scholarly journals Subjective Visual Vertical during Caloric Stimulation in Healthy Subjects: Implications to Research and Neurorehabilitation

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Martha Funabashi ◽  
Aline I. Flores ◽  
Amanda Vicentino ◽  
Camila G. C. Barros ◽  
Octavio M. Pontes-Neto ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Cognitive Strategies ◽  
Semicircular Canals ◽  
Subjective Visual Vertical ◽  
Caloric Stimulation ◽  
Neurologic Disorders ◽  
Significant Difference ◽  
Sensitive Tool ◽  
Visual Vertical ◽  
The Mean

Background. The subjective visual vertical (SVV) is a perception often impaired in patients with neurologic disorders and is considered a sensitive tool to detect otolithic dysfunctions. However, it remains unclear whether the semicircular canals (SCCs) are also involved in the visual vertical perception.Objective. The aim of this study was to analyze the influence of horizontal SCCs on SVV by caloric stimulation in healthy subjects.Methods. SVV was performed before and during the ice-cold caloric stimulation (4°C, right ear) in 30 healthy subjects.Results. The mean SVV tilts before and during the caloric stimulation were 0.31° ± 0.39 and −0.28° ± 0.40, respectively. There was no significant difference between the mean SVV tilts before and during stimulationp=0.113.Conclusion. These results suggest that horizontal SCCs do not influence SVV. Therefore, investigations and rehabilitation approaches for SVV misperceptions should be focused on otolithic and cognitive strategies.

scholarly journals The use of a neck brace does not influence visual vertical perception

2011 ◽  
Vol 69 (3) ◽  
pp. 509-512 ◽  
Author(s):  
Martha Funabashi ◽  
Natya N.L. Silva ◽  
Luciana M. Watanabe ◽  
Taiza E.G Santos-Pontelli ◽  
José Fernando Colafêmina ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Afferent Input ◽  
Subjective Visual Vertical ◽  
Sensory Receptors ◽  
Ocular Torsion ◽  
Vertical Orientation ◽  
Mean Values ◽  
Visual Vertical ◽  
The Mean

Subjective visual vertical (SVV) evaluates the individual's capacity to determine the vertical orientation. Using a neck brace (NB) allow volunteers' heads fixation to reduce cephalic tilt during the exam, preventing compensatory ocular torsion and erroneous influence on SVV result. OBJECTIVE: To analyze the influence of somatosensory inputs caused by a NB on the SVV. METHOD: Thirty healthy volunteers performed static and dynamic SVV: six measures with and six without the NB. RESULTS: The mean values for static SVV were -0.075º±1.15º without NB and -0.372º±1.21º with NB. For dynamic SVV in clockwise direction were 1.73º±2.31º without NB and 1.53º±1.80º with NB. For dynamic SVV in counterclockwise direction was -1.50º±2.44º without NB and -1.11º±2.46º with NB. Differences between measurements with and without the NB were not statistically significant. CONCLUSION: Although the neck has many sensory receptors, the use of a NB does not provide sufficient afferent input to change healthy subjects' perception of visual verticality.

The Y-shaped trabecular bone structure in the odontoid process of the axis: a CT scan study in 54 healthy subjects and biomechanical considerations

2019 ◽  
Vol 30 (5) ◽  
pp. 585-592 ◽  
Author(s):  
Nicola Montemurro ◽  
Paolo Perrini ◽  
Vittoriano Mangini ◽  
Massimo Galli ◽  
Andrea Papini
Keyword(s):  
Ct Scan ◽  
Healthy Subjects ◽  
Bone Structure ◽  
Cone Beam Ct ◽  
Odontoid Process ◽  
Trabecular Structure ◽  
Anatomical Entity ◽  
Significant Difference ◽  
Axial Ct ◽  
The Mean

