Visual vertigo: Vertigo of oculomotor origin

Optokinetic stimulation in the rehabilitation of visually induced dizziness in people with vestibular disorders: A systematic review

OBJECTIVE

This systematic review and meta-analysis investigates the effects optokinetic stimulation in people with vestibular disorders, with a specific focus on people with visually induced dizziness.

DATA SOURCES

A systematic review was conducted using three electronic databases, CINAHL, PubMed and Physiotherapy Evidence Database (PEDro), from 2000 up to February 2024.

REVIEW METHODS

Randomised controlled trials were included, which compared: (a) adults above 18 years old with vestibular disorders, (b) the study evaluated interventions using optokinetic stimulation, (c) the intervention was compared with usual care; placebo or to no intervention, (d) the study included at least one outcome measure evaluating vestibular symptoms and (e) published in English. The methodological quality of the included studies was assessed using the PEDro scale and PROSPERO's registration number ID: CRD42021273382).

RESULTS

Eleven randomised control trials, reported in 12 records, fulfilled the inclusion criteria. All of the studies were considered to have 'good' methodological quality according to the PEDro scale. All studies showed significant improvement in vestibular symptoms in both the intervention and control groups. A meta-analysis performed on six of the records found a preference towards the addition of OKS to conventional vestibular rehabilitation helped to further reduce dizziness symptoms for patients, but the results were not statistically significant.

CONCLUSION

No optimal duration or frequency for OKS has been determined. The addition of OKS to conventional vestibular rehabilitation may be beneficial in further improving vestibular symptoms in patients with dizziness. OKS could help to improve enjoyment and adherence to vestibular rehabilitation.

Evaluation of Subjective Visual Vertical and Cervical Neuromotor Control in Young Nomophobians: A Cross Sectional Study

Misperceptions of subjective visual vertical are associated with poor balance, increasing the risk of falls and accidents. The aim of the present study was to evaluate the effect of nomophobia on verticality perception using subjective visual vertical (S.V.V.) test and cervical neuromotor control of the deep neck flexors (DNF) in adults aged 18-29 years old. This cross-sectional study employed convenience sampling and was conducted at a tertiary health institute over an eight-month period.After obtaining the written informed consent, 102 participants were asked to fill the Nomophobia Questionnaire (NMP-Q) and based on the responses participants were stratified into mild (n1 = 34), moderate(n2 = 34), and severe(n3 = 34) nomophobian group. Each nomophobian group underwent testing for verticality perception by using the SVV test and cervical neuromotor control. 102 healthy age and gender matched controls were recruited and underwent testing for verticality perception by using the SVV test and cervical neuromotor control. The mean age of the study participants was 22 ± 3.15 years with 35(33.98%) males and 67(65.04%) females. There was a statistically significant difference between the median scores across the three nomophobian groups with S.V.V. (p = 0.005), activation score (p = 0.012), and endurance score (p = 0.000) of the deep neck flexors in the severe nomophobia group. This study demonstrated that SVV and cervical neuromotor control was predominantly affected in the severe nomophobian group.

Visual fixations and visually induced dizziness: An exploratory study

BACKGROUND

Visually induced dizziness can develop as a sequala of a vestibular disorder and is characterized by symptoms of nausea, dizziness, and imbalance in rich visual environments such as supermarkets and shopping malls. To date the mechanisms underlying visually induced dizziness are poorly understood.

RESEARCH QUESTION

What are the characteristics of visual fixations and postural sway in adults with visually induced dizziness compared to healthy adults when exposed to increasingly complex visual environments?

METHODS

We recruited 20 adults with visually induced dizziness and 20 healthy adults to this cross-sectional exploratory study. Participants were instructed to maintain gaze on letters projected on a large screen with backgrounds of differing visual complexity. The number of visual refixations, movement of the centre of pressure, and movement of the head and body centres of mass were recorded.

RESULTS

Adults with visually induced dizziness showed a significantly higher number of visual refixations (F= 10.592, p < 0.01), and increased mean velocity of head and body centres of mass movement (F= 14.034, p < 0.01 and F= 6.553, p < 0.05 respectively) compared to healthy adults.

