Effect of vestibular stimulation using a rotatory chair in human rest/activity rhythm
Authors: Jan Bulla
Ga√´lle Quarck
Pierre Denise
Tristan Martin
Nicolas Bessot
Florane Pasquier
Antoine Gauthier
Journal: Chronobiology International (2020)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: Actigraphy; circadian rhythms; motor activity; rest/activity rhythm; vestibular system.
Affiliations: Normandie University, Unicaen, Inserm, Comete, Gip Cyceron, Caen, France, Department of Mathematics, University of Bergen, Bergen, Norway, Department of Psychiatry and Psychotherapy, University Regensburg, Regensburg, Germany

Abstract:  The vestibular system is responsible for sensing every angular and linear head acceleration, mainly during periods of motor activity. Previous animal and human experiments have shown biological rhythm disruptions in small rodents exposed to a hypergravity environment, but also in patients with bilateral vestibular loss compared to a control population. This raised the hypothesis of the vestibular afferent influence on circadian rhythm synchronization. The present study aimed to test the impact of vestibular stimulation induced by a rotatory chair on the rest/activity rhythm in human subjects. Thirty-four healthy adults underwent both sham (SHAM) and vestibular stimulation (STIM) sessions scheduled at 18:00 h. An off-vertical axis rotation on a rotatory chair was used to ecologically stimulate the vestibular system by head accelerations. The rest/activity rhythm was continuously registered by actigraphy. The recording started one week before the first session (BASELINE), continued in the week between the two sessions and one week after the second session. Vestibular stimulation caused a significant decrease in the average activity level in the evening following the vestibular stimulation. A significant phase advance in the rest/activity rhythm occurred two days after the 18:00 h vestibular stimulation session. Moreover, the level of motion sickness symptoms increased significantly after vestibular stimulation. The present study confirms previous results on the effect of vestibular stimulation and the role of vestibular afferents on circadian biological rhythmicity. Our results support the hypothesis of the implication of vestibular afferents as non-photic stimuli acting on circadian rhythms. 

Retracted: No

PubPeer comments:
 The study is described as a prospective research in humans, performed in France: * The present study aimed to test the impact of vestibular stimulation induced by a rotatory chair on the rest activity rhythm in human subjects. Thirty-four healthy adults underwent both sham (SHAM) and vestibular stimulation (STIM) sessions scheduled at 18:00 h. An off-vertical axis rotation on a rotatory chair was used to ecologically stimulate the vestibular system by head accelerations. The rest activity rhythm was continuously registered by actigraphy. * The study has been performed on healthy volunteers, medical parameters were collected such as actigraphy measure. As a consequence, It is definitely a prospective research in human (RIPH) with regards of the french law. In France, all RIPHs (whatever the level) require the approval from a CPP before to start the recruitment of participants. Starting a prospective research in humans in France without a CPP is a serious breach to the Health French Law. The ethic statement of this study is described as follows: * The protocol was approved by the national Ethic Committee for the Research in Sciences and Technics of Physical Activity and Sports (CERSTAPS, 2020u201317-01-42), and conducted in accordance with current national and international laws and regulations governing the use of human subjects (Declaration of Helsinki II), and complied with the ethical and methodological standards for laboratory and medical human biological rhythm research (Portaluppi et al. 2010). All participants provided written informed consent after having received explanations about the study procedures in detail. * The CERSTAPS is not a Comitu00e9 de Protection des Personnes (CPP). As mentioned on the [CERSTAPS website] itself, a prospective research in humans in France MUST obtain an approval from a CPP before to start. The ethics statement do not provide any information related to a CPP approval. Can the authors clarify: - If they obtain a CPP approval before to start the recruitment? - If they request a CPP approval? In this case, what was the answer of the CPP ? If a CPP provides a waiver for the approval, the article should mention it and detail the waiver in order to raise any question on ethics procedure. However, if the CPP approval or a waiver from a CPP has not been obtained, this is a major infringement to the Health French Law and the Declaration of Helsinki (article 23). ,