OBJECTIVEOdontoid process fractures are very common in both young and geriatric patients. The axial trabecular architecture of the dens appears to be crucial for physiological and biomechanical function of the C1–2 joint. The aim of this study is to demonstrate the presence of a Y-shaped trabecular structure of the dens on axial CT and to describe its anatomical and biomechanical implications.METHODSFifty-four C2 odontoid processes in healthy subjects were prospectively examined for the presence of a Y-shaped trabecular structure at the odontocentral synchondrosis level with a dental cone beam CT scan. Length, width, and axial area of the odontoid process were measured in all subjects. In addition, measurements of the one-third right anterior area of the Y-shaped structure were taken.RESULTSThe Y-shaped trabecular structure was found in 79.6% of cases. Length and width of the odontoid process were 13.5 ± 0.6 mm and 11.2 ± 0.9 mm, respectively. The mean area of the odontoid process at the odontocentral synchondrosis was 93.5 ± 4.3 mm2, whereas the mean one-third right anterior area of the odontoid process at the same level was 29.3 ± 2.5 mm2. The mean area of the odontoid process and its length and width were similar in men and women (p > 0.05). No significant difference was found in the mean area of the odontoid process in people older than 65 years (94 ± 4.2 mm2) compared to people younger than 65 years (93.3 ± 4.4 mm2; p > 0.05).CONCLUSIONSThe authors identified a new anatomical entity, named the Y-shaped trabecular structure of the odontoid process, on axial CT scans. This structure appears to be the result of bone transformation induced by the elevated dynamic loading at the C1–2 level. The presence of the Y-shaped structure provides new insights into biomechanical responses of C2 under physiological loading and traumatic conditions.

VESTIBULAR AFFERENTS POPULATION ACTIVATED BY VARIOUS MODES FOR ELICITING OCULAR AND CERVICAL VESTIBULAR-EVOKED MYOGENIC POTENTIALS

2011 ◽  
Vol 23 (06) ◽  
pp. 527-532 ◽  
Author(s):  
Shou-Jen Wang ◽  
Fu-Shan Jaw ◽  
Yi-Ho Young
Keyword(s):  
Healthy Subjects ◽  
Mean Amplitude ◽  
Vestibular Evoked Myogenic Potentials ◽  
Force Level ◽  
Characteristic Parameters ◽  
Stimulation Mode ◽  
Vestibular Afferents ◽  
Significant Difference ◽  
The Mean

This study compared cervical and ocular vestibular-evoked myogenic potentials (cVEMPs and oVEMPs) between air-conducted sound (ACS) and bone-conducted vibration (BCV) modes to determine whether these two stimulation modes activate the same population of primary vestibular afferents. Fifteen healthy subjects underwent cVEMP and oVEMP tests using ACS stimuli at 127 dB pe SPL and BCV stimuli at 128 dB force level. The characteristic parameters of cVEMPs and oVEMPs were compared between ACS and BCV modes. The mean p13 and n23 latencies of ACS-cVEMPs were significantly longer than those of BCV-cVEMPs. Likewise, the mean nI and pI latencies for ACS-oVEMPs were also significantly longer than those for BCV-oVEMPs. There was no significant difference in the mean amplitude of cVEMPs between the ACS and BCV modes. However, comparing the oVEMP amplitude, a relationship: (Amplitude of BCV-oVEMP) = 2.3 x (Amplitude of ACS-oVEMP) was demonstrated. In conclusion, the population of primary vestibular afferents activated by ACS and BCV stimuli is similar for cVEMPs. In contrast with oVEMPs, BCV mode activates more number of primary vestibular afferents than ACS mode does. In interpreting oVEMP and cVEMP results, stimulation mode should be checked first.

scholarly journals Quantitative assessment of choriocapillaris flow deficits in diabetic retinopathy: A swept-source optical coherence tomography angiography study

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243830
Author(s):  
Yining Dai ◽  
Hao Zhou ◽  
Qinqin Zhang ◽  
Zhongdi Chu ◽  
Lisa C. Olmos de Koo ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Optical Coherence ◽  
Swept Source ◽  
Significant Difference ◽  
En Face ◽  
The Mean