SIGNIFICANCE

Adults with visually induced dizziness exhibited visual fixational instability and increased postural and head sway compared to healthy adults. This was mainly observed in conditions with complex and moving backgrounds. This may account for reports from adults with visually induced dizziness of worsening symptoms in busy environments. The results from the study may assist in guiding intervention development to reduce symptoms of visually induced dizziness.

Visually induced dizziness

PURPOSE OF REVIEW

Visually induced dizziness (VID) is a common phenomenon in vestibular disorders of both peripheral and central causes. This article provides a review of the most updated understandings of definition, pathophysiology, and treatment options.

RECENT FINDINGS

The pathophysiology is complex and its severity or persistence may be related both to the underlying cause and heritable factors. Environmental and psychological factors may influence the degree of impact of VID on daily life function. Treatment is mostly empiric at this point but includes pharmacologic, desensitization, cognitive behavioral therapies, visual rehabilitation, and treatment of the underlying cause whenever present. Additional research is needed to clarify the best management of this vestibular symptom as well as some of the other conditions with which it is commonly associated.

SUMMARY

VID is a fairly common vestibular syndrome constitutng spatial disorientation without illusory motion. As it is seen in both peripheral and central vestibular disorders, it should be considered a syndrome or constellation of symptoms rather than a discrete disorder. In some cases, it may be the presenting symptom with no other clear disorder linked to it.

Cervical and ocular vestibular evoked myogenic potentials in epileptic patients

Background

Vertigo and dizziness are very common complaints that may be related to epilepsy. The purpose of this study was to assess vestibulo-spinal and linear vestibulo-ocular function in epileptic patients in the inter ictal period. The current observational study was carried out in audio-vestibular unit Menoufia University. Subjects in the current study were divided into two groups: The control group included 30 normal individuals not complaining from any dizzy symptoms and the epileptic cases group included 30 epileptic patients. All subjects in the study were submitted to cervical and ocular vestibular evoked myogenic potential.

Results

There was no significant difference between the control and epileptic group regarding the age and sex distribution. Sixty-seven percent of epileptic cases had dizzy symptoms. There was statistically significant difference in the latency and amplitude of c and o VEMP between the control and the epileptic group, 39/60 ears (65%) in the study group had cVEMP abnormalities, 32/60 ears (53%) had oVEMP abnormalities. Abnormal c and o VEMP were reported in 28/60 ears (46.7%). There was statistically significant relationship between VEMP abnormalities and duration of seizures, frequency of epileptic attacks, and type of therapy.

Conclusion

Vestibular abnormalities were frequently reported in epileptic patients in the current study which may be related to the severity and control of epilepsy.

Virtual reality versus optokinetic stimulation in visual vertigo rehabilitation

BACKGROUND

Visual vertigo (VV) is a condition at which there is worsening or triggering of vestibular symptoms in certain visual environments with large size (full field) repetitive or moving visual patterns as shopping malls.

PURPOSE

This work was designed to study effect of virtual reality and optokinetic stimulation on rehabilitation of VV.

METHOD

A total of 60 subjects divided into 2 groups that were simply randomized by the concealed envelope method: Group I consisted of 30 VV patients underwent vestibular rehabilitation using virtual reality. Group II consisted of 30 VV patients underwent vestibular rehabilitation using optokinetic stimulation.

RESULTS

Significant improvement in performance in the two groups after rehabilitation with no statistically significant difference when comparing both groups.

CONCLUSIONS

A combined intense rehabilitation program including OPK stimulation or VR rehabilitation combined with home-based exercises appeared to be equally effective for management of patients with VV and improving their quality of life.

Detecting positional vertigo using an ensemble of 2D convolutional neural networks

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We trained Deep Neural Networks to detect attacks of motion provoked dizziness.

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2D Convolutional Deep Neural Networks outperform 1D network architectures.

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Best results were provided by input features combining eye- and head-movement.

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An ensemble of five networks outperformed each individual network alone.

