Visual‑Vestibular Integration Assessment: Understanding Dizziness and Balance Disorders
- Ana Souto
- Jan 23
- 3 min read
Visual‑Vestibular Integration Assessment
The visual, vestibular, and somatosensory systems provide the main sensory inputs for spatial orientation and balance control. Under normal circumstances, the visual and somatosensory systems contribute most to spatial orientation. As described by Bronstein (2016), there is substantial overlap and redundancy in the information provided by these three systems. Despite this redundancy, the vestibular system is the only one capable of detecting head acceleration, angular via the semicircular canals and linear via the otolithic organs. In contrast, the visual system is more ambiguous and can misinterpret environmental motion as self‑motion, leading to the illusory sensation known as vection.
When this happens, the Central Nervous System (CNS) uses information from the remaining sensory systems to verify whether the visually perceived motion corresponds to real body movement. This process reflects the concept of sensory weighting, which describes how the CNS assigns relative importance to each sensory system at any given moment(Peterka, 2002).
A clear and commonly experienced example of this phenomenon is seen when a person is sitting inside a stationary train, and at that moment, the train on the adjacent track begins to move. The first feeling is often that their own train has started to move, because visual information temporarily receives a high sensory weight. However, quickly, vestibular information contradicts this impression and confirms that the body is not moving (Bronstein, 2016). The sensory weighting mechanism adjusts the contribution of each sensory system, increasing the influence of vestibular information while reducing the weight of visual cues.
A similar process takes place in certain disorders or lesions, where the Central Nervous System temporarily compensates for reduced or lower‑quality input from one of the sensory systems. Although initially adaptive, this compensation can persist and become maladaptive, leading to excessive reliance on the remaining systems. When visual dependence increases, visually complex environments such as crowds, traffic, or intense and repetitive light and colour patterns frequently trigger dizziness and unsteadiness. For this reason, assessing visual–vestibular integration is essential in patients who report dizziness and instability in visually demanding situations, as it helps guide rehabilitation toward the use of the most appropriate sensory inputs.
Optokinetic Stimulation (OKS) in Visual‑Vestibular Integration Assessment
Optokinetic stimulation (OKS) is an important tool in this context. OKS consists of exposure to large‑field moving visual stimuli, introducing controlled visual motion that creates a sensory conflict. This conflict forces the brain to reweight sensory information and reveals how effectively visual and vestibular signals are integrated. Studies have shown that OKS activates cortical areas related to visual motion sensitivity, ocular motor function, and vestibular processing (Obrero-Gaitán et al., 2024).
Normal visual‑vestibular integration is reflected in a controlled or adaptive postural sway during OKS. The presence of an induced sway is expected during sensory conflict. However, a marked or disproportionate increase in postural sway may indicate excessive visual influence (Holten et al., 2016; Tsutsumi et al., 2010).
Understanding these patterns allows clinicians to tailor rehabilitation toward sensory integration approaches, including habituation exercises that support a gradual central recalibration, helping patients feel more stable and reducing symptoms in visually demanding environments
Go check the Otoneuro System Product Sheet
Ana Souto
Meet Ana, a physiotherapist with a master's degree in human physiology and certified by the American Institute of Balance.
Ana currently serves as the clinical specialist at PhysioSensing, a cutting-edge Balance Assessment and training device. Her approach is firmly rooted in the latest scientific findings, ensuring that PhysioSensing users receive the most effective and up-to-date care. In addition to her role in designing tailored programs, Ana plays a pivotal role in guiding new clients through the learning process of using PhysioSensing. She also provides advanced training and support to existing customers seeking to further deepen their clinical practice knowledge and stay on top of the latest scientific advancements.
References
Bronstein, A. M. (2016). Multisensory integration in balance control. In Handbook of Clinical Neurology (Vol. 137, pp. 57–66). Elsevier. https://doi.org/10.1016/B978-0-444-63437-5.00004-2
Holten, V., Van Der Smagt, M. J., Verstraten, F. A. J., & Donker, S. F. (2016). Interaction effects of visual stimulus speed and contrast on postural sway. Experimental Brain Research, 234(1), 113–124. https://doi.org/10.1007/s00221-015-4438-y
Obrero-Gaitán, E., Sedeño-Vidal, A., Peinado-Rubia, A. B., Cortés-Pérez, I., Ibáñez-Vera, A. J., & Lomas-Vega, R. (2024). Optokinetic stimulation for the treatment of vestibular and balance disorders: A systematic review with meta-analysis. European Archives of Oto-Rhino-Laryngology, 281(9), 4473–4484. https://doi.org/10.1007/s00405-024-08604-1
Peterka, R. J. (2002). Sensorimotor Integration in Human Postural Control. Journal of Neurophysiology, 88(3), 1097–1118. https://doi.org/10.1152/jn.2002.88.3.1097
Tsutsumi, T., Murakami, M., Kawaishi, J., Chida, W., Fukuoka, Y., & Watanabe, K. (2010). Postural stability during visual stimulation and the contribution from the vestibular apparatus. Acta Oto-Laryngologica, 130(4), 464–471. https://doi.org/10.3109/00016480903292718