Further exploration of the classification and clinical value of head-shaking nystagmus / 临床耳鼻咽喉头颈外科杂志

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.

Recovery Phase Spontaneous Nystagmus, Its Existence and Clinical Implication

BACKGROUND AND OBJECTIVES: Determination of the lesion side based on the direction of the nystagmus could result in confusions to the clinicians due to mismatch between the vestibular function tests and also between vestibular and audiologic features. To minimize these mistakes, we elucidated the clinical manifestation and vestibular function test results in cases with recovery spontaneous nystagmus (rSN). SUBJECTS AND METHODS: Patients who visited ENT clinic of tertiary referral hospital for acute onset continuous vertigo from January 2008 to December 2011 were enrolled. In these patients, we assessed onset time of vertigo, time point of paralytic spontaneous nystagmus (SN) and time point of rSN. At each time point of SN, vestibular function tests and hearing function tests were performed. RESULTS: We confirmed the rSN among patients with unilateral vestibulopathy and demonstrated that high gain of the rotatory chair test (slow harmonic acceleration) and/or mismatch of the SN direction and contralateral caloric weakness could indicate the recovery state of patients and nystagmus observed in this stage is recovery phase nystagmus. CONCLUSIONS: In acute vestibulopathy patients, recovery phase nystagmus was observed and on this stage of disease vestibular function tests shows several features that could predict recovery state.

Clinical Significance of Spontaneous Nystagmus in Horizontal Semicircular Canal Benign Paroxysmal Positional Vertigo / 대한평형의학회지

OBJECTIVES: We aimed to assess the clinical significance of spontaneous nystagmus (SN) in horizontal semicircular canal benign paroxysmal positional vertigo (HC-BPPV). METHODS: Twenty-four patients who were diagnosed with HC-BPPV in Eulji University Hospital from January 2015 to December 2016 were recruited. Various bed-side examinations including SN in both sitting and supine position, head roll test, and bithermal caloric test were evaluated. The number of canalith repositioning maneuvers were counted in all patients. RESULTS: SN was observed in 18.2% of geotropic HC-BPPV and 38.5% of apogeotropic HC-BPPV, respectively. There was no significant difference between presence of SN and the direction of initial nystagmus (p=0.386, 2-tailed Fisher exact test). The mean number of otolith repositioning maneuvers in patients with SN was 3.29±1.799 and this was significantly higher than in patients without SN (1.76±0.831) (p=0.009). Although the mean number of repositioning maneuver in patients in apogeotropic HC-BPPV and SN (3.80±1.924) tended to be higher than those who were diagnosed with apogeotropic HC-BPPV without SN (1.88±1.991) (p=0.035), the post hoc analysis with Bonferroni correction revealed that it was not significant because it was higher than the adjusted p-value (p=0.017). The initial direction of nystagmus was changed into the opposite direction in 29.17% of patient. However, this change was not different according to presence of SN (p=0.374, 2-tailed Fisher exact test). CONCLUSIONS: The presence of SN in HC-BPPV may be associated with lower treatment response. In particular, cautions are needed in patients with apogeotropic HC-BPPV.

Pseudo-Spontaneous Nystagmus and Head-Shaking Nystagmus in Horizontal Canal Benign Paroxysmal Positional Vertigo / 대한평형의학회지

OBJECTIVES: The purpose of this study was to examine the clinical manifestations and significance of pseudo-spontaneous nystagmus (PSN) and head-shaking nystagmus (HSN) in horizontal canal benign paroxysmal positional vertigo (HC-BPPV). METHODS: Two hundred fifty-two patients diagnosed as HC-BPPV were reviewed retrospectively. After excluding 55 patients with ipsilateral vestibular diseases, multiple canal BPPV, or those who were lost to follow-up, we analyzed the direction of PSN and HSN in patients with HC-BPPV. We also compared the clinical characteristics and treatment outcome between PSN-positive and PSN-negative groups. RESULTS: Our study included 197 patients composed of 80 patients with geotropic HC-BPPV and 117 patients with apogeotropic HC-BPPV. PSN was observed in 13.7% patients and HSN was observed in 45.2%. The incidence of HSN was higher in apogeotropic HC-BPPV, while the proportion of PSN was not statistically significant between the two subtypes. There was no directional preponderance in geotropic HC-BPPV, while ipsilesional PSN and contralesional HSN showed higher incidence in apogeotropic HC-BPPV. The dizziness handicap inventory score in the PSN-positive group was higher than that in the PSN-negative group (p<0.001), and the duration of symptom onset in the PSN-positive group was shorter than that in the PSN-negative group (p=0.047). However, there was no significant difference in the treatment outcome between the two groups. CONCLUSIONS: The incidence of HSN was higher than that of PSN in patients with apogeotropic HC-BPPV. Patients with HC-BPPV showing PSN demonstrated more severe initial symptoms and visited the hospital in a shorter period of time after the onset of symptoms.

