General vestibular testing

Multidisciplinary Care for Moebius Syndrome and Related Disorders: Building a Management Protocol

Moebius syndrome is a collection of orofacial anomalies with highly variable features affecting many different systems but characterised by bilateral facial palsy and absent eye abduction. We largely regard Moebius syndrome as a diagnosis of exclusion. Lack of awareness and knowledge means that children often fall between services, leading to treatment delays and difficulty interfacing with social care and schools, with long-term impact on physical health and psychosocial development. We developed a multidisciplinary team comprising core clinicians (lead physician, geneticist, speech and language therapist, psychologist and specialist nurse) and an expanded group to encompass the other affected systems. The interactions between our specialties lead to the development of a treatment protocol, which we present. The protocol harnesses the aspects of care of children with a range of other rare diseases at a specialised paediatric centre and synthesises them into a holistic approach for MBS and related conditions. Management is sequenced on an "ABC-style" basis, with airway, feeding, vision and speech taking priority in the early years. We define management priorities as airway stabilisation with swallow assessment, ocular surface protection and maintenance of nutritional support. Management principles for issues such as speech, reflux, drooling and sleep issues are outlined. In later years, psychological support has a prominent role geared towards monitoring and interventions for low mood, self-esteem and bullying.

Smooth Pursuit and Reflexive Saccade in Discriminating Multiple-System Atrophy With Predominant Parkinsonism From Parkinson's Disease

BACKGROUND AND PURPOSE

Performing the differential diagnosis of Parkinson's disease (PD) and multiple-system atrophy of parkinsonian type (MSA-P) is challenging. The oculomotor performances of patients with PD and MSA-P were investigated to explore their potential role as a biomarker for this differentiation.

METHODS

Reflexive saccades and smooth pursuit were examined in 56 patients with PD and 34 with MSA-P in the off-medication state.

RESULTS

Patients with PD and MSA-P had similar oculomotor abnormalities of prolonged and hypometric reflexive saccades. The incidence rates of decreased reflexive saccadic velocity and saccadic smooth pursuit were significantly higher in MSA-P than in PD (p<0.05 for both). Multiple logistic regression analysis indicated that slowed reflexive saccades (odds ratio [OR]=8.14, 95% confidence interval [CI]=1.45-45.5) and saccadic smooth pursuit (OR=5.27, 95% CI=1.24-22.43) were significantly related to MSA-P.

CONCLUSIONS

The distinctive oculomotor abnormalities of saccadic smooth pursuit and slowed reflexive saccades in MSA-P may serve as useful biomarkers for discriminating MSA-P from PD.

A nystagmus extraction system using artificial intelligence for video-nystagmography

Benign paroxysmal positional vertigo (BPPV), the most common vestibular disorder, is diagnosed by an examiner changing the posture of the examinee and inducing nystagmus. Among the diagnostic methods used to observe nystagmus, video-nystagmography has been widely used recently because it is non-invasive. A specialist with professional knowledge and training in vertigo diagnosis is needed to diagnose BPPV accurately, but the ratio of vertigo patients to specialists is too high, thus necessitating the need for automated diagnosis of BPPV. In this paper, a convolutional neural network-based nystagmus extraction system, ANyEye, optimized for video-nystagmography data is proposed. A pupil was segmented to track the exact pupil trajectory from real-world data obtained during field inspection. A deep convolutional neural network model was trained with the new video-nystagmography dataset for the pupil segmentation task, and a compensation algorithm was designed to correct pupil position. In addition, a slippage detection algorithm based on moving averages was designed to eliminate the motion artifacts induced by goggle slippage. ANyEye outperformed other eye-tracking methods including learning and non-learning-based algorithms with five-pixel error detection rate of 91.26%.

Chronic symptoms in patients with unilateral vestibular hypofunction: systematic review and meta-analysis

Objective

To systematically evaluate the full spectrum of self-reported chronic symptoms in patients with unilateral vestibular hypofunction (UVH) and to investigate the effect of interventions on these symptoms.

Methods

A systematic review was conducted following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis Statement (PRISMA). A literature search was performed in Pubmed, Web of Science, Embase, and Scopus to investigate self-reported symptoms and self-report questionnaires in patients with UVH. All original studies ranging from full-text clinical trials to case reports, written in English, German, and French, were included. The frequency of self-reported symptoms was presented. For self-report questionnaires, a meta-analysis was carried out to synthesize scale means by the pre- and post-intervention means and mean changes for studies that investigated interventions.

Results

A total of 2,110 studies were retrieved. Forty-seven studies were included after title-abstract selection and full-text selection by two independent reviewers. The symptoms of UVH patients included chronic dizziness (98%), imbalance (81%), symptoms worsened by head movements (75%), visually induced dizziness (61%), symptoms worsened in darkness (51%), and oscillopsia (22%). Additionally, UVH could be accompanied by recurrent vertigo (77%), tiredness (68%), cognitive symptoms (58%), and autonomic symptoms (46%). Regarding self-report questionnaires, UVH resulted on average in a moderate handicap, with an estimated mean total score on the Dizziness Handicap Inventory (DHI) and the Vertigo Symptom Scale (VSS) of 46.31 (95% CI: 41.17-51.44) and 15.50 (95% CI: 12.59-18.41), respectively. In studies that investigated the effect of vestibular intervention, a significant decrease in the estimated mean total DHI scores from 51.79 (95% CI: 46.61-56.97) (pre-intervention) to 27.39 (95% CI: 23.16-31.62) (post intervention) was found (p < 0.0001). In three studies, the estimated mean total Visual Analog Scale (VAS) scores were 7.05 (95% CI, 5.64-8.46) (pre-intervention) and 2.56 (95% CI, 1.15-3.97) (post-intervention). Finally, a subgroup of patients (≥32%) persists with at least a moderate handicap, despite vestibular rehabilitation.

Conclusion

A spectrum of symptoms is associated with UVH, of which chronic dizziness and imbalance are most frequently reported. However, semi-structured interviews should be conducted to define the whole spectrum of UVH symptoms more precisely, in order to establish a validated patient-reported outcome measure (PROM) for UVH patients. Furthermore, vestibular interventions can significantly decrease self-reported handicap, although this is insufficient for a subgroup of patients. It could therefore be considered for this subgroup of patients to explore new intervention strategies like vibrotactile feedback or the vestibular implant.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42023389185].

The value of vestibular graviceptive pathway evaluation in the diagnosis of unilateral peripheral vestibular dysfunction

BACKGROUND

Evaluation of vestibular graviceptive pathway (VGP) in patients with unilateral peripheral vestibular dysfunction (UPVD) has received increasing attention from researchers. The study aimed to investigate the value of VGP evaluation in the diagnosis of UPVD.

METHODS

Ninety-five UPVD patients were divided into attack and remission phase groups. VGP evaluation-related indicators, including subjective visual vertical (SVV), subjective visual horizontal (SVH), head tilt, ocular torsion (OT), and skew deviation (SD), were measured, and their correlations with cochleovestibular function test results were analyzed. The possible etiologies of contralesional VGP (c-VGP) were analyzed.

RESULTS

Positive rates of SVV, SVH, OT, and SD were significantly higher, and the degrees of SVV, SVH, and OT were significantly greater in the attack phase group than the remission phase group. The sides with abnormal VGP evaluation results were correlated with the sides with hearing loss, abnormal caloric, and video head impulse test (vHIT) results. A total of 14 patients showed c-VGP, and possible etiologies included contralateral benign paroxysmal positional vertigo (n = 4), bilateral hearing loss (n = 8), bilateral vHIT gain reduction (n = 1), autoimmune diseases (n = 6), vascular risk factors (n = 6), lacunar infarction (n = 3), and endolymphatic hydrops (n = 3).

CONCLUSIONS

Alterations in SVV, SVH, OT, and SD were noted in UPVD patients in different phases, which are presumed to be related to dynamic vestibular compensation; correlations between VGP evaluation results and cochleovestibular function test results indicate that VGP evaluation may be helpful for the diagnosis of the side affected in UPVD; the presence of c-VGP may be related to bilateral labyrinth lesions or endolymphatic hydrops on the affected side; and the involvement of autoimmune mechanisms also deserves attention.

