Early Vestibular Rehabilitation Research Articles

Early vestibular rehabilitation initiation is associated with faster recovery after sport related concussion

ObjectivesVestibular rehabilitation is a recommended treatment after sport related concussion (SRC), but the optimal timing is not fully understood. This research examined the association between the timing of vestibular rehabilitation initiation and recovery time in adolescent patients with SRC. DesignRetrospective cross-sectional. Methods112 patients with SRC were referred to vestibular rehabilitation at a specialty concussion clinic. Vestibular rehabilitation initiation was defined as days from date of injury to date of first vestibular rehabilitation assessment. Patients were dichotomized by vestibular rehabilitation initiation: EARLY (8–10 days) and LATE (>10 days). Recovery time was defined as days between injury and medical clearance from the clinic. Results60 (average age 15.22 ± 1.61 years; 51.7 % male) patients were in the EARLY group and 52 (average age 15.37 ± 1.31 years, 28.9 % male) patients were in the LATE group. There were more female patients in the LATE group (p = 0.01) and the LATE group had their first clinic visit later than the EARLY group (p < 0.02). The EARLY group had shorter recovery time (median 26, IQR [21, 32.5] days) compared to the LATE group (median 31, IQR [23.5, 52.5] days; p = 0.02). After controlling for confounding variables, the LATE group had recovery times that were 1.39 times as long as the EARLY group (p < 0.01). ConclusionsFor patients with vestibular issues after SRC, early vestibular rehabilitation initiation is associated with faster recovery time after SRC. The current study provides clarity on the optimal timing of vestibular rehabilitation after SRC.

Vestibular assessment in children with sensorineural hearing loss: diagnostic accuracy and proposal for a diagnostic algorithm.

Vestibular assessment in children with sensorineural hearing loss (SNHL) is critical for early vestibular rehabilitation therapy to promote (motor) development or guide decision making towards cochlear implantation (timing of surgery and laterality). It can be challenging from a clinical viewpoint to decide which vestibular tests should be performed for a pediatric patient. The aim of this study was to evaluate the diagnostic accuracy of several clinically available vestibular tests in children with SNHL, and to provide recommendations for the implementation of vestibular testing of children in clinical practice, to screen for vestibular hypofunction (VH). A two-center retrospective chart review was conducted. Eighty-six patients between the age of 0 and 18 years were included in this study with SNHL. Vestibular tests included video headimpulse test (VHIT), caloric test (performed at the age of four or higher), rotatory chair and cervical vestibular evoked myogenic potential (cVEMP). A combination of the clinical assessment and (combinations of) vestibular test outcomes determined the diagnosis. The diagnostic quality of tests and combination of tests was assessed by diagnostic accuracy, sensitivity and specificity. VH was diagnosed in 44% of the patients. The VHIT and caloric test showed the highest diagnostic accuracy compared to the rotatory chair and cVEMP. All combinations of VHIT, caloric test and cVEMP showed improvement of the diagnostic accuracy compared to the respective tests when performed singularly. All combinations of tests showed a relatively similar diagnostic accuracy, with the VHIT combined with the caloric test scoring the highest. Adding a third test did not substantially improve the diagnostic accuracy. Vestibular testing is feasible and VH is highly prevalent in children with SNHL. A proposed diagnostic algorithm recommends starting with VHIT, followed by cVEMP for children under the age of four, and caloric testing for older children if VH is not confirmed with the first test. Performing a third test is redundant as the diagnostic accuracy does not improve substantially. However, challenges remain, including the lack of a gold standard and the subjective nature of the diagnosis, highlighting the need for standardized testing and increased understanding of VH in this population.

Early vestibular rehabilitation training of peripheral acute vestibular syndrome-a systematic review and meta-analysis.

