Does spectacle use lead to vestibular suppression?

2016 ◽  
Vol 130 (11) ◽  
pp. 1033-1038
Author(s):  
A Thakar
Keyword(s):  
Retinal Image ◽  
Contact Lenses ◽  
Preliminary Investigation ◽  
Significant Proportion ◽  
Head Impulse Test ◽  
Caloric Test ◽  
Image Size ◽  
Cross Sectional ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

AbstractBackground:Laboratory experiments indicate that changes in retinal image size result in adaptive recalibration or suppression of the vestibulo-ocular reflex. Myopia correction with spectacles or contact lenses also leads to retinal image size changes, and may bring about similar vestibulo-ocular reflex alterations.Methods:A hypothesis-generating preliminary investigation was conducted. In this cross-sectional study, findings of electronystagmography including bithermal caloric testing were compared between 17 volunteer myopes using spectacles or contact lenses and 17 volunteer emmetropes (with no refractive error).Results:Bilateral hypoactive caloric responses were demonstrated in 6 of 11 spectacle users, in 1 of 6 contact lens users and in 1 of 17 emmetropes. Hypoactive caloric responses were significantly more likely in spectacle users than in emmetropes (p < 0.01; relative risk = 9.3).Conclusion:A significant proportion of myopes using spectacles have vestibulo-ocular reflex suppression, as demonstrated by the caloric test. This has implications for the interpretation of electronystagmography and videonystagmography results, and highlights spectacle use as a possible cause of vestibular impairment. Further corroboration of these findings is warranted, with more precise and direct vestibulo-ocular reflex tests such as rotational tests and the head impulse test.

S223 – Effect of Myopia on the Caloric Test

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P150-P150
Author(s):  
Alok Thakar
Keyword(s):  
Retinal Image ◽  
Contact Lenses ◽  
Significant Proportion ◽  
Control Group ◽  
Caloric Test ◽  
Case Group ◽  
Direct Evaluation ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
The Impact

Objectives To assess the impact of corrected myopia on the caloric test. Correction of myopia with spectacles or contact lenses results in alteration of the size of the retinal image. Previous laboratory experiments have demonstrated that gross changes in the size of the retinal image can result in recalibration or suppression of the vestibulo-ocular reflex (VOR). Methods Case-control study. 17 evaluable healthy volunteers with myopia corrected either by spectacles or contact lenses (case group) compared to 17 volunteers with no refractive error (control group). Complete Electro-Nystagmography inclusive of bithermal caloric testing undertaken for cases and controls. Assessment of hypoactive caloric responses based on normative laboratory values. Results 7 of 17 cases and 1 of 17 controls demonstrated hypoactive caloric responses. In the spectacle users group, 6 of 11 (55%) had hypoactive responses. Spectacle users were significantly more likely than emmetropic controls to have hypoactive caloric responses (p<0.01; relative risk 9.3 {95 % Confidence Interval 1.3 to 66.9}). Conclusions 1) A significant proportion of myopes using spectacles have suppression of the vestibulo-ocular reflex as demonstrated by the caloric test. This has implications for the interpretation of ENG results, and also as a cause of vestibular impairment. 2) Further studies in myopes are warranted for precise and direct evaluation of the VOR by rotation or impulse testing.

scholarly journals Vestibulo-Ocular Reflex Function in Adolescents With Sport-Related Concussion: Preliminary Results

2019 ◽  
Vol 11 (6) ◽  
pp. 479-485 ◽  
Author(s):  
Abdulaziz A. Alkathiry ◽  
Anthony P. Kontos ◽  
Joseph M. Furman ◽  
Susan L. Whitney ◽  
Eric R. Anson ◽  
...  
Keyword(s):  
Vestibular System ◽  
Rank Order ◽  
Head Impulse Test ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Horizontal Semicircular Canal ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Impulse Function ◽  
Vestibulo Ocular Reflex

