Characteristics of spontaneous nystagmus and its correlation to video head impulse test findings in vestibular neuritis.

Objective: To explore the direction and SPV (slow phase velocity) of the components of spontaneous nystagmus (SN) in patients with vestibular neuritis (VN) and the correlation between SN components and affected semicircular canals (SCCs). Additionally, we aimed to elucidate the role of directional features of peripheral SN in diagnosing acute vestibular syndrome. Materials and methods: A retrospective analysis was conducted on 38 patients diagnosed with VN in our hospital between 2022 and 2023. The direction and SPV of SN components recorded with three-dimensional videonystagmography (3D-VNG) and the video head impulse test (vHIT) gain of each SCC were analyzed as observational indicators. We examined the correlation between superior and inferior vestibular nerve damage and the direction and SPV of SN components, and vHIT gain values in VN patients. Results: The median illness duration of between symptom onset and moment of testing was 6 days among the 38 VN patients (17 right VN and 21 left VN). In total, 31 patients had superior vestibular neuritis (SVN), and 7 had total vestibular neuritis (TVN). Among the 38 VN patients, all had horizontal component with an SPV of (7.66 ± 5.37) °/s, 25 (65.8%) had vertical upward component with a SPV of (2.64 ± 1.63) °/s, and 26 (68.4%) had torsional component with a SPV of (4.40 ± 3.12) °/s. The vHIT results in the 38 VN patients showed that the angular vestibulo-ocular reflex (aVOR) gain of the anterior (A), lateral (L), and posterior (P) SCCs on the ipsilesional side were 0.60 ± 0.23, 0.44 ± 0.15 and 0.89 ± 0.19, respectively, while the gains on the opposite side were 0.95 ± 0.14, 0.91 ± 0.08, and 0.96 ± 0.11, respectively. There was a statistically significant difference in the aVOR gain between the A-, L-SCC on the ipsilesional side and the other SCCs (p < 0.001). The aVOR gains of A-, L-, and P-SCC on the ipsilesional sides in 31 SVN patients were 0.62 ± 0.24, 0.45 ± 0.16, and 0.96 ± 0.10, while the aVOR gains on the opposite side were 0.96 ± 0.13, 0.91 ± 0.06, and 0.98 ± 0.11, respectively. There was a statistically significant difference in the aVOR gain between the A-, L-SCC on the ipsilesional side and the other SCCs (p < 0.001). In 7 TVN patients, the aVOR gains of A-, L-, and P-SCC on the ipsilesional side were 0.50 ± 0.14, 0.38 ± 0.06, and 0.53 ± 0.07, while the aVOR gains on the opposite side were 0.93 ± 0.17, 0.90 ± 0.16, and 0.89 ± 0.09, respectively. There was a statistically significant difference in the aVOR gain between the A-, L-, and P-SCC on the ipsilesional side and the other SCCs (p < 0.001). The aVOR gain asymmetry of L-SCCs in 38 VN was 36.3%. The aVOR gain asymmetry between bilateral A-SCCs and bilateral P-SCCs for VN patients with and without a vertical upward component was 12.8% and 8.3%, which was statistically significant (p < 0.05). For VN patients with and without a torsional component, the aVOR gain asymmetry of bilateral vertical SCCs was 17.0% and 6.6%, which was statistically significant (p < 0.01). Further analysis revealed a significant positive correlation between the aVOR gain asymmetry of L-SCCs and the SPV of the horizontal component of SN in all VN patients (r = 0.484, p < 0.01), as well as between the asymmetry of bilateral vertical SCCs and the SPV of torsional component in 26 VN patients (r = 0.445, p < 0.05). However, there was no significant correlation between the aVOR gains asymmetry of bilateral A-SCCs and P-SCCs and the SPV of the vertical component in 25 VN patients. Conclusion: There is a correlation between the three-dimensional direction and SPV characteristics of SN and the aVOR gain of vHIT in VN patients. These direction characteristics can help assess different SCCs impairments in patients with unilateral vestibular diseases.

[Further exploration of the classification and clinical value of head-shaking nystagmus].

