Reduced Balance Restoration Capacities Following Unilateral Vestibular Insult in Elderly Mice

Abstract

Acute vestibular syndrome (AVS) is characterized by severe posturo-locomotor and vestibulo-oculomotor impairment and accompanies several types of peripheral vestibulopathies (PVP). We know very little about its etiology, how its various symptoms are expressed and how it evolves with age. Robust repair capabilities of primary vestibular synapses have recently been shown to restore behavioral functionality. In this study, we used a mouse model of an excitotoxically induced unilateral vestibular lesion to compare the ability to restore balance and posture between old and young adult mice. We compared the temporal evolution of the evoked vestibular syndrome using a battery of behavioral tests to follow the evolution of postural-locomotor alterations and equilibrium. For the first time, we show that young adult (3 months) and elderly (22 months) mice are together able to restore normal postural-locomotor function following transient unilateral excitotoxic vestibular insult, though with different time courses. This animal study paves way for future, more detailed studies of how the early postural and locomotor disturbances following a unilateral insult are compensated for by various plasticity mechanisms, and in particular how age influences these mechanisms.

Microglial Dynamics Modulate Vestibular Compensation in a Rodent Model of Vestibulopathy and Condition the Expression of Plasticity Mechanisms in the Deafferented Vestibular Nuclei

“…In particular, aging increases the risks of peripheral and central damage to the vestibular system and about 35% of older adults suffer from vestibular dysfunction (for reviews see [ 131 , 132 ]). Aging is usually associated with poor vestibular compensation both in animals [ 133 , 134 , 135 ] and humans [ 136 ]. Interestingly, the neuroinflammatory response appears to be age-dependent and aging is associated with enhanced microglial reaction [ 137 ].…”

Determinants of functioning and health-related quality of life after vestibular stroke

“…Previous studies suggested that older patients with vestibular disorders might recover to a similar extent as younger patients with a comparable vestibular lesion ( 49 ). However, other groups have documented some age-dependency of central vestibular compensation and plasticity ( 50 , 51 ). One factor, which needs to be considered for this study cohort, is the mean age of 66 years.…”

How Does the Central Nervous System for Posture and Locomotion Cope With Damage-Induced Neural Asymmetry?

“…It is noteworthy, however, that the time course of vestibular sensory deprivation directly impacts the ability to use visual cues for motor deficit compensation, as observed in human patients where a fast unilateral loss of vestibular information results in lesser visual dependence and stronger inability to maintain postural stability ( Tjernström et al, 2019 ). In addition, after partial vestibular lesion the modification of both the organization and weight of residual vestibular afferents onto CVN neurons ( Goto et al, 2002 ) as well as the possibility of peripheral plasticity in vestibular endorgans ( Gaboyard-Niay et al, 2016 ) certainly participate in CVN adaptation and subsequent posturo-locomotor recovery ( Cassel et al, 2018 ). Indeed, the degree of proprioceptive information utilization to control posture in UVD patients increase with their inability to use residual vestibular information ( Peterka et al, 2011 ).…”