CCMV Public Health and Policy Conference Series: Pediatric Vestibular Dysfunction

CCMV Public Health and Policy Conference Series: Pediatric Vestibular Dysfunction

Author: Dr. Megan Pesch

In October of 2023, researchers, clinicians and families from around the world gathered in Salt Lake City, Utah for the Congenital CMV Public Health and Policy Conference. It was an exciting three-and-a-half days-- jam packed with presentations about the latest clinical practices and research findings, as well as congenital CMV families sharing their experiences and lessons learned from their own journeys. This series highlights some of the presenters and their work featured at the conference, to share with our NCMVF community. In this installment, Dr. Karen Hendrick and Margot Gray answer questions about pediatric vestibular dysfunction.

Dr. Karen Hendrick is a pediatric audiologist, with a clinical practice specialization in vestibular testing at Children’s Hospital Colorado. Dr. Hendrick received her doctorate of audiology from the University of Washington following an externship at Seattle Children’s Hospital. She has been a practicing audiologist for over 8 years and has focused on building the vestibular program at Children’s Hospital Colorado in these past 5 years. Current research projects include a case series on vestibular findings in pediatric patients with central nervous system disorders including posterior fossa syndrome, multiple sclerosis, and traumatic brain injuries, and a multi-site study on vestibular findings in pediatric patients with congenital cytomegalovirus.

Margot Gray PT, DPT is a pediatric physical therapist at Children’s Hospital Colorado (CHCO). She is the Vestibular Program Lead for the physical therapy program specializing in treating children with vestibular dysfunction and concussion. Margot received her Doctor of Physical Therapy from Regis University in 2013. She has worked at Children’s Hospital Colorado for the past 6 years treating both in and outpatient settings. She currently focuses her practice on seeing children with complex concussion and children with vestibular dysfunction in the outpatient setting. She received her certificate of competency in Pediatric Vestibular Rehabilitation in 2018 and is a member of the CHCO Multidisciplinary Pediatric Vestibular and Balance Disorders Clinic where she helps to diagnose and treat children with vestibular dysfunction. Margot has presented for a variety of audiences on Pediatric Vestibular Rehabilitation at CHCO. She serves as the pediatric liaison for the Vestibular Special Interest Group of the American Physical Therapy Association Neurological Section. She has authored journal articles as well as served as an article reviewer for the Section on Pediatrics Journal.  
 
1. Can you explain what the vestibular system is and how it is related to hearing? 

The vestibular system is part of our overall balance system, and it is located in the inner ear next to the cochlea (hearing organ). Each ear has five vestibular organs that are constantly sensing gravity and movement in every direction. Our ears send this information up the 8^th cranial nerve to our brain, where the central vestibular system processes this information. The brain then sends instructions to the rest of our body to maintain our balance and to stabilize our visual field.
 
In each ear, there are two organs, the saccule and utricle, that sense gravity and linear movement (up/down, forward/backward and side to side). Each ear also has three semicircular canals that sense angular movement (head turning) in all directions. Ears combined, each person has 10 vestibular organs and structures that are constantly sensing movement in every direction and providing this information to the brain.
 
People with sensorineural hearing loss (SNHL) are at risk for vestibular disorders due to the proximity these vestibular organs are to the hearing organ, and the shared endolymph fluid that flows throughout the inner ear structures. People with hearing loss secondary to congenital cytomegalovirus (cCMV) infection are at high risk for vestibular dysfunction because the virus can impact the entire inner ear labyrinth, vestibular and hearing organs included.
 
2. What are vestibular disorders? 

Vestibular dysfunction arises when some of these peripheral organs are not working well, or if the brain is not processing the information correctly. Sometimes vestibular dysfunction occurs in only one ear, leaving the individual with one functioning vestibular system in the normal ear. People can also experience partial vestibular dysfunction if some of the organs in one or both ears are not responding. Complete vestibular hypofunction occurs when all of the vestibular organs are not working, resulting in the brain not receiving the information from the ears.
 
One of the biggest impacts of bilateral vestibular hypofunction is on the vestibular-ocular reflex (VOR). The VOR is a system where the ears and the eyes work together to stabilize vision with head movements. Without a VOR, objects around us may appear to move or “bounce” in response to body movement.
 
3. What might it feel like for a child who has vestibular dysfunction – what sensations might they not feel or experience differently than people with typical vestibular functions? 

How a child feels will depend on the extent of their vestibular dysfunction. When there is partial vestibular dysfunction, the child may feel off balanced when they are in challenging environments such as areas with uneven surfaces, dim lighting, and complex visual stimuli. They may also feel dizzy when moving their head quickly. With bilateral hypofunction, where none of the vestibular organs are working, these children will experience significant imbalance in those environments and may need assistance to navigate safely. These children must rely on their visual and somatosensory systems to maintain their balance and have spatial awareness. If they close their eyes, the only sense they have for knowing where they are in space, is their proprioception, or how the ground feels beneath them. Children with bilateral vestibular hypofunction usually do not report dizziness but may say things “bounce” in their visual field due to a dysfunctional vestibular-ocular reflex (VOR).
 