Objective:To investigate the classification of head shaking nystagmus（HSN） and its clinical value in vestibular peripheral diseases. Methods:Clinical data of 198 patients with peripheral vestibular disorders presenting with HSN were retrospectively analyzed. Video Nystagmograph（VNG） was applied to detect spontaneous nystagmus（SN）, HSN, and Caloric Test（CT）. The intensity and direction of SN and HSN as well as the unilateral weakness（UW） and direction preponderance（DP） values in caloric test was analyzed in patients. Results:Among the 198 patients with vestibular peripheral disease, there were 105 males and 93 females, with an average age of（49.1±14.4） years （range: 14-87 years）. One hundred and thirty seven patients were diagnosed as Vestibular Neuritis（VN）, 12 as Meniere's Disease（MD）, 41 as sudden deafness（SD） and 8 as Hunt's syndrome accompanied by vertigo. Among them, there were 116 patients in the acute phase, including 68 cases（58.6%） with decreased HSN, 4 cases（3.4%） with increased HSN, 5 cases（4.3%） with biphasic HSN, 38 cases（32.8%） with unchanged HSN, and 1 case（0.9%） with perverted HSN. There were 82 cases in the non-acute phase, 51 cases（62.2%） with decreased HSN, 3 cases（3.6%） with increased HSN, 9 cases（11.0%） with biphasic HSN, and 19 cases（23.2%） with unchanged HSN. In biphasic HSN, the intensity of phase I nystagmus was usually greater than that of phase II, and the difference was statistically significant（P<0.01）. There was no correlation between HSN type and course of disease or DP value. The intensity of HSN was negatively correlated with the course of disease（r=-0.320, P<0.001） and positively correlated with DP value（r=0.364, P<0.001）, respectively. The intensity of unchanged nystagmus and spontaneous nystagmus were（8.0±5.7） °/s and（8.5±6.4）°/s, respectively. There was no statistically significant difference in the intensity of nystagmus before and after shaking the head. Conclusion:HSN can be classified into five types and could be regarded as a potential SN within a specific frequency range （mid-frequency）. Similarly, SN could also be considered as a common sign of unilateral vestibular impairment at different frequencies. HSN intensity can reflect the dynamic process of vestibular compensation, and is valuable for assessing the frequency of damage in peripheral vestibular diseases and monitoring the progress of vestibular rehabilitation.

Assessing vestibular function using electroencephalogram rhythms evoked during the caloric test.

Introduction: The vestibular system is responsible for motion perception and balance preservation in the body. The vestibular function examination is useful for determining the cause of associated symptoms, diagnosis, and therapy of the patients. The associated cerebral cortex processes and integrates information and is the ultimate perceptual site for vestibular-related symptoms. In recent clinical examinations, less consideration has been given to the cortex associated with the vestibular system. As a result, it is crucial to increase focus on the expression of the cortical level while evaluating vestibular function. From the viewpoint of neuroelectrophysiology, electroencephalograms (EEG) can enhance the assessments of vestibular function at the cortex level. Methods: This study recorded nystagmus and EEG data throughout the caloric test. Four phases were considered according to the vestibular activation status: before activation, activation, fixation suppression, and recovery. In different phases, the distribution and changes of the relative power of the EEG rhythms (delta, theta, alpha, and beta) were analyzed, and the correlation between EEG characteristics and nystagmus was also investigated. Results: The results showed that, when the vestibule was activated, the alpha power of the occipital region increased, and the beta power of the central and top regions and the occipital region on the left decreased. The changes in the alpha and beta rhythms significantly correlate with nystagmus values in left warm stimulation. Discussion: Our findings offer a fresh perspective on cortical electrophysiology for the assessment of vestibular function by demonstrating that the relative power change in EEG rhythms can be used to assess vestibular function.

Three-dimensional characteristics of nystagmus induced by low frequency in semicircular canals of healthy young people.

