[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.

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.

Diagnosing and localizing the acute vestibular syndrome - Beyond the HINTS exam.

When assessing the acutely dizzy patient, the HINTS 'Plus' (Head Impulse, Nystagmus, Test of Skew, 'Plus' a bedside assessment of auditory function) exam is a crucial component of the bedside exam. However, there are additional ocular motor findings that can help the clinician distinguish peripheral from central etiologies and enable accurate localization, especially when the patient has acute dizziness, vertigo and/or imbalance but without spontaneous nystagmus. We will review the literature on these findings which are 'beyond HINTS' and include saccades/ocular lateropulsion, smooth pursuit, and provocative maneuvers including head-shaking and positional testing (not part of the HINTS exam). Additionally, we will expound on the localizing value of nystagmus, ocular alignment and the ocular tilt reaction (parts of the HINTS exam). The paper has been organized neuroanatomically, based on brainstem and cerebellar structures that have been reported to cause the acute vestibular syndrome.

Head-shaking-induced nystagmus reflects dynamic vestibular compensation: A 2-year follow-up study.

Purpose: We aimed to assess the ability of a head-shaking test (HST) to reflect vestibular compensation in patients after unilateral peripheral vestibular loss and to provide missing evidence and new insights into the features of head-shaking-induced nystagmus (HSN) over a 2-year follow-up. Background: HSN may occur after a prolonged sinusoidal oscillation of the head. HSN is frequently observed in subjects with vestibular function asymmetry; it usually beats toward the functionally intact or "stronger" ear and can be followed by a reversal of its direction. Study design: A prospective observational case-control study. Settings: A tertiary academic referral center. Methods: A total of 38 patients after acute unilateral vestibular loss (22 patients with vestibular neuronitis and 16 patients after vestibular neurectomy) and 28 healthy controls were followed for four consecutive visits over a 2-year period. A complex vestibular assessment was performed on all participants, which included spontaneous nystagmus (SPN), the caloric test, the head-shaking test (HST), the video head impulse test (vHIT), the Timed Up and Go (TUG) test, and the Dizziness Handicap Inventory (DHI) questionnaire. We established the criteria for the poorly compensated group to assess different compensatory behaviors and results. Results: We found a time-related decrease in HSN (ρ < -0.84, p < 0.001) after unilateral vestibular loss. After 2 years of follow-up, HSN intensity in compensated patients reached the level of the control group; TUG and DHI also improved to normal; however, the caloric and vHIT tests remained abnormal throughout all follow-ups, indicating a chronic vestibular deficit. Besides, poorly compensated patients had a well-detectable HSN throughout all follow-ups; TUG remained abnormal, and DHI showed at least a moderate deficit. Conclusions: Our study showed that, after a unilateral peripheral vestibular loss, the intensity of HSN decreased exponentially over time, reflecting an improvement in dynamic ability and self-perceived deficit. HSN tended to decline to the value of the control group once vestibular compensation was satisfactory and sufficient for a patient's everyday life. In contrast, well-detectable HSN in poorly compensated patients with insufficient clinical recovery confirmed the potential of HSN to reflect and distinguish between adequate and insufficient dynamic compensation. HSN could serve as an objective indicator of stable unilateral vestibular loss.

[The occurrence and evaluation methods of horizontal semicircular canal dysfunction in patients with common vestibular diseases].