Vestibular Neuritis With Minimal Canal Paresis: Characteristics and Clinical Implication

OBJECTIVES: To analyze the clinical characteristics of vestibular neuritis patients with minimal canal paresis (canal paresis <25%). METHODS: Patients clinically diagnosed with vestibular neuritis and treated at our institute (n=201) underwent otoneurological examination and vestibular function tests. Patients were categorized in terms of the results of caloric testing (canal paresis<25%, n=58; canal paresis≥25%, n=143). Clinical characteristics and laboratory outcomes were compared between two groups. RESULTS: Existence of underlying diseases, preceding symptoms, and direction of spontaneous nystagmus were not different between the groups. The mean duration of spontaneous nystagmus was shortest in the minimal canal paresis group (P<0.001) and the direction of spontaneous nystagmus changed more frequently in this group (P<0.001) during recovery. Among the subgroup with minimal canal paresis, only 29.5% had an abnormal finding on the rotatory chair test, as compared to 81.5% of the canal paresis group. The minimal canal paresis group showed higher sensory organization test scores in computerized dynamic posturography. CONCLUSION: Patients with minimal canal paresis (canal paresis <25%) show similar clinical manifestations as conventional vestibular neuritis patients, but have faster recovery of symptoms and a higher incidence of recovery nystagmus. This finding support that the minimal canal paresis could be considered as a milder type of vestibular neuritis.

Competence in Suppressing the Visual Fixation among Different Types of Frenzel Glasses / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Several manufacturers supply different types of Frenzel glasses, but the quality of these varied Frenzel glasses seems to be quite different. The aim of this study was to compare the competence in suppressing visual fixation (VF) among different types of Frenzel glasses. The second aim was to develop a new type of Frenzel glasses which is cheaper and more convenient to carry, but has an equivalent competence. MATERIALS AND METHODS: Four different types of Frenzel glasses were evaluated: 30 diopter Frenzel glasses manufactured by Nagashima (N), 10 diopter Frenzel glasses manufactured by Jungang (J), 13 diopter conventional magnifying glasses (M) and 17 diopter Fresnel lens glasses assembled by the authors. The amplitude of the spontaneous nystagmus (SN) was measured though the electronystagmography system. The SN was measured 35 times from 15 patients who were diagnosed as vestibular neuritis. RESULTS: The mean amplitude of the SN was 8.8+/-3.2degrees/sec when measured with the videonystagmography goggles. When the same SN was measured through the 4 different Frenzel glasses, it was 7.5+/-2.8 (N), 6.3+/-3.0 (F), 6.2+/-3.0 (M), and 5.7+/-2.6 (J)degrees/sec respectively. The amplitude of the SN was significantly bigger when wearing the N glasses compared to the other 3 glasses. The SN was significantly smaller when wearing the J glasses compared to the F glasses. CONCLUSION: The competence of suppressing VF was significantly different among the varied types of glasses. The F glasses seem to have a similar or better competence with the J glasses. F glasses seems to be a fairly good alternative which is very portable and cheap.

Effects of Galvanic Stimulation on Spontaneous Nystagmus in Meniere's Disease and Vestibular Neuritis: A Preliminary Study / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Galvanic vestibular stimulation (GVS) is known to induce nystagmus, ocular torsion, a tilt of subjective visual vertical, and perceptual and postural shift. The aim of this study was to compare the findings of GVS among the patients with spontaneous nystagmus (SN) caused by Meniere's disease (MD) or vestibular neuritis (VN). MATERIALS AND METHODS: Three-dimensional video-oculography was performed without fixation in 4 patients with MD and 2 with VN, as diagnosed by history, independent vestibular function tests and neuroimaging. We recorded the eye-movements in response to bilateral, bipolar, and surface GVS (2.5~3 mA) for 30 seconds, and analyzed mean slow phase velocity of SN. RESULTS: Of the 4 patients with MD, two exhibited a suppression of the left beating SN during anode stimulation of left mastoid and an augmentation of the nystagmus during cathode stimulation of left mastoid. The same patterns of galvanic modulation were observed in the other 2 patients with right beating SN due to MD. In contrast, the patients with VN showed an absent or decreased response to GVS. CONCLUSION: In MD, the responses to GVS were preserved while the responses were impaired in VN. These results suggest that the irregular vestibular fibers, which are sensitive to GVS, are relatively spared in MD. In contrast, both regular and irregular fibers appear to be damaged in VN. GVS may be helpful in discriminating MD from VN, especially when the patients presented without auditory symptoms.