Objective: The study aimed to analyze the three-dimensional characteristics of nystagmus induced by different semicircular canal combinations in healthy young people, and to determine the reference range of nystagmus slow phase velocity (SPV) and its asymmetry. Materials and methods: Fifty-two healthy volunteers (26 males and 26 females, aged 17-42 years, average 23.52 ± 6.59), were recruited to perform the manual triaxial rotation testing with a 3D-Videonystagmography (3D-VNG) device (VertiGoggles (ZT-VNG-II), Shanghai ZEHNIT Medical Technology Co., Ltd., Shanghai, China) using a 0.3 Hz prompt beat and a 90° amplitude, respectively. The induced nystagmus around the Z-, X-, and Y-axes were recorded in the yaw, pitch, and roll planes. The directions and slow phase velocities of the horizontal, vertical, and torsional components of the induced nystagmus under different semicircular canal combinations (the left lateral and right lateral semicircular canal combination, bilateral anterior semicircular canals, bilateral posterior semicircular canals combination, and the anterior and posterior semicircular canals combination of each ear), as well as their asymmetry, were taken as the observation indexes to analyze the characteristics of the nystagmus vectors of different combinations. Results: Fifty-two healthy volunteers had no spontaneous nystagmus. The characteristic nystagmus was induced by the same head movement direction in all three axial rotation tests. The SPVs of the left and right nystagmus were 44.45 ± 15.75°/s and 43.79 ± 5.42°/s, respectively, when the subjects' heads were turned left or right around the Z-axis (yaw). The SPVs of vertically upward and downward nystagmus were 31.67 ± 9.46°/s and 30.01 ± 9.20°/s, respectively, when the subjects' heads were pitched around the X-axis (pitch). The SPVs of torsional nystagmus, with the upper poles of the eyes twisting slowly to the right and left ears (from the participant's perspective), were 28.99 ± 9.20°/s and 28.35 ± 8.17°/s, respectively, when the subjects' heads were turned left or right around the Y-axis (roll). There was no significant difference in the SPVs of nystagmus induced by the same rotation axis in two opposite directions (p > 0.05). The reference ranges for the slow phase velocities (SPVs) of nystagmus induced by the triaxial rotation testing were as follows: For the Z-axis (yaw), the SPVs were 13.58-75.32°/s for leftward head rotation and 13.56-74.02°/s for rightward head rotation. For the X-axis (pitch), the SPVs were 13.13-50.21°/s for upward head nystagmus and 11.98-48.04°/s for downward head nystagmus. For the Y-axis (roll), the SPVs were 10.97-47.02°/s for the left-sided head rotation and 12.34-44.35°/s for the right-sided head rotation. Conclusion: This study clarified the three-dimensional characteristics of nystagmus induced by different semicircular canal combinations in healthy young people. It also established a preliminary reference range of SPVs and SPV asymmetry of nystagmus induced by the vertical semicircular canal. It can further provide a basis for the mechanism of semicircular canal-induced nystagmus and the traceability of nystagmus in patients with otogenic vertigo. It is shown that the portable 3D-VNG eye mask can be used for the manual triaxial rotation testing to achieve the evaluation of the low-frequency angular vestibulo-ocular reflex (aVOR) function of the vertical semicircular canal, which is convenient, efficient, and practical.

The 3D characteristics of nystagmus in posterior semicircular canal benign paroxysmal positional vertigo.

Objective: The aim of this study was to observe the 3-dimensional (3D; horizontal, vertical, and torsional) characteristics of nystagmus in patients with posterior semicircular canal canalithiasis (PSC-can)-related benign paroxysmal positional vertigo (BPPV) and investigate its correlation with Ewald's. Methods: In all, 84 patients with PSC-can were enrolled. The latency, duration, direction, and slow-phase velocity induced by the Dix-Hallpike test in the head-hanging and sitting positions were recorded using 3D video nystagmography (3D-VNG). The characteristics of the horizontal, vertical, and torsional components of nystagmus were quantitatively analyzed. Results: 3D-VNG showed that the fast phase of the vertical components and torsional components of left and right ear PSC-can as induced by the head-hanging position of the Dix-Hallpike test were upward, clockwise and counterclockwise, and horizontal components were mainly contralateral. The median slow-phase velocity of each of the three components for consecutive 5 s was 26.3°/s (12.3-45.8), 25.0°/s (15.7-38.9), and 9.2°/s (4.9-13.7). When patients were returned to the sitting position, the fast phase of the vertical and torsional components of nystagmus was reversed. Only 54 patients had horizontal components of nystagmus, and 32 of them remained in the same direction. The median slow-phase velocity of the three components for consecutive 5 s was 9.4°/s (6.0-11.7), 6.8°/s (4.5-11.8), and 4.9°/s (2.8-8.0). The ratios of the slow-phase velocity of the horizontal, vertical, and torsional components of the head-hanging position to the sitting position were close to 1.85 (1.0-6.6), 3.7 (1.9-6.6), and 5.1 (2.6-11.3). The ratios of the slow-phase velocity of the vertical to horizontal component, the torsional to horizontal component, and the vertical to torsional component of the head-hanging position were close to 3.3 (1.7-7.6), 3.9 (1.8-7.6), and 1.0 (0.5-1.8). The ratios of the slow-phase velocity of the vertical to horizontal component, the torsional to horizontal component, and the vertical to torsional component of the sitting position were close to 2.1 (1.1-6.8), 1.5 (1.0-3.8), and 1.2 (0.8-2.8). Conclusion: There were three components of nystagmus induced by the Dix-Hallpike test in patients with PSC-can. The vertical component was the strongest and the horizontal component was the weakest. The 3D characteristics of nystagmus were consistent with those of physiological nystagmus associated with the same PSC with a single-factor stimulus, in accordance with Ewald's law.

[The changes in subjective visual vertical after otolith reduction in patients with BPPV].

