Optokinetic stimulation for the treatment of vestibular and balance disorders: a systematic review with meta-analysis.

OBJECTIVES: To analyse the effectiveness of optokinetic stimulation (OKS) for improving symptoms and function in patients with vestibular and balance disorders. METHODS: PubMed (MEDLINE), SCOPUS, Web of Science (WOS), CINAHL Complete, and PEDro databases were searched to identify randomized controlled trials (RCTs) that included patients with vestibular and balance disorders and compared the effects of OKS versus other interventions or no intervention on subjective or objective functional outcomes. Data were analysed by the standardized mean difference (SMD) and its 95% confidence interval. RESULTS: A total of 10 studies were selected including 468 patients, 177 of whom received OKS. There were no significant differences in scores on the Dizziness Handicap Inventory (DHI) (SMD = 0.02; 95% CI - 0.18 to 0.23; p = 0.83) or the visual analogue scale (VAS) for vertigo (SMD = 0.16; 95% CI - 1.25 to 1.58; p = 0.82). However, there were statistically significant differences in the timed up and go (TUG) test, with a large effect (SMD = - 1.13; 95% CI -2 to - 0.28; p = 0.009), and in the sensory organization test (SOT), with a medium effect (SMD = - 0.7; 95% CI - 1.21 to - 0.19; p = 0.007). Subgroup analysis showed significant effects of OKS on VAS (p = 0.017), TUG (p = 0.009) and SOT (p = 0.001) only in patients with balance disorders without vestibular disease (p > 0.05). CONCLUSIONS: OKS may improve dizziness intensity measured with VAS or dynamic balance measured whit TUG and SOT in patients with balance disorders not due to vestibular disease. The quality of the evidence was low or very low due to the small number of included studies. PROSPERO REGISTRY NUMBER: CRD42023445024.

Combined optokinetic stimulation and cueing-assisted reading therapy to treat hemispatial neglect: A randomized controlled crossover trial.

BACKGROUND: Hemispatial neglect is a disabling cognitive disorder following stroke and effective therapies are required. OBJECTIVES: To evaluate the effects of combined optokinetic stimulation (OKS) and cueing-assisted reading therapy (READ) on the remission of hemispatial neglect following stroke. METHODS: Randomized, controlled, two-period, crossover trial conducted at a German neurorehabilitation center. Twenty participants with left neglect following right hemispheric stroke (mean age 66 years (SD 11), mean time since stroke 50 days (SD 33)) finished the trial (12 received OKSREAD first, 8 CONTROL first). The intervention consisted of 15 daily sessions of OKS (20 min) and text reading assisted by a therapist providing cues (20 min). The control treatment was a same-number, same-length neuropsychological treatment not targeting visuospatial attention. Primary outcomes were the change in performance of a customized neuropsychological test battery for neglect (0% worst - 100% best) and a test of neglect-related functional disability (Catherine Bergego Scale, 0 no impairment - 30 severest impairment), assessed before and after each treatment period. Secondary outcomes were performance in the 6 single tests composing the battery (e.g., omissions in text reading, center of cancellation in the Bells test, spatial bias of fixations when freely viewing photographs) and a clinical test of anosognosia. RESULTS: Overall performance in the neglect test battery improved slightly more after OKSREAD than after CONTROL (d=6%; p=0.002). The remission of neglect-related functional disability did not differ between treatments (d=-2; p=0.291). Ipsilesional fixation bias during free viewing was the only secondary outcome that was improved by OKSREAD as compared to CONTROL (d= -2.8°; p=0.005). CONCLUSION: At the applied intensity, the combined OKSREAD intervention slightly attenuated the ipsilesional attention bias in persons with neglect, but it did not improve neglect-related functional disability, anosognosia, or other neglect symptoms to a clinically meaningful degree. CLINICAL TRIAL REGISTRATION: URL: http://www. CLINICALTRIALS: gov. Unique identifier: NCT04273620.

Evaluation of effects of optokinetic and rotational stimuli with functional head impulse test (fHIT) in individuals with motion sickness.

