What are vestibular disorders?

Vestibular disorders are pathologies stemming from a dysfunction of the vestibular system. They may have a peripheral origin (alteration of the functioning or lesion of the vestibular sensory organs of the inner ear) or a central origin (tumours, strokes).

These vestibular disorders are of varying severity and incidence, ranging from strong occasional (vestibular neuritis) or recurrent (Meniere’s disease) vertigo, which zre particularly disabling for patients, to postural instability in the elderly, which is responsible for falls with serious consequences, and certain types of motion sickness.

Troubles Vestibulaires

Peripheral vestibular disorders, on which Vertidiag’s action is focused, are characterised by well-defined symptoms grouped under the term “vertiginous syndrome”:

  • Perceptual deficits: vertigo, that is, an erroneous sensation of movement in the environment, often more severe than drunkedness- or cardiovascular-related vertigo (vagal discomfort);
  • Loss of balance and altered quality of walking (deviations, falls);
  • Uncontrolled eye movements (nystagmus) and loss of the ability to focus on a target when moving the head (oscillopsia);
  • Impairment of major regulatory functions – nausea, vomiting, disturbance of heart rhythm, blood pressure, body temperature, bone density, disturbance of hormonal system, etc. ;
  • Cognitive and perceptual deficits, such as spatial disorientation and loss of body lairs

Vestibular disorders can in some cases be accompanied by emotional and motivational disorders (anxiety, anguish, fear of leaving home). Depressive symptoms are also reported in patients with Ménière’s disease.

 

 
 

The pathogenic conditions leading to vestibular disorders are varied. The most common are:

  • Aging;
  • Stroke affecting the inner ear vascular system, bacterial or viral infections (especially herpes);
  • Trauma (accidents, sports activities…);
  • Ototoxicity, i.e. intoxication with compounds specifically toxic to the inner ear (in particular some antibiotics such as aminoglycosides, some foods – undercooked manioc – and platinum salts – anticancer compounds against dry tumours).

Four main types of vestibular disorders can be distinguished:

  • Meniere’s disease, which is particularly disabling because of the recurrence of attacks. This disease can be recognized by the concomitant presence of rotational vertigo, tinnitus and hearing loss;
  • Benign paroxysmal positional vertigo (BPPV), the most common form of vertigo. It is triggered when the patient tilts his or her head to a particular position. The patient suffers from a feeling of instability, discomfort and apprehension between attacks;
  • Vestibular neuritis, which is characterized by the sudden onset of intense rotational vertigo associated with nausea and vomiting, immobilizing patients for several days;
  • Other peripheral vertigo, which are characterized by a very heterogeneous etiology, with or without hearing problems, migraines, whose attacks can last from a few seconds to several days.
 

The neurophysiological mechanisms at the origin of the vertiginous syndrome have been identified since the 1960s, on the basis of electrophysiological recordings made in the vestibular nuclei of the brainstem of vestibulosed animals. These studies demonstrated that the neurophysiological support of the vertiginous syndrome resulted from a disruption of the electrophysiological equilibrium between the contralateral vestibular nuclei.

This electrical activity asymmetry in the vestibular nuclei area alters the vestibulo-spinal and vestibulo-ocular reflexes, but also the vestibulo-cortical signals, as shown in the figure below.

How important are vestibular disorders ?

The chart below summarizes the most recent and comprehensive study on the prevalence of vestibular disorders.

  • Vestibular disorders are common, affecting 1.6% of the whole population.
  • Women are more affected than men and account for about two-thirds of patients with vestibular disorders.
  • Vestibular disorders increase sharply with age: while less than 1% of people under 30 years of age are subject to vestibular disorders, this is the case for 2.7% of people over 60 years of age.

These rates can be extrapolated to all industrialized countries

Vestibular disorders are a public health issue

Beyond their impact on the quality of life of patients, vestibular disorders are a real public health problem and are costly to society. To underline their importance, their impact in three particular areas is studied: (i) the cost of treating them in the A&E departments, (ii) the cost of sick leave, and (iii) the increased prevalence of falls due to vertigo.

The cost of treating vertigo in hospital emergency departments

Dizziness complaints account for 3.3% of hospital emergency room admissions in the United States. Of these, about one-third are due to vestibular disorders, representing between 1% and 1.3% of total admissions, depending on the study. It is estimated that the cost of a patient admitted to the emergency department for vestibular disorders is US$768, mainly because of the many expensive tests that need to be performed. Patients with vestibular disorders therefore cost hospital emergency departments in the United States about $770 million annually.

US$ 770 millions
This is the annuel cost of patients with vestibular disorders to A&E departments in the US.

Vertigo impacts the careers of patient

A study of patients with vestibular disorders in 13 countries [1] estimated that among employed patients with vertigo, 5.7% of them left their jobs because of vertigo, 4.6% had to change jobs because of vertigo and 63.3% took at least one day off work due to vertigo.

Another study focusing on Ménière’s disease puts the cost of this disease to society at around $5,400 per person per year, or more than $9 billion per year in developed countries.

[1] H. Benecke, S. Agus, G. Goodall, D. Kuessner, M. Strupp, Front. Neurol. 4, 136 (2013), [2] J. Tyrrell, D. J. Whinney, T. Taylor, Ear Hear. 37, e202–e209 (2016).

Vertigo is responsible for a high rate of falls among the elderly.

Age-related degeneration of the connexions between nerve fibres and vestibular hair cells can induce an inadequate response to disturbances of balance leading to a fall.

Falls account for 90% of domestic accidents in the elderly, with more than 2 million falls per year in people over 65 years of age, their frequency increasing with age. It should be noted that falls are the 6th leading cause of death among people over 75 years old and that at the same age, a fall multiplies the risk of death within a year by about four. Falls can also have potentially serious psychosocial consequences because the elderly person who falls becomes aware of his or her fragility and fears of falling again, thereby leading half of the time to a restriction of their daily activities and a loss of autonomy. This can lead to dependence, the social cost of which is particularly high.

This gradual loss of balance, one of the symptoms of which is vertigo, is very common in the elderly, and is one of the major challenges of “ageing well”.