Correlation between Spontaneous Nystagmus and Vestibular Function Test Parameters according to Gender and Age in Vestibular Neuritis

BACKGROUND AND OBJECTIVES: There are caloric test, SCEP, DP in Step velocity and VOR asymmetry in SHA test as parameters for evaluation in unilateral peripheral vestibulopathy in parameter of vestibular function test. The aim of this study is to assess the correlation between these parameters and intensity of spontaneous nystagmus in vestibular neuritis. MATERIALS AND METHOD: We evaluated 75 patients who were diagnosed as vestibular neuritis with 3 degree spontaneous nystagmus at vestibular function test lab from January 2000 to July 2005 in Dankook university hospital. The correlations between direction and intensity of spontaneous nystagmus and monothermal caloric test, SCEP and DP in step velocity, VOR asymmetry (0.01, 0.04, 0.16 Hz) in SHA test were analysed. And correlations according to sex, age were also analysed. RESULTS: The correlation coefficient between intensity of spontaneous nystagmus and monothermal caloric test was 0.60. The correlation coefficient between intensity of spontaneous nystagmus and SCEP was 0.35. The correlation coefficient between intensity of spontaneous nystagmus and Tc DP was 0.36 and it showed no significant correlation. The correlation coefficient between intensity of spontaneous nystagmus and VOR asymmetry (0.01, 0.04, 0.16) was 0.57, 0.46, 0.51, respectively and there was higher correlation in man, age under 60. CONCLUSION: Intensity of spontaneous nystagmus showed close relations to monothermal caloric test, VOR asymmetry of SHA, Tc DP, SCEP DP in sequence. In addition, young male patients tends to be closely related to intensity of spontaneous nystagmus.

Effect of Ginkgo biloba on Expression of c-Fos Protein in the Vestibular Nuclear Complex following Unilateral Labyrinthectomy in Rats

BACKGROUND AND OBJECTIVES: The neuroprotective effect of Ginkgo biloba has been demonstrated in several in vivo and in vitro models. The effect of Ginkgo biloba on vestibular compensation following unilateral labyrinthectomy (UL) was investigated. Material and Methods: Spontaneous nystagmus and c-Fos protein expression were measured following UL in Sprague-Dawley rats with pretreatment of Ginkgo biloba (50 mg/kg, i.p.). RESULTS: After pretreatment with Ginkgo biloba (50 mg/kg, i.p.) expression of c-Fos protein in the vestibular nuclear complex and frequency of spontaneous nystagmus were measured till 24 hours after UL. UL produced spontaneous nystagmus with frequency of 124+/-.2 beats/min at post-op 2 hrs and 70+/-.1 beats/min at post-op 24 hrs. Pretreatment with Ginkgo biloba significantly decreased the frequency of spontaneous nystagmus till post-op 24 hrs compared to control group (p<0.05). UL produced marked expression of c-Fos protein in bilateral medial vestibular nucleus, inferior vestibular nucleus, and superior vestibular nucleus, and the number of expression was significantly higher in contralateral vestibular nuclei to the lesion than ipsilateral vestibular nuclei at post-op 2 hrs (p<0.01). The number of c-Fos protein expression was decreased with time and significantly higher in ipsilateral vestibular nuclei than contralateral ones at post-op 24 hrs (p<0.01). Pretreatment with Ginkgo biloba significantly decreased the number of c-Fos protein expression following UL (p<0.01) and abolished the asymmetry of c-Fos protein expression in bilateral vestibular nuclei at post-op 24 hrs. CONCLUSION: These results suggest that Ginkgo biloba may facilitate vestibular compensation following UL through modulation of neurotransmitters and neuroprotective effects.