Objective:To understand the occurrence of horizontal semicircular canal functional impairment in patients with common vestibular diseases and to explore the characteristics and clinical value of different evaluation methods of horizontal semicircular canal. Methods:From July 2013 to December 2016, patients who attended the vertigo clinic of the First Affiliated Hospital of Dalian Medical University and completed more than three horizontal semicircular canal function tests were retrospectively analyzed. A total of 396 patients diagnosed as vestibular migraine （VM）, Ménière's disease （MD）, benign paroxysmal positional vertigo （BPPV）, vestibular neuritis （VN） and 104 patients with unknown diagnosis were enrolled. The results of caloric test （CT）, rotation test （RT）, head-shaking nystagmus test （HSN） and video head impulse test （vHIT） were collected and the abnormal detection rates of different detection methods were calculated. The sensitivity, specificity and coincidence rate of various detection methods were statistically analyzed using CT as the gold standard. Results:①The abnormal rates of the four evaluation methods from high to low were HSN, CT, RT, vHIT （51.20%, 50.80%, 25.76%, 19.74%, respectively）; ②Taking CT as the gold standard, among these four common vestibular diseases, the sensitivity and specificity of vHIT were 0.13-0.41 and 0.69-1.00, the sensitivity and specificity of HSN were 0.44-0.76 and 0.29-0.69, and the sensitivity and specificity of RT were 0.25-0.45 and 0.50-0.84;③According to statistical analysis, only HSN and CT results showed no statistically significant difference in the 4 diseases. There was no significant difference between RT and CT in VM and BPPV, and vHIT and CT in BPPV. Conclusion:The abnormal rate of HSN results in common vestibular diseases is highest, and it could be recommended as a routine vestibular function screening item. The specificity of vHIT is highest and worthy of promotion. CT is still an irreplaceable method to evaluate the function of horizontal semicircular canal.

Is There an "Acquired Idiopathic Head-Shaking Nystagmus"?-A Discussion of Mechanisms and Clinical Implications Based on a Case Report.

Background: Head-shaking nystagmus (HSN) occurs in both peripheral and central vestibular disorders. In most cases, HSN can be attributed to an asymmetric peripheral vestibular input or a structural lesion mostly in the cerebellum affecting the central velocity storage mechanism. An isolated HSN is very rare. Case Presentation: We report on a young female patient with the clinical picture of recurrent episodes of vertigo, which were induced by fast head movements and were accompanied by a severe right-beating HSN with a long time constant of 60 s. There was no other clinical and instrument-based evidence of peripheral vestibular dysfunction (including video head impulse test, caloric test, vestibular-evoked myogenic potentials) or indication of a structural lesion in the nodulus, uvula or pontomedullary brainstem on fine-slice magnetic resonance imaging. She had no previous history of migraine, hearing deficits, or other focal neurological symptoms. Diagnostic criteria for vestibular paroxysmia, vestibular migraine, benign peripheral paroxysmal vertigo, or any other known vestibular disorders were not fulfilled. Chart review in the database of the German Center for Vertigo and Balance Disorders indicated eight additional patients with a similar clinical phenotype between 2018 and 2022. Conclusion: We propose a clinical entity called acquired idiopathic head shaking nystagmus (aiHSN) as a rare cause of episodic vertigo induced by fast head movements. Nystagmus characteristics suggest a subtle functional pathology of the central velocity storage mechanism in the nodulus and uvula, which is exacerbated during symptomatic episodes.

Head-Shaking Nystagmus in Posterior Canal Benign Paroxysmal Positional Vertigo with Canalolithiasis.

BACKGROUND: There have been several studies about head-shaking nystagmus (HSN) in posterior canal benign paroxysmal positional vertigo (PC-BPPV). The purpose of the study was to determine the characteristics of HSN and its relationship with head-bending nystagmus (HBN) and lying-down nystagmus (LDN) in PC-BPPV and to suggest a possible pathomechanism of HSN based on these findings. METHODS: During the study period, 992 patients with BPPV were initially enrolled. After excluding horizontal or anterior canal BPPV, multiple canals involvement, secondary causes of BPPV, identifiable central nervous system (CNS) disorders, unidentifiable lesion side, or poor cooperation, 240 patients with unilateral PC-BPPV were enrolled. We assessed the frequency, pattern of HSN, and correlation with other induced nystagmus after positional maneuvers such as head bending, lying down, head-turning, and Dix-Hallpike test. RESULTS: Approximately 32% of patients with PC-BPPV showed HSN. Among patients with HSN, approximately 61% of patients showed predominantly downbeat nystagmus, and two-third of them had a torsional component. The torsional component was mostly directed to the contralesional side. Horizontal nystagmus (36%) and upbeat nystagmus (3%) were also observed after head-shaking in PC-BPPV. The presence of HSN was significantly correlated with that of HBN in PC-BPPV (p = 0.00). The presence of a torsional component of HSN was also significantly correlated with that of HBN in PC- BPPV (p = 0.00). DISCUSSION: Perverted HSN, a typical sign of central vestibulopathy, is common in posterior canal BPPV and related to HBN. For generating HSN in PC-BPPV, the otolithic movements related to the endolymph dynamics seem to be more important than the velocity storage mechanism.