The aim of the work presented here was to develop a system that can automatically identify attacks of dizziness occurring in patients suffering from positional vertigo, which occurs when sufferers move their head into certain positions. We used our novel medical device, CAVA, to record eye- and head-movement data continually for up to 30 days in patients diagnosed with a disorder called Benign Paroxysmal Positional Vertigo. Building upon our previous work, we describe a novel ensemble of five 2D Convolutional Neural Networks, using composite recognition features, including eye-movement data and three-channel accelerometer data. We achieve an F1 score of 0.63 across an 11-fold cross-fold validation experiment, demonstrating that the system can detect a few seconds of motion provoked dizziness from within over a 100 h of normal eye-movement data. We show that the system outperforms our previous 1D Neural Network approach, and that our ensemble classifier is superior to each of the individual networks it contains. We also demonstrate that our composite recognition features provide improved performance over results obtained using the individual data sources independently.

Modification of Eye-Head Coordination With High Frequency Random Noise Stimulation

The vestibulo-ocular reflex (VOR) plays an important role in controlling the gaze at a visual target. Although patients with vestibular hypofunction aim to improve their VOR function, some retain dysfunction for a long time. Previous studies have explored the effects of direct current stimulation on vestibular function; however, the effects of random noise stimulation on eye–head coordination have not previously been tested. Therefore, we aimed to clarify the effects of high frequency noisy vestibular stimulation (HF-nVS) on eye–head coordination related to VOR function. Thirteen healthy young adult participants with no serious disease took part in our study. The current amplitude and density used were 0.4 mA and 0.2 mA/cm², respectively, with a random noise frequency of 100–640 Hz. The electrodes were located on both mastoid processes. The stimulus duration and fade in/out duration were 600 and 10 s, respectively. Subjects oscillated their head horizontally, gazing at the fixation point, at 1 Hz (0.5 cycles/s) for 30 repetitions. The coordination of eye–head movements was measured by eye-tracking and a motion capture system. Peak-to-peak angles for eye and head movement and deviation of the visual line from the fixation target revealed no significant differences between HF-nVS and sham. The lag time between the eye and head movement with HF-nVS post-stimulation was significantly shorter than that of the sham. We found that HF-nVS can reduce the lag time between eye and head movement and improve coordination, contributing to a clear retinal image. This technique could be applied as a form of VOR training for patients with vestibular hypofunction.

Visual Fixations and Motion Sensitivity: Protocol for an Exploratory Study

Background

Motion sensitivity after vestibular disorders is associated with symptoms of nausea, dizziness, and imbalance in busy environments. Dizziness and imbalance are reported in places such as supermarkets and shopping malls which have unstable visual backgrounds; however, the mechanism of motion sensitivity is poorly understood.

Objective

The main aim of this exploratory observational study is to investigate visual fixations and postural sway in response to increasingly complex visual environments in healthy adults and adults with motion sensitivity.

Methods

A total of 20 healthy adults and 20 adults with motion sensitivity will be recruited for this study. Visual fixations, postural sway, and body kinematics will be measured with a mobile eye tracker device, force plate, and 3D motion capture system, respectively. Participants will be exposed to experimental tasks requiring visual fixation on letters, projected on a range of backgrounds on a large screen during quiet stance. Descriptive statistics (mean and standard deviation) will be calculated for each of the variables. One-way independent-measures analyses of variance will be performed to investigate the differences between groups for all variables.

Results

Data collection was started in May 2019 and was completed by February 2020. It was approved by Health and Disability Ethics Committees, Ministry of Health, New Zealand on November 2, 2018 (Ethics ref: 18/CEN/193). We are currently processing the data and will begin data analysis in July 2020. We expect the results to be available for publication by the end of 2020. The trial was funded by the Neurology Special Interest Group, Physiotherapy New Zealand, and the Eisdell Moore Centre in November 2018.

Conclusions

This study will provide a detailed investigation of visual fixations in response to increasingly complex visual environments. Investigating characteristics of visual fixations in healthy adults and those with motion sensitivity will provide insight into this disabling condition and may inform the development of new intervention strategies which explicitly cater to the needs of this population.

Trial Registration

Australian New Zealand Clinical Trials Registry, ACTRN12619000254190; https://tinyurl.com/yxbn7nks

International Registered Report Identifier (IRRID)

PRR1-10.2196/16805