Effects of MK801 on Neuronal Activity of the Contralateral Medial Vestibular Nuclei Following Unilateral Labyrinthectomy in Rats / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Several lines of evidence suggest that recovery of symptoms following unilateral labyrinthectomy (ULX) is due to the restoration of neuronal activity in the ipsilateral vestibular nuclei, leading to the reestablishment of bilateral symmetry in the resting neuronal activity. Effects of dizocilpine maleate (MK801), a non-competitive NMDA receptor antagonist, on vestibular compensation following unilateral labyrinthectomy (ULX) were investigated in adult Sprague-Dawley rats. MAERIAL AND METHODS: Responses of spontaneous nystagmus and neuronal activity of the contralateral medial vestibular nuclei (MVN) to labyrinthectomy were recorded in course of time after intraperitoneal injection of MK801. RESULT: Spontaneous nystagmus decreased gradually with time, but recovery of the nystagmus was aggravated 2 to 4 hours after administration of MK801 (p<0.05). In the labyrinthine intact rats, MK801 treatment significantly increased resting activity of type I and II in MVN compared with non-treated rats, and the effect of MK801 on neuronal activity was more prominent in the type I neurons than in the type II neurons. After 6 hours of ULX, the activities of type I and II neurons were decreased compared with labyrinthine intact rats, and type II neurons showed higher activity than the type I neurons. MK801 treated ULX rats showed higher resting activity in the type I and II neurons than in the labyrinthine intact rats or ULX rats, but lower resting activity than the MK801 treated labyrinthine intact rats. In the neuronal activity induced by sinusoidal rotation, gain was the highest in the MK801 treated ULX rats among the 4 experimental groups, and sensitivity was decreased in the type I & II neurons by treatment of MK801. CONCLUSION: These results suggest that MK801 deteriorates asymmetry of the resting activity in the bilateral MVN by inhibition of cerebellar Purkinje system inhibiting the intact MVN, which results in decompensation of the vestibular function following ULX.

Studies on the Vestibular Compensation after Contralateral Labyrinthectomy in Unilateral Labyrinthectomized Rats / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Vestibular compensation is a process of behavioral recovery following unilateral labyrinthectomy (ULX). The neural plasticity in vestibular compensation was assessed by observing changes of behavioral response and c-Fos expression following contralateral labyrinthectomy (second labyrinthectomy) in ULX rats. MATERIAL AND METHODS: Contrala-teral labyrinthectomy was performed 2 weeks after ULX in Sprague-Dawley rats, each weighing 250-300 gm. Changes of spontaneous nystagmus, head tilt, and c-Fos expression in the medial vestibular nucleus (MVN) and nucleus prepositus hypoglossi (PrH) were measured. RESULT: In ULX, spontaneous nystagmus with the slow phase directed to the lesion side was 3.5+/-0.5 beats/sec and head tilt deviated to the lesion side was 71+/-16 degrees just after ULX. Spontaneous nystagmus disappeared within 72 hours, but head tilt was maintained at 28+/-8 degrees until 2 weeks after ULX. The number of c-Fos proteins 2 hours after ULX was 81+/-25 and 212+/-63 in MVN of the lesion side and the intact side, respectively. And PrH showed 136+/-37 in the lesion side and 94+/-19 in the intact side, which was opposite of MVN in spatial expression of c-Fos. In second labyrinthectomy, direction of spontaneous nystagmus and head tilt was opposite to the first ULX and their decrement was faster. c-Fos was expressed more in the MVN of the first labyrinthectomized side than in the second one and PrH showed the opposite pattern to MVN, which was opposite to the first ULX in spatial expression. CONCLUSION: These results suggest that recovery of vestibuloocular reflex in vestibular compensation is accomplished by restoration of neuronal activity in the central nervous system including MVN and PrH.

Effects of electrical stimulation of the vestibular system on neuronal activity of the ipsilateral medial vestibular nuclei following unilateral labyrinthectomy in rats

The purpose of this study was to evaluate the effects of electrical stimulation on vestibular compensation following ULX in rats. Electrical stimulation (ES) with square pulse (100 ~ 300 uA, 1.0 ms, 100 Hz) was applied to ampullary portion bilaterally for 6 and 24 hours in rats receiving ULX. After ES, animals that showed the recovery of vestibular symptoms by counting and comparing the number of spontaneous nystagmus were selected for recording resting activity of type I, II neurons in the medial vestibular nuclei (MVN) of the lesioned side. And then the dynamic neuronal activities were recorded during sinusoidal rotation at a frequency of 0.1 Hz and 0.2 Hz. The number of spontaneous nystagmus was significantly different 24 hours (p< 0.01, n = 10), but not 6 hours after ULX+ES. As reported by others, the great reduction of resting activity only in the type I neurons ipsilateral to lesioned side was observed 6, 24 hours after ULX compared to that of intact labyrinthine animal. However, the significant elevation (p < 0.01) of type I and reduction (p < 0.01) of type II neuronal activity were seen 24 hours after ULX+ES. Interestingly, gain, expressed as maximum neuronal activity(spikes/sec)/maximum rotational velocity (deg/sec), was increased in type I cells and decreased in type II cells 24 hours after ULX+ES in response to sinusoidal rotation at frequencies of both 0.1 Hz and 0.2 Hz. This result suggests that accompanying the behavioral recovery, the electrical stimulation after ULX has beneficial effects on vestibular compensation, especially static symptoms (spontaneous nystagmus), by enhancing resting activity of type I neurons and reducing that of type II neurons.