Experimental Analysis of Virtual Reality as a Stimulus in Posturography

The aim of this Master Thesis was to measure and quantify the effect of a continuous visual stimulus on postural stability. The visual stimulus was applied using a Head Mounted Display through which the image of a vertically rotating cylinder was projected. It was hoped that the relationship between the speed of rotation of the cylinder and the body sway of the subject would be quantified through the process of System Identification. By creating a model of how a healthy subject reacts to the visual stimulus it is hoped that this technology may be used to diagnose and treat those with deficient postural control

Virtual reality in vestibular assessment and rehabilitation

Previous experiences on vestibular compensation showed that multisensorial stimulations affect postural unbalance recovery. Virtual Environment (VE) exposure seems very useful in vestibular rehabilitation, since the experience gained during VE exposure is transferable to the reai world. The rearrangement of the hierarchy of the postural cues was evaluated in 105 patients affected by visual, labyrinthic and somatosensory pathology in normal conditions and during sensoriai deprivation. They were divided into five groups according to pathology and compared to 50 normal controls. Our data show that VE exposure is a reliable method to identify the deficient subsystem and the level of substitution. Moreover, Virtual Reality (VR) would accelerate the compensation of an acute loss of labyrinthine function, related to adaptive modifications of thevestibulo-ocularandvestibulo-spinal reflexes, overstimulating the residual labyrinthine function. The residual labyrinthine function is poor in chronic bilateral vestibular deficit and VE exposure should provide sensory substitution or sensory motor reorganisation, thereby modulating the external spatial reference and promoting the reorganisation of the multiple sensory input. The potential for VE exposure perspectives seerns very promising when dealing with the vestibular system where there is a continuous rearrangement of different sensorial informations as a result of environmental and age-related changes

Postural instability in an immersive Virtual Reality adapts with repetition and includes directional and gender specific effects

The ability to handle sensory conflicts and use the most appropriate sensory information is vital for successful recovery of human postural control after injury. The objective was to determine if virtual reality (VR) could provide a vehicle for sensory training, and determine the temporal and spatial nature of such adaptive changes. Twenty healthy subjects participated in the study (10 females). The subjects watched a 90-second VR simulation of railroad (rollercoaster) motion in mountainous terrain during five repeated simulations, while standing on a force platform that recorded their stability. The immediate response to watching the VR movie was an increased level of postural instability. Repeatedly watching the same VR movie significantly reduced both the anteroposterior (62%, p < 0.001) and lateral (47%, p = 0.001) energy used. However, females adapted more slowly to the VR stimuli as reflected by higher use of total (p = 0.007), low frequency (p = 0.027) and high frequency (p = 0.026) energy. Healthy subjects can significantly adapt to a multidirectional, provocative, visual environment after 4–5 repeated sessions of VR. Consequently, VR technology might be an effective tool for rehabilitation involving visual desensitisation. However, some females may require more training sessions to achieve effects with VR

Effect of Vestibular Adaptation Exercises on Chronic Motion Sensitivity

Dizziness is one of the most common complaints reported to primary care physicians. It is often associated with vestibular dysfunction and typically impacts postural stability. Motion sickness, or motion sensitivity, is stimulated by abnormal spatial orientation and is a common symptom related to dizziness and postural instability. The main cause of the motion sensitivity is aberrant sensory input from the visual, vestibular and somatosensory systems. The aim of this study was to measure the effect of vestibular adaptation exercises on postural stability in young healthy adults with subjective awareness of chronic motion sensitivity. Methods: Fifty healthy male and female participants between 20 to 40 years of age with chronic motion sensitivity were randomly assigned to either an experimental or control group. Postural stability measurements were taken at baseline and after 6 weeks using computerized dynamic posturography with immersion virtual reality. The experimental group performed daily vestibular adaptation exercises for 6 weeks. Results. There was no significant difference between the two groups at baseline in terms of mean age, height, weight, BMI or baseline postural stability scores (p\u3e0.05). Significant differences in mean postural stability scores were observed post intervention in both groups but larger improvements were detected in the experimental group (p=0.002). Conclusions: Minimal dosage of vestibular adaptation exercises improved postural stability in younger adults with chronic motion sensitivity. Additionally, familiarity of the testing environment during post-test measurements may have contributed to improvements in the control group over time; however, changes were greater in the experimental group

