the research. of vestibular disorders.
The survey is the first to capture current views and practices in pediatric vestibular medicine in the UK. There is a shortage of trained clinicians and dedicated clinics in this field. Given the recent evidence that vestibular dysfunction is one of the most common consequences of cCMV, the argument is growing for more clinicians with expertise in this field, who can diagnose vestibular dysfunction and advise on appropriate treatment. The inclusion of simple clinical tests of vestibular function assessment in management guidelines for cCMV should be considered, especially when there is a delay in early gross motor milestones, as the diagnosis informs the provision of therapy and safety advice. In addition, consideration should be given to including vestibular function as an outcome measure in future randomized controlled treatment studies.
This research demonstrates the variation in vestibular clinical practice and access to resources. This coupled with NICE-approved guidelines4 recommending that all children with SNHL should undergo a vestibular assessment, and Teissier5 suggesting that all children with cCMV should undergo a vestibular assessment, reinforces the case for increased awareness, training and access to national vestibular research in children.