Vestibular and Ocular Motor Properties in Lateral Medullary Stroke Critically Depend on the Level of the Medullary Lesion.

Background: Lateral medullary stroke (LMS) results in a characteristic pattern of brainstem signs including ocular motor and vestibular deficits. Thus, an impaired angular vestibulo-ocular reflex (aVOR) may be found if the vestibular nuclei are affected. Objective: We aimed to characterize the frequency and pattern of vestibular and ocular-motor deficits in patients with LMS. Methods: Patients with MR-confirmed acute/subacute unilateral LMS from a stroke registry were included and a bedside neuro-otological examination was performed. Video-oculography and video-based head-impulse testing (vHIT) was obtained and semicircular canal function was determined. The lesion location/extension as seen on MRI was rated and involvement of the vestibular nuclei was judged. Results: Seventeen patients with LMS (age = 59.4 ± 14.3 years) were included. All patients had positive H.I.N.T.S. vHIT showed mild-to-moderate aVOR impairments in three patients (ipsilesional = 1; ipsilesional and contralesional = 1; contralesional = 1). Spontaneous nystagmus (n = 10/15 patients) was more often beating contralesionally than ipsilesionally (6 vs. 3) and was accompanied by upbeat nystagmus in four patients. Head-shaking nystagmus was noted in seven subjects, ipsilesionally beating in six and down-beating in one. On brain MRI, damage of the most caudal parts of the medial and/or inferior vestibular nucleus was noted in 13 patients. Only those two patients with lesions affecting the rostral medulla oblongata demonstrated an ipsilaterally impaired aVOR. Conclusions: While subtle ocular motor signs pointed to damage of the central-vestibular pathways in all 17 patients, aVOR deficits were infrequent, restricted to those patients with rostral medullary lesions and, if present, mild to moderate only. This can be explained by lesions located too far caudally and too far ventrally to substantially affect the vestibular nuclei.

Clinical implications of head-shaking nystagmus in central and peripheral vestibular disorders: is perverted head-shaking nystagmus specific for central vestibular pathology?

BACKGROUND AND PURPOSE: The patterns of head-shaking nystagmus (HSN) aid in differentiation between central and peripheral vestibular disorders, and perverted HSN (pHSN) has been considered a central sign. The aim was to determine the characteristics of HSN in a large number of patients with either peripheral or central vestibular disorders in a dizziness clinic of a university hospital. METHODS: The medical records of 7544 dizzy patients were reviewed during a year and 822 patients with a clinical diagnosis of vestibular disorders were recruited. The findings of spontaneous nystagmus (SN) and HSN in these patients were compared with those of healthy controls (n = 48). RESULTS: A total of 217 of the 822 patients (26.4%) were classified as having a central vestibular disorder, whilst 397 (48.3%) had a peripheral vestibular disorder. In the peripheral vestibular disorder group, SN was observed in 14.1% and HSN in 40.8%, amongst whom 24.1% were the pHSN form. In the central group, SN was observed in 17.5% and HSN in 24.0% of whom 57.7% was pHSN. HSN was more frequently observed in the peripheral vestibular disorder group than in the central group (40.8% vs. 24.0%, P < 0.01). However, the proportion of pHSN was significantly increased in the central group compared to the peripheral vestibular patient group (57.7% vs. 24.1%, P < 0.01). CONCLUSIONS: Since pHSN is not specific for central vestibular disorders, other clinical features should be considered in pursuing a central lesion in patients with pHSN.

Abnormal Oculomotor Functions in Amyotrophic Lateral Sclerosis.