OBJECTIVES: To evaluate effects of optokinetic and rotational stimulus in individuals with and without motion sickness (MS) using fHIT. METHODS: The study included subjects aged 18-40; 35 subjects with MS for MS group and 35 subjects without vertigo for control group. Percentage of the correct answer (% CA) with and without optokinetic stimulus (o-fHIT) in the frontal plane in the fHIT test was compared in both groups. In addition, both group subjects were seated on an ordinary rotating office chair. % CA was compared between groups by applying rotational fHIT (r-fHIT) test after the subjects were rotated randomly to the right and left and also simultaneously moved their heads in the vertical plane. RESULTS: There was no significant difference in % CA in fHIT o-fHIT and r-fHIT in the control group. Both groups showed a significant difference in % CA for fHIT, o-fHIT, and r-fHIT for all SCCs (p < 0.05). CONCLUSIONS: Since individuals with MS are affected by optokinetic and rotational stimuli, fHIT performed after these stimuli can be used as an objective confirming test for diagnosing MS.

Effects of attentional shifts along the vertical axis on number processing: An eye-tracking study with optokinetic stimulation.

Previous studies suggest that associations between numbers and space are mediated by shifts of visuospatial attention along the horizontal axis. In this study, we investigated the effect of vertical shifts of overt attention, induced by optokinetic stimulation (OKS) and monitored through eye-tracking, in two tasks requiring explicit (number comparison) or implicit (parity judgment) processing of number magnitude. Participants were exposed to black-and-white stripes (OKS) that moved vertically (upward or downward) or remained static (control condition). During the OKS, participants were asked to verbally classify auditory one-digit numbers as larger/smaller than 5 (comparison task; Exp. 1) or as odd/even (parity task; Exp. 2). OKS modulated response times in both experiments. In Exp.1, upward attentional displacement decreased the Magnitude effect (slower responses for large numbers) and increased the Distance effect (slower responses for numbers close to the reference). In Exp.2, we observed a complex interaction between parity, magnitude, and OKS, indicating that downward attentional displacement slowed down responses for large odd numbers. Moreover, eye tracking analyses revealed an influence of number processing on eye movements both in Exp. 1, with eye gaze shifting downwards during the processing of small numbers as compared to large ones; and in Exp. 2, with leftward shifts after large even numbers (6,8) and rightward shifts after large odd numbers (7,9). These results provide evidence of bidirectional links between number and space and extend them to the vertical dimension. Moreover, they document the influence of visuo-spatial attention on processing of numerical magnitude, numerical distance, and parity. Together, our findings are in line with grounded and embodied accounts of numerical cognition.

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.

Prism Adaptation and Optokinetic Stimulation Comparison in the Rehabilitation of Unilateral Spatial Neglect.

Prism adaptation (PA) is one of the most effective treatments for the rehabilitation of unilateral spatial neglect. Optokinetic stimulation (OKS) has also been demonstrated to be effective in ameliorating symptoms of neglect. The aim of this study is to compare the effectiveness of these two methods in a group of neglect patients using a crossover design. A group of 13 post-acute brain-damaged patients with unilateral spatial neglect, who had never been rehabilitated, were treated using PA and OKS. Each treatment was applied for 10 sessions, twice a day, to all patients with both treatments in crossed order (i.e., PA followed by OKS or vice versa). Neuropsychological assessments were performed: before the first (T1), at the end of the first/beginning of the second (T2) and at the end of the second training sessions (T3), and two weeks after the end of treatment (T4). Both procedures produced a significant improvement in clinical tests at T2, independent of the type of training. The results suggest that either PA or OKS induces a significant amelioration of neglect in right brain-damaged patients, mainly in the first block of treatment. Since no differences between treatments were found, they could be applied in clinical practice, according to the requirements of the individual patient.

Customised vestibular rehabilitation with the addition of virtual reality based therapy in the management of persistent postural-perceptual dizziness.