4. Are children with congenital CMV at increased risk of vestibular dysfunction? 

Children with cCMV, are at risk for vestibular dysfunction, regardless of whether the CMV is symptomatic or asymptomatic and if the child has hearing loss or not. Pinninti and colleagues published a study in 2021 that found vestibular dysfunction in 45% of asymptomatic children, including those with and without hearing loss. Conversely, Bernard et al., 2015, found vestibular dysfunction in 92% of children with symptomatic CMV and severe to profound sensorineural hearing loss. Dhondt and colleagues published a longitudinal study in 2021 revealing that like hearing loss in children with cCMV, vestibular dysfunction can affect one or both ears, can be partial loss or complete hypofunction, and can be progressive. Due to these risks, more and more pediatric centers are including vestibular monitoring as part of their standard of care for infants and children with cCMV.
 
5. How do you monitor/test vestibular function in children with cCMV? 

Similar to hearing loss in this population, vestibular dysfunction can progress in early childhood years, therefore monitoring is recommended. At Children’s Hospital Colorado, we recommend that all children with cCMV have vestibular testing at three ages, or more often if concerns for a change in balance arise. As the child ages, additional tests can be completed that are developmentally appropriate for their age.

• 1 year: Cervical Vestibular Evoked Myogenic Potential (cVEMP) and lateral Head Impulse Test
  • Abnormal results: add Rotational Chair testing
• 3 years: Limited Vestibular Evaluation
  • Cervical Vestibular Evoked Myogenic Potential (cVEMP)
  • Ocular Vestibular Evoked Myogenic Potential (oVEMP)
  • Video Head Impulse Test (vHIT)
  • Rotational Chair testing
• 7 years: Comprehensive Vestibular Evaluation
  • Cervical Vestibular Evoked Myogenic Potential (cVEMP)
  • Ocular Vestibular Evoked Myogenic Potential (oVEMP)
  • Video Head Impulse Test (vHIT)
  • Rotational Chair testing
  • Oculomotor test battery
  • High Frequency Headshake test
  • Positional testing
  • Caloric testing

 
6. We are both lucky to have Pediatric Vestibular Specialists at our centers, mine in Michigan and yours in Colorado. But what about children with cCMV who do not have a Pediatric Vestibular Clinic nearby or even in their state? Is there any other testing or screening that could be done by a local provider? 

While diagnostic vestibular results are helpful for customizing a treatment strategy, they are not required to get started on vestibular rehabilitation therapy. There are bedside screens and questionnaires that can help identify when vestibular dysfunction is likely present in this high-risk population.
 
Gross motor delays will be one of the earliest “red flags” for vestibular involvement in children with cCMV. If your child is not meeting these milestones, a physical therapy evaluation is warranted.

• Sitting independently by 8 months
• Walking independently by 15 months 

There are some simple gross motor screens that can be completed with older children with cCMV. If they are unable to complete these tasks without falling or needing to open their eyes, a physical therapy evaluation is warranted.

• 2-year-olds: Stand on two feet with eyes closed for 5 seconds
• 3-year-olds: Stand on tandem feet with eyes closed for 5 seconds
• 4 to 6-year-olds: Stand on one leg with eyes closed for 8 seconds
• 7 years and older: Modified Clinical Test of Sensory Interaction on Balance (mCTSIB)

 
7. What treatments are available for children with vestibular dysfunction?

Vestibular physical therapy is performed by a physical therapist with extensive training in vestibular rehabilitation. Physical therapy interventions may look different in young children compared to older children and adolescents. Younger children can present with gross motor developmental delay secondary to vestibular dysfunction. Treatment sessions will be more focused on the child attaining gross motor skills while incorporating methods to treat the vestibular system. Vestibular rehabilitation in older children and adolescents can include exercises for improving vision with head movements, dizziness and balance.  All physical therapy plans of care are designed to meet the individual needs and goals of the patient and their family.  Physical therapy appointments may be weekly, biweekly or monthly depending on the impairments and functional limitations of the patient.

8. Where can a physical therapist seek further training in vestibular rehabilitation in children?

The “Pediatric Vestibular Rehabilitation Competency Course” is offered annually in Jacksonville, Florida. In this 5-day course, physical therapists will learn how to identify and treat pediatric vestibular disorders. It is taught by leaders in clinical practice and research including Jennifer Braswell-Christy, PT, PhD and Rose Marie Rine, PT, PhD.  

Here are some resources for physical therapists to get started on learning more about vestibular rehabilitation:

https://specialtytherapy.com/ (online training, CEUs included)

Recognizing Vestibular Problems in Children (PDF)

Part I: Pediatric Vestibular Disorders. Vestibular Impairments in Children: Incidence, Diagnoses, Assessment and Intervention (PDF)

Part II: Pediatric Vestibular Disorders. Vestibular Assessment for Children (PDF)

Part III: Pediatric Vestibular Disorders. Effective Intervention or Treatment for Vestibular Related Impairments in Children (PDF)

9. What are some of your favorite resources and websites for families who want to learn more about vestibular dysfunction?

Vestibular Disorders Association: https://vestibular.org/