The effect of body awareness on trunk control, affected upper extremity function, balance, fear of falling, functional level, and level of independence in patients with stroke

OBJECTIVES

This study was conducted to examine the effects of body awareness on trunk control, affected upper extremity function, balance, fear of falling, functional level, and level of independence in patients with stroke.

METHODS

35 individuals between the ages of 21 and 78 who were diagnosed with stroke were included in the study. The body awareness of the individuals participating in the study was determined with the Body Awareness Questionnaire (BAQ), trunk control with Trunk Impairment Scale (TIS), the affected upper extremity functions with Motor Activity Log-28 (MAL,-28), and Fugl-Meyer Upper Extremity Assessment (FMUEA), balance with Berg Balance Scale (BBS), fear of falling with Tinetti Falls Efficacy Scale (TFES), functional level with Barthel Activities of Daily Living Index (BI) and level of independence with Functional Independence Measures (FIM).

RESULTS

For patients participating in the study, 26% were female, 74% were male and 43% showed left, 57% showed right hemisphere involvement. In simple linear regression analysis, BAQ measurement had a statistically significant effect on TIS (F = 25.439 p = 0.001), MAL-28 (F = 7.852 p = 0.008), FMUEA (F = 12.155 p = 0.001), BBS (F = 13.506 p = 0.001), TFES (F = 13.119 p = 0.001), BI (F = 19.977 p = 0.001) and FIM (F = 22.014 p = 0.001) in patients with stroke.

CONCLUSIONS

In conclusion, body awareness was found to be one of the factors affecting trunk control, affected upper extremity function, balance, fear of falling, functional level, and level of independence in patients with stroke. It was thought that there was a need for assessment of body awareness and include bodyawareness in rehabilitation programs in patients with stroke.

Subjective visual vertical and postural control in patients following cochlear implantation

BACKGROUND

Cochlear implantation (CI) is associated with changes in the histopathology of the inner ear and impairment of vestibular function.

OBJECTIVE

The objectives of our study were to evaluate patients for clinical manifestations of space perception and balance changes before surgery, compare them with asymptomatic subjects (controls), and report changes in posturography and subjective visual vertical (SVV) during the acute post-surgery period in patients.

METHODS

Examination was performed using static posturography and the SVV measurement. We examined 46 control subjects and 39 CI patients. Patients were examined pre-surgery (Pre), 2nd day (D2) and then 14th day (D14) after implantation.

RESULTS

Baseline SVV was not different between patients and control group. There was a statistically significant difference (p < 0.001) in SVV between subgroups of right- and left-implanted patients at D2 (-1.36±3.02° and 2.71±2.36°, right and left side implanted respectively) but not Pre (0.76±1.07° and 0.31±1.82°) or D14 (0.72±1.83° and 1.29±1.60°). Baseline posturography parameters between patients and control group were statistically significantly different during stance on foam with eyes closed (p < 0.05). There was no statistically significant difference in posturography among Pre, D2 and D14.

CONCLUSIONS

CI candidates have impaired postural control before surgery. CI surgery influences perception of subjective visual vertical in acute post-surgery period with SVV deviation contralateral to side of cochlear implantation, but not after two weeks.

Postural control among individuals with and without chronic obstructive pulmonary disease: A cross-sectional study of motor and sensory systems

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is considered a heterogenic syndrome with systemic effects, including muscle dysfunction. There is evidence of postural control impairments among individuals with COPD, partly related to muscle weakness. However, research is scarce regarding the other underlying systems of postural control, such as the visual, somatosensory and vestibular system. The aim was to compare postural control, as well as the motor and sensory systems, between individuals with and without COPD.

METHODS

Twenty-two participants with COPD (mean age 74.0 ±6.2 years) and 34 non-obstructive references (mean age 74.9 ±4.9 years) participated in this cross-sectional study. Postural control was assessed with center of pressure trajectory of postural sway in quiet as well as a limits of stability test, calculating mediolateral and anteroposterior amplitudes for each test. Assessment of function in the motor system included maximum hand grip strength, as well as maximum strength in muscles around the hip, knee and ankle joints. Visual acuity, pressure sensibility, proprioception, vestibular screening, and reaction time were also included. Data was compared between groups, and significant differences in postural control were further analyzed with an orthogonal projection of latent structures regression model.

RESULTS

There was a significantly increased sway amplitude in the mediolateral direction in quiet stance on soft surface with eyes open (p = 0.014) as well as a smaller anteroposterior amplitude in the limits of stability test (p = 0.019) in the COPD group. Regression models revealed that the mediolateral amplitude was related to visual acuity and the burden of tobacco smoking assessed as pack-years. Further, muscle strength associated with anteroposterior amplitude in limits of stability test in the COPD group, and with age and ankle dorsal flexion strength among the referents. Besides for lower ankle plantar flexion strength in the COPD group, there were however no significant differences in muscle strength.

CONCLUSIONS

Individuals with COPD had a decreased postural control and several factors were associated with the impairments. The findings imply that the burden of tobacco smoking and reduced visual acuity relate to increased postural sway in quiet stance, and that muscle weakness is related to decreased limits of stability, among individuals with COPD.

Impact of Sensory Afferences in Postural Control Quantified by Force Platform: A Protocol for Systematic Review

Older adults’ postural balance is a critical domain of research as balance deficit is an important risk factor for falls that can lead to severe injuries and death. Considering the effects of ageing on sensory systems, we propose that posturographic evaluation with a force platform exploring the effect of sensory deprivation or perturbation on balance could help understand postural control alterations in the elderly. The aim of the future systematic review and meta-analysis described in this protocol is to explore the capacity of older adults to maintain their balance during sensory perturbations, and compare the effect of perturbation between the sensory channels contributing to balance. Seven databases will be searched for studies evaluating older adults’ balance under various sensory conditions. After evaluating the studies’ risk of bias, results from similar studies (i.e., similar experimental conditions and posturographic markers) will be aggregated. This protocol describes a future review that is expected to provide a better understanding of changes in sensory systems of balance due to ageing, and therefore perspectives on fall assessment, prevention, and rehabilitation.

The Role of Video Head Impulse Test (Vhit) in Diagnosing Benign Paroxysmal Positional Vertigo (BPPV)

Benign paroxysmal positional vertigo (BPPV) is a common clinical disorder characterized by brief recurrent spells of vertigo often brought about by certain head position changes. General treatment for BPPV is by clinical examination by Dix-Hallpike maneuver, Video head impulse test (VHIT) is a novel test that enhances diagnostic opportunities and enables a clinician to precisely localize the site of vestibular disorders. This interested us to investigate its potential in diagnosis of BPPV.The aim of the present study is to assess the role of Video head impulse test (VHIT) in confirming the clinically diagnosed case of BPPV.All patients above the age of 18 years who were clinically diagnosed with BPPV underwent VHIT and results were correlated with clinical findings. Total 60 patients were studied in the period of 2016-2018.Among the 60 patients clinically diagnosed with BPPV, 41 were males and 19 were females. Majority of patients were in the age group of 51-60 years. Posterior canal is most commonly affected (97%) than anterior and lateral canals in BPPV. In unilateral posterior canal BPPV and bilateral posterior canal BPPV VOR (Vestibulo- ocular reflex) gains was reduced but were not statistically significant. Saccades were present only in 17 cases. There is no relationship between the presence of saccades, the canal involved and the side of the lesion.From the present study we conclude that the currently available equipment for VHIT is not useful in diagnosing BPPV. Also, strongly recommends advanced research on this to record minute changes in VOR gain.

A link between frontal white matter integrity and dizziness in cerebral small vessel disease

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Idiopathic dizziness in older people is associated with more vascular risk.

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Idiopathic dizziness is also associated with impaired balance and cognition.

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These findings co-occur with more frontal markers of cerebral small vessel disease.

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Small vessel disease may contribute to dizziness through its effects on balance.