This study aimed to investigate the impact of early vestibular rehabilitation training combined with corticosteroids initiated within 2 weeks, compared with corticosteroid treatment, after the peripheral acute vestibular syndrome (pAVS) onset. PubMed, CINAHL, EMBASE, and SCOPUS. From inception to January 24, 2024. The International Prospective Register of Systematic Reviews approved this study (CRD42023422308). Five studies involving 235 patients were included in this systematic review and meta-analysis. The subjective outcome measure Dizziness Handicap Inventory (DHI) was pooled for a meta-analysis and was statistically significantly in favor of early vestibular rehabilitation training (early VRT) plus corticosteroids compared with corticosteroids alone: at one-month follow-up (p = 0.00) and 12 months follow-up (p = 0.01). DHI was a critical outcome for measuring the differences in effect of early VRT. The objective outcome measures of caloric lateralization, cervical vestibular-evoked myogenic potentials, and posturography were gathered for a narrative synthesis. This meta-analysis showed that early VRT in combination with corticosteroids was more effective for treating pAVS than corticosteroid treatment alone. No adverse effects were reported for early VRT.

Effects of Early Vestibular Rehabilitation in Patients With Acute Vestibular Disorder: A Systematic Review and Meta-Analysis.

To investigate the effect of early vestibular rehabilitation on physical function and dizziness in patients with acute vestibular disorders. The electronic databases examined included PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE (via Dialog), and PEDro. The inclusion criteria in terms of the study participants were patients 20 years and older with an acute unilateral peripheral vestibular disorder. We included individual randomized controlled trials (RCTs), cluster-RCTs, quasi-RCTs, and crossover trials. The outcomes were gait, balance (eyes open, eyes close), activities of daily living, dizziness, and vestibular function. Early vestibular rehabilitation was defined as rehabilitation within 14 days of vestibular disorder onset or surgery. Main outcome measures were gait, balance (eyes open, eyes close), activities of daily living, dizziness, and vestibular function. Twelve trials involving 542 participants were included. Early vestibular rehabilitation improved the Dizziness Handicap Inventory by -7.18 (95% confidence interval [CI], -10.48 to -3.88), balance during eyes close by -1.40 (95% CI, -2.42 to -0.39), and dizziness by -1.47 (95% CI, -2.74 to -0.21) compared with no intervention or placebo. The present study demonstrated that early vestibular rehabilitation improved the Dizziness Handicap Inventory, balance (eyes close), and subjective dizziness in a patient with acute vestibular disorders. This result indicates that early vestibular rehabilitation can promote vestibular compensation.

Vestibular rehabilitation improves spontaneous nystagmus normalization in patients with acute unilateral vestibulopathy.

Spontaneous nystagmus (SN) can be observed after acute unilateral vestibulopathy (AUVP). The slow phase eye velocity of the SN progressively decreases in darkness as the result of rebalanced neurophysiological activity between both vestibular nuclei, a process that can take several months. Although this compensatory process can occur spontaneously, there is poor evidence that vestibular rehabilitation (VR) can facilitate the process. We documented the natural time course of SN reduction in patients with AUVP, as well as the effects of VR by means of a unilateral rotation paradigm. In a retrospective study (Study 1: n = 126 AUVP patients), we compared the time course of the SN reduction in patients with VR (n = 33) and without VR (n = 93). In a prospective study (Study 2: n = 42 AUVP patients), we compared the effects of early VR (n = 22; initiated within the first two weeks of symptoms onset) or late VR (n = 20; initiated after the second week of symptoms onset) on the time course of the SN reduction. Study 1 showed shorter median time of SN normalization in patients with VR compared to patients without VR (14 days and 90 days, respectively). Study 2 showed that AUVP patients with early and late VR had a similar median time of SN normalization. The SN slow phase eye velocity was significantly decreased as early as the end of the first VR session in both groups, and kept decreasing at each subsequent VR session. In the early VR group, 38% of the patients had slow phase eye velocity below 2°/s after the first VR session, 100% after the fifth session. Similar findings were observed in the late VR group. Taken together, these results indicate that VR with a unidirectional rotation paradigm speeds up the normalization of SN. This effect seems independent of the time between symptoms onset and commencement of VR, but early intervention is recommended to speed up the SN reduction.

Posture Deficits and Recovery After Unilateral Vestibular Loss: Early Rehabilitation and Degree of Hypofunction Matter.