Objective:To observe and analyze the changes in subjective visual vertical（SVV） after otolith reduction in patients with BPPV. Methods:46 patients with confirmed BPPV recieving successful otolith reduction were selected as the test group. 31 cases of posterior canal stones and 15 cases of horizontal semicircular canal stones, 29 cases of right ear and 17 cases of left ear. Fifty cases of healthy young volunteers were in the control group. Using the virtual reality SVV examination system, 0° SVV in the positive head were tested in the test group patients before and after the reduction of SVV , and were tested in the control group .The deviation angle of the SVV before and after the otolith reduction in the test group were analyzed. Results:Before otoliths reduction, the SVV was （0.08±3.83）° of right BPPV and was （-1.69±2.23）° of left BPPV. After otoliths reduction, the SVV was （-1.52±3.74）° of right BPPV and was （-1.04±2.50）° of left BPPV. In the control group, the SVV was（-1.57±2.28）° . The changes of SVV deflection angle between the control group and the right BPPV before the otolith reduction, and before and after the otolith reduction in the right BPPV were analyzed, and the differences were all statistically significant. There was no significant difference in SVV deflection angle between the left BPPV（before and after reduction） and the control group. In the test group, after the otolith reduction, 18 cases had larger bias angles, 28 cases had smaller bias angle among which 13 cases the deviation angle even turned to the contralateral side. Conclusion:Utriculare dysfunction in patients with BPPV leads to the judgment error of SVV. Reduction of otolithoid can cause new stimulation to the eutricule and affect its functional status. SVV detection can provide help for the evaluation of utricular function in patients with BPPV.

The horizontal and vertical components of nystagmus evoked by the supine roll test in horizontal semicircular canal canalolithiasis.

Objective: The characteristics of horizontal and vertical components of nystagmus evoked by the supine roll test in patients with horizontal semicircular canal canalolithiasis (HSC-Can) were analyzed, according to Ewald's first law. It provided a basis for the study of human horizontal semicircular canal function and structure, objective diagnosis, and treatment of benign paroxysmal positional vertigo (BPPV). Materials and methods: The records of patients that had been tested with 2-dimensional videonystagmography (2D-VNG) were reviewed between June 2019 and June 2021. The intensity and direction of horizontal and vertical nystagmus elicited by the supine roll test were analyzed in 189 patients with idiopathic HSC-Can. Results: All the 189 patients with HSC-Can were induced horizontal nystagmus with the same direction as head-turning (geotropic) in the supine roll test, of which 119 patients (63.96%) had a weak vertical upward component of nystagmus on the affected and unaffected sides, 57 patients (30.16%) had a vertical downward component of nystagmus on the affected side and/or the unaffected side, and 13 patients (6.88%) had no vertical component of nystagmus on both the sides. The intensity values of the horizontal component on the affected and unaffected sides were 42.14 ± 24.78 (range: 6.26-138.00°/s) and 17.48 ± 10.91°/s (range: 2.40-53.83°/s), with a ratio of 2.96 ± 2.17:1, representing a significant difference (p < 0.001). We analyzed the characteristics of horizontal and vertical components in 119 patients with HSC-Can (57 L-HSC-Can and 62 R-HSC-Can) on the supine roll test. The intensity values of the horizontal component on the affected and unaffected sides were 43.17 ± 23.76 (range: 8.60-124.51°/s) and 17.98 ± 10.99°/s (range: 2.40-53.83°/s), and the intensity values of the vertical component on the affected and unaffected sides were 10.65 ± 8.46 (range: 1.90-50.83°/s) and 4.81 ± 3.45°/s (range: 0.30-20.43°/s), representing a significant difference between groups (p < 0.001). Among 119 patients with HSC-Can who had a vertical upward component on both the affected and unaffected sides in the supine roll test, unilateral weakness (UW) was normal in 53 cases and abnormal in 51 cases, and 15 cases did not undergo the caloric test. We compared the horizontal and vertical components of nystagmus induced on the affected and unaffected sides in the supine roll test in 53 patients with normal UW and 51 patients with abnormal UW, and the difference was not statistically significant. Conclusion: There is mostly a vertical upward component based on the horizontal component in HSC-Can, and the direction and intensity characteristics of nystagmus accord with Ewald's first law, which can provide a basis for the study of human HSC function and structure, objective diagnosis, and treatment of BPPV.

[Three-dimensional characteristics of torsional nystagmus in induced by posterior semicircular canals canalithasis].