Virtual reality to improve postural control in patients with schizophrenia: study protocol for a single-blind parallel group randomised controlled trial

Impairment in postural control is prevalent in patients with schizophrenia, and often limit occupational performance. Virtual reality (VR) has proven its benefits for improving postural control and among schizophrenia population. Remarkably, the effectiveness of a VR game-based intervention on postural control in this population has never been evaluated. The primary aim of this study is to examine the effects and impact of VR on postural control parameters in patients with schizophrenia. This is a single-blinded, randomised controlled trial with two parallel groups. Thirty-four patients with schizophrenia are randomly assigned to the virtual reality group (VR) or the inactive control group (CG). The intervention consists of 3 30 min sessions for 4 weeks. Assessments are performed at baseline, post-intervention and 1-month follow-up. The primary outcome is postural control. The center of pressure (COP) displacement and velocity in anteroposterior (AP) and mediolateral (ML) directions are measured by PhyisoSensing pressure platform. This study protocol comprises parameters that are thought to be crucial to the success of the intervention. There are used objective and quantitative measures to evaluate the outcomes for effectively plan postural control interventions in schizophrenia with more reliable and valid results. The results of the study will be useful to clarify the effect of VR on postural control in patients with schizophrenia and provide insight into the validity of this approach as an intervention technique. It is expected that the results confirm the positive findings supporting the therapeutic prospects of VR.info:eu-repo/semantics/publishedVersio

Frequency-dependent tuning of the human vestibular "sixth sense" by transcranial oscillatory currents

Objective: The vestibular cortex is a multisensory associative region that, in neuroimaging investigations, is activated by slow-frequency (1-2&nbsp;Hz) galvanic stimulation of peripheral receptors. We aimed to directly activate the vestibular cortex with biophysically modeled transcranial oscillatory current stimulation (tACS) in the same frequency range. Methods: Thirty healthy subjects and one rare patient with chronic bilateral vestibular deafferentation underwent, in a randomized, double-blind, controlled trial, to tACS at slow (1 or 2&nbsp;Hz) or higher (10&nbsp;Hz) frequency and sham stimulations, over the Parieto-Insular Vestibular Cortex (PIVC), while standing on a stabilometric platform. Subjective symptoms of motion sickness were scored by Simulator Sickness Questionnaire and subjects' postural sways were monitored on the platform. Results: tACS at 1 and 2&nbsp;Hz induced symptoms of motion sickness, oscillopsia and postural instability, that were supported by posturographic sway recordings. Both 10&nbsp;Hz-tACS and sham stimulation on the vestibular cortex did not affect vestibular function. As these effects persisted in a rare patient with bilateral peripheral vestibular areflexia documented by the absence of the Vestibular-Ocular Reflex, the possibility of a current spread toward peripheral afferents is unlikely. Conversely, the 10&nbsp;Hz-tACS significantly reduced his chronic vestibular symptoms in this patient. Conclusions: Weak electrical oscillations in a frequency range corresponding to the physiological cortical activity of the vestibular system may generate motion sickness and postural sways, both in healthy subjects and in the case of bilateral vestibular deafferentation. Significance: This should be taken into account as a new side effect of tACS in future studies addressing cognitive functions. Higher frequencies of stimulation applied to the vestibular cortex may represent a new interventional option to reduce motion sickness in different scenarios

Fifteen years of wireless sensors for balance assessment in neurological disorders