Postural instability and balance impairment are disabling symptoms in patients with acute unilateral peripheral vestibular hypofunction (UVH). Vestibular rehabilitation (VR) is known to improve the vestibular compensation process, but (1) its effect on posture recovery remains poorly understood, (2) little is known about when VR must be done, and (3) whether the degree of vestibular loss matters is uncertain. We analyzed posture control under static (stable support) and dynamic (unstable support) postural tasks performed in different visual conditions [eye open (EO); eyes closed (EC); and optokinetic stimulation] using dynamic posturography. Non-linear analyses of the postural performance (wavelet transform, diffusion analysis, and fractal analysis) were performed in two groups of patients with UVH subjected to the same VR program based on the unidirectional rotation paradigm and performed either early (first 2 weeks) or later (fifth to the sixth week) after vertigo attack. Distribution of the angular horizontal vestibulo-ocular reflex (aVOR) gain values recorded on the hypofunction side before rehabilitation differentiated two distinct sub-groups (cluster analysis) with aVOR gains below or above 0.20. The postural performance of the four sub-groups of patients with UVH (early rehabilitation with aVOR gain <0.20: n = 25 or gain >0.20: n = 19; late rehabilitation with aVOR gain <0.20: n = 15 or gain >0.20: n = 10) tested before VR showed significantly altered postural parameters compared with healthy controls. Greater instability, higher energy to control posture, larger sway without feedback corrections, and lower time of automatic control of posture were observed in static conditions. The four sub-groups recovered near-normal postural performance after VR in the EO and EC conditions, but still exhibited altered postural performance with optokinetic stimulation. In dynamic posturography conditions and before VR, the percentage of patients able to perform the postural tasks with EC and optokinetic stimulation was significantly lower in the two sub-groups with aVOR gain <0.20. After VR, the improvement of the postural parameters depended on the stage of rehabilitation and the degree of vestibular hypofunction. The best balance function recovery was found in the sub-group with early VR and pre-rehabilitation aVOR gain above 0.20, the worst in the sub-group with late rehabilitation and aVOR gain below 0.20. These differences were seen when the vestibular input remains the main sensory cue to control balance, that is, on unstable support without vision or altered visual motion cues. These findings extend to dynamic balance recovery the crucial roles of early rehabilitation and degree of vestibular hypofunction which we have already highlighted for vestibulo-ocular reflex recovery.

Two conditions to fully recover dynamic canal function in unilateral peripheral vestibular hypofunction patients.

The crucial role of early vestibular rehabilitation (VR) to recover a dynamic semicircular canal function was recently highlighted in patients with unilateral vestibular hypofunction (UVH). However, wide inter-individual differences were observed, suggesting that parameters other than early rehabilitation are involved. The aim of the study was to determine to what extent the degree of vestibular loss assessed by the angular vestibulo-ocular reflex (aVOR) gain could be an additional parameter interfering with rehabilitation in the recovery process. And to examine whether different VR protocols have the same effectiveness with regard to the aVOR recovery. The aVOR gain and the percentage of compensatory saccades were recorded in 81 UVH patients with the passive head impulse test before and after early VR (first two weeks after vertigo onset: N = 43) or late VR (third to sixth week after onset: N = 38) performed twice a week for four weeks. VR was performed either with the unidirectional rotation paradigm or gaze stability exercises. Supplementary outcomes were the dizziness handicap inventory (DHI) score, and the static and dynamic subjective visual vertical. The cluster analysis differentiated two distinct populations of UVH patients with pre-rehab aVOR gain values on the hypofunction side below 0.20 (N = 42) or above 0.20 (N = 39). The mean gain values were respectively 0.07±0.05 and 0.34±0.12 for the lateral canal (p < 0.0001), 0.09±0.06 and 0.44±0.19 for the anterior canal (p < 0.0001). Patients with aVOR gains above 0.20 and early rehab fully recovered dynamic horizontal canal function (0.84±0.14) and showed very few compensatory saccades (18.7% ±20.1%) while those with gains below 0.20 and late rehab did not improve their aVOR gain value (0.16±0.09) and showed compensatory saccades only (82.9% ±23.7%). Similar results were found for the anterior canal function. Recovery of the dynamic function of the lateral canal was found with both VR protocols while it was observed with the gaze stability exercises only for the anterior canal. All the patients reduced their DHI score, normalized their static SVV, and exhibited uncompensated dynamic SVV. Early rehab is a necessary but not sufficient condition to fully recover dynamic canal function. The degree of vestibular loss plays a crucial role too, and to be effective rehabilitation protocols must be carried out in the plane of the semicircular canals.