One in three older people (>60 years) complain of dizziness which often remains unexplained despite specialist assessment. We investigated if dizziness was associated with vascular injury to white matter tracts relevant to balance or vestibular self-motion perception in sporadic cerebral small vessel disease (age-related microangiopathy). We prospectively recruited 38 vestibular clinic patients with idiopathic (unexplained) dizziness and 36 age-matched asymptomatic controls who underwent clinical, cognitive, balance, gait and vestibular assessments, and structural and diffusion brain MRI. Patients had more vascular risk factors, worse balance, worse executive cognitive function, and worse ankle vibration thresholds in association with greater white matter hyperintensity in frontal deep white matter, and lower fractional anisotropy in the genu of the corpus callosum and the right inferior longitudinal fasciculus. A large bihemispheric white matter network had less structural connectivity in patients. Reflex and perceptual vestibular function was similar in patients and controls. Our results suggest cerebral small vessel disease is involved in the genesis of dizziness through its effect on balance.

The clinical course of vestibular neuritis from the point of view of the ocular vestibular evoked myogenic potential

Background

Studying otolith functions after unilateral vestibular neuritis using ocular vestibular-evoked myogenic potentials and subjective visual vertical tests could give different results.

Method

A total of 39 patients underwent a vestibular assessment that included the Dizziness Handicap Inventory and horizontal and vertical semicircular canal function testing with video head impulse testing, ocular vestibular-evoked myogenic potential testing, cervical vestibular-evoked myogenic potentials and subjective visual vertical testing.

Results

All patients showed a significant alteration (asymmetry ratio more than 40 per cent) for ocular vestibular-evoked myogenic potentials as well as for subjective visual vertical testing (more than −2° to more than +2°) during the acute phase, whereas after 72 hours from the acute vertigo attack normal values (asymmetry ratio less than 40 per cent) were found in 6 out of 39 patients for ocular vestibular-evoked myogenic potentials and 36 out of 39 for the subjective visual vertical (less than −2° to less than +2°).

Conclusion

Ocular vestibular-evoked myogenic potentials are the most suitable test to evaluate otolith functions in patients with unilateral vestibular neuritis in the acute and sub-acute phase.

Predictive model for diagnosing central lesions in emergency department patients with isolated dizziness who undergo diffusion-weighted magnetic resonance imaging

OBJECTIVES

Only 5% to 10% of patients who visit the emergency department (ED) with isolated dizziness without neurologic abnormalities may have central lesions; however, it is important to distinguish central lesions through brain imaging. This study was conducted to create a nomogram to provide an objective medical basis for selectively performing magnetic resonance imaging (MRI) among patients with isolated dizziness.

METHODS

This retrospective observational study enrolled patients who visited the ED of a tertiary hospital with isolated dizziness and underwent diffusion-weighted MRI and subsequently consulted with the departments of neurology, neurosurgery, or otorhinolaryngology. Multivariable logistic regression analysis was performed to identify risk factors in patients diagnosed with central lesions to create a nomogram with the significant variables.

RESULTS

Of the 1,078 patients who were screened, 119 were diagnosed with central lesions. Significant variables in the multivariable logistic regression analysis were albumin levels (odds ratio [OR] = 0.339, 95% confidence interval [CI] = 0.188 to 0.610, p = 0.0003), inorganic phosphate levels (OR = 0.891, 95% CI = 0.832 to 0.954, p = 0.0010), history of ischemic stroke (OR = 3.170, 95% CI = 1.807 to 5.560, p < 0.0001), presyncope (OR = 3.152, 95% CI = 1.184 to 8.389, p = 0.0216), and nystagmus (OR = 0.365, 95% CI = 0.237 to 0.561, p < 0.0001). The area under the receiver operating characteristic curve of the nomogram created with these variables was 0.7315 (95% CI = 0.6842 to 0.7788, p < 0.0001).

CONCLUSIONS

Albumin, inorganic phosphate, previous stroke, presyncope, and nystagmus were associated with the predictive diagnosis of central lesions among patients admitted to the ED with isolated dizziness. The novel nomogram created using these variables can help in objectively determining the need for MRI in patients presenting with isolated dizziness to the ED.

Vestibular and oculomotor function in patients with vestibular migraine

AIM

The purpose of this study was to assess the vestibular and oculomotor function in patients with vestibular migraine (VM). And we also investigate the relationship between testing results and effectiveness of preventive medications in VM.

MATERIAL AND METHOD

41 patients with VM were recruited in this study and examined with cervical and ocular vestibular evoked myogenic potential(cVEMP, oVEMP), video head impulse test(vHIT), caloric test and videonystagmography. All patients were treated with preventive medications. We calculated symptomatic improvement and record episodes frequency in patients with VM. Six months later, the effectiveness of preventive medications were evaluated and the relationship between vestibular testing and effectiveness of preventive medications were analyzed further.

RESULTS

In vestibular function testing, 73% of patients with VM showed abnormal results. Abnormal cVEMP, oVEMP, vHIT, and caloric test were found in 20%, 44%, 32% and 56% respectively. The abnormal rate of oVEMP was significantly higher than that of cVEMP(p < 0.05). And the proportion of abnormal caloric test was obviously higher than that of vHIT (p < 0.05). In oculomotor function testing, 42% of the patients with VM showed pathological results which was significantly lower than that of vestibular function testing(p < 0.05). After 6 months follow-up, the proportion of prophylactic medication effectiveness was significantly higher in normal vestibular function testing group compared with the abnormal group (p < 0.05).

CONCLUSION

Abnormal vestibular and oculomotor functions are commonly observed in patients with VM. And these patients with abnormal vestibular function possess a weak effectiveness of preventive medications.

Subjective visual vertical imprecision during lateral head tilt in patients with chronic dizziness

Most prior studies of the subjective visual vertical (SVV) focus on inaccuracy of subjects' SVV responses with the head in an upright position. Here we investigated SVV imprecision during lateral head tilt in patients with chronic dizziness compared to healthy controls. Forty-five dizzy patients and 45 healthy controls underwent SVV testing wearing virtual reality (VR) goggles, sitting upright (0°) and during head tilt in the roll plane (± 30°). Ten trials were completed in each of three static head positions. The SVV inaccuracy and SVV imprecision were analyzed and compared between groups, along with systematic errors during head tilt, i.e., A-effect and E-effect (E-effect is a typical SVV response during head tilts of ± 30°). The SVV imprecision was found to be affected by head position (upright/right head tilt/left head tilt, p < 0.001) and underlying dizziness (dizzy patients/healthy controls, p = 0.005). The SVV imprecision during left head tilt was greater in dizzy patients compared to healthy controls (p = 0.04). With right head tilt, there was a trend towards greater SVV imprecision in dizzy patients (p = 0.08). Dizzy patients were more likely to have bilateral (6.7%) or unilateral (22.2%) A-effect during lateral head tilt than healthy controls (bilateral (0%) or unilateral (6.7%) A-effect, p < 0.01). Greater SVV imprecision in chronically dizzy patients during head tilts may be attributable to increased noise of vestibular sensory afferents or disturbances of multisensory integration. Our findings suggest that SVV imprecision may be a useful clinical parameter of underlying dizziness measurable with bedside SVV testing in VR.

The Supine Superior Semicircular Canal Dehiscence Test

Purpose The purpose of this clinical focus article is to describe a new method for assessment of superior semicircular canal dehiscence by laying the patient supine during Valsalva-induced nystagmus testing. Method The traditional Valsalva-induced nystagmus test is described, followed by a new method for assessment of superior semicircular dehiscence conducted by laying the patient supine during testing. A case study is presented to illustrate this new testing technique known as the Supine Superior Semicircular Canal Dehiscence Test. Results It is hypothesized that during Valsalva-induced nystagmus testing performed in the upright, seated position, the dura mater could potentially seal the superior semicircular canal fistula, thereby concealing a defect in the bony labyrinth and yielding a false-negative test. To circumvent this, the patient should be placed in the supine position during Valsalva-induced nystagmus testing in order to prevent the dura mater from inadvertently sealing itself against the petrous portion of the temporal bone. The Supine Superior Semicircular Canal Dehiscence Test may reveal the defect in the bony labyrinth and improve the sensitivity of the Valsalva-induced nystagmus test. Conclusions The Supine Superior Semicircular Canal Dehiscence Test may be more sensitive for identifying superior semicircular canal dehiscence in patients with traditional symptoms and a negative Valsalva-induced nystagmus test in the seated position. While a case study is presented to illustrate the potential benefits of including the Supine Superior Semicircular Canal Dehiscence Test in the battery of diagnostic tests, further research is needed in larger samples.