OBJECTIVE: Visual-vestibular mismatch patients experience persistent postural and perceptual dizziness. Previous studies have shown the benefit of vestibular rehabilitation for visual desensitisation using gaze stabilisation exercises and optokinetic stimulation. This study assessed the benefit of customised vestibular rehabilitation with visual desensitisation and virtual reality based therapy rehabilitation in the management of patients with persistent postural-perceptual dizziness. METHODS: This retrospective study included 100 patients with Situational Characteristic Questionnaire scores of more than 0.9. All patients received virtual reality based therapy along with usual vestibular rehabilitation using gaze stabilisation exercises with a plain background followed by graded visual stimulation and optokinetic digital video disc stimulation. Patients' symptoms were assessed before and after vestibular rehabilitation using the Situational Characteristic Questionnaire, Generalised Anxiety Disorder Assessment-7, Nijmegen Questionnaire and Dizziness Handicap Inventory. RESULTS: There were statistically significant improvements in Situational Characteristic Questionnaire scores, Nijmegen Questionnaire scores and Dizziness Handicap Inventory total score. However, there was a statistically insignificant difference in Generalised Anxiety Disorder Assessment-7 scores. There was a significant positive correlation between post-rehabilitation Situational Characteristic Questionnaire scores and other questionnaire results. CONCLUSION: Incorporating virtual reality based therapy with customised vestibular rehabilitation exercises results in significant improvement in persistent postural-perceptual dizziness related symptoms.

Visually Evoked Postural Responses (VEPRs) in Children with Vestibular Migraine.

Vestibular migraine (VM) is the most common cause of episodic vertigo in children. Vertigo, nausea, dizziness and unsteadiness are often complained of by children with migraine, which can precede, follow or be present simultaneously with headache. The aim of this study was to use posturography to investigate the visually evoked postural responses (VEPRs) of children with VM and compare them to data obtained from children with primary headache (M) and controls (C). Twenty children diagnosed as affected by VM, nineteen children with M without aura and twenty healthy subjects were recruited in this cross-sectional study. Posturography was performed by a standardized stabilometric force-platform (Svep-Politecnica) in the following conditions: open eyes (OE), closed eyes (CE) and during full-field horizontal optokinetic stimulation (OKN-S). Electronystagmography was performed simultaneously to analyze optokinetic reflex parameters. In the OE condition, no difference was found between groups with respect to body sway area. In contrast, this parameter increased in the two pathological groups with respect to controls in the CE condition. The optokinetic stimulations also induced a similar increase of body sway area in the M group relative to controls, but a further increase was elicited in the VM group. Electronystagmographic recording also revealed different optokinetic reflex parameters in the latter groups. This study disclosed an abnormal sensitivity of children with M and VM to full-field moving scenes and a consequent destabilization of posture, as documented by the abnormal VEPRs. Children with VM were particularly exposed to this risk. Possible clinical implications of these findings are discussed.

Can auditory cues improve visuo-spatial neglect? Results of two pilot studies.

Although neglect is known to be a multimodal deficit, current interventions often address the visual modality only. Experimental studies, however, found that neglect patients can partially overcome their spatial inattention temporarily when being exposed to auditory cues that move towards the neglected side of space. Two pilot studies investigated the impact of dynamic auditory cueing on egocentric neglect severity in a clinical-therapeutic setting. In both studies, the patient groups received 15 sessions of intervention. Study 1, designed as double-blinded trial with a historical control group, targeted severely impaired early-acute patients who listened to music or audio books which were presented as moving dynamically from right to left. Results showed a reduction in egocentric neglect severity that persisted after therapy termination in the intervention but not in the historical control group. In study 2, based on the comparison with reported effect sizes of previous studies, dynamic meaningful auditory cues and optokinetic stimulation were combined in a computer-based training. Both studies found a significant reduction of neglect severity. Results provide evidence for the reduction of egocentric neglect severity after repetitive auditory cueing therapy in both severely and moderately impaired patients. Our promising findings should be verified thoroughly in randomized-controlled trials.

Perception of postural verticality in roll and pitch while sitting and standing in healthy subjects.