Audiovestibular neuropathy in an immunocompetent man with cryptococcal meningitis

IntroductionCryptococcus spp. is a fungus responsible for 600,000 deaths per year worldwide, mainly in immunosuppressed subjects. However, 20% of cases occur in immunocompetent subjects. Neuropathic disorders involving the auditory nerve have been reported, but vestibular disorders have never been described in detail. We report the case of an immunocompetent man, who presented audiovestibular disorders leading to a diagnosis of cryptococcal meningitis. Case reportA 39-year-old man was referred for balance disorders and right sensorineural hearing loss. He presented right vestibulo-saccular impairment and bilateral absence of auditory brainstem responses. Brain MRI was suggestive of cryptococcal meningitis. A cystic lesion in the right flocculus compressed the vestibulocochlear nerve. During monthly follow-up, pure tone audiometry gradually improved and speech audiometry in silence returned to normal. Partial resynchronization of the auditory afferent pathways was observed only on the contralateral side to vestibulocochlear nerve compression, while complete recovery of saccular function was observed. DiscussionCryptococcal meningitis in immunocompetent subjects may be accompanied by lesions of the auditory and vestibular afferent pathways. Recovery of hearing and balance was observed in response to medical treatment and early vestibular rehabilitation.

An electronystagmographic study in post head injury vertigo patients

Vertigo is a well-known sequelae in post head injury patients. Etiopathology is multifactorial. Vertigo is recognized in all types of head injury-mild-to-severe and is a part of the post-concussion syndrome. However, it may also present later due to degenerative process involving the vestibular system. The observations made by the analysis of the tracings of electronystagmography and by noting the corresponding code we can identify the site and side of the vestibular lesion. The present study intends to understand post head injury vertigo using electronystagmography. Objectives of the Study: To evaluate post head injury vertigo using electronystagmography, to determine the side and site of origin of vertigo, and to localize the level of lesion – peripheral, central, or combined. Methodology: Fifty patients with post head injury vertigo presenting to ENT OPD of Dr. B. R. Ambedkar Medical College and Hospital were included in the study after taking their consent. Observations and Results: Fifty patients with post head injury vertigo were subjected to electronystagmography. Young adults between the age group of 20 and 30 years were found to be the most common group involved, constituted 34% of the patients. Equal gender predisposition was observed. 1111 ENG CODE was found to be the most common type seen in 18% of the cases, followed by 0000 in 16% of patients, and 0222 seen in 16% of the patients. Bilateral peripheral lesion was the most common type seen in 36% of patients followed by unilateral peripheral lesion in 20% of patients, central lesion in 22%, and normal in 20%. Conclusion: Electronystagmography is an effective tool in the assessment of post head injury vertigo. It is useful in identifying the cause of vertigo and to localize the lesion for timely management and early vestibular rehabilitation of the patient providing better clinical outcome.

Effect of Early Vestibular Rehabilitation on Vertigo and Unsteadiness in Patients with Acute and Sub-Acute Head Trauma.

Vestibular rehabilitation is a treatment option for the management of vertigo and unsteadiness, which are very common in head trauma patients and more challenging in the early months after trauma. This study evaluated the effectiveness of a vestibular rehabilitation program in the recovery of acute and sub-acute head trauma patients. The goal of this study was evaluation of the effect of early vestibular rehabilitation on patients with acute and sub-acute head trauma. This study was performed in 20 head trauma patients with vertigo and unsteadiness. The patients were randomly divided into two groups: one group received medical therapy (Betaserc) and the other received rehabilitation and medical therapy. An individualized vestibular rehabilitation program was designed that was then revised and verified by a joint committee of vestibular rehabilitation groups. The effectiveness of interventions was measured using the Dizziness Handicap Inventory (DHI) by comparing the results before and after therapy. The physical conditions and DHI scores of patients in both groups were similar at baseline. After 1 month of rehabilitation, patients receiving vestibular rehabilitation and medication showed greater progress than patients receiving medication only (P=0.000). Vestibular rehabilitation can aid in the recovery from vertigo and increase the stability of head trauma patients. Simultaneous treatment with medicine and vestibular rehabilitation exercises can result in quicker and better therapeutic effects.