Background: Oculomotor impairments, dizziness, and imbalance are common after sports-related concussion (SRC) in adolescents and suggest a relationship between SRC and vestibular system dysfunction. However, it is not clear whether the source of these problems is attributable to the peripheral or central vestibular system. Hypothesis: The video Head Impulse Test (vHIT), which assesses peripheral vestibular function, will show differences in gain between adolescents with and without SRC. Furthermore, there will be an association between vHIT and clinical balance and vestibular/oculomotor testing. Study Design: Cross-sectional study. Level of Evidence: Level 2. Methods: Twenty-five symptomatic adolescents aged between 12 and 19 years with a recent (within 10 days) SRC and 22 healthy controls aged 13 to 20 years were assessed using the vHIT, Balance Error Scoring System (BESS), and Vestibular Ocular Motor Screening (VOMS) tools. The vestibulo-ocular reflex (VOR) gain was calculated independently for right and left head impulses. Independent-samples t tests or Mann-Whitney U tests for nonnormal distributions were used to compare concussed patients and controls on the measures. Spearman rank-order correlations were used to assess the association of vHIT with BESS and VOMS. Results: VOR gain in all adolescents with SRC was greater than 0.8, which is considered within normal limits. VOR gain and BESS scores were not significantly different between groups. Adolescents with SRC had significantly worse VOMS item scores than adolescents without SRC ( P < 0.001). There were no significant correlations among vHIT gain and VOMS or BESS. Conclusion: There was no evidence for dysfunction in the peripheral horizontal semicircular canal function at high rotation speeds (ie, vHIT) after SRC, and vHIT was unrelated to balance and vestibular/oculomotor symptoms and dysfunction. However, adolescents with SRC scored worse on vestibular and oculomotor testing than those without SRC. Vestibular dysfunction and symptoms after SRC may be centrally derived. Clinical Relevance: We do not recommend the assessment of head impulse function in adolescents with SRC unless more definitive signs of peripheral vestibular injury are present. We recommend using the VOMS to assess symptoms of suspected SRC injury in adolescents.

Prognosis after acute unilateral vestibulopathy: Usefulness of the suppression head impulse paradigm (SHIMP)

2021 ◽  
pp. 1-10
Author(s):  
Augusto Pietro Casani ◽  
Rachele Canelli ◽  
Francesco Lazzerini ◽  
Elena Navari
Keyword(s):  
Cross Sectional Study ◽  
Head Impulse Test ◽  
Cross Sectional ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Group 2 ◽  
Unilateral Vestibulopathy ◽  
Vestibular Damage ◽  
Acute Unilateral Vestibulopathy

OBJECTIVES: This cross-sectional study aims to describe the features of the suppression head impulse paradigm (SHIMP) in acute unilateral vestibulopathy (AUV) and to define its role in predicting the recovery of patients. METHODS: Thirty patients diagnosed with AUV were retrospectively analyzed. The dizziness handicap inventory score and video head impulse test parameters performed 4–8 weeks from the AUV onset constituted the main outcome measures. Patients with a worse recovery (Group 1) and patients who recovered spontaneously (Group 2) were compared. RESULTS: The SHIMP vestibulo-ocular reflex (VOR) gain was statistically significantly lower than the conventional head impulse paradigm (HIMP) VOR gain (P <  0.001). The SHIMP VOR gain was negatively correlated with the DHI (P <  0.001) and was positively correlated with the HIMP VOR gain (P <  0.001) and the SHIMP overt saccades (%) (P <  0.001). Patients with a worse recovery exhibited the following: higher DHI (P <  0.001), lower SHIMP and HIMP VOR gain (P <  0.001 and P = 0.007, respectively), and lower SHIMP and greater HIMP overt saccade prevalence values (P = 0.007 and P = 0.032, respectively). CONCLUSIONS: The SHIMP and HIMP help in improving our approach to AUV. SHIMP appears to better identify the extent of the vestibular damage in patient suffering from AUV than HIMP and could provide interesting information about the course of the disease. Particularly, the analysis of SHIMP VOR gain and overt saccade prevalence would provide useful information about the recovery of patients.

scholarly journals Clinical Implication of Caloric and Video Head Impulse Tests for Patients With Enlarged Vestibular Aqueduct Presenting With Vertigo