Balance impairment is a major mechanism behind falling along with environmental hazards. Under physiological conditions, ageing leads to a progressive decline in balance control per se. Moreover, various neurological disorders further increase the risk of falls by deteriorating specific nervous system functions contributing to balance. Over the last 15 years, significant advancements in technology have provided wearable solutions for balance evaluation and the management of postural instability in patients with neurological disorders. This narrative review aims to address the topic of balance and wireless sensors in several neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, stroke, and other neurodegenerative and acute clinical syndromes. The review discusses the physiological and pathophysiological bases of balance in neurological disorders as well as the traditional and innovative instruments currently available for balance assessment. The technical and clinical perspectives of wearable technologies, as well as current challenges in the field of teleneurology, are also examined

Quantifying Time Awake Posturographically

This thesis focuses on the issue of testing sleepiness quantitatively. The issue is relevant to policymakers concerned with traffic- and occupational safety; such testing provides a tool for safety legislation and -surveillance. The findings of this thesis provide guidelines for a posturographic sleepiness tester. Sleepiness ensuing from staying awake merely 17 h impairs our performance as much as the legally proscribed blood alcohol concentration 0.5 does. Hence, sleepiness is a major risk factor in transportation and occupational accidents. The lack of convenient, commercial sleepiness tests precludes testing impending sleepiness levels contrary to simply breath testing for alcohol intoxication. Posturography is a potential sleepiness test, since clinical diurnal balance testing suggests the hypothesis that time awake could be posturographically estimable. Relying on this hypothesis this thesis examines posturographic sleepiness testing for instrumentation purposes. Empirical results from 63 subjects for whom we tested balance with a force platform during wakefulness for maximum 36 h show that sustained wakefulness impairs balance. The results show that time awake is posturographically estimable with 88% accuracy and 97% precision which validates our hypothesis. Results also show that balance scores tested at 13:30 hours serve as a threshold to detect excessive sleepiness. Analytical results show that the test length has a marked effect on estimation accuracy: 18 s tests suffice to identify sleepiness related balance changes, but trades off some of the accuracy achieved with 30 s tests. The procedure to estimate time awake relies on equating the subject s test score to a reference table (comprising balance scores tested during sustained wakefulness, regressed against time awake). Empirical results showed that sustained wakefulness explains 60% of the diurnal balance variations, whereas the time of day explains 40% of the balance variations. The latter fact implies that time awake estimations also must rely on knowing the local times of both test and reference scores.Valvominen vaikuttaa suorituskykyymme alkoholin tavoin. Jo 17 h:n yhtäjaksoinen valvominen vaikuttaa 0.5 :n humalatilan tavoin, ja 20 h:n valvominen vaikuttaa 1 :n tavoin. Tästä syystä väsymys on vakava onnettomuustekijä mm. liikenteessä. Suomessa kuten muissakin teollisuusmaissa säädetään rattijuopumusta vastaan ja valvontaviranomaiset mittaavat kuljettajien humalatilaa puhallusalkometrillä. Rattijuopumusanalogiaa mukaillen edistettäisiin liikenneturvallisuutta mittaamalla myös kuljettajien väsymystä. Tämän toteuttamiseksi valvontaviranomaiset tarvitsevat uuden mittarin, sillä toisin kuin humalatilan mittaaminen puhallusalkometrillä, vastaavanlaista nopeaa ja helppoa väsymystestiä ei ole. Tässä väitöskirjatyössä tutkittiin voidaanko ihmisen valveillaoloaikaa mitata tasapainolevyllä. Tutkimukseen osallistui 63 henkilöä. Mittasimme heidän tasapainoa 2 h:n välein, enimmillään 36 h:n yhtäjaksoisen valvomisen aikana. Valvominen heikensi tasapainoa, ja lineaarinen regressioanalyysi selitti 60 % valveillaoloajan aikana tapahtuvista tasapainomuutoksista. Loput muutoksista johtuivat lähinnä vuorokausirytmistä; väsymyksellä on huippu sekä iltapäivällä (klo 14-17) että aamuyöllä (klo 2-7) huolimatta siitä onko valvottu vai ei. Mittasimme myös henkilöitten tasapainoa kerran päivässä viikon aikana joka päivä eri valveillaoloajalla. Käyttämällä lineaarista tasapaino-valveillaoloaikakorrelaatiota, samalla huomioiden vuorokausirytmin vaikutus tasapainoon, estimoitiin henkilöiden hetkellinen valveillaoloaika 88 %:n tarkkuudella. Tällöin (lineaarinen) korrelaatio estimoitujen ja todellisten valveillaoloaikojen välillä oli 0.85. Tehtyjen tasapainomittausten kesto oli 30 s. Mittauskeston analyyttinen lyhentäminen osoitti, että 18 s:n mittaus riittää tunnistamaan valveillaoloajan aiheuttamat tasapainomuutokset, mutta heikentää valveillaoloajan estimointitarkkuutta. Tapaturmaehkäisyä varten tasapainotestillä tehty valveillaolomittaus soveltuisi riskiryhmien, kuten kirurgien, lentäjien, lennonjohtajien, bussi- ja junakuljettajien, ydin- ja vesivalvomoiden, viranomaisvalvontaan. Tätä ennen tulisi tutkia, päättää ja säätää laittoman väsymyksen raja-arvo tunteina