Assessment of verticality perception is increasingly used in patients with disorders of upright body orientation, e.g. in pusher behavior after hemispheric stroke or in retropulsion in neurovascular or degenerative diseases. The subjective postural vertical (SPV) assesses the individual's perceived upright body orientation in space and can be determined in a sitting or a standing position. As somatosensory input differs between sitting and standing, we suppose a different representation of verticality. Thus, the aim of this study was to compare the SPV while sitting and while standing, and to determine the influence of proprioceptive and visual stimulations on the SPV in both positions. Twenty healthy subjects (18-40 years, 9 female) participated in two experiments. In experiment 1 the SPV was assessed in the pitch and roll planes while sitting and standing. In experiment 2 we additionally applied somatosensory Achilles tendon vibration and visual optokinetic stimulation. Results of experiment 1 revealed no difference of the SPV error between sitting and standing. Though, we found an increased SPV variability while sitting. Experiment 2 showed no effect of sensory manipulation in the pitch plane, but an effect of optokinetic stimulation in the roll plane. The tilt in direction of the visual stimuli was more pronounced while sitting. Optokinetic stimulation also resulted in a larger SPV variability in roll, indicating larger insecurity in verticality estimation during stimulation. In conclusion, even though the SPV assessment while sitting and standing resulted in similar mean values, the larger variability and the higher sensitivity to visual stimuli while sitting suggest different strategies for verticality estimation while sitting and while standing.

The integration of multisensory motion stimuli is impaired in vestibular migraine patients.

BACKGROUND: Vestibular migraine (VM) is a relatively recently acknowledged vestibular syndrome with a very relevant prevalence of about 10% among patients complaining of vertigo. The diagnostic criteria for VM have been recently published by the Bárány Society, and they are now included in the latest version of the International Classification of Headache Disorders, yet there is no instrumental test that supports the diagnosis of VM. OBJECTIVE: In the hypothesis that the integration of different vestibular stimuli is functionally impaired in VM, we tested whether the combination of abrupt vestibular stimuli and full-field, moving visual stimuli would challenge vestibular migraine patients more than controls and other non-vestibular migraineurs. METHODS: In three clinical centers, we compared the performance in the functional head impulse test (fHIT) without and with an optokinetic stimulus rotating in the frontal plane in a group of 44 controls (Ctrl), a group of 42 patients with migraine (not vestibular migraine, MnoV), a group of 39 patients with vestibular migraine (VM) and a group of 15 patients with vestibular neuritis (VN). RESULTS: The optokinetic stimulation reduced the percentage of correct answers (%CA) in all groups, and in about 33% of the patients with migraine, in as many as 87% of VM patients and 60% of VN patients, this reduction was larger than expected from controls' data. CONCLUSIONS: The comparison of the fHIT results without and with optokinetic stimulation unveils a functional vestibular impairment in VM that is not as large as the one detectable in VN, and that, in contrast with all the other patient groups, mainly impairs the capability to integrate different vestibular stimuli.

Torsional component of microsaccades during fixation and quick phases during optokinetic stimulation.

While many studies have characterized the eye movements during visual fixation, includ-ing microsaccades, in most cases only horizontal and vertical components have been rec-orded and analyzed. Thus, little is known about the torsional component of microsaccades. We took advantage of a newly developed software and hardware to record eye movements around the three axes of rotation during fixation and torsional optokinetic stimulus. We found that the average amplitude of the torsional component of microsaccades during fixation was 0.34 ± 0.07 degrees with velocities following a main sequence with a slope comparable to the horizontal and vertical components. We also found the size of the tor-sional displacement during microsaccades was correlated with the horizontal but not the vertical component. In the presence of an optokinetic stimulus a nystagmus was induced producing a more frequent and larger torsional quick phases compared to microsaccades produced during fixation with a stationary stimulus. The torsional component and the vertical vergence component of quick phases grew larger with higher velocities. Addition-ally, our results validate and show the feasibility of recording torsional eye movements using video eye tracking in a desktop mounted setup.

Optokinetic stimulation efficiency for sea sickness treatment.