2021 ◽  
Vol 12 ◽  
Author(s):  
Ming Li ◽  
Yangming Leng ◽  
Bo Liu
Keyword(s):  
Head Impulse Test ◽  
Caloric Test ◽  
Enlarged Vestibular Aqueduct ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Vestibular Aqueduct ◽  
Vestibulo Ocular Reflex ◽  
Unilateral Case ◽  
Caloric Response ◽  
Caloric Tests

Background: By examining the clinical features and results of video head impulse test (vHIT) and caloric tests in patients with enlarged vestibular aqueduct (EVA) presenting with vertigo, we aimed to investigate the function of angular vestibulo-ocular reflex (VOR) and its clinical implications.Methods: Nine patients with EVA manifesting with vertigo were enrolled. The medical history, audiological examination, imaging, and the results of the caloric test and the vHIT were analyzed.Results: Of the nine patients with EVA (eight bilateral and one unilateral case), five were pediatric cases. All 17 ears exhibited sensorineural hearing loss (SNHL). Enlarged vestibular aqueduct patients can present with recurrent (seven cases) or single (two cases) vertigo attack, trauma-induced (two cases), or spontaneous (seven cases) vertigo. Diminished caloric responses were observed in 77.8% (7/9) of the patients (four cases unilaterally and three bilaterally), while unilateral abnormal vHIT results in 11.1% (1/9) patients. Abnormal caloric and normal horizontal vHIT responses were found in 66.7% (6/9) of EVA patients.Conclusions: Vestibular manifestations in EVA are diverse. Enlarged vestibular aqueduct patients with vertigo can present with a reduced caloric response and normal horizontal vHIT, and this pattern of angular VOR impairment was also found in other hydropic ear diseases.

Viewing Target Distance Influences the Vestibulo-Ocular Reflex Gain when Assessed Using the Video Head Impulse Test

2018 ◽  
Vol 23 (5) ◽  
pp. 285-289 ◽  
Author(s):  
Patricia Castro ◽  
Sara Sena Esteves ◽  
Florencia Lerchundi ◽  
David Buckwell ◽  
Michael A. Gresty ◽  
...  
Keyword(s):  
Head Movements ◽  
Target Distance ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Gaze Stabilization ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Significant Difference ◽  
Vestibulo Ocular Reflex ◽  
Reflex Gain

Gaze stabilization during head movements is provided by the vestibulo-ocular reflex (VOR). Clinical assessment of this reflex is performed using the video Head Impulse Test (vHIT). To date, the influence of different fixation distances on VOR gain using the vHIT has not been explored. We assessed the effect of target proximity on the horizontal VOR using the vHIT. Firstly, we assessed the VOR gain in 18 healthy subjects with 5 viewing target distances (150, 40, 30, 20, and 10 cm). The gain increased significantly as the viewing target distance decreased. A second experiment on 10 subjects was performed in darkness whilst the subjects were imagining targets at different distances. There were significant inverse relationships between gain and distance for both the real and the imaginary targets. There was a statistically significant difference between light and dark gains for the 20- and 40-cm distances, but not for the 150-cm distance. Theoretical VOR gains for different target distances were calculated and compared with those found in light and darkness. The increase in gain observed for near targets was lower than predicted by geometrical calculations, implying a physiological ceiling effect on the VOR. The VOR gain in the dark, as assessed with the vHIT, demonstrates an enhancement associated with a reduced target distance.

scholarly journals Vestibulo-ocular reflex and the head impulse test

2012 ◽  
Vol 70 (12) ◽  
pp. 942-944 ◽  
Author(s):  
Eliana T. Maranhão ◽  
Péricles Maranhão-Filho
Keyword(s):  
Diagnostic Method ◽  
Vestibular Dysfunction ◽  
Head Impulse Test ◽  
Emergency Rooms ◽  
Brainstem Infarction ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Peripheral Vestibulopathy ◽  
Vestibulo Ocular Reflex

The authors highlights the importance of the vestibulo-ocular reflex examination through the head impulse test as a diagnostic method for vestibular dysfunction as well as, and primarily, a bedside semiotic resource capable of differentiating between acute peripheral vestibulopathy and a cerebellar or brainstem infarction in emergency rooms.