Purpose To quantitatively assess choriocapillaris (CC) flow deficits in eyes with diabetic retinopathy (DR) using swept-source optical coherence tomography angiography (SS-OCTA). Methods Diabetic subjects with different stages of DR and age-matched healthy subjects were recruited and imaged with SS-OCTA. The en face CC blood flow images were generated using previously published and validated algorithms. The percentage of CC flow deficits (FD%) and the mean CC flow deficit size were calculated in a 5-mm-diameter circle centered on the fovea from the 6×6-mm scans. Results Forty-five diabetic subjects and 27 control subjects were included in the study. The CC FD% in diabetic eyes was on average 1.4-fold greater than in control eyes (12.34±4.14% vs 8.82±2.61%, P < 0.001). The mean CC FD size in diabetic eyes was on average 1.4-fold larger than in control eyes (2151.3± 650.8μm2 vs 1574.4±255.0 μm2, P < 0.001). No significant difference in CC FD% or mean CC FD size was observed between eyes with nonproliferative DR and eyes with proliferative DR (P = 1.000 and P = 1.000, respectively). Conclusions CC perfusion in DR can be objectively and quantitatively assessed with FD% and FD size. In the macular region, both CC FD% and CC FD size are increased in eyes with DR. SS-OCTA provides new insights for the investigations of CC perfusion status in diabetes in vivo.

scholarly journals Influence of Fasting followed by Acute Water Ingestion on Subfoveal Choroidal Thickness in Eyes of Healthy Subjects

2017 ◽  
Vol 1 (1) ◽  
pp. oapoc.0000013
Author(s):  
Rocio Blanco-Garavito ◽  
Polina Astroz ◽  
Salomon Yves Cohen ◽  
Eric H. Souied
Keyword(s):  
Healthy Volunteers ◽  
Healthy Subjects ◽  
Choroidal Thickness ◽  
Enhanced Depth Imaging ◽  
Hydration Status ◽  
Subfoveal Choroidal Thickness ◽  
Water Ingestion ◽  
Case Series Study ◽  
Significant Difference ◽  
The Mean

Purpose To investigate the influence of at least 12 hours of fasting followed by acute water ingestion on macular choroidal thickness in eyes of healthy subjects. Methods Prospective case series study including healthy volunteers from April 1, 2015 to May 31, 2015. Macular choroidal thickness was measured on enhanced depth imaging optical coherence tomography (EDI-OCT) and on swept-source (SS)-OCT after 12 hours of fasting, and 60 minutes after acute water ingestion (750 mL in 5 minutes). Results A total of 52 eyes of 26 healthy volunteers were included in this study. The mean age for participants was 32 years old. After 12 hours of fasting, the mean (±SD) subfoveal choroidal thickness was 335.43 (±104.82) μm on EDI-OCT and 286.16 (±80.32) μm on SS-OCT. The mean (±SD) subfoveal choroidal thickness after acute water intake was 352.32 (±120.36) μm and 290.5 (±85.86) μm, respectively. There was no significant difference between the mean subfoveal thickness at baseline and 60 minutes after acute water ingestion for any of the choroidal imaging techniques (p = 0.1386 for EDI-OCT and p = 0.0659 for SS-OCT). Conclusions These results suggest that choroidal circulation can physiologically quickly adapt to systemic vascular changes in healthy eyes. Choroidal thickness did not depend upon the hydration status for the subjects participating in this study.

scholarly journals Evaluation of Optical Low Coherence Reflectometry Parameters in Patients with Exfoliation Syndrome

2015 ◽  
Vol 2015 ◽  
pp. 1-4
Author(s):  
Emrullah Beyazyıldız ◽  
Özlem Beyazyıldız ◽  
Süleyman Günaydın ◽  
Emrah Kan ◽  
Mert Şimşek ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Exfoliation Syndrome ◽  
Low Coherence ◽  
Significant Difference ◽  
The Mean ◽  
Group 2 ◽  
Optical Low Coherence Reflectometry ◽  
Group 1