BACKGROUND: Sea sickness is the type of motion sickness induced by maritime transport. Its prevention through optokinetic exercises is efficient. The object of this study is to evaluate the efficiency experienced by the patients as well as the impact on other motion sicknesses. MATERIALS AND METHODS: One hundred and forty-one patients underwent optokinetic treatment methods between 2006 and 2014. The following parameters were studied and scored on a numeric scale: sea sickness, intensity of vomiting and ability to hold position and duties on board. RESULTS: Study parameters significantly improved by optokinetic reeducation method. Sea sickness was reduced by a factor of 2. Study settings were also stable over years. Other motion sicknesses were also improved with this optokinetic stimulation. CONCLUSIONS: Treating sea sickness by optokinetic stimulation reeducation gives good results particularly improving its related clinical manifestations, therefore allowing seamen to properly hold their functions on board. Its efficiency lasts in time and seems promising for the management of other motion sicknesses.

Assessment of visual sensation, psychiatric profile and quality of life following vestibular schwannoma surgery in patients prehabituated by chemical vestibular ablation.

AIMS: Preoperative chemical vestibular ablation can reduce vestibular symptoms in patients who have gone through vestibular schwannoma resection. The goal of this study was to determine whether chemical vestibular prehabituation influences the patients' post-operative perception of visual stimulation, mental status and quality of life. We also tried to find out whether increases of optokinetic nystagmus, measured by routine electronystagmography, correlate with subjective symptoms. METHODS: We preoperatively administered (2 months prior to surgery) 0.5 - 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic instillations in 11 patients. Head impulse and caloric tests confirmed reduction of vestibular function in all patients. The control group consisted of 21 patients. Quality of life in both groups was evaluated using the Glasgow Benefit Inventory, the Glasgow Health Status Inventory and the Dizziness Handicap Inventory questionnaires. Visual symptoms and optokinetic sensation were evaluated using a specific questionnaire developed by our team and by measuring gains preoperatively and postoperatively in both groups using routine electronystagmography. The psychological profile was evaluated using the Zung Self-Rating Depression Scale and the Generalised Anxiety Disorder Assessment questionnaires. RESULTS: There were no statistically significant differences between both groups with regards to the results of the questionnaires. Patients who received preoperative gentamicin were less sensitive to visual stimulation (P<0.10) and many of them had a significantly higher gain in the optokinetic nystagmus than the control group in the preoperative stage. CONCLUSION: Pre-treatment with gentamicin helps to lower anxiety levels in patients and improves their general postoperative status. Pre-treated patients are also less sensitive to optokinetic stimulation. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03638310.

A case-control study of visually evoked postural responses in childhood with primary headaches.

BACKGROUND: Disorientation, nausea, confusion, dizziness, and displacement are frequently complained by headache-suffering children. Anyhow, the cause of these symptoms is still unclear, and a dysfunction of vestibular pathways or their alteration due to central pain pathways hyper-activation, has been proposed. The aim of this study is to use posturography to explore the balance function of headache-suffering children during pain-free periods. METHODS: Posturography was performed on 19 migraineurs, 11 tension-type headache sufferers, and 20 healthy controls. Posturographic measures were performed during headache-free periods under different conditions: with eyes opened, eyes closed, and during right and left optokinetic stimulation. The last 2 conditions were used to mimic unreliable visual signals that can confound vestibular system. RESULTS: During eyes-closed conditions, headache-suffering children displayed higher displacements than healthy controls, since statokinesiogram surface was higher in tension-type headache sufferers and migraineurs compared with controls (P value = 0.0095). Romberg's index, indicating the overall stability of the subject, was lower in healthy controls than in headache sufferers (P = 0.0139), thus suggesting a vestibular impairment in the seconds. Moreover, both during right and left optokinetic stimulation, the statokinesiogram length was higher in headache-suffering children (P < 0.0001). Thereafter, statokinesiogram surface was higher in migraineurs during right optokinetic stimulation (P = 0.0388) than in tension-type headache sufferers when stimulation was directed on the opposite side (P = 0.0249). CONCLUSIONS: These results suggest a central alteration of vestibular pathways in headache-suffering children, that makes balance function more dependent from visual inputs than healthy subjects, even in inter-ictal phases.

Modulation of the human electro-cerebellogram (ECeG) during vestibular and optokinetic stimulation.