The Value of Subjective Visual Vertical in Diagnosis of Vestibular Migraine

OBJECTIVE

To study the value of the subjective visual vertical (SVV) in the diagnosis of vestibular migraine (VM).

METHODS

This study recruited 128 VM patients and 64 age-matched normal subjects. We detected the SVV during the interval between attacks in both groups, in sitting upright, and the head tilted at 45° to the left or right. We then examined the correlation between the SVV results with the vestibular evoked myogenic potential (VEMP) and canal paresis (CP).

RESULTS

It was found there was a significant difference in SVV at the upright position between VM patients and normal controls (P=0.006) and no significant difference was found at the tilts of 45° to the left or right between the two groups. The SVV results at the upright position were significantly correlated with cervical VEMP (P=0.042) whereas not significantly correlated with CP and VEMP. There existed no significant difference in the conformity to the Müller effect (M effect) between the two groups. ROC analysis exhibited that the sensitivity, specificity of SVVs at the upright were 67.200% and 62.500% respectively. The diagnostic value of SVV at the upright position was significantly higher than that at tilts of 45° to the left and right (P=0.006). Nonetheless the diagnostic accuracy was relatively low.

CONCLUSION

Abnormality in SVV possibly stems from the lasting functional disorder of cerebellar or high-level cortical centers in VM patients or is linked to the vestibular compensation. The SVV is of low diagnostic value for VM and the value of SVV in VM warrants further study.

Cerebrospinal fluid analysis lacks diagnostic specificity in dogs with vestibular disease

BACKGROUND

Although, vestibular syndrome is a common neurological presentation, little is known about the diagnostic value of cerebrospinal fluid (CSF) analysis in vestibular syndrome in dogs.

METHODS

Medical records were retrospectively reviewed, and dogs with vestibular disease that had undergone magnetic resonance imaging of the head, CSF analysis and were diagnosed with central or peripheral vestibular syndrome were included. Disorders affecting the central vestibular system included meningoencephalitis of unknown origin (MUO), brain neoplasia, ischaemic infarct, intracranial empyema or metronidazole toxicity. Disorders affecting the peripheral vestibular system included idiopathic vestibular disease, otitis media/interna or neoplasia affecting the inner ear structures. Total nucleated cell concentration (TNCC), total protein concentration (TP) and cytologic assessment were recorded.

RESULTS

A total of 102 dogs met the inclusion criteria. The sensitivity and specificity of increased CSF TNCC to differentiate central from peripheral vestibular syndrome was 49% and 90%, while the sensitivity and specificity of increased TP was 58% and 39%, respectively. The TNCC and TP in dogs with MUO were significantly higher than in dogs with idiopathic vestibular disease (p = 0.000 and p = 0.004). MUO was associated with lymphocytic pleocytosis, while idiopathic vestibular disease and ischaemic infarct were associated with the presence of activated macrophages or normal cytology (p = 0.000).

CONCLUSION

Although consistent CSF abnormalities were observed in dogs with MUO, CSF analysis did not allow reliable differentiation between central and peripheral vestibular syndrome. CSF analysis is not reliable as the sole diagnostic technique in dogs with vestibular disease.

Eye Movement Technique to Improve Executive Function in Patients With Stroke: A Randomized Controlled Trial

Objective: To investigate the efficacy of eye movement technique for the treatment of executive dysfunction of patients with stroke.

Methods: This was a prospective, single-blinded, randomized, controlled, single-center clinical trial conducted from June 2018 to December 2019 in patients with stroke. The patients were randomized 1:1 to the routine (conventional management) and eye-move group (routine management plus eye movement technique: 5-min goal management training, 5-min computer-aided working memory, and 10 min of inhibitory control training and set conversion training). The intervention lasted 6 weeks, followed by a 4-week follow-up. The primary endpoint was the Behavioral Assessment of the Dysexecutive Syndrome (BADS) score. The secondary endpoints mainly included the Montreal Cognitive Assessment (MoCA), Wisconsin Card Sorting Test (WCST), and modified Barthel Index (MBI) scores.

Results: Sixty-four patients were enrolled (32/group). After the 6-week intervention, the BADS and WCST scores of the eye-move group were significantly improved than those of the routine group (all P < 0.05), but the effects were attenuated in certain subscores after follow-up (all P > 0.05). The MoCA and MBI scores of the eye-move group were significantly higher, and the reaction time was significantly lower than those of the routine group at 4 weeks after the intervention (all P < 0.05). After follow-up, the MBI scores of the eye-move group were still higher than that of the routine group (P < 0.001), but there were no differences for MoCA scores and reaction time (both P > 0.05).

Conclusion: The eye movement technique could improve the executive function of patients with stroke. These results have to be confirmed.

This was a prospective, single-blinded, randomized, controlled, single-center clinical trial (ChiCTR2000036393).

Clinical Trial Registration: [www.chictr.org.cn], identifier [ChiCTR2000036393].

Selective Asymmetry of Ocular Vestibular-Evoked Myogenic Potential in Patients with Acute Utricular Macula Loss

OBJECTIVES

We retrospectively evaluated a chart review of 3,525 patients evaluated for any acute disturbance. A total of 1,504 patients with acute vestibular syndrome (AVS) received an instrumental vestibular assessment within 72 h from the onset of the symptoms evaluated using simultaneously a combination of ocular vestibular-evoked myogenic potential (oVEMPs), cervical vestibular-evoked myogenic potential (cVEMPs), video head-impulse test (vHIT), and subjective visual vertical (SVV) were included in this study.

MATERIALS AND METHODS

A total of 41 patients with AVS that showed a normal horizontal canal function tested with vHIT, a normal cVEMP function, unilaterally reduced or absent oVEMP n10, and an altered SVV were enrolled.

RESULTS

We found that although these patients referred acute vertigo and presented spontaneous nystagmus, they showed physiological values of vHIT and a normal saccular function, as shown by symmetrical cVEMPs.

CONCLUSION

Our findings support the hypothesis that a percentage of patients evaluated during an AVS using an instrumental vestibular assessment could present selective utricular macula dysfunction.

Impairments in path integration, rotational memory and balancing in patients with temporal lobe epilepsy

Objectives

The vestibulo-medial temporal lobe (MTL) axis model proposes that the vestibular system and the MTL are tightly linked both structurally and functionally so that alterations of one structure should entail disturbances in the other. Accordingly, patients with temporal lobe epilepsy (TLE) with their functional and possible structural temporal lobe pathology should show deficits in vestibular-related behaviour. This study aimed at assessing behavioural deficits related to a suspected disturbance of the vestibulo-MTL axis in patients with TLE.

Methods

Twenty patients with TLE (46.7±15.1 years, seven females) and their age-matched and gender-matched controls (46.7±15.1, seven females) underwent three test batteries that challenged vestibular and MTL functions: balancing, path integration (triangle completion test) and rotational memory. In addition, participants underwent a structural MRI for grey matter analysis using voxel-based morphometry.

Results

Compared with controls, patients with TLE showed significantly inferior performance in all three behavioural tests, with large effect sizes. There were no significant grey matter differences between the two groups.

Conclusion

These results indicate a potential disturbance in the vestibulo-MTL axis in TLE; these are to be verified by future large-scale studies. In the current study, these behavioural deficits emerged without evidence of any brain volume differences between the patients and their controls as depicted by high-resolution MRI. This speaks for a dissociation between functional and structural alterations in TLE.

