Physiology of Balance in Children

11.2.1 Maturation and Development

In children, as in adults, the maintenance of equilibrium depends on sensory input from three major systems:

• 
  

  Proprioceptive.

  
  
• 
  

  Visual.

  
  
• 
  

  Vestibular.

In addition, cognitive function plays an important role.

Motor control of movement rests in the cerebral cortex, and the responses to afferent input are modified and processed in the brainstem and the cerebellum ( ▶ Fig. 11.1). Pathology in any of these systems can and does cause dysequilibrium.

In order to achieve postural control, these visual, vestibular, and proprioceptive inputs need to develop and be successfully integrated.

The balance system constantly improves and matures from birth to adulthood. Although all systems are anatomically present from birth, they need time to mature during childhood and adolescence.

A successful balance strategy includes inputs from each of the three systems, and the relative importance of visual, proprioceptive, and vestibular system changes during development. Growth and postural maturity proceeds cephalocaudally, with the baby achieving head control first and standing stability later.

The relative predominance of each of the three systems that control the physiology of balance at any one time during childhood is uncertain, but it seems that very young children in the process of acquiring balance rely much on visual input. Adults in contrast rely much more on somatosensory inputs. ^{1,​ 6}

The mature vestibular system can suppress incongruent information, but this maturity is probably not reached until the age of 12 years, so children are less well able to select and control misleading visual information. ⁷ Among the three sensory inputs, the vestibular system is the least efficient and the last to develop in children, not reaching maturity before the age of 10 to 15 years. ^{6,​ 8,​ 9}

The relative dominance of different components of the system varies not only during development but also from child to child. This variable maturation helps to explain the changing patterns of differential diagnosis of imbalance in children.

11.2.2 Vestibular Reflexes

Afferent impulses from the visual, vestibular, and somatosensory/proprioceptive systems are processed in the vestibular nuclei and the cerebellum and are converted into efferent impulses to the muscles controlling the eyes, neck, and spinal cord ( ▶ Fig. 11.1).

These vestibular reflexes (vestibulo-ocular, vestibulocollic, and vestibulospinal) allow us to maintain balance.

The responses differ between various age groups, and their examination can provide diagnostic help in evaluating the complaint of dizziness and disequilibrium. Their assessment can guide us in the diagnosis of vestibular pathology.

Vestibulo-Ocular Reflex

The vestibulo-ocular reflex (VOR) stabilizes the image on the retina during head movement through a reflexive eye movement opposite to the direction of head movement.

Both semicircular canals and the otolith organs are involved in this reflex arc.

• 
  

  It can be assessed by caloric testing, which mainly tests the horizontal semicircular canal.

  
  
• 
  

  A simple but effective way to measure vestibular function in the older child in the office is the “head impulse test,” which involves the examiner moving the patient’s head to the left to stimulate the semicircular canal in the left ear, observing the eye movement response while the patient tries to keep looking at a stationary target straight ahead, and repeating the maneuver for the right ear.

The VOR is present at birth but develops throughout childhood. Full maturity might only happen in preadolescence, ¹ but an absent VOR by the age of 10 months is considered abnormal.

Vestibulocollic Reflex

This helps to stabilize vision while the body is in motion by minimizing head movement and head bobbing through engagement of neck muscles. The main vestibular organ involved is the saccule.

The vestibulocollic reflex can be specifically tested through vestibular evoked myogenic potentials (VEMPs). This gives information about saccular and inferior vestibular nerve function but these are specialized and rarely needed in everyday clinical practice.

The reflex is present at birth but continues to mature into adolescence.

Vestibulospinal Reflex

The vestibulospinal reflex helps stabilize the body in relationship to gravity. The afferents combine proprioceptive input from the periphery, as well as visual and labyrinthine afferents. It is tested with basic balance tests like Romberg’s test.

It is also present at birth and continues to mature into adolescence.

11.3 Clinical Presentation

Children and their parents seldom complain directly of “dizziness,” as particularly young children are unable to articulate this.

The incidence from large epidemiological studies and even from special interest clinics is quoted to be less than 1%. ^{10,​ 11}

The consultation will typically be initiated by parents who might have noticed the child being “clumsy” or not meeting the milestones his/her peers or siblings have.

The presentation can be varied and includes unsteadiness, clinginess and fretfulness, crying, and torticollis. The older child and teenager can be more precise in their description of the symptoms, but even here difficulties in verbalization arise.

Through a combination of history and examination in most cases, a diagnosis can be reached in the outpatient department and treatment or appropriate referral instigated.

11.3.1 History

A systematic approach to questioning can lead to important clinical information ( ▶ Table 11.1).

True vertigo points toward a vestibular origin, but this level of clarity and accuracy in the description and characterization of symptoms is rare, even in adults. If the imbalance is aggravated by movement, this points further to a vestibular origin of the problem. Turning over in bed or other quick head movements worsen or set off benign paroxysmal postural vertigo (BPPV), and straining worsens the vertigo caused by the very rare “third window” phenomena such as perilymph fistula.

The duration of symptoms can be divided into:

• 
  

  Seconds to minutes.

  
  
• 
  

  Hours.

  
  
• 
  

  Days to weeks.