Purpose. To evaluate optical low coherence reflectometry (OLCR) parameters in patients with exfoliation syndrome (EXS) undergoing cataract surgery.Methods. Forty-seven eyes of 47 patients with EXS (Group 1), and 55 eyes of 55 healthy subjects (Group 2) were included in the study. Anterior chamber depth (ACD), lens thickness (LT), axial length (AL), central corneal thickness (CCT), horizontal corneal length (HCL), and pupil diameter (PD) parameters were measured by OLCR (Lenstar LS 900, Haag-Streit) and compared between groups. Shapiro-Wilk test and Mann WhitneyUtests were used for statistical analyses.Results. The mean ACD, HCL, and PD values were significantly lower in EXS group than in healthy subjects (P= 0.01,P= 0.04, andP<0.001, resp.). The mean LT was significantly higher in EXS group than in healthy subjects (P= 0.007). There was no significant difference between groups in means of AXL and CCT.Conclusions. According to OLCR measures, eyes with EXS have shallower ACD, smaller PD, thicker LT, shorter HCL, and no significantly different CCT levels.

scholarly journals Gravity Dependence of Subjective Visual Vertical Variability

2009 ◽  
Vol 102 (3) ◽  
pp. 1657-1671 ◽  
Author(s):  
A. A. Tarnutzer ◽  
C. Bockisch ◽  
D. Straumann ◽  
I. Olasagasti
Keyword(s):  
Inertial Force ◽  
Semicircular Canals ◽  
The Body ◽  
Otolith Organs ◽  
Subjective Visual Vertical ◽  
Visual Vertical ◽  
Head Roll ◽  
Static Head ◽  
Experimental Findings ◽  
Vertical Variability

The brain integrates sensory input from the otolith organs, the semicircular canals, and the somatosensory and visual systems to determine self-orientation relative to gravity. Only the otoliths directly sense the gravito-inertial force vector and therefore provide the major input for perceiving static head-roll relative to gravity, as measured by the subjective visual vertical (SVV). Intraindividual SVV variability increases with head roll, which suggests that the effectiveness of the otolith signal is roll-angle dependent. We asked whether SVV variability reflects the spatial distribution of the otolithic sensors and the otolith-derived acceleration estimate. Subjects were placed in different roll orientations (0–360°, 15° steps) and asked to align an arrow with perceived vertical. Variability was minimal in upright, increased with head-roll peaking around 120–135°, and decreased to intermediate values at 180°. Otolith-dependent variability was modeled by taking into consideration the nonuniform distribution of the otolith afferents and their nonlinear firing rate. The otolith-derived estimate was combined with an internal bias shifting the estimated gravity-vector toward the body-longitudinal. Assuming an efficient otolith estimator at all roll angles, peak variability of the model matched our data; however, modeled variability in upside-down and upright positions was very similar, which is at odds with our findings. By decreasing the effectiveness of the otolith estimator with increasing roll, simulated variability matched our experimental findings better. We suggest that modulations of SVV precision in the roll plane are related to the properties of the otolith sensors and to central computational mechanisms that are not optimally tuned for roll-angles distant from upright.

scholarly journals The Value of Subjective Visual Vertical in Diagnosis of Vestibular Migraine

2021 ◽  
Vol 41 (4) ◽  
pp. 654-660
Author(s):  
Fei Li ◽  
Jin Xu ◽  
Gen-ru Li ◽  
Rui Gao ◽  
Chen-yong Shang ◽  
...  
Keyword(s):  
Normal Subjects ◽  
Diagnostic Value ◽  
Upright Position ◽  
Vestibular Migraine ◽  
Subjective Visual Vertical ◽  
Vestibular Evoked Myogenic Potential ◽  
Significant Difference ◽  
Visual Vertical ◽  
High Level ◽  
Sensitivity Specificity

Abstract 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.

scholarly journals Examination of IQ in 7 to 14 years old children with sickle cell disease compared with healthy children