Objective:The three-dimensional direction feature of torsional nystagmus induced by posterior semicircular canal canalithasis （PSC-Can） was recorded and analyzed using three-dimensional video nystagmography （3D-VNG）. Methods:Sixty patients （22 on the left side and 38 on the right side） with PSC-Can were enrolled for torsional nystagmus evoked by Dix-Hallpike test in the affected-side head-hanging and sitting positions, and the direction characteristics of the horizontal, vertical and torsional components were analyzed. Results:Vertical torsional nystagmus was induced in 60 PSC-Can patients in the head-hanging and sitting positions evoked by Dix-Hallpike test, respectively. Horizontal, vertical, and torsional components of were presented in the 3D-VNG. In the head-hanging position, the direction of horizontal component in the left/right PSC-Can nystagmus was contralateral in 46 cases（the other 14 cases were ipsilateral）, the vertical component was upward, and the torsional component was upward/downward, respectively. The intensity of nystagmus induced in the three components in the sitting position is weaker than in the head-hanging position, and the direction of nystagmus was reversed in both vertical and torsional components compared with the head-hanging position. However, the direction of the horizontal component was reversed in 39 cases and not reversed in 21 cases in the sitting position. Conclusion:The horizontal, vertical and torsional components of the torsional nystagmus in PSC-Can patients recorded by 3D-VNG, which provided more comprehensive and objective information for the analysis of PSC-Can and the study of semicircular canal physiological function.

Evaluation of Vestibular Function in Diagnosis of Vestibular Schwannomas.

Vestibular schwannomas (VS) are benign tumors of the vestibular nerve. The common first symptoms are hearing loss and tinnitus, followed by imbalance, vertigo, and facial nerve involvement. The subjective symptoms of VS patients are not consistent with the severity of vestibular lesions and the results of vestibular tests, which often interfere with clinicians' diagnoses. Thus, the main screening and diagnostic methods for VS are audiometry and magnetic resonance imaging (MRI), ignoring the evaluation of vestibular function at the source of pathological lesions. With the development and improvement of vestibular evaluation technology and its wide application in the clinic, modern vestibular examination technology can reflect the severity and frequency of vestibular lesions and compensation from multiple perspectives, providing an objective basis for the diagnosis and treatment of vestibular diseases. In this report, we review the results and characteristics of vestibular tests in VS patients and further clarify the clinical value of vestibular function assessment in the diagnosis and treatment of VS.

Key Signaling Pathways Regulate the Development and Survival of Auditory Hair Cells.

The loss of auditory sensory hair cells (HCs) is the most common cause of sensorineural hearing loss (SNHL). As the main sound transmission structure in the cochlea, it is necessary to maintain the normal shape and survival of HCs. In this review, we described and summarized the signaling pathways that regulate the development and survival of auditory HCs in SNHL. The role of the mitogen-activated protein kinase (MAPK), phosphoinositide-3 kinase/protein kinase B (PI3K/Akt), Notch/Wnt/Atoh1, calcium channels, and oxidative stress/reactive oxygen species (ROS) signaling pathways are the most relevant. The molecular interactions of these signaling pathways play an important role in the survival of HCs, which may provide a theoretical basis and possible therapeutic interventions for the treatment of hearing loss.

[A study of the effect of hot and cold gas perfusion sequence on caloric test results].

Objective: To study whether the warm/cold air injection sequence affects the test results in the caloric test, and provide a basis for the specification and quality control of the caloric test. Methods:Video nystagmography and warm and cold air stimulation apparatus were applied for caloric test. Thirty healthy volunteers （60 ears） were divided into two groups of 15 （30 ears） each. The first group was given cold air stimulation followed by warm air stimulation, and the second group was given heat followed by cold. The differences in nystagmus maximal slow phase velocity （SPV）, semicircular canal paresis （CP） and dominant preponderance （DP） were compared between the two groups of subjects under different perfusion sequences of caloric test. Results:The intensity of nystagmus evoked by subjects in group 1 （cold first and then warm） and group 2 （warm first and then cold） were similar. Paired t-test showed that intra-group analysis of the SPV values of the two groups, comparison of the intensity of nystagmus evoked by different temperatures of the same ear or different sides of ear with the same temperature, the difference was not statistically significant （all P>0.05）. Independent samples t-test showed that between-group analysis of SPV values of two groups, the intensity of nystagmus induced by the same and different temperature stimuli in the ipsilateral ear, the difference was not statistically significant （all P>0.05）. Independent samples t-test showed that the CP values of the two groups were analyzed between groups, and the difference was not statistically significant （all P>0.05）. Independent samples t-test showed that DP values of both groups were in the normal range and the difference was not statistically significant （all P>0.05）. Conclusion:Different perfusion sequences of warm and cold air do not affect the results of caloric tests, and the order of warm and cold air stimulation is not the normative and quality control research direction of caloric test.

A Show of Ewald's Law: I Horizontal Semicircular Canal Benign Paroxysmal Positional Vertigo.