Internal Carotid Artery Dissection Presenting as Partial Horner's Syndrome and Vertigo

Distinguishing between central and peripheral causes of vertigo can be challenging not only in an acute setting but also in chronic settings. A thorough review of systems and physical exam can assist providers in differentiating central versus peripheral etiologies and the need for urgent imaging. In this case, a 47-year-old man presented with vertigo, right-sided hearing loss, right-sided headache, and right-sided facial pain that began 4 weeks before while the patient was on a cruise ship. His physical exam findings were notable for anisocoria with right pupil 3.5 and left pupil 4.5, mild ptosis on the right side, positive Romberg test to the right, and Fakuda test with deviation to the right. Urgent magnetic resonance imaging revealed dissection of the right cervical internal carotid artery with a nonocclusive intramural hematoma. This case illustrates the importance of imaging in vertigo patients in which a central etiology is suspected. It further demonstrates that isolated partial Horner's or unilateral headache may indeed be the only presenting sign in a carotid dissection.

Better balance: a randomised controlled trial of oculomotor and gaze stability exercises to reduce risk of falling after stroke

OBJECTIVE

To assess the effect of a domiciliary program of oculomotor and gaze stability exercises on the incidence of falls and risk of fall in stroke survivors.

DESIGN

Two-arm, non-blinded parallel randomized controlled trial.

SUBJECTS

Stroke survivors older than 60 years, with positive Romberg test and autonomous gait after the stroke.

SETTING

Physiotherapy outpatient clinic of a tertiary care hospital.

INTERVENTIONS

Every participant accomplished the current rehabilitation program; the intervention group was randomly allocated into an additional three weeks intervention with a domiciliary program of oculomotor and gaze stability exercises.

MAIN MEASURES

Primary outcome was the incidence of falls through the three weeks after the intervention started; in addition, the variation of the estimated risk for falling assessed by both Berg Balance Scale (four points) and Timed Up and Go Test (four seconds) was the secondary outcome.

RESULTS

79 patients were recruited and 68 completed the protocol (control group 35; intervention group 33). During the follow up, falls were registered in 4/35 participants in the control group and no event occurred in the intervention group (P = 0.064). The estimated risk for falling decreased in 11/35 control group participants and in 28/33 intervention group participants (RR 0.37; 95%CI 0.22-0.62; P < 0.001).

CONCLUSION

After three weeks of a domiciliary program of oculomotor and gaze stability exercises, the estimated risk of falling significantly diminished and no falls occurred among the intervention group. These findings encourage further exploration of this promising intervention.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02280980.

Vestibular stimulation by 2G hypergravity modifies resynchronization in temperature rhythm in rats

Input from the light/dark (LD) cycle constitutes the primary synchronizing stimulus for the suprachiasmatic nucleus (SCN) circadian clock. However, the SCN can also be synchronized by non-photic inputs. Here, we hypothesized that the vestibular system, which detects head motion and orientation relative to gravity, may provide sensory inputs to synchronize circadian rhythmicity. We investigated the resynchronization of core temperature (Tc) circadian rhythm to a six-hour phase advance of the LD cycle (LD + 6) using hypergravity (2 G) as a vestibular stimulation in control and bilateral vestibular loss (BVL) rats. Three conditions were tested: an LD + 6 exposure alone, a series of seven 2 G pulses without LD + 6, and a series of seven one-hour 2 G pulses (once a day) following LD + 6. First, following LD + 6, sham rats exposed to 2 G pulses resynchronized earlier than BVL rats (p = 0.01), and earlier than sham rats exposed to LD + 6 alone (p = 0.002). Each 2 G pulse caused an acute drop of Tc in sham rats (-2.8 ± 0.3 °C; p < 0.001), while BVL rats remained unaffected. This confirms that the vestibular system influences chronobiological regulation and supports the hypothesis that vestibular input, like physical activity, should be considered as a potent time cue for biological rhythm synchronization, acting in synergy with the visual system.

Recovery Pattern of High-Frequency Acceleration Vestibulo-Ocular Reflex in Unilateral Vestibular Neuritis: A Preliminary Study

Objective: To explore the recovery pattern of the high-frequency acceleration vestibulo-ocular reflex (VOR) function in unilateral vestibular neuritis (UVN).

Methods: Forty-seven consecutive patients with UVN were recruited within 10 days of symptom onset for this study. The high-frequency acceleration horizontal VOR function was assessed using the video head impulse test (vHIT). Patients returned for follow-up evaluation at ~6 months after the onset of symptoms. According to the dizziness handicap inventory questionnaire (DHI), the patients were classified into the normal to mild dizziness group (DHI score ≤30) and moderate to severe dizziness group (DHI score >30) at the follow-up. All the obtained horizontal vHIT gains and corrective saccades parameters were analyzed.

Results: vHIT results showed a significantly horizontal VOR gain recovery in UVN patients at the follow-up on the lesion side (p < 0.01). A significantly reduction in the occurrence of corrective saccades (overt and covert) and velocity of corrective saccades (overt and covert) were observed at the follow-up (p < 0.05). At the follow-up, the normal to mild dizziness group (DHI score ≤30) had a significantly higher normal rate of VOR gain, the mean vHIT gains and occurrence of isolated covert saccades (P < 0.05). Furthermore, the occurrence of mixed saccades and the mean velocity of covert saccades were significantly lower in normal to mild dizziness group (P < 0.05).

Conclusion: Apart from the recovery of the VOR gain, recovery pattern of corrective saccades can play a key role in vestibular compensate.

Qualitative postural control differences in Idiopathic Parkinson's Disease vs. Progressive Supranuclear Palsy with dynamic-on-static platform tilt

OBJECTIVES

We aimed to assess whether postural abnormalities in Progressive Supranuclear Palsy (PSP) and Idiopathic Parkinson's Disease (IPD) are qualitatively different by analysing spontaneous and reactive postural control.

METHODS

We assessed postural control upon platform tilts in 17 PSP, 11 IPD patients and 18 healthy control subjects using a systems analysis approach.

RESULTS

Spontaneous sway abnormalities in PSP resembled those of IPD patients. Spontaneous sway was smaller, slower and contained lower frequencies in both PSP and IPD as compared to healthy subjects. The amount of angular body excursions as a function of platform angular excursions (GAIN) in PSP was qualitatively different from both IPD and healthy subjects (GAIN cut-off value: 2.9, sensitivity of 94%, specificity of 72%). This effect was pronounced at the upper body level and at low as well as high frequencies. In contrast, IPD patients' stimulus-related body excursions were smaller compared to healthy subjects. Using a systems analysis approach, we were able to allocate these different postural strategies to differences in the use of sensory information as well as to different error correction efforts.

CONCLUSIONS

While both PSP and IPD patients show abnormal postural control, the underlying pathology seems to be different.

SIGNIFICANCE

The identification of disease-specific postural abnormalities shown here may be helpful for diagnostic as well as therapeutic discriminations of PSP vs. IPD.

Postural Stabilization Differences in Idiopathic Parkinson's Disease and Progressive Supranuclear Palsy during Self-Triggered Fast Forward Weight Lifting

Progressive supranuclear palsy (PSP) and late-stage idiopathic Parkinson’s disease (IPD) are neurodegenerative movement disorders resulting in different postural instability and falling symptoms. IPD falls occur usually forward in late stage, whereas PSP falls happen in early stages, mostly backward, unprovoked, and with high morbidity. Self-triggered, weighted movements appear to provoke falls in IPD, but not in PSP. Repeated self-triggered lifting of a 0.5–1-kg weight (<2% of body weight) with the dominant hand was performed in 17 PSP, 15 IPD with falling history, and 16 controls on a posturography platform. PSP showed excessive force scaling of weight and body motion with high-frequency multiaxial body sway, whereas IPD presented a delayed-onset forward body displacement. Differences in center of mass displacement apparent at very small weights indicate that both syndromes decompensate postural control already within stability limits. PSP may be subject to specific postural system devolution. IPD are susceptible to delayed forward falling. Differential physiotherapy strategies are suggested.

