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Airsickness and Space Sickness
Published in Carrie H. Kennedy, Gary G. Kay, Aeromedical Psychology, 2013
Erik Viirre, Jonathan B. Clark
Of course, even with our eyes closed, we can sense movement. Pressure sensors throughout the body can impart motion sensation, but the primary sensors for motion are in the vestibular system. The otoliths are large calcium carbonate crystals that rest on hair cells in the utricle. They are sensors for tilt or linear acceleration of the head. Also in each inner ear are the semi-circular canals that are rotational accelerometers, good for detecting rapid rotations of the head. The semi-circular canals can detect motion in three dimensions and are optimized for detection of rapid onset and high-frequency movements of the head. They are directly connected to centers in the brainstem that drive vision stabilizing movements of the eyes. Signals from the canal also rapidly drive balance reflexes and go to high-cortex regions to deliver self-motion information.
Biomechanical studies for understanding falls in older adults
Published in Youlian Hong, Roger Bartlett, Routledge Handbook of Biomechanics and Human Movement Science, 2008
Daina L. Sturnieks, R. Stephen
The vestibular system involves inner ear structures that detect position and motion of the head, relative to gravity, and is important for posture and coordination of head, eye and body movements. Recent studies have reported significant associations between vestibular impairment and fall-related fractures. Kristinsdottir and colleagues have used a head-shaking stimulus applied when subjects were in a supine position to induce nystagmus — a sign indicating asymmetry of the vestibular reflexes. In an initial study comprising 19 subjects (mean age 72 years) with hip fracture and 28 aged-matched controls, they found that 68 per cent of the hip fracture subjects demonstrated a nystagmus following the head-shake stimulus compared with 32 per cent of the controls (Kristinsdottir et al., 2000). Similar findings were reported in a subsequent study of older wrist fracture patients (Kristinsdottir et al., 2001). Vestibular function is less amenable to assessment with simple screening tests compared with vision and peripheral sensation. However, these recent studies provide preliminary evidence that when assessed with greater precision, impaired vestibular function may be an important risk factor for falls and fall-related fractures in older people.
Introduction and Background
Published in Haym Benaroya, Mark Nagurka, Seon Han, Mechanical Vibration, 2017
Haym Benaroya, Mark Nagurka, Seon Han
Hearing. The sounds we hear are there sult of molecules in the air banging into each other. So how is it that we hear these molecules? The eardrum vibrates when colliding molecules hit it. Tiny bones connect to the eardrum and transmit these vibrations along to the cochlea, a structure in theinnerear that contains fluid. The vibrations exert pressure on the fluid within the cochlea, and the organ of Corti, another structure within the inner ear, translates these changes in pressure into electrical impulses that travel along the auditory nerve to the brain, which then interprets these signals as sound.
A new method with an explant culture of the utricle for assessing the influence of exposure to low-frequency noise on the vestibule
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Nobutaka Ohgami, Tingchao He, Reina Oshino-Negishi, Yishuo Gu, Xiang Li, Masashi Kato
The vestibule, which consists of hair cells covered by the otoconial membrane with otoconia in the saccule and utricle in the inner ears, is a sensory organ for balance. In previous studies, the influence of LFN exposure on vestibular function in humans was noted (Evans and Tempest 1972; Harrison 2015; Takigawa et al. 1988). In our studies, in vivo exposure to LFN was found to impair balance in mice, while there was no marked influence on hearing (Tamura et al. 2012; Ohgami et al., 2017; Ninomiya et al. 2018). Chen et al. (2020) presented in vitro a cell line for screening of preventive drugs for noise-induced hearing loss. However, preventive methods for LFN-mediated imbalance have not been fully developed. At present, there is no apparent technique with in vitro or ex vivo assessments to effectively evaluate LFN-mediated imbalance by direct administration of preventive chemicals in the vestibule.
A computational framework to simulate the endolymph flow due to vestibular rehabilitation maneuvers assessed from accelerometer data
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Carla F. Santos, Jorge Belinha, Fernanda Gentil, Marco Parente, Bruno Areias, Renato Natal Jorge
Vertigo is a type of dizziness that normally occurs due to a dysfunction in the vestibular system, which is located in the inner ear. The patient has the perception of a spinning motion, a feeling of displacement of the environment relative to the individual or an intensive sensation of rotation inside the head (Taylor and Goodkin 2011). In these situations, it is important to avoid falls. Such symptoms are often associated with nausea and vomiting, and it can cause difficulties in standing or walking if it is related with central lesions (Karatas 2008). Other debilitating symptoms such as blurred vision and hearing loss may also occur (Strupp et al. 2011). Vertigo can be classified as either peripheral or central, depending on the location of the dysfunction in the vestibular pathway, and its most common cause is benign paroxysmal positional vertigo (BPPV) (Karatas 2008), although it can be caused by other factors (Wippold and Turski 2009).
Smart platform for the analysis of cupula deformation caused by otoconia presence within SCCs
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Radun Vulović, Milica Nikolić, Nenad Filipović
Humans have the ability to detect angular motion due to the specific structures of the inner ear: three semicircular canals (SCCs) with cupulae located within their ampullae. During angular head movements, a fluid (endolymph) inside the SCCs starts to flow thus forcing the afferent hair cells in the SCC’s wall to start their movement. Unfortunately, that flow can be disturbed by the small particles called otoconia, i.e. otoliths, which leads to benign paroxysmal positional vertigo. Such condition is called canalithiasis.