Objective: To evaluate horizontal semicircular canal (HSC) effects according to Ewald's law and nystagmus characteristics of horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV) in the supine roll test. Methods: Patients with HSC-BPPV (n = 72) and healthy subjects (n = 38) were enrolled. Latency, duration, and intensity of nystagmus elicited by supine roll test were recorded using video nystagmography. Results: In patients with HSC-BPPV, horizontal nystagmus could be elicited by right/left head position (positional nystagmus) and during head-turning (head-turning nystagmus), and nystagmus direction was the same as that of head turning. Mean intensity values of head-turning nystagmus in HSC-BPPV patients were (44.70 ± 18.24)°/s and (44.65 ± 19.27)°/s on the affected and unaffected sides, respectively, which was not a significant difference (p = 0.980), while those for positional nystagmus were (40.81 ± 25.56)°/s and (17.69 ± 9.31)°/s (ratio, 2.59 ± 1.98:1), respectively, representing a significant difference (p < 0.0001). There was no positional nystagmus in 49 HSC-BPPV patients after repositioning treatment, nor in the 38 healthy subjects. No significant difference in head-turning nystagmus was detected in HSC-BPPV patients with or without repositioning. Conclusions: The direction and intensity of nystagmus elicited by supine roll test in patients with HSC-BPPV, was broadly consistent with the physiological nystagmus associated with a same HSC with single factor stimulus. Our findings suggest that HSC-BPPV can be a show of Ewald's law in human body.

[Study on normal reference range of smooth tracking gain for healthy young people].

Objective:Analysis of normal reference value of smooth pursuit test for normal young people. Method:Thirty normal young volunteers were tested by Synapsys videonystagmography. The maximum horizontal tracking angle was 30 °, the vertical maximum tracking angle was 20°, and the frequency was 0.30 Hz, 0.45 Hz and 0.60 Hz, respectively， and the gain under different conditions is used as the observation index. Result:When the frequency is 0.3 Hz, 0.45 Hz, 0.60 Hz, the left and right horizontal gain is 0.92±0.07/0.93±0.07, 0.87±0.08/0.88±0.11, 0.79±0.11/0.78±0.13, respectively, and the asymmetry of left/right gain is 0.021±0.017, 0.031±0.026, 0.037±0.040; the up and down vertical gain is 0.82±0.16/0.80±0.16, 0.78±0.17/0.72±0.15, 0.68±0.20/0.61±0.15, and the asymmetry of the upper/lower gain is 0.046±0.045, 0.069±0.058, 0.109±0.076. Comparing and analyzing the paired left and right gain values of the three frequencies by paired t test, the differences were not statistically significant （P>0.05）. Paired t -test of gain value for different frequency of up and down stationary tracking, the difference was not statistically significant at 0.30 Hz（P>0.05）, but the gain at 0.45 Hz and 0.60 Hz has significant difference（P<0.05）. Comparing the gains of different frequencies in the same direction, the differences in analysis of variance were statistically significant（P<0.05）. Conclusion:The gain value of smooth pursuit test for normal young people can be affected by tracking frequency and direction. At the same frequency, the left/right tracking of 3 frequencies and the up/down tracking gain values of 0.30 Hz are symmetrical, but at 0.45 Hz and 0.6 Hz, the up tracking gain is greater than the down tracking gain, and the gain value in the same direction gradually decreases with the increase of frequency, is the clinical smooth pursuit test is mainly based on 0.30 Hz.

[Observation of early clinical effect of percutaneous transforaminal endoscopic technology in treating cervical spondylotic radiculopathy].

OBJECTIVE: To explore the early clinical effect and safety of percutaneous transforaminal endoscopic technology for cervical spondylotic radiculopathy. METHODS: From August 2016 to September 2017, 14 patients with cervical spondylotic radiculopathy who responded poorly to non-surgical treatment for at least 6 weeks underwent percutaneous transforaminal endoscopic discectomy via posterior approach. There were 6 males and 8 females, aging from 32 to 68 years old with an average of (40.5±7.6) years. The course of disease ranged from 0.5 to 13.0 months with an average of (6.0±1.33) months. The lesions involved C4,5 in 2 cases, C5,6 in 8 cases, C6,7 in 4 cases. Visual analogue scale (VAS), Japanese Orthopedic Association (JOA), Short Form 36 health survey questionnaire(SF-36) were recorded preoperatively and during the latest follow-up to evaluate the clinical outcome. Horizontal displacement and angular displacement of vertebral body were measured by cervical dynamic X-rays. RESULTS: All operations were successful. No spinal cord injury, nerve root or vascular injuries were found. Operation time was from 60 to 100 min with a median of 75 min;intraoperative bleeding was from 30 to 80 ml with a median of 40 ml. All patients were followed up for 2 to 13 months with a median of 9 months. During the follow-up period, the patients with neck and shoulder pain were significantly relieved without recurrence. No nucleus pulposus protrusion was found in the primary surgical segment, and there was no obvious sign of degeneration in the adjacent vertebral body. At the latest follow-up, VAS, JOA and SF-36 scores were obviously improved(P<0.05). There was no significant difference in horizontal displacement and angular displacement of vertebral body before and after the operation (P>0.05). The cervical curvature at the latest follow-up was higher than preoperative findings (P<0.05). And there was no significant difference in intervertebral disc height preoperatively and postoperatively(P>0.05). CONCLUSIONS: Percutaneous transforaminal endoscopic discectomy in treating cervical spondylotic radiculopathy can effectively and safely relieve neck and shoulder pain, improving nerve function, enhance life quality, maintaining cervical stability. It is worthwhile to generalize and apply in clinical settings.