Current diagnostic procedures for diagnosing vertigo and dizziness

Vertigo is a multisensory syndrome that otolaryngologists are confronted with every day. With regard to the complex functions of the sense of orientation, vertigo is considered today as a disorder of the sense of direction, a disturbed spatial perception of the body. Beside the frequent classical syndromes for which vertigo is the leading symptom (e.g. positional vertigo, vestibular neuritis, Menière’s disease), vertigo may occur as main or accompanying symptom of a multitude of ENT-related diseases involving the inner ear. It also concerns for example acute and chronic viral or bacterial infections of the ear with serous or bacterial labyrinthitis, disorders due to injury (e.g. barotrauma, fracture of the oto-base, contusion of the labyrinth), chronic-inflammatory bone processes as well as inner ear affections in the perioperative course. In the last years, diagnostics of vertigo have experienced a paradigm shift due to new diagnostic possibilities. In the diagnostics of emergency cases, peripheral and central disorders of vertigo (acute vestibular syndrome) may be differentiated with simple algorithms. The introduction of modern vestibular test procedures (video head impulse test, vestibular evoked myogenic potentials) in the clinical practice led to new diagnostic options that for the first time allow a complex objective assessment of all components of the vestibular organ with relatively low effort. Combined with established methods, a frequency-specific assessment of the function of vestibular reflexes is possible. New classifications allow a clinically better differentiation of vertigo syndromes. Modern radiological procedures such as for example intratympanic gadolinium application for Menière’s disease with visualization of an endolymphatic hydrops also influence current medical standards. Recent methodical developments significantly contributed to the possibilities that nowadays vertigo can be better and more quickly clarified in particular in otolaryngology.

Intermediate Latency-Evoked Potentials of Multimodal Cortical Vestibular Areas: Galvanic Stimulation

Introduction

Human multimodal vestibular cortical regions are bilaterally anterior insulae and posterior opercula, where characteristic vestibular-related cortical potentials were previously reported under acoustic otolith stimulation. Galvanic vestibular stimulation likely influences semicircular canals preferentially. Galvanic stimulation was compared to previously established data under acoustic stimulation.

Methods

14 healthy right-handed subjects, who were also included in the previous acoustic potential study, showed normal acoustic and galvanic vestibular-evoked myogenic potentials. They received 2,000 galvanic binaural bipolar stimuli for each side during EEG recording.

Results

Vestibular cortical potentials were found in all 14 subjects and in the pooled data of all subjects (“grand average”) bilaterally. Anterior insula and posterior operculum were activated exclusively under galvanic stimulation at 25, 35, 50, and 80 ms; frontal regions at 30 and 45 ms. Potentials at 70 ms in frontal regions and at 110 ms at all of the involved regions could also be recorded; these events were also found using acoustic stimulation in our previous study.

Conclusion

Galvanic semicircular canal stimulation evokes specific potentials in addition to those also found with acoustic otolith stimulation in identically located regions of the vestibular cortex. Vestibular cortical regions activate differently by galvanic and acoustic input at the peripheral sensory level.

Significance

Differential effects in vestibular cortical-evoked potentials may see clinical use in specific vertigo disorders.

Isolated transient vertigo: posterior circulation ischemia or benign origin?

Background

Isolated transient vertigo can be the only symptom of posterior circulation ischemia. Thus, it is important to differentiate isolated vertigo of a cerebrovascular origin from that of more benign origins, as patients with cerebral ischemia have a much higher risk for future stroke than do those with ‘peripheral’ vertigo. The current study aims to identify risk factors for cerebrovascular origin of isolated transient vertigo, and for future cerebrovascular events.

Methods

From the files of 339 outpatients with isolated transient vertigo we extracted history, clinical and technical findings, diagnosis, and follow-up information on subsequent stroke or transient ischemic attack (TIA). Risk factors were analyzed using multivariate regression models (logistic or Cox) and reconfirmed in univariate analyses.

Results

On first presentation, 48 (14.2%) patients received the diagnosis ‘probable or definite cerebrovascular vertigo’. During follow-up, 41 patients suffered stroke or TIA (event rate 7.9 per 100 person years, 95% confidence interval (CI) 5.5–10.4), 26 in the posterior circulation (event rate 4.8 per 100 person years, 95% CI 3.0–6.7). The diagnosis was not associated with follow-up cerebrovascular events. In multivariate models testing multiple potential determinants, only the presentation mode was consistently associated with the diagnosis and stroke risk: patients who presented because of vertigo (rather than reporting vertigo when they presented for other reasons) had a significantly higher risk for future stroke or TIA (p = 0.028, event rate 13.4 vs. 5.4 per 100 person years) and for future posterior circulation stroke or TIA (p = 0.044, event rate 7.8 vs. 3.5 per 100 person years).

Conclusions

We here report for the first time follow-up stroke rates in patients with transient isolated vertigo. In such patients, the identification of those with cerebrovascular origin remains difficult, and presentation mode was found to be the only consistent risk factor. Confirmation in an independent prospective sample is needed.

Effects of oculomotor and gaze stability exercises on balance after stroke: Clinical trial protocol

Highlights

Balance problems after stroke are an important risk factor for falling.The inability to maintain balance decreased potential for recovery.This trial assesses the effect of oculomotor and gaze stability training on balance.

Background

The inability to maintain balance after stroke is an important risk factor for falling and relates to decreased potential for recovery. The vestibular system and gaze stability contribute respectively to postural stability and to maintain balance. Rehabilitation may be more effective with domiciliary training.

Objective

This trial aims to verify if balance impairment after stroke improves with a domiciliary oculomotor and gaze stability training program.

Methods

Individuals older than 60 years, discharged after suffering brain stroke with referral to the physiotherapy department, will be assessed for orthostatic balance. Patients with stroke diagnosis 3-15 months before recruitment, positive Romberg test and able to walk 3 m alone are invited to participate in this randomized controlled trial. Participants will be allocated in two intervention groups through block randomization, either the current rehabilitation program or to a supplemental intervention focused on oculomotor and gaze stability exercises to be applied at home twice a day for three weeks. Primary outcome measures are the Motor Assessment Scale, Berg Balance Scale and Timed Up and Go Test. Trial registration: ClinicalTrials.gov (NCT02280980).

Results

A minimum difference of four seconds in the TUG and a minimum difference of four points in BBS will be considered positive outcomes.

Conclusions

Oculomotor and gaze stability exercises may be a promising complement to conventional physiotherapy intervention after brain stroke, improving the balance impairment.

Differential diagnosis of a patient referred to physical therapy for dizziness: a case report

STUDY DESIGN

Case report.

BACKGROUND

Dizziness is a common and debilitating condition across the lifespan. Patients with this complaint must be carefully examined to determine the cause of dizziness, rule out the presence of central nervous system dysfunction, and determine the appropriateness of physical therapy intervention.

CASE DESCRIPTION

A 90-year-old male was referred to physical therapy six months after the onset of dizziness. A thorough history was taken and examination was performed. Signs consistent with central nervous system dysfunction and peripheral vestibular dysfunction were observed. The patient was treated for the peripheral vestibular disorder and referred back to his physician for further testing. Imaging revealed that the patient had idiopathic normal pressure hydrocephalus.

DISCUSSION

This case illustrates the need for physical therapists to perform thorough examinations of patients with a primary complaint of dizziness and properly interpret positive central signs, indicating a potential need for referral to a physician or other healthcare provider when they appear.

A Practical Concussion Physical Examination Toolbox

CONTEXT

With heightened awareness of concussion, there is a need to assess and manage the concussed patient in a consistent manner. Unfortunately, concussion physical examination has not been standardized or supported by evidence. Important questions remain about the physical examination.