We have recently shown that it is possible to record vestibular cerebellar evoked potentials (VsCEPs) in the form of a contralateral short-latency biphasic positive-negative wave with surface electrodes placed over the posterior fossa and, in parallel with this, the spontaneous electrocerebellogram (or ECeG). VsCEPs were further shown to exhibit considerable plasticity depending on visual context and in this article we show additionally that the ECeG power and cerebro-cerebellar coherence which accompanies the VsCEPs also changes systematically during vestibular and optokinetic stimuli. In a sample of nine healthy human subjects, half of whom had VsCEPs, we recorded in parallel the ECeG and for comparison the EEG from central scalp sites. The results showed that during vection with vestibular stimulation there is actually a reduction in the power of the ECeG accompanied by an increase in cerebro-cerebellar coherence, both of which correlate with the subjective sensation of vection. Only the VsCEPs present group showed the significant power reduction and increase in coherence, indicating a link between the VsCEP and plasticity in the ECeG. We suggest that these data are consistent with a human cerebro-cerebellar network associated with control of the VOR. The network exhibits the plasticity expected from the known inhibitory properties of Purkinje cells and the pausing of spontaneous Purkinje cell activity following a climbing-fibre evoked response with conjunctive inputs from the mossy-fibre system.

Brain Activations During Optokinetic Stimulation in Acute Right-Hemisphere Stroke Patients and Hemispatial Neglect: An fMRI Study.

Objective. Leftward optokinetic stimulation (OKS) is a promising therapeutic approach for right-hemisphere stroke patients with left hemispatial neglect. We questioned whether the putative neural basis is an activation of frontoparietal brain regions involved in the control of eye movements and spatial attention. Methods. We used functional magnetic resonance imaging to investigate brain activations during OKS in acute right-hemisphere stroke patients (RHS, n = 19) compared with healthy control subjects (HC, n = 9). Based on neuropsychological testing we determined the ipsilesional attention bias in all RHS patients, 11 showed manifest hemispatial neglect. Results. In HC subjects, OKS in either direction led to bilateral activation of the visual cortex (V1-V4), frontal (FEF) and supplementary (SEF) eye fields, intraparietal sulcus (IPS), basal ganglia, and thalamus. RHS patients' activations were generally reduced compared with HC. Nevertheless, leftward OKS bilaterally activated the visual cortex (V1-V4), FEF, SEF, IPS, and thalamus. The neural response to OKS was negatively correlated with patients' behavioral impairment: The greater the individual attention bias/neglect the weaker the brain activations. Conclusion. In RHS patients, leftward OKS activates frontoparietal regions (FEF, IPS) that are spared from structural brain damage and functionally involved in both oculomotor control and spatial attention. This may provide a neural basis for the known therapeutic effects of OKS on hemispatial neglect. In acute stroke stages, reduced activation levels correlating with neglect severity indicate functional downregulation of the underlying dorsal attention network. Therefore, chronic RHS patients with less severe neglect after recovery of network disturbances may be more suitable candidates for OKS rehabilitation.

Sham-Controlled Study of Optokinetic Stimuli as Treatment for Mal de Debarquement Syndrome.