Very short-lived episodes (typically seconds) indicate BPPV. Endolymphatic hydrops symptoms last for hours or occasionally days but the pattern can be similar for the more common migrainous disorders, and the symptoms of vestibular neuritis or labyrinthitis can last for days to weeks.

It is important to note that children will compensate much more quickly than adults and will often recover in days rather than in weeks and months.

Associated symptoms are of particular importance and will help delineate between otological, neurologic, and other origins of symptoms.

• 
  

  Nausea and/or vomiting are indicative of vestibular involvement but can also be associated with migraines.

  
  
• 
  

  Syncope, loss of consciousness, headaches, and seizures or “fitting” point to a central (i.e., neurologic) origin of symptoms.

  
  
• 
  

  Tinnitus, aural fullness, and hearing loss, particularly when these symptoms are fluctuant, can be an indication of endolymphatic hydrops.

  
  
• 
  

  Sweating, palpitations, lightheadedness, or dyspnea in association with balance dysfunction can point toward orthostatic reactions. Adolescent girls are particularly susceptible to this, probably because of the rapid physiological changes associated with puberty and the commencement of menstruation, but endocrine and metabolic changes in boys can also precipitate balance dysfunction.

  
  
• 
  

  A history of sensorineural hearing loss (SNHL) may be related to a syndromic, nonsyndromic, congenital, or acquired cause of deafness, and such presentations warrant further investigations.

  
  
  
  

  
  

  “Dizzy spells,” sometimes with hyperventilation, are a common component of anxiety or panic attacks in both sexes.

The most common diagnoses in children with balance disorders involve the migrainous spectrum including migraine precursors such as:

• 
  

  Migrainous vertigo.

  
  
• 
  

  Benign paroxysmal vertigo of childhood (BPVC).

  
  
• 
  

  Paroxysmal torticollis.

Headaches can be very variable or even absent and do not necessarily have to be in a specific location or to have a typical temporal relation to the dizziness. ¹²

The background medical and family history may provide obvious pointers to the differential diagnosis.

Neurologic deficit and declining hearing after head trauma should prompt neuroimaging to exclude a CNS lesion or malformation such as enlarged vestibular aqueduct.

Medications and known otological vascular or ophthalmological disease may be implicated. Head trauma (temporal bone fracture) and intracranial/otological surgery can cause balance disturbances, but children often compensate quickly and completely for unilateral vestibular losses. In contrast with adults, even children with a known temporal bone fracture and SNHL will not usually have vestibular complaints. ¹³

Take a careful and detailed social history, focusing on the child’s interaction with teachers and peers at school. Anxiety, depression, stress, and bullying at school can all manifest with symptoms of dizziness. Adolescent girls are particularly susceptible to eating disorders and may present with features such as syncope, dizzy spells, or unexplained episodes of loss of balance. The eating pattern can be surreptitious and the family may not be aware that the girl is undernourished. If such conditions are suspected, prompt and sensitive referral to the child mental health service can greatly improve outcome.

A positive family history might support a diagnosis of migraine or very rarely point to conditions such as neurofibromatosis type 2 (NF2) or acoustic neuroma.

11.3.2 Examination

A thorough examination of the child is paramount ( ▶ Table 11.2). This should include a basic neurologic as well as a full ear, nose, and throat (ENT) assessment.

Clinical examination can prove challenging particularly in the younger child, but with time and patience, most of the important physical findings can be elicited.

Otoscopy and Audiology

Examination of the ears is particularly important and must include an age-appropriate hearing assessment.

OME, chronic suppurative otitis media (CSOM), acute otitis media, and mastoiditis can cause balance disturbances.

Balance Assessment

A thorough yet speedy balance examination can be carried out in the outpatient setting and does not require specialist equipment. As the child enters the consulting room, observe his/her gait, stance, balance, and overall age-appropriate motor function. ¹⁴ This can be expanded by performing Romberg’s test. The “sharpened” (tandem) Romberg test and the Fukuda stepping test are also useful.

Romberg and “Sharpened Romberg” Test

Romberg’s test is carried out with the patient standing eyes open and then closed, arms in neutral position and feet together. In the sharpened Romberg test, the feet are placed in a heel to toe position.

Swaying or toppling when visual control is removed is considered a positive test and indicates a vestibular disorder or proprioceptive deficit.

Fukuda (Unterberger) Stepping Test

The patient is asked to march on the spot with her eyes closed for 20 seconds. Deviation/rotation to one side of more than 45 degrees is considered pathological. The deviation is toward the side of vestibular dysfunction, but the reliability of this test has been disputed.

Testing Eye Movements

A full neuro-ophthalmological examination is complex and beyond the scope of this chapter, but a basic examination should be carried out and may give important diagnostic aid in the ENT clinic. Examine the child’s eye movements and record if there is nystagmus, smooth pursuit, and/or saccades.

Nystagmus most commonly consists of a slow drift and a quick corrective phase (jerk nystagmus). Its direction is described by the quick phase, a corrective saccade bringing the eye back on target.

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Anesthesia and Perioperative Care
2. Nasal Obstruction in Children
3. Airway Obstruction in Children
4. Acquired Disorders of the Larynx, Trachea, and Bronchi

Stay updated, free articles. Join our Telegram channel

Join