EVIDENCE ACQUISITION

Review of ClinicalKey, Cochrane, MEDLINE, and PubMed prior to July 2015 was performed using search terms, including concussion, mTBI, physical examination, mental status, cranial nerves, reflexes, cervical, vestibular, and oculomotor. The references of the pertinent articles were reviewed for other relevant sources.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

The pertinent physical examination elements for concussion include evaluation of cranial nerves, manual muscle testing, and deep tendon reflexes; inspecting the head and neck for trauma or tenderness and cervical range of motion; Spurling maneuver; a static or dynamic balance assessment; screening ocular examination; and a mental status examination that includes orientation, immediate and delayed recall, concentration, mood, affect, insight, and judgment. Other examination elements to consider, based on signs, symptoms, or clinical suspicion, include testing of upper motor neurons, cervical strength and proprioception, coordination, pupillary reactivity, and visual acuity; examination of the jaw, temporomandibular joint, and thoracic spine; fundoscopic evaluation; orthostatic vital signs; assessment of dynamic visual acuity; and screening for depression, anxiety, substance abuse disorders, and preinjury psychiatric difficulties.

CONCLUSION

Various elements of the physical examination, such as screening ocular examination, cervical musculoskeletal examination, static and/or dynamic balance assessment, and mental status examination, appear to have utility for evaluating concussion; however, data on validity are lacking.

Normobaric Hypoxia Effects on Balance Measured by Computerized Dynamic Posturography

Wagner, Dale R., Skyler Saunders, Brady Robertson, and John E. Davis. Normobaric hypoxia effects on balance measured by computerized dynamic posturography. High Alt Med Biol. 17:222-227, 2016.-Background/Aim: Equilibrium was measured by computerized dynamic posturography at varying levels of normobaric hypoxia before and after exercise.

METHODS

Following a familiarization trial, 12 males (27.3 ± 7.1 years) completed three sessions in random order on a NeuroCom SMART Balance Master: a sham trial at the ambient altitude of 1500 m and simulated altitudes of 3000 and 5000 m created by a hypoxic generator. The NeuroCom provided composite scores for a sensory organization test of equilibrium and a motor control test to assess the appropriate motor response. Additional information on somatosensory, visual, and vestibular responses was obtained. Each session consisted of 20 minutes of rest followed by the NeuroCom test, then 10 minutes of exercise, and 10 minutes of recovery followed by a second NeuroCom test, all while connected to the hypoxic generator. Mean differences were identified with a two-way (pre/postexercise and altitude condition), repeated-measures analysis of variance.

RESULTS

The composite sensory score was significantly lower (p < 0.001) during the 5000 m trial (73.4 ± 12.0) compared to the 1500 m (80.8 ± 7.0) and 3000 m (84.1 ± 5.0) altitudes. The inability to ignore inaccurate visual cues in a situation of visual conflict was the most common sensory error. Motor control was not affected by altitude or exercise.

DISCUSSION

These results suggest that moderate hypoxia does not affect balance, but severe hypoxia significantly reduces equilibrium. Furthermore, it appears that the alterations in equilibrium are primarily from impairments in visual function.

The effects of eye movement training on gait function in patients with stroke

[Purpose] The present study examined the effects of eye movement training on gait function in patients with stroke. [Subjects and Methods] Fourteen patients with stroke were randomly assigned to either an experimental group or a control group. The experimental group underwent eye movement training while the control group underwent general gait training five times per week for six weeks. [Results] Patient walking speed, cadence, and step length were measured by ink-footprint. The experimental group exhibited significant changes in walking speed, cadence, and step length following training, while the control group exhibited no differences. [Conclusion] Findings indicate that eye movement training should be considered as part of a functional gait training program for patients with stroke.

Dissociating vestibular and somatosensory contributions to spatial orientation

Inferring object orientation in the surroundings heavily depends on our internal sense of direction of gravity. Previous research showed that this sense is based on the integration of multiple information sources, including visual, vestibular (otolithic), and somatosensory signals. The individual noise characteristics and contributions of these sensors can be studied using spatial orientation tasks, such as the subjective visual vertical (SVV) task. A recent study reported that patients with complete bilateral vestibular loss perform similar as healthy controls on these tasks, from which it was conjectured that the noise levels of both otoliths and body somatosensors are roll-tilt dependent. Here, we tested this hypothesis in 10 healthy human subjects by roll tilting the head relative to the body to dissociate tilt-angle dependencies of otolith and somatosensory noise. Using a psychometric approach, we measured the perceived orientation, and its variability, of a briefly flashed line relative to the gravitational vertical (SVV). Measurements were taken at multiple body-in-space orientations (-90 to 90°, steps of 30°) and head-on-body roll tilts (30° left ear down, aligned, 30° right ear down). Results showed that verticality perception is processed in a head-in-space reference frame, with a systematic SVV error that increased with larger head-in-space orientations. Variability patterns indicated a larger contribution of the otolith organs around upright and a more substantial contribution of the body somatosensors at larger body-in-space roll tilts. Simulations show that these findings are consistent with a statistical model that involves tilt-dependent noise levels of both otolith and somatosensory signals, confirming dynamic shifts in the weights of sensory inputs with tilt angle.

Up-Down Chair: A novel mechatronic device to assess otolith function in patients with vestibular disorders

This paper describes a novel mechatronic platform, named "Up-Down Chair" (UDC), aimed at investigating otolith function in patients with vestibular disorders. The UDC was designed to provide a wide range of repeatable and controllable vertical oscillations of the head whose kinematic features match those encountered during daily activities. The following parameters were assessed to characterize the performance of the UDC: accordance between expected and measured kinematics in both loaded and unloaded conditions; Dynamic Visual Acuity (DVA) of a group of 15 healthy subjects who were asked to identify a set of Snellen optotypes while being repeatedly moved at different perturbation intensities. Results revealed a good agreement between expected and measured kinematic patterns, and excellent reliability of DVA assessed across enrolled participants. In addition, we observed that the proposed paradigm was effective in inducing oscillopsia in enrolled subjects and that the frequency of the oscillation significantly induced blurred vision during the experimental tests. The UDC appears to be usable as a complementary vestibular clinical test to investigate the effects of therapeutic treatments while applying a wide range of physiological stimuli compatible with those encountered during daily activities.

Migraine patients consistently show abnormal vestibular bedside tests

Migraine and vertigo are common disorders, with lifetime prevalences of 16% and 7% respectively, and co-morbidity around 3.2%. Vestibular syndromes and dizziness occur more frequently in migraine patients. We investigated bedside clinical signs indicative of vestibular dysfunction in migraineurs. Objective To test the hypothesis that vestibulo-ocular reflex, vestibulo-spinal reflex and fall risk (FR) responses as measured by 14 bedside tests are abnormal in migraineurs without vertigo, as compared with controls. Method Cross-sectional study including sixty individuals – thirty migraineurs, 25 women, 19-60 y-o; and 30 gender/age healthy paired controls. Results Migraineurs showed a tendency to perform worse in almost all tests, albeit only the Romberg tandem test was statistically different from controls. A combination of four abnormal tests better discriminated the two groups (93.3% specificity). Conclusion Migraine patients consistently showed abnormal vestibular bedside tests when compared with controls.

Clinical applications of correlational vestibular autorotation test

CONCLUSION

The correlational vestibular autorotation test (VAT) system has the advantages of good test-retest reliability and calibrations of absolute degrees of eye movement are unnecessary when acquiring a cross correlation coefficient (CCC). The approach is able to efficiently detect peripheral vestibulopathies.

OBJECTIVE

A VAT has some drawbacks including poor test-retest reliability and slippage of sensor. This study aimed to develop a correlational VAT system and to evaluate the reliability and applicability of this system.

METHODS

Twenty healthy participants and 10 vertiginous patients were enrolled. Vertical and horizontal autorotations from 0 to 3 Hz with either closed or open eyes were performed. A small sensor and a wireless transmission technique were used to acquire the electro-ocular graph and head velocity signals. The two signals were analyzed using CCCs to assess the functioning of the vestibular ocular reflex (VOR).

RESULTS

The results showed a significantly greater CCC for open-eye versus closed-eye of head autorotations. The CCCs also increased significantly with head rotational frequencies. Moreover, the CCCs significantly correlated with the VOR gains at autorotation frequencies ≥1.0 Hz. The test-retest reliability was good (intraclass correlation coefficients ≥0.85). The vertiginous participants had significantly lower individual CCCs and overall average CCC than age- and-gender matched controls.