BACKGROUND AND PURPOSE: Although traditionally regarded as spared, a range of oculomotor dysfunction has been recognized in amyotrophic lateral sclerosis (ALS) patients. ALS is nowadays considered as a neurodegenerative disorder of a third compartment comprising widespread areas of extra-motor brain including cerebellum. Our objective was to perform an observational study to examine for ocular motor dysfunction in patients with ALS and for any differences between bulbar-onset and spinal-onset patients. METHODS: Thirty two ALS patients (bulbar onset: 10, spinal onset: 22) underwent the standardized systemic evaluations using video-oculography. RESULTS: Oculomotor dysfunctions such as square wave jerks, saccadic dysmetria, abnormal cogwheeling smooth pursuits and head shaking and positional nystagmus of central origin have been observed in the ALS patients at a relatively early stage. Abnormal smooth pursuits and saccadic dysmetria were increased in the bulbar-onset compared to the spinal-onset (p<0.05). CONCLUSIONS: These oculomotor abnormalities may be a marker of neuro-degeneration beyond motor neurons in ALS, especially in bulbar-onset disease. Future longitudinal studies of eye movement abnormalities have provided insights into the distribution and nature of the disease process.

Abnormal Oculomotor Functions in Amyotrophic Lateral Sclerosis

BACKGROUND AND PURPOSE: Although traditionally regarded as spared, a range of oculomotor dysfunction has been recognized in amyotrophic lateral sclerosis (ALS) patients. ALS is nowadays considered as a neurodegenerative disorder of a third compartment comprising widespread areas of extra-motor brain including cerebellum. Our objective was to perform an observational study to examine for ocular motor dysfunction in patients with ALS and for any differences between bulbar-onset and spinal-onset patients. METHODS: Thirty two ALS patients (bulbar onset: 10, spinal onset: 22) underwent the standardized systemic evaluations using video-oculography. RESULTS: Oculomotor dysfunctions such as square wave jerks, saccadic dysmetria, abnormal cogwheeling smooth pursuits and head shaking and positional nystagmus of central origin have been observed in the ALS patients at a relatively early stage. Abnormal smooth pursuits and saccadic dysmetria were increased in the bulbar-onset compared to the spinal-onset (p < 0.05). CONCLUSIONS: These oculomotor abnormalities may be a marker of neuro-degeneration beyond motor neurons in ALS, especially in bulbar-onset disease. Future longitudinal studies of eye movement abnormalities have provided insights into the distribution and nature of the disease process.

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.

Spontaneous, headshaking, and positional nystagmus in post-lateral medullary infarction dizziness.

BACKGROUND AND PURPOSE: Lateral medullary infarction (LMI) sometimes causes long-lasting dizziness. However, the characteristics of nystagmus in patients with post-LMI dizziness are unknown. We undertook a prospective, comparative study of nystagmus in patients with and without post-LMI dizziness to determine the characteristic pattern of nystagmus of chronic post-LMI dizziness. METHODS: We evaluated and compared nystagmus under spontaneous, head-shaking, and positional testing conditions in 12 patients with post-LMI dizziness and in 6 patients without post-LMI dizziness. RESULTS: In the dizziness group, contralateral spontaneous nystagmus, ipsilateral head-shaking nystagmus, and horizontal direction-changing geotropic positional nystagmus were observed in patients in whom the LMI had occurred <60days previously (subacute period). In patients with dizziness in whom the LMI had occurred >90days previously (chronic period), the nystagmus was ipsilateral under all conditions. In the non-dizziness group, ipsilateral nystagmus was observed in 1 of the 2 subacute patients only after head-shaking and in 1 of the 4 chronic patients only during positional testing. CONCLUSIONS: Ipsilateral nystagmus observed under all spontaneous, head-shaking, and positional testing conditions characterizes chronic post-LMI dizziness.

Characteristics and mechanism of perverted head-shaking nystagmus in central lesions: Video-oculography analysis.

