Ageing‐related changes in the cortical processing of otolith information in humans. (6th November 2017)

• Record Type: Journal Article
• Authors: zu Eulenburg, Peter; Ruehl, Ria Maxine; Runge, Pia; Dieterich, Marianne
• Is Part Of: European journal of neuroscience. Volume 46:Number 12(2017)
• Page Start: 2817
• Page End: 2825
• Publication Date: 2017-11-06
• Subjects: ageing -- fMRI -- otolith processing -- vestibular cortex -- vestibular evoked myogenic potential; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.13755
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Acoustic short tone bursts (STB) trigger ocular and cervical vestibular‐evoked myogenic potentials (oVEMPs/cVEMPs) by activating irregular otolith afferents. Simultaneously, STBs introduce an artificial net acceleration signal of otolith origin into the vestibular network. VEMP parameters as diagnostic otolith processing markers have been shown to decline after the age of thirty. To delineate the differential effects of healthy ageing on the cortical vestibular subnetwork processing otolith information, we measured cVEMPs and the differential effects of unilateral STB in three age groups (20–40, 40–60 and 60+; n = 42) using functional neuroimaging. STB evoked responses in the main vestibular hubs in the parieto‐opercular cortex. Whereas cVEMP amplitudes declined linearly with age, analysis of the BOLD response size depicted a u‐shaped curve. Vestibular perception of the otolith stimulus on the other hand remained unchanged with age. Therefore, we propose that the comparably larger BOLD responses past the age of sixty could reflect a mechanism of central sensitisation for otolith perception to counterbalance the concurrent peripheral vestibular and somatosensory function decline. Abstract : Otolith stimulation gave robust responses in vestibular core region OP2 in all groups. Analysis of the BOLD response size between the age groups depicted a u‐shaped curve, contrasting with the constant decline in cervical vestibular‐evoked myogenic potential amplitudes with age. These findings might hint at a central sensitisation of otolith perception to counterbalance peripheral vestibular loss. The diminished deactivation pattern with age possibly reflects a reduced inhibitory interaction between sensory and higher order cognitive networks as a more general ageing phenomenon.