Decrease of Horizontal Canal Vestibulo-Oculomotor Reflex Gain in the Elderly with Dysequilibrium without Lifetime Vertigo

Twenty-four-hour variation of vestibular function in young and elderly adults

Animal and human studies demonstrate anatomical and functional links between the vestibular nuclei and the circadian timing system. This promotes the hypothesis of a circadian rhythm of vestibular function. The objective of this study was to evaluate the vestibular function through the vestibulo-ocular reflex using a rotatory chair at different times of the day to assess circadian rhythmicity of vestibular function. Two identical studies evaluating temporal variation of the vestibulo-ocular reflex (VOR) were performed, the first in young adults (age: 22.4 ± 1.5 y), and the second in older adults (70.7 ± 4.7 y). The slow phase velocity and time constant of the VOR were evaluated in six separate test sessions, i.e., 02:00, 06:00, 10:00, 14:00, 18:00, and 22:00 h. In both studies, markers of circadian rhythmicity (temperature, fatigue, and sleepiness) displayed expected usual temporal variation. In young adults, the time constant of the VOR showed variation throughout the day (p < .005), being maximum 12:25 h (06:00 h test session) before the acrophase of temperature circadian rhythm. In older adults, the slow phase velocity and time constant also displayed temporal variation (p < .05). Maximum values were recorded at 10:35 h (06:00 h test session) before the acrophase of temperature circadian rhythm. The present study demonstrates that vestibular function is not constant throughout the day. The implication of the temporal variation in vestibular system in equilibrium potentially exposes the elderly, in particular, to differential risk during the 24 h of losing balance and falling.

Normative video head impulse test data in subjects with and without vascular risk factors

Purpose

There is a paucity of age- and vascular risk factor-stratified video head impulse test (vHIT) vestibulo-ocular reflex (VOR) data in the literature. The aim of this study was to investigate the vHIT VOR properties in healthy subjects of different ages and subjects with vascular risk factors.

Methods

This was a prospective observational single-center study at a tertiary referral university hospital in northern Sweden. Healthy participants and subjects with vascular risk factors were investigated with a floor standing external camera vHIT device. Age-stratified mean VOR gain among healthy adults and between group gain and gain asymmetry differences were calculated.

Results

We included eighty-eight healthy adults with a mean (range) age of 50 (22–85) years and n = 48 stroke ward patients with vascular risk factors (but without vestibular disease) with a mean (range) age of 74 (42–92) years. The mean VOR gain of horizontal canals decreased at higher ages in healthy subjects (r = − 0.32, p < 0.01, n = 167 canals). The age-stratified mean (SD) VOR gains were < 30 years: 0.98 (0.07), 30–39 years: 0.97 (0.07), 40–49 years: 0.98 (0.06), 50–59 years: 0.99 (0.06), 60–69 years: 0.93 (0.08), ≥ 70 years: 0.89 (0.15). No consistent differences between healthy subjects and subjects with vascular risk factors were seen except for a trend towards more pronounced gain asymmetries in the latter group.

Conclusions

Age, but not vascular risk factors influence VOR gain. Age-adjusted vHIT-measurements may be useful in acute vertigo stroke risk differentiation.

Associations between Age-Related Changes in the Core Vestibular Projection Pathway and Balance Ability: A Diffusion Tensor Imaging Study

Objective

We investigated the changes of the vestibulospinal tract (VST) and parietoinsular vestibular cortex (PIVC) using diffusion tensor imaging (DTI) and relation to balance between old and young healthy adults.

Methods

This study recruited eleven old adults (6 males, 5 females; mean age 63.36 ± 4.25 years) and 12 young adults (7 males, 5 females; mean age 28.42 ± 4.40 years). The lateral and medial VST and PIVC were reconstructed using DTI. Fractional anisotropy (FA), mean diffusivity (MD), and tract volume were measured. The six-minute walk test (6-MWT), the timed up and go test (TUG), and the Berg balance scale (BBS) were conducted. Spatiotemporal parameters during tandem gait and values of sway during one-leg standing using the wearable sensors were measured. All parameters between two groups were analyzed by the Mann-Whitney U test and independent t-test.

Results

Statistically significant decrease in old adults was detected in the tract volume of lateral (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (p = 0.005) and medial VST (.

Conclusion

The results suggested that there was a relationship between DTI parameters in the vestibular neural pathway and balance according to aging.