Preliminary evidence of improved cognitive performance following vestibular rehabilitation in children with combined ADHD (cADHD) and concurrent vestibular impairment

ObjectiveBalance function has been reported to be worse in ADHD children than in their normal peers. The present study hypothesized that an improvement in balance could result in better cognitive performance in children with ADHD and concurrent vestibular impairment. This study was designed to evaluate the effects of comprehensive vestibular rehabilitation therapy on the cognitive performance of children with combined ADHD and concurrent vestibular impairment. MethodsSubject were 54 children with combined ADHD. Those with severe vestibular impairment (n=33) were randomly assigned to two groups that were matched for age. A rehabilitation program comprising overall balance and gate, postural stability, and eye movement exercises was assigned to the intervention group. Subjects in the control group received no intervention for the same time period. Intervention was administered twice weekly for 12 weeks. Choice reaction time (CRT) and spatial working memory (SWM) subtypes of the Cambridge Neuropsychological Test Automated Battery (CANTAB) were completed pre- and post-intervention to determine the effects of vestibular rehabilitation on the cognitive performance of the subjects with ADHD and concurrent vestibular impairment. ANCOVA was used to compare the test results of the intervention and control group post-test. ResultsThe percentage of correct trial scores for the CRT achieved by the intervention group post-test increased significantly compared to those of the control group (p=0.029). The CRT mean latency scores were significantly prolonged in the intervention group following intervention (p=0.007) compared to the control group. No significant change was found in spatial functioning of the subjects with ADHD following 12 weeks of intervention (p>0.05). ConclusionThe study highlights the effect of vestibular rehabilitation on the cognitive performance of children with combined ADHD and concurrent vestibular disorder. The findings indicate that attention can be affected by early vestibular rehabilitation, which is a basic program for improving memory function in such children. Appropriate vestibular rehabilitation programs based on the type of vestibular impairment of children can improve their cognitive ability to some extent in children with ADHD and concurrent vestibular impairment (p>0.05).

Interaction between Vestibular Compensation Mechanisms and Vestibular Rehabilitation Therapy: 10 Recommendations for Optimal Functional Recovery.

This review questions the relationships between the plastic events responsible for the recovery of vestibular function after a unilateral vestibular loss (vestibular compensation), which has been well described in animal models in the last decades, and the vestibular rehabilitation (VR) therapy elaborated on a more empirical basis for vestibular loss patients. The main objective is not to propose a catalog of results but to provide clinicians with an understandable view on when and how to perform VR therapy, and why VR may benefit from basic knowledge and may influence the recovery process. With this perspective, 10 major recommendations are proposed as ways to identify an optimal functional recovery. Among them are the crucial role of active and early VR therapy, coincidental with a post-lesion sensitive period for neuronal network remodeling, the instructive role that VR therapy may play in this functional reorganization, the need for progression in the VR therapy protocol, which is based mainly on adaptation processes, the necessity to take into account the sensorimotor, cognitive, and emotional profile of the patient to propose individual or “à la carte” VR therapies, and the importance of motivational and ecologic contexts. More than 10 general principles are very likely, but these principles seem crucial for the fast recovery of vestibular loss patients to ensure good quality of life.

Betahistine Dihydrochloride With and Without Early Vestibular Rehabilitation for the Management of Patients With Balance Disorders Following Head Trauma: A Preliminary Randomized Clinical Trial