Introduction: Mal de Debarquement Syndrome (MdDS) is a condition characterized by a perception of self-motion in the absence of a stimulus, with two onset types: Motion-Triggered and Spontaneous. Currently, the pathophysiology is unknown and consequently, the therapeutic options are limited. One proposed treatment protocol, developed by Dai and colleagues is based on optokinetic stimulation, which aims to re-adapt the vestibular ocular reflex. This study aimed to reproduce the treatment protocol developed by Dai and colleagues and to assess if a placebo effect is present in the treatment protocol and lastly, aimed to further investigate the treatment on MdDS patient outcomes. Method: Twenty-five MdDS patients (13 Motion-Triggered and 12 Spontaneous) were exposed to 5 consecutive days of optokinetic treatment (consisting of exposure to optokinetic stimuli with head movements). Eleven of these 25 patients were also exposed to 2 days of a sham treatment prior to the OKN treatment. Posturography measurements and reported symptoms [e.g., using the visual analog scale (VAS)] of patients were assessed throughout the treatment. Posturography data of the patients was compared with the data of 20 healthy controls. Results: No placebo effect was recorded with any changes in postural data and VAS scale. After the optokinetic treatment, a significant improvement in postural control was observed in 48% of patients, of whom 70% were of the Motion-Triggered subtype (p-values: Area under the Curve-Anterior Posterior < 0.001; Area under the Curve-Medio Lateral p < 0.001, Confidence Ellipse Area (CEA) < 0.001, Velocity < 0.001). Conclusion: The protocol was effective in approximately half of the MdDS patients that took part in the study, with no placebo effect recorded. The Motion-Triggered group responded better to treatment than the Spontaneous group. In addition to this, this study indicates that the greatest postural changes occur within the first 3 days of treatment, suggesting that a shorter protocol is possible. Overall, these findings support what was previously observed in Dai's studies, that optokinetic stimulation can reduce and ease self-motion perception in those with MdDS. Thus, validating the reproducibility of this protocol, suggesting that a consistent and uncomplicated implementation across treatment centers is possible.

Rod and frame test and posture under optokinetic stimulation used to explore two complementary aspects of the visual influence in postural control after stroke.

BACKGROUND: Balance rehabilitation should consider individual comportments according to visual input (VI). Indeed, visual dependence (VD), defined as the predominance given to the VI whatever the circumstances, frequent after stroke it could disturb balance. Because the term VD is a bit restrictive and cannot be deduced from clinical tests, the term visual sensitivity (VS) is preferred here. HYPOTHESIS: VI could have different influence depending on the task for a given individual. METHODS: We retrospectively compared 2 VS tests routinely used: the rod and frame test (RFT) and optokinetic stimulation (OKS). In RFT, VS was defined by a misperception of the visual verticality induced by a tilted frame (VS RFT) and in OKS by tilted sitting posture induced by rotational OKS (VS OKS). We studied the relations between VS RFT and VS OKS. RESULTS: We analysed data for 84 patients, mean age 55±10years, 45±30days after stroke. Scores for both tests were correlated with autonomy measured by the functional independence measure (r=-0.3, p=0.01 and r=-0.2, p=0.02). VS OKS score was also correlated with balance measured by the postural assessment scale for stroke (r=-0.3, p=0.03). VS RFT score was not correlated with VS OKS score (p=0.4, r=0.04). DISCUSSION - CONCLUSION: A patient may display VS for one test without sensitivity for the other because these tests investigate different neural organisation - perception for RFT or action for OKS. Their relation to balance disorders should be further investigated to build individualized rehabilitation programs.

Visual-vestibular processing deficits in mild traumatic brain injury.

BACKGROUND: The search for reliable and valid signs and symptoms of mild traumatic brain injury (mTBI), commonly synonymous with concussion, has lead to a growing body of evidence that individuals with long-lasting, unremitting impairments often experience visual and vestibular symptoms, such as dizziness, postural and gait disturbances. OBJECTIVE: Investigate the role of visual-vestibular processing deficits following concussion. METHODS: A number of clinically accepted vestibular, oculomotor, and balance assessments as well as a novel virtual reality (VR)-based balance assessment device were used to assess adults with post-acute concussion (n = 14) in comparison to a healthy age-matched cohort (n = 58). RESULTS: Significant between-group differences were found with the VR-based balance device (p = 0.001), with dynamic visual motion emerging as the most discriminating balance condition. The symptom reports collected after performing the oculomotor and vestibular tests: rapid alternating horizontal eye saccades, optokinetic stimulation, and gaze stabilization, were all sensitive to health status (p < 0.05), despite the absence of oculomotor abnormalities being observed, except for near-point convergence. The BESS, King-Devick, and Dynamic Visual Acuity tests did not detect between-group differences. CONCLUSION: Postural and visual-vestibular tasks most closely linked to spatial and self-motion perception had the greatest discriminatory outcomes. The current findings suggest that mesencephalic and parieto-occipital centers and pathways may be involved in concussion.