OBJECTIVE: Perverted downbeat head-shaking nystagmus (pdHSN) has been considered a sign of central pathology. Two hypotheses have been advanced as the mechanisms of pdHSN without proper validation. This study aimed to elucidate the mechanism of pdHSN. METHODS: Eighteen patients with pdHSN due to central lesions were subjected to analyses of their oculographic characteristics. The peak velocity, temporal features including the duration and time constant (TC), rotational axis of pdHSN were analyzed. To determine the most relevant mechanism of pdHSN, we compared the TCs of pdHSN with those of downbeat nystagmus after vertical head-shaking in four subjects, and with the TCs of horizontal head-shaking nystagmus (HSN) in three subjects who had both horizontal and downbeat nystagmus after head-shaking. RESULTS: The duration of pdHSN ranged from 14 to 25s and the estimated TC was from 3.9 to 7.8s. When the data were pooled after the intensities of the nystagmus in each patient were normalized, the TC was 5.2 (95% CI=5.0-5.4) seconds from nonlinear regression test. The rotational vectors of pdHSN (n=8) were mostly aligned between the anterior semicircular canals. The estimated TC of downbeat nystagmus after vertical head-shaking (5.8s) was similar to that of pdHSN (6.0s) in four subjects tested. In contrast, the TC of horizontal HSN (10.9s) was significantly larger than that of pdHSN (4.9s) in three subjects. CONCLUSIONS: The characteristics of TCs of HSN in our patients with central lesions suggest that pdHSN is due to enhanced activities of the central anterior canal pathway. SIGNIFICANCE: pdHSN is a sign indicative of central pathology causing cerebellar dysfunction, especially when it associated with other neuro-otological signs.

Vestibular asymmetry increases double support time variability in a counter-balanced study on elderly fallers.

Vestibular asymmetry is a common cause of dizziness in the elderly, for whom it precipitates the risk of falling. Previous studies have shown that those with vestibular asymmetry displayed an altered variability in double support time (DST) compared to controls. However, swing time (SwT) variability findings are conflicting. In this study, we investigated if vestibular asymmetry might be causally connected to increased DST variability. We studied a group of eight elderly fallers with wrist fractures across three months, during which time four of them regained vestibular symmetry while four others developed an asymmetry. We evaluated the variability of DST and SwT, both when the participants suffered from vestibular asymmetry and when they did not. On average, variability in DST was significantly greater by 2.38%CV (coefficient of variation) when participants scored positive for vestibular asymmetry compared to when not, t(5)=4.39, p=0.01, ξ=1.67. In contrast, SwT variability differed non-significantly by 0.44%CV when participants had tested positive versus negative for vestibular asymmetry, t(5)=-0.87, p=0.39, ξ=-0.29. As a possible rationale for our results, we propose that increased DST variability may be the result of a re-stabilization strategy. Further research on DST variability and its correlation to the duration of vestibular asymmetry is recommended.

Perverted Head-Shaking and Positional Downbeat Nystagmus in Essential Tremor.

Even though the pathophysiology is not completely understood, cerebellar dysfunction has been invoked in essential tremor (ET). We evaluated cerebellar dysfunction in ET with the presence of perverted head-shaking (pHSN) and positional downbeat nystagmus (pDBN) which are known to reflect cerebellar dysfunction. First, we reviewed the videooculography (VOG) of 185 patients with ET from March 2007 to April 2010. Seventeen of 28 patients with pHSN and pDBN were followed up for at least a 1.8-year interval from baseline to determine the clinical course. And then, we recruited 52 consecutive patients with ET and compared their ocular motor findings with 51 normal controls using VOG. Among the 185 patients with ET, 28 (15.1 %) showed pHSN (n = 23, 12.4 %) or pDBN (n = 8, 4.3 %). Seventeen of them who were followed up did not develop Parkinsonism or other neurologic deficits during the observation period. The subsequent case-control study showed a higher prevalence of pHSN or pDBN (11/52, 21.2 %, pHSN in nine and pDBN in five) in patients with ET than in the normal controls (2/51, 3.9 %, pHSN only, P = 0.015). The tremor rating scale or involved body sites did not differ between the patients with and without pHSN/pDBN. pHSN and pDBN were more common in patients with ET than in the normal controls. This result supports that cerebellar dysfunction is associated with ET.