Vestibulo-ocular reflex assessed with Video Head Impulse Test in children with Vestibular Migraine: Our experience

2020 ◽  
Vol 137 ◽  
pp. 110161
Author(s):  
Rosana Rodríguez-Villalba ◽  
Miguel Caballero-Borrego ◽  
Vanessa Villarraga ◽  
Victoria Rivero de Jesús ◽  
Maria Antonia Claveria ◽  
...  
Keyword(s):  
Vestibular Migraine ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

scholarly journals Microbiological analysis of contact lens cases and effective health behaviors

2020 ◽  
Vol 7 (2) ◽  
pp. e17-e17
Author(s):  
Fatemeh Eslami ◽  
Hamid Reza Ghasemi Basir ◽  
Abbas Moradi ◽  
Mina Bayat
Keyword(s):  
Health Behaviors ◽  
Contact Lens ◽  
Bacterial Contamination ◽  
Contact Lenses ◽  
Significant Proportion ◽  
Enterobacter Aerogenes ◽  
Cross Sectional Study ◽  
Microbial Culture ◽  
Microbiological Analysis ◽  
Cross Sectional

Introduction: Contact lenses are increasingly being used for cosmetic or therapeutic purposes, followed by subsequent contamination and complications such as keratitis. The lens case is one of the most common places to find the cause of contamination. Objectives: This study was designed to evaluate the health behaviors affecting the lens case contamination and its relationship with the result of lens case culture which can help in prevention of complications. Patients and Methods: In this cross-sectional study that was performed in northwest of Iran, 150 asymptomatic participants were assessed for health behaviors affecting the lens case contamination and their lens cases were sampled for culture and antibiogram. Data were analyzed with SPSS-16 software. Results: The frequency of positive microbial culture in medical and cosmetic contact lens cases was 30.7% and 66.8%, respectively and 32.7% in general. Among the isolated bacteria observed in positive cultures, Alcaligenes,Enterobacter aerogenes, gram-positive Diphtheroid bacilli, Pseudomonas aeruginosa and Staphylococcus epidermidis were the most common microorganisms, respectively. Conclusion: A significant proportion of contact lens cases, especially those used for cosmetic purposes had bacterial contamination. Failure to replace the lens case for more than 9 months and the mismatch of the lens solution brand with its storage case will increase bacterial contamination. Washing the lens case with soap and water, and drying it after washing, will reduce bacterial contamination.

scholarly journals Vestibulo-ocular reflex gain and compensatory saccades in three semicircular canals by video head impulse test

2019 ◽  
Author(s):  
Homa Zarrinkoob ◽  
Hadi Behzad ◽  
Seyed Mehdi Tabatabaee
Keyword(s):  
High Velocity ◽  
Semicircular Canals ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Low Velocity ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Reflex Gain ◽  
The Right

Background and Aim: One of the tools for ass­essing the vestibulo-ocular reflex (VOR) is using video head impulse test (vHIT). In this test by placing the head at different angles and shaking the head, three semicircular canals of the vestibular system in each ear can be exami­ned separately. The purpose of this study was to investigate the relationship between the low and high velocities of the vHIT test with VOR and its compensatory saccades. Methods: The vHIT test was performed by an examiner in 49 normal individuals aged 23–39 at low and high velocities. All participants had normal hearing, visual, and vestibular systems. Results: Mean gains in the horizontal, anterior and posterior semicircular canals in the right ear respectively were 0.92, 1 and 0.90 and in the left ear 0.93, 0.99 and 0.95 for low velocity and 0.78, 0.92 and 0.79 in the right ear and 0.80, 0.85 and 0.86 in the left ear for high velocity. Also, the number of compensatory saccade at high velocity was higher than those at the low velocity and the latency of compensatory sacc­ade was lower at the higher velocity. Conclusion: In the vHIT test, VOR gain decreases at high velocity that is statistically significant. Also, compensatory saccades are more likely to occur at high velocity with sma­ller delay. Therefore, high-velocity vHIT test is not recommended for the purpose of examining the VOR gain and compensatory saccade.

Sign in / Sign up

Export Citation Format

Share Document