Stress Writing Textured Graphite Conducting Wires/Patterns in Insulating Amorphous Carbon Matrix as Interconnects.

This study reports a mechanical stress-based technique that involves scratching or imprinting to write textured graphite conducting wires/patterns in an insulating amorphous carbon matrix for potential use as interconnects in future carbonaceous circuits. With low-energy post-annealing below the temperature that is required for the thermal graphitization of amorphous carbon, the amorphous carbon phase only in the mechanically stressed regions transforms into a well aligned crystalline graphite structure with a low electrical resistivity of 420 µΩ-cm, while the surrounding amorphous carbon matrix remains insulating. Micro-Raman spectra with obvious graphitic peaks and high-resolution transmission electron microscopic observations of clear graphitic lattice verified the localized phase transformation of amorphous carbon into textured graphite exactly in the stressed regions. The stress-induced reconstruction of carbon bonds to generate oriented graphitic nuclei is believed to assist in the pseudo-self-formation of textured graphite during low-temperature post annealing.

The clinical utility of vestibular autorotation test in patients with vestibular migraine.

OBJECTIVE: To investigate the characteristics and clinical utility of vestibular autorotation test (VAT) in patients with vestibular migraine. METHODS: This study included two groups, an experimental group (441 patients) and a control group (65 healthy subjects). Both groups undertook VAT; the parameters evaluated were horizontal gain/phase, vertical gain/phase and asymmetry. The differences in VAT results between the two groups were investigated. RESULTS: There were no statistical differences between the VAT data of the control group when compared to the reference value from the manufacturer (p > .05). There were statistically significant differences in VAT results between the experimental and control group, namely elevated horizontal gain at frequency 2, 3, 4 and 5 Hz, horizontal phase delay at frequency 2, 4, 5 and 6 Hz, elevated vertical gain at frequency 2 6Hz and vertical phase delay at frequency 4 6Hz. CONCLUSION: The results of this study using VAT in VM patients demonstrate elevated horizontal gain, vertical gain and delay in horizontal phase, vertical phase. We suggest the application of VAT as a diagnostic tool which may provide objective evidence that can contribute to the diagnosis of VM and also in differential diagnosis.

[The application of subjective visual gravity in assessment of vestibular compensation: a pilot study].

OBJECTIVE: To discuss the characteristics of subjective visual gravity (subjective visual vertical/horizontal, SVV/SVH) and assess its clinical application for peripheral unilateral vestibular compensation. METHODS: 69 cases of acute peripheral unilateral vestibular dysfunction patients (case group) accepted SVV/SVH, spontaneous nystagmus (SN), caloric test (CT) and other vestibular function tests. 49 healthy people (control group) accepted SVV/SVH only. SVV/SVH, SN and unilateral weakness (UW) were selected as for the observation indicators. The correlations between SVV/SVH, SN, UW and courses were investigated respectively, as well as the characteristic of SVV/SVH, SN in period of vestibular compensation. RESULTS: Among case group SVV, SVH positive in 42 patients(60.9%) and 44 patients(63.8%), the absolute values of the skew angle were in the range between 2.1°-20.0°, 2.1°-22.2°. Skew angles of SVV/SVH in control were in the range between -1.5°-2.0° and -2.0°-1.6°, and had no statistical significance with case group(t=5.336 and 5.864, P<0.05). SN-positive 28 cases (40.6%), the range of intensities at 2.4°-17.1°; UW-positive 50 cases (72.5%). In case group, positive correlation between SVV and SVH(r=0.948, P=0.00), negatively correlated between SVV/SVH and SN respectively(r values were -0.720, -0.733, P values were 0.00), no correlation between the skew angle of SVV/SVH, strength of SN and UW value(r values were 0.191, 0.189, and 0.179, P>0.05), there was no correlation between the absolute value of SVV, SVH, SN, UW with the duration (rs values were -0.075, -0.065, -0.212, and 0.126, P>0.05). CONCLUSION: Subjective visual gravity can be used not only to assess the range of unilateral peripheral vestibular dysfunction, but also help assess the static compensatory of otolithic, guidance and assessment of vestibular rehabilitation.