2020 ◽  
Vol 5 (1) ◽  
pp. e13-e13
Author(s):  
Arash Alghasi ◽  
Zohreh Hassanpour ◽  
Mohammad Bahadoram ◽  
Somayeh Ashrafi ◽  
Seyed Mohammad Kazem Nourbakhsh
Keyword(s):  
Standard Deviation ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Healthy Subjects ◽  
Healthy Children ◽  
Brain Circulation ◽  
Cell Disease ◽  
Significant Difference ◽  
The Mean ◽  
Iq Scores

Introduction: Sickle cell disease (SCD) is a genetic disorder that can be diagnosed by early onset screening tests. In embryos and newborns with sickle cell syndrome, the anatomic development and brain circulation is less than the normal people, and brain circulation plays an important role in brain development. Objectives: The purpose of this study was to evaluate the level of IQ in children with SCD. Patients and Patients and Methods: The study was a descriptive-epidemiologic. The population of the present study was all children aged 7-14 years old with SCD in Ahvaz. The sample of this study was 50 children with SCD. They were selected from among clients referring to the hepatitis clinic of Shafa hospital in Ahvaz. About 50 healthy children were selected from the first or second-degree family members of the patients with SCD as the control group. The data was collected using Raven’s Progressive Matrices (RPM) and demographic information questionnaire. Results: The mean and standard deviation of IQ scores of the patients with SCD was 94.52 ± 14.41, and the mean and standard deviation of IQ scores of healthy subjects was 105.86 ± 11.38. The results showed a significant difference between the two groups in terms of IQ score (P<0.05). Moreover, the results showed that IQ level in patients with SCD was significant regarding their place of residence (P<0.05), however IQ level was not significant in patients with SCD regarding gender and race (P>0.05). Conclusion: The results showed that IQ in children with SCD is lower than that of the healthy subjects. Thus, the present study showed the importance of SCD on children’s IQ.

scholarly journals Impaired Subjective Visual Vertical and Increased Visual Dependence in Older Adults With Falls

2021 ◽  
Vol 13 ◽  
Author(s):  
Milda Totilienė ◽  
Virgilijus Uloza ◽  
Vita Lesauskaitė ◽  
Gytė Damulevičienė ◽  
Rima Kregždytė ◽  
...  
Keyword(s):  
Older Adults ◽  
Odds Ratio ◽  
Assessment Tools ◽  
Subjective Visual Vertical ◽  
Risk Of Falling ◽  
Falls Risk ◽  
Visual Vertical ◽  
The Mean ◽  
Visual Dependence ◽  
Tinetti Test

Aging affects the vestibular system and may disturb the perception of verticality and lead to increased visual dependence (VD). Studies have identified that abnormal upright perception influences the risk of falling. The aim of our study was to evaluate subjective visual vertical (SVV) and VD using a mobile virtual reality-based system for SVV assessment (VIRVEST) in older adults with falls and evaluate its relationship with clinical balance assessment tools, dizziness, mental state, and depression level. This study included 37 adults &gt;65 years who experienced falls and 40 non-faller age-matched controls. Three tests were performed using the VIRVEST system: a static SVV, dynamic SVV with clockwise and counter-clockwise background stimulus motion. VD was calculated as the mean of absolute values of the rod tilt from each trial of dynamic SVV minus the mean static SVV rod tilt. Older adults who experienced falls manifested significantly larger biases in static SVV (p = 0.012), dynamic SVV (p &lt; 0.001), and VD (p = 0.014) than controls. The increase in static SVV (odds ratio = 1.365, p = 0.023), dynamic SVV (odds ratio = 1.623, p &lt; 0.001) and VD (odds ratio = 1.460, p = 0.010) tilt by one degree significantly related to falls risk in the faller group. Fallers who had a high risk of falling according to the Tinetti test exhibited significantly higher tilts of dynamic SVV than those who had a low or medium risk (p = 0.037). In the faller group, the increase of the dynamic SVV tilt by one degree was significantly related to falls risk according to the Tinetti test (odds ratio = 1.356, p = 0.049). SVV errors, particularly with the dynamic SVV test (i.e., greater VD) were associated with an increased risk of falling in the faller group. The VIRVEST system may be applicable in clinical settings for SVV testing and predicting falls in older adults.

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