Vestibular loss disrupts daily rhythm in rats

Hypergravity disrupts the circadian regulation of temperature (Temp) and locomotor activity (Act) mediated through the vestibular otolithic system in mice. In contrast, we do not know whether the anatomical structures associated with vestibular input are crucial for circadian rhythm regulation at 1 G on Earth. In the present study we observed the effects of bilateral vestibular loss (BVL) on the daily rhythms of Temp and Act in semipigmented rats. Our model of vestibular lesion allowed for selective peripheral hair cell degeneration without any other damage. Rats with BVL exhibited a disruption in their daily rhythms (Temp and Act), which were replaced by a main ultradian period (τ <20 h) for 115.8 ± 68.6 h after vestibular lesion compared with rats in the control group. Daily rhythms of Temp and Act in rats with BVL recovered within 1 wk, probably counterbalanced by photic and other nonphotic time cues. No correlation was found between Temp and Act daily rhythms after vestibular lesion in rats with BVL, suggesting a direct influence of vestibular input on the suprachiasmatic nucleus. Our findings support the hypothesis that the vestibular system has an influence on daily rhythm homeostasis in semipigmented rats on Earth, and raise the question of whether daily rhythms might be altered due to vestibular pathology in humans.

A vestibular prosthesis with highly-isolated parallel multichannel stimulation

This paper presents an implantable vestibular stimulation system capable of providing high flexibility independent parallel stimulation to the semicircular canals in the inner ear for restoring three-dimensional sensation of head movements. To minimize channel interaction during parallel stimulation, the system is implemented with a power isolation method for crosstalk reduction. Experimental results demonstrate that, with this method, electrodes for different stimulation channels located in close proximity ( mm) can deliver current pulses simultaneously with minimum inter-channel crosstalk. The design features a memory-based scheme that manages stimulation to the three canals in parallel. A vestibular evoked potential (VEP) recording unit is included for closed-loop adaptive stimulation control. The main components of the prototype vestibular prosthesis are three ASICs, all implemented in a 0.6- μm high-voltage CMOS technology. The measured performance was verified using vestibular electrodes in vitro.

Does the human immunodeficiency virus influence the vestibulocollic reflex pathways? A comparative study

BACKGROUND

This study compared vestibulocollic reflex and vestibulo-ocular reflex functioning in subjects with and without human immunodeficiency virus. It also described test results throughout progression of the disease and compared the results of human immunodeficiency virus positive subjects who were receiving antiretroviral therapies with those not receiving this treatment.

METHODS

Subjects comprised 53 adults with human immunodeficiency virus (mean age 38.5 ± 4.4 years) and 38 without human immunodeficiency virus (mean age 36.9 ± 8.2 years). Clinical examinations included cervical vestibular-evoked myogenic potential and bithermal caloric testing.

RESULTS

Abnormal cervical vestibular-evoked myogenic potential and caloric results were significantly higher in the human immunodeficiency virus positive group (p = 0.001), with an odds ratio of 10.2. Vestibulocollic reflex and vestibulo-ocular reflex involvement increased with progression of the disease. There were more abnormal test results in subjects receiving antiretroviral therapies (66.7 per cent) than in those not receiving antiretroviral therapies (63.6 per cent), but this difference was insignificant.

CONCLUSION

Human immunodeficiency virus seems to influence vestibulocollic reflex pathways. Combining cervical vestibular-evoked myogenic potential and caloric testing may be useful to detect early neurological involvement in human immunodeficiency virus positive subjects.

Differences in Symptoms among Adults with Canal versus Otolith Vestibular Dysfunction: A Preliminary Report

Despite the importance of symptomatology in the diagnosis of vestibular dysfunction, the qualitative nature of the symptoms related to semicircular canal (canal) versus otolith dysfunction is not fully understood. The purpose of this study was to compare symptoms, and their severity, in individuals with canal versus otolith peripheral vestibular dysfunction. A subjective tool, the Descriptive Symptom Index (DSI), was developed to enable categorization of symptoms as rotary, linear, imbalance or falls, and nondistinct. Fourteen adults were recruited and grouped based on vestibular function testing: canal only dysfunction, otolith only dysfunction, or canal and otolith dysfunction. Also, the Dizziness Handicap Inventory (DHI) was used to grade the severity of perceived limitations due to symptoms. The DSI was reliable and differentiated those with canal (rotary symptoms) versus otolith (linear symptoms) dysfunction. Most individuals with otolith only dysfunction did not report rotary symptoms. DHI scores were significantly higher in those with otolith dysfunction, regardless of canal functional status. All who experienced falls had otolith dysfunction and none had canal only dysfunction. Results support the importance of using linear and rotary descriptors of perceived disorientation as part of diagnosing vestibular dysfunction.

[Dizziness from the viewpoint of otorhinolaryngology]

Dizziness is a common symptom in daily clinical practice. Dizziness and vertigo affect the quality of life as they are associated with the risk of falls leading to limited ability of independent locomotion and thus to a reduction in social contact. The source of problems with dizziness is localized in the area of visual, somatosensory and vestibular sense inputs. The ear nose and throat (ENT) specialist is involved in an interdisciplinary context to elucidate and treat peripheral vestibular disorders. The subjective symptoms of dizziness have to be clarified by taking a careful patient history. By means of objective tests (cVEMP, oVEMP, video-head impulse test) the ENT specialist is able to selectively analyze the function of the five vestibular receptors; therefore, a topological assignment in peripheral vestibulopathy is possible. The exact diagnosis is a prerequisite for a specific therapy and many diseases can be evidence-based, safe and effectively treated.

Beyond the cover test: the motor half of the sensorimotor exam

The cover tests fulfill both the "sensory" and the "motor" requirements of the sensorimotor exam because they not only detect and quantify strabismus but also evaluate control. Control is achieved through various types of vergence, but vergence is not the only type of eye movement that is integral to fusion. The function of all eye movements is to position and maintain similar images on corresponding areas of the retinae in order to sustain binocular vision. Therefore, a complete motor exam should include evaluation of all eye movement systems. Such an exam can be performed without expensive and complicated equipment, without supplementary education, without significantly extending exam time, and within the confines of an average exam lane, because much of the exam is concealed within the standard sensorimotor evaluation. The term "sensorimotor exam" underscores the fact that sensory and motor fusion, and their respective cortical pathways, are inextricably linked, and function simultaneously and cooperatively to achieve normal visual experience.

The galvanic whole-body sway response in health and disease

OBJECTIVE

To explore the galvanic-evoked vestibulospinal reflex in health and disease.

METHODS

Vestibular-evoked whole-body movement was measured in 60 controls and eight patients with bilateral vestibular impairment, using 1mA × 2s Galvanic Vestibular Stimulation (GVS). The displacement (s) and velocity (v) of 7 markers placed on the head, neck, shoulders, mid-thorax and hips and ground reaction forces (F) were recorded.

RESULTS

Monaural GVS evoked anterolateral whole-body movement away from the cathode. For controls, peak response magnitudes were 22.3 ± 12.4mm, 25.9 ± 14.3 mms(-1) and 3.2 ± 1.3N for s, v and F. Left right asymmetry measured using the Jongkee's formula was 12.59 ± 8.64%, 11.94 ± 11.09% and 11.68 ± 8.99% for s, v and F. All three measures were symmetrical for left and right mastoid stimulation and showed good to excellent test retest reliability. Patients with bilateral vestibular failure had absent or attenuated responses. For this patient group, the ("R/B") ratios between the "response period" and baseline body-sway for s, v and F were 2.1 ± 0.8, 1.7 ± 1.1 and 1.3 ± 0.6, which were significantly lower than 5.4 ± 4.2, 4.1 ± 2.5 and 2.3 ± 0.8 for controls, with s and v providing better separation between controls and patients. There were no significant correlations between the amplitudes of galvanic body sway responses and vestibular-evoked myogenic potentials (VEMPs).

CONCLUSION

GVS enables non-invasive assessment of the vestibulospinal reflex.

SIGNIFICANCE

This method offers a clinically applicable, test of vestibular contributions to standing balance.