[A clinical study into the vestibular function and therapy of patients with chronic positional symptoms after acute vestibular syndrome].

Objective:To investigate the status of the vestibular function of the patients with chronic positional symptoms after peripheral acute vestibular syndrome (AVS) and the curative effect of the vestibular rehabilitation therapy (VRT). Method:Using caloric test (CT), head shaking nystagmus test (HST), cervical vestibular evoked myogenic potentials as well as ocular vestibular evoked myogenic potentials to estimate the function of semicircular canal and otolith organs. The patients with normal VEMPs are divided as Group A. Otherwise are as Group B. Both groups are treated with VRT. The curative effect is estimated by vestibular symptom index (VSI) and Berg balance scale (BBS). Result:Thirty-three of 37 patients (86.5%) had an abnormal result of CT and HST, with 23 of these patients (65.7%) had an abnormal of both test. Twenty-two patients (59.5%) were in Group A and 15 (40.5%) in Group B. Before the therapy, Group B had a higher score of the balance and dizziness symptoms of VSI (P<0.05), and Group A had a higher score of the BBS (P<0.05). After the therapy, the VSI scores of both groups dropped and scores of the BBS raised. Conclusion:Patients with chronic positional symptoms after peripheral AVS have dynamic vestibular lesions to different extents. Those with otolith organs lesions tend to have a worse function of balance. Nevertheless, patients have a better off after VRT.

A clinical study into the vestibular function and therapy of patients with chronic positional symptoms after acute vestibular syndrome / 临床耳鼻咽喉头颈外科杂志

Objective:To investigate the status of the vestibular function of the patients with chronic positional symptoms after peripheral acute vestibular syndrome (AVS) and the curative effect of the vestibular rehabilitation therapy (VRT). Method:Using caloric test (CT), head shaking nystagmus test (HST), cervical vestibular evoked myogenic potentials as well as ocular vestibular evoked myogenic potentials to estimate the function of semicircular canal and otolith organs. The patients with normal VEMPs are divided as Group A. Otherwise are as Group B. Both groups are treated with VRT. The curative effect is estimated by vestibular symptom index (VSI) and Berg balance scale (BBS). Result:Thirty-three of 37 patients (86.5%) had an abnormal result of CT and HST, with 23 of these patients (65.7%) had an abnormal of both test. Twenty-two patients (59.5%) were in Group A and 15 (40.5%) in Group B. Before the therapy, Group B had a higher score of the balance and dizziness symptoms of VSI (P<0.05), and Group A had a higher score of the BBS (P<0.05). After the therapy, the VSI scores of both groups dropped and scores of the BBS raised. Conclusion:Patients with chronic positional symptoms after peripheral AVS have dynamic vestibular lesions to different extents. Those with otolith organs lesions tend to have a worse function of balance. Nevertheless, patients have a better off after VRT.

Increased double support variability in elderly female fallers with vestibular asymmetry.

There is a broad consensus on the coupling of deteriorating gait and vestibular asymmetry, which has proved predictive of falls in the elderly. To date, research on this coupling remains inconclusive and has not focused specifically on fallers. In the present study, differences in gait variability were examined in a population of elderly females with fall-related wrist fractures, divided into samples with positive (N=28, 73±9 years) and negative head-shaking tests (N=6, 67±9 years). Swing, stance, and double support time variability were measured in preferred speed walking using GAITRite(®) and statistically evaluated in multivariate analysis of covariance with age as covariate. Results showed overall greater gait variability for the positive nystagmus group (p=0.03) despite non-significant adjustment of the covariate (p=0.18). In post-hoc analysis, the effect on variability in double support time emerged as a significant and large contributor to this difference (p=0.009, ηp(2)=0.20). Conversely, the ability of swing and stance time variability to discriminate between groups was both non-significant and small (p=0.25, ηp(2)=0.04 and p=0.34, ηp(2)=0.03 respectively). We believe that the increased variability might stem from a strategic use of double support to re-stabilize from balance perturbations during gait. To some extent, these results diverge from previous findings and need to be reassessed in future studies.