- Postural instability (HP:0002172): A tendency to fall or the inability to keep oneself from falling; imbalance. The retropulsion test is widely regarded as the gold standard to evaluate postural instability, Use of the retropulsion test includes a rapid balance perturbation in the backward direction, and the number of balance correcting steps (or total absence thereof) is used to rate the degree of postural instability. Healthy subjects correct such perturbations with either one or two large steps, or without taking any steps, hinging rapidly at the hips while swinging the arms forward as a counterweight. In patients with balance impairment, balance correcting steps are often too small, forcing patients to take more than two steps. Taking three or more steps is generally considered to be abnormal, and taking more than five steps is regarded as being clearly abnormal. Markedly affected patients continue to step backward without ever regaining their balance and must be caught by the examiner (this would be called true retropulsion). Even more severely affected patients fail to correct entirely, and fall backward like a pushed toy soldier, without taking any corrective steps. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:171684)
- Oscillopsia (HP:0034773): A visual disturbance in which objects in the visual field appear to oscillate (jump, jiggle, vibrate). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:171684)
- Gait imbalance (HP:0002141). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:171684)
- Vertigo (HP:0002321): An abnormal sensation of spinning while the body is actually stationary. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:171684)
- Abnormal vestibulo-ocular reflex (HP:0007670): An abnormality of the vestibulo-ocular reflex (VOR). The VOR attempts to keep the image stable on the retina. Ideally passive or active head movements in one direction are compensated for by eye movements of equal magnitude. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:171684)
- Abnormal vestibulo-spinal reflex (HP:6001104): An abnormality of the vestibulospinal (VS) reflexes, which contribute to the control of postural orientation. In this task, they continuously collaborate with reflexes elicited by stimulation of visual and somatosensory receptors. Labyrinthine receptors are sensitive to modifications (i) of the head position with respect to the earth vertical or (ii) of the angular/linear velocity of head motion in space. This information can be used to monitor deviations from the maintained body position. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:171684)
- Anxiety (HP:0000739): Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:171684)
- Memory impairment (HP:0002354): An impairment of memory as manifested by a reduced ability to remember things such as dates and names, and increased forgetfulness. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:171684)
- Diminished ability to concentrate (HP:0031987): The inability to focus or concentrate on a specific task, activity, or object. The subject may find themselves unable to grasp or understand written text and re-reads frequently without understanding. Familiar tasks or activities are severely compromised due to the lack of ability to concentrate. Thinking through multi-step problems is typically very difficult or impossible, leading to avoidance of such activities. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:171684)
- Pathological sadness (HP:5200273): A negative emotional state characterized by sadness, unhappiness, or sorrow that is excessive in intensity, duration, or resistance to self-regulation compared with culturally appropriate norms or the individual's usual emotional range. It may arise spontaneously or in response to significant life events, but when reactive, it is disproportionate to or persists beyond what is typically expected for the context. Pathological sadness can be associated with feelings of hopelessness, helplessness, anhedonia, and a pessimistic outlook, but these features are not invariably present. It may also be accompanied by increased tearfulness, low energy, cognitive difficulties such as impaired concentration, and somatic changes including disrupted sleep or appetite. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:171684)
These phenotypes are associated with the disease Idiopathic bilateral vestibulopathy (ORPHA:171684).
The following phenotypes are NOT associated with this disease:
- Sensorineural hearing impairment (HP:0000407): A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve. Evidence: TAS. (ORPHA:171684)