Postural control during galvanic vestibular stimulation in patients with persistent perceptual–postural dizziness
- 180 Downloads
Over the past years galvanic vestibular stimulation (GVS) has been increasingly applied to stimulate the vestibular system in health and disease, but not in patients with persistent postural–perceptual dizziness (PPPD) yet. We functionally tested motion perception thresholds and postural responses to imperceptible noisy (nGVS) and perceptible bimastoidal GVS intensities in patients with PPPD with normal vestibulo-ocular reflexes. We hypothesized that GVS destabilizes PPPD patients under simple postural conditions stronger compared to healthy controls. They were compared to healthy subjects under several conditions each with the eyes open and closed: baseline with firm platform support, standing on foam and cognitive demand (count backward). Low and high GVS intensities (range 0.8–2.8 mA) were applied according to the individual thresholds and compared with no GVS. PPPD patients showed a reduced perception threshold to GVS compared to healthy control subjects. Median postural sway speed increased with stimulus intensity and on eye closure, but there was no group difference, irrespective of the experimental condition. Romberg’s ratio was consistently lower during nGVS than in all other conditions. Group-related dissociable effects were found with the eyes closed in (i) the baseline condition in which high GVS elicited higher postural sway of PPPD patients and (ii) in the foam condition, with better postural stability of PPPD patients during perceptible GVS. Group and condition differences of postural control were neither related to anxiety nor depression scores. GVS may be helpful to identify thresholds of vestibular perception and to modulate vestibulo-spinal reflexes in PPPD, with dissociable effects with respect to perceptible and imperceptible stimuli. The sway increase in the baseline of PPPD may be related to an earlier transition from open- to closed-loop mode of postural control. In contrast, the smaller sway of PPPD in the foam condition under visual deprivation is in line with the known balance improvement under more demanding postural challenges in PPPD. It is associated with a prolonged transition from open- to closed-loop postural feedback control. It could also reflect a shift of intersensory weighting with a smaller dependence on proprioceptive feedback control in PPPD patients under complex tasks. In summary, GVS discloses differences between simple and complex balance tasks in PPPD.
KeywordsPersistent perceptual–postural dizziness Postural control Galvanic vestibular stimulation
We like to thank all participants in our study for their patience and compliance. Furthermore, we are grateful for helpful discussions on SDA analyses to Janis Sprenger (M.Sc. Informatics, German Research Center for Artificial Intelligence, Saarbrücken, Germany).
Compliance with ethical standards
Conflicts of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
The study has been approved by the University Ethics Committee and has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki.
- 14.Ertl M, Klimek M, Boegle R, Stephan T, Dieterich M, Vestibular perception thresholds tested by galvanic vestibular stimulation. J Neurol (2018)Google Scholar
- 24.Pal S, Rosengren SM, Colebatch JG (2009) Stochastic galvanic vestibular stimulation produces a small reduction in sway in Parkinson’s disease. J Vestib Res 19:137–142Google Scholar
- 28.Staab JP, Eckhardt-Henn A, Horii A, Jacob R, Strupp M, Brandt T, Bronstein A (2017) Diagnostic criteria for persistent postural-perceptual dizziness (PPPD): Consensus document of the committee for the classification of vestibular disorders of the Barany Society. J Vestib Res 27:191–208CrossRefGoogle Scholar
- 38.Indovina I, Riccelli R, Chiarella G, Petrolo C, Augimeri A, Giofre L, Lacquaniti F, Staab JP, Passamonti L (2015) Role of the insula and vestibular system in patients with chronic subjective dizziness: an fMRI study using sound-evoked vestibular stimulation. Front Behav Neurosci 9:334CrossRefGoogle Scholar
- 71.Kim J-J, Lee AR, Won Y (2011) Analysis on effects of galvanic vestibular stimulation on postural stability using 3D motion analysis. Appl Math Comput Eng 11:201–2016Google Scholar