Effect of Progressive Gaze Stability Exercises on Holistic Aspects of Chronic Motion Sensitivity

Background: Motion sensitivity, also referred to as motion sickness, is a common condition among general population. It is a complex syndrome and is associated with presence of nausea and vomiting headache, drowsiness, cold sweating, pallor of varying degrees, increased salivation. Postural instability and anxiety are also identified to be associated with motion sensitivity. There is a close relationship between the vestibular system and motion sensitivity and vestibular system. The aim of this study was to investigate the effect of progressive gaze stability exercises on holistic aspects of chronic motion sensitivity. Methods: A single blind randomized controlled trial was conducted where participants were blinded to type of intervention. Forty one healthy young adults of both genders within the age group of 20 to 40 years with chronic motion sensitivity were recruited in the study. Baseline and post intervention assessment of postural stability, motion sensitivity, and anxiety was measured for each participant using, Bertec Balance Advantage-Dynamic Computerized Dynamic Posturography with Immersion Virtual Reality (CDP-IVR), Motion Sensitivity Quotient (MSQ), Motion Sensitivity Susceptibility Questionnaire Short Form (MSSQ-Short), and State-Trait Anxiety Inventory for Adults (STAI Form Y-2). Results: There was a significant difference for condition 2 (p=0.05), but not for condition 1 (p=0.44) for the mean CDP-IVR average score post intervention between the intervention and sham groups. For condition 2, the intervention group had 117% increase in CDP-IVR average score compared to 35.2% increase in the sham group. Also, there was a significant difference in mean MSQ between the two groups (p=0.045). There was a significant inverse correlation between MSQ and CDP-IVR average equilibrium % of Condition 1 (ρ = -0.44, p = 0.004). Conclusions: Progressive gaze stability exercises reduced motion sensitivity and improved postural stability in participants with chronic motion sensitivity. Also, perception of motion sensitivity was observed to be inversely correlated with postural stability. There was no impact of gaze stability exercises observed on subjective perception of anxiety among this population. Also, HEP adherence strategies were beneficial to ensure exercise adherence in participants with chronic motion sensitivity

m- and e-Health applications in diagnosis and rehabilitation of balance disorders - Εφαρμογές m- και e-health για τη διάγνωση και αποκατάσταση διαταραχών ισορροπίας

