Age-Related Vestibular Loss: Current Understanding and Future Research Directions

Abstract

The vestibular system sub-serves a number of reflex and perceptual functions, comprising the peripheral apparatus, the vestibular nerve, the brainstem and cerebellar processing circuits, the thalamic relays, and the vestibular cerebral cortical network. This system provides signals of self-motion, important for gaze and postural control, and signals of traveled distance, for spatial orientation, especially in the dark. Current evidence suggests that certain aspects of this multi-faceted system may deteriorate with age and sometimes with severe consequences, such as falls. Often the deterioration in vestibular functioning relates to how the signal is processed by brain circuits rather than an impairment in the sensory transduction process. We review current data concerning age-related changes in the vestibular system, and how this may be important for clinicians dealing with balance disorders.

The Aging Navigational System

“…Age-related degeneration of the vestibular system (i.e., progressive neuronal loss) is a multifactorial process, affecting the peripheral end-organs, the brainstem, the cerebellum and the cerebral cortex (Arshad and Seemungal, 2016). Age-related neuronal loss in the vestibular nucleus has been reported in both humans (Lopez et al, 1997) and mice (Sturrock, 1989).…”

Sources of path integration error in young and aging humans

“…Recent evidence from neuroimaging studies indicates that signatures of grid-cell-like activity in human entorhinal cortex are reduced in old age, and this reduction is associated with larger path integration errors (Stangl et al, 2018). Certain aspects of the vestibular system also deteriorate with age (for a review, see Allen et al, 2016), and vestibular loss affects path integration performance (Glasauer et al, 2002;Xie et al, 2017). These findings support the possibility that an increase in noise on a neuronal level, possibly from a loss of the signal-to-noise ratio from degrading circuitry in the grid cell or the vestibular system may be responsible for deficient computations of pose in old age.…”

Homeostatic cerebellar compensation of age-related changes of vestibulo-ocular reflex adaptation: a computational epidemiology study

“…Also, the number of neurons in the vestibular nuclei undergoes a 3% loss per decade, starting at approximately 40 years of age (Alvarez et al, 2000, Lopez et al, 1996. As a consequence, throughout ageing, fewer primary vestibular afferents reach the brain, in particular the downstream control structures responsible for VOR adaptation, such as the cerebellum (Allen et al, 2017). Thus, ageing gradually hinder the detection and encoding of head displacements (in particular head factors (including increased sensitivity to afferent nerve fibres) may counterbalance agerelated vestibular losses, thus preserving, to a certain extent, VOR in older adults (Jahn et al, 2003, Li et al, 2015, McGarvie et al, 2015.…”