[Changes of Forest Canopy Spectral Reflectance with Seasons in Lang Ya Mountains].

The physiological mechanism and ecological structure of forest trees can change with the changes of years. In a certain extent, the changes were expressed through the canopy spectral features. The mastery of changing rules about spectral characteristics of trees over the years is benefit to remote sensing interpretation and provide scientific basis for the classification of different trees. The study adopted high-resolution spectrometer to measure the canopy spectral characteristics for seven major deciduous trees and seven evergreen trees to gain the spectrum curve of four different ages and calculate the first derivative curve. The analysis of changing rules about spectral characteristics of different deciduous trees and evergreen trees and the comparison of changes about spectrum of various trees in the visible and infrared band could find the best year and best band for identification of trees. The results showed that the canopy spectral reflectance of deciduous and evergreen trees increases with the increase of age. And the spectral changes of two species were most obvious in the near infrared band.

[Feature of semicircular canal function in obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: The aim of this study was to evaluate the effects of obstructive sleep apnea-hypopnea syndrome (OSAHS) on semicircular canal function. METHODS: By means of a series prospective study at Department of Otolaryngology Head and Neck Surgery of our hospital, the study was performed on 77 patients suffering from OSAHS in a period from 2012 to 2014, who underwent polysomnography (PSG) and caloric test. The maximal slow-phase velocity (SPV) and unilateral weakness (UW) were used to measure the vestibular function. Severity of OSAHS was evaluated by the lowest oxygen saturation (LSaO2) and apnea hypopnea index (AHI). The SPV after cool was signed, warm test was performed for each ear, and the sum of left ear SPV were calculated, and then, the SPV of right ear was counted as the same way. Finally, the relationships between LSaO2, AHI, age, BMI, and SPV of caloric test were analyzed. RESULTS: Caloric vestibular tests in the 77 OSAHS patients demonstrated abnormal findings in 52 patients (67.5%) and normal vestibular functions in the remaining 25 patients (32.5%). Of the 52 patients with an abnormal test result, 16 (20.8%) patients had unilateral vestibular hyporeflexia and 36 (46.7%) patients revealed a bilateral vestibular hyporeflexia. There was no linear relationship between AHI, age, BMI with SPV of caloric test (P > 0.05). The SPV had significant difference between Lower LSaO2group (LSaO2< 50%) and higher LSaO2group (LSaO2≥ 80%) (P < 0.05). LSaO2was lower in patients undertaken bilateral vestibular hyporeflexia. CONCLUSIONS: OSAHS patients with long-term intermittent hypoxia can disturb the vestibular organs and reduce semicircular canal function. The heavier hypoxemia will lead to the lower reflex of semicircular canal, with the heavier degree of hypoxemia, and the bilateral horizontal semicircular canal involvement may also be higher at the same time. Due to the effect of vestibule centre compensatory, OSAHS patients lack of dizziness and symptoms from balance disturbances such as typically acute vestibular damage.

[Clinical values of the sensory organization test in vestibular diseases].

OBJECTIVE: To explore the clinical values of Sensory Organization Test (SOT) of dynamic posturography in the diagnosis of peripheral vertigo. METHODS: A total of 112 patients with peripheral vertigo were retrospectively analyzed. All the patients firstly underwent the inspection of SOT followed by caloric test. The results were conducted a comparative analysis. Assessments of SOT evaluated the patient's effective use of visual, vestibular, and somatosensory information for balance control during a variety of changing task conditions. The unilateral weakness was selected as assessment parameter of caloric test. Fourty-two healthy subjects were selected as control group underwent the dynamic posturography. RESULTS: Among the 42 cases of control group, results of SOT in dynamic posturography were normal. The SOT composite scores owned a significant difference between control and peripheral vertigo subjects. Among the 112 cases with peripheral vertigo, results of SOT in dynamic posturography were abnormal in 37 cases, with a sensitivity of 33.0%; caloric test was abnormal in 72 cases, with a sensitivity of 64.3%. There existed a significant difference between dynamic posturography and caloric test. CONCLUSION: SOT is a key test in dynamic posturography that reflects the balance reconstruction after peripheral injury, and provides information about the integration and proportion of the visual, proprioceptive, and vestibular components of balance.