Υπόβαθρο: Η ισορροπία είναι μια αρχέγονη ανθρώπινη αίσθηση που απαιτεί πολυαισθητηριακή ολοκλήρωση από το αιθουσαίο, το οπτικό και το ιδιοδεκτικό σύστημα και συμμετοχή της παρεγκεφαλίδας και αρκετών άλλων νευρωνικών κυκλωμάτων. Επιπλέον, εμπλέκονται ένας αριθμός αντανακλαστικών, όπως το αιθουσοοφθαλμικό και το αιθουσονωτιαίο αντανακλαστικό, μαζί με πολλές άλλες ανώτερες εγκεφαλικές λειτουργίες. Υπό συγκεκριμένες συνθήκες, μια περιφερική ή κεντρική βλάβη μπορεί να συμβεί στο σύστημα οδηγώντας σε αστάθεια και συμπτωματολογία ιλίγγου. Από τη 1940, όταν οι Cooksey και Cawthorne ξεκίνησαν να διερευνούν την αποκατάσταση μετά από τέτοιες βλάβες, πολλά πράγματα έχουν αλλάξει στο πεδίο της αποκατάστασης ισορροπίας και κατά τις τελευταίες δεκαετίες οι νέες τεχνολογίες έχουν ενσωματωθεί σε αυτή την προσπάθεια. Σήμερα, ένας μεγάλος αριθμός από εφαρμογές mHealth, eHealth και εικονικής πραγματικότητας έχον αναπτυχθεί με σκοπό να συνεισφέρουν στη διάγνωση ή/και αποκατάσταση ασθενών με αιθουσαίες διαταραχές. Μεθοδολογία: Η ηλεκτρονική βάση δεδομένων MEDLINE διερευνήθηκε για σχετικές εργασίες από την 1η Ιανουαρίου 2015 έως την 15η Απριλίου 2021. Οι συμπεριληφθείσες στην ανασκόπηση εργασίες καθορίστηκαν βάσει συγκεκριμένων κριτηρίων ένταξης και αποκλεισμού. Αποτελέσματα: Ένας συνολικός αριθμός από 187 εργασίες προέκυψε μετά την αρχική στρατηγική αναζήτησης, από τις οποίες 43 κρίθηκαν επιλέξιμες και συμπεριλήφθηκαν σε αυτή την ανασκόπηση. Χωρίστηκαν σε 5 μείζονες κατηγορίες και συζητήθηκαν περαιτέρω. Συζήτηση: Οι κονσόλες παιχνιδιών, όπως το Nintendo Wii, το Nintendo Wii Fit και το Sony PlayStation 2 EyeToy, και οι εφαρμογές Internet έχουν χρησιμοποιηθεί τα τελευταία χρόνια για να συνδράμουν στη διάγνωση και αποκατάσταση ασθενών με διαταραχές ισορροπίας. Καθώς αναδύονται νέες τεχνολογίες και τα smartphones γίνονται βασικό μέρος της καθημερινότητας μας, η αιθουσαία διάγνωση και αποκατάσταση θα βασίζονται όλο και περισσότερο σε εφαρμογές για γυαλιά εικονικής πραγματικότητας, για smartphones και για εξελιγμένες πλατφόρμες.Background: Balance is a primary human sense which requires multisensory integration from the vestibular, the visual and the proprioceptive systems and involvement of the cerebellum and several other neural circuits. Additionally, a number of reflexes, such as the vestibuloocular and the vestibulospinal reflexes, along with many other higher cerebral functions are engaged. Under certain circumstances, a peripheral or central lesion can occur to the system leading to instability and vertigo symptomatology. Since the 1940s, when Cooksey and Cawthorne began to investigate rehabilitation following such lesions, many things have changed in the field of balance rehabilitation and during the last decades modern technologies have been incorporated in this effort. Nowadays, a great amount of mHealth, eHealth and Virtual Reality applications have been developed aiming to contribute in diagnosis or/and rehabilitation of patients with vestibular disorders. Methods: The electronic database MEDLINE was searched for relevant studies from January 1, 2015 up to April 15, 2021. The papers included in this review were determined according to certain inclusion and exclusion criteria. Results: A total number of 187 studies occurred after the initial search strategy, out of which 43 were considered eligible and included in this review. They were subdivided into 5 major categories and further discussed. Discussion: Gaming consoles, such as the Nintendo Wii, Nintendo Wii Fit and Sony PlayStation 2 EyeToy and Internet-based applications have been implemented during the last years to assist in the diagnosis and rehabilitation of patients with balance disorders. As novel technologies emerge and smartphones become an essential part of our everyday lives, vestibular diagnosis and rehabilitation will rely more and more on head-mounted display, mobile phone and sophisticated platform applications