ObjectiveThe purpose of this study was to compare the effect of betahistine dihydrochloride alone and in combination with vestibular rehabilitation for the management of patients with balance disorders following head trauma. MethodsIn this preliminary clinical trial, a group of patients with head trauma was referred to our university-based tertiary care balance unit over a 1-year period. The study included 60 patients with balance disorder following head trauma. Patients were randomly divided into 3 groups with 20 patients each. The first group was treated by betahistine dihydrochloride tablets 48 mg/d alone. The second group was treated with a standard vestibular rehabilitation program. The third group was given betahistine dihydrochloride tablets (48 mg/d) in addition to the early standard vestibular rehabilitation program. Videonystagmography was used in the diagnosis, characterization, and monitoring of all patients with balance disorders, with improvement of the pretreatment objective results taken as a marker for treatment progress. ResultsRecovery time was within the first 3 months following head trauma in 57 (95%) of the patients. Recovery was faster after mild head trauma than after moderate and severe traumas. Patients who underwent vestibular rehabilitation immediately after the onset of head trauma (with or without addition of betahistine dihydrochloride) recovered earlier than those treated with betahistine dihydrochloride alone. ConclusionBased on these preliminary findings in a small group of patients, early vestibular rehabilitation with the concomitant use of betahistine dihydrochloride showed better results than the other 2 treatments alone in patients with balance disorders following head trauma. Early vestibular rehabilitation seemed to improve recovery that was enhanced by the use of betahistine dihydrochloride, and may have depressed the associated adverse effects such as nausea and vomiting.

Early rehabilitation for unilateral peripheral vestibular disorders: a prospective, randomized investigation using computerized posturography

Patients with unilateral vestibular lesions have a set of deficits requiring compensation based on the inherent plasticity of the central nervous system. In the 1940s, it was reported that patients with unilateral vestibular dysfunctions who exercised recovered faster than those who did not. The present prospective, randomized investigation aimed to assess the role of a computerized posturography-assisted early vestibular rehabilitation protocol combined with a home-based exercise program in the treatment of patients with unilateral peripheral vestibular disorders occurring 2 weeks previously. Fifteen patients were randomly assigned to a 5-week posturography-assisted vestibular rehabilitation protocol and a home-based exercise program (Group A), while 15 simply awaited spontaneous compensation (Group B). All patients underwent computerized posturography approximately 2 weeks after their vestibular disorder was diagnosed and again after 6 weeks. Ten healthy volunteers were also studied (Group C). After rehabilitation, Group A patients improved significantly in most sensory measures [modified clinical test of sensory organization and balance (mCTSIB)] and motor parameters [limits of stability (LOS)] by comparison with preliminary outcomes, and there were no significant differences in sensory (mCTSIB) and motor (LOS) findings between Group A and the healthy volunteers. At the same time point, several motor (LOS) parameters were still altered in Group B by comparison with the healthy volunteers. These preliminary outcomes support the hypothesis that the compensation achievable after 6 weeks with a customized program of posturography-assisted vestibular rehabilitation and home-based exercises is superior to the results of physiological spontaneous compensation.

The effect of early customized vestibular rehabilitation on balance after acoustic neuroma resection

Objective: To compare the effect of early customized vestibular rehabilitation with general instructions in patients after acoustic neuroma surgery. Setting: Tertiary referral centre. Subjects: Fifty-three patients after surgery. Design: A prospective assessor-blinded, randomized controlled trial. Interventions: After stratification for age (<50 years; ≥50 years), patients were randomly allocated into groups receiving general instructions or customized vestibular rehabilitation protocols for 12 weeks. Outcome measures: Standing Balance Sum, Timed Up and Go test, Tandem Gait and Dynamic Gait Index. Balance performance was assessed preoperatively, at discharge (one week after surgery), three, six, nine, 12, 26 and 52 weeks after surgery. Results and discussion: All subjects clearly improved within the first six weeks after surgery. However, older subjects receiving vestibular rehabilitation performed significantly (P<0.05) better on standing balance, Timed Up and Go test and Tandem Gait, when compared with the older group that received only general instructions. This effect persisted up to 12 weeks and also became apparent on the Dynamic Gait Index. In addition, the older vestibular rehabilitation group had better balance scores at 12 weeks when compared with their original preoperative scores (P<0.05). This pattern remained even up to one year after surgery (P<0.05). Conclusion: In patients over 50, early vestibular rehabilitation facilitates recovery of postural control after acoustic neuroma surgery. Customized vestibular rehabilitation should be given in addition to general instructions that stress the need of exposure to movement. Retention of the early beneficial effects even one year after surgery stresses the importance of customized vestibular rehabilitation.

Recovery after early vestibular rehabilitation in patients with acute unilateral vestibular loss

The aims of this study were to follow the recovery process, and explore the disease impact on sick leave in patients with acute unilateral vestibular loss (AUVL). Another aim was to investigate whether initial signs of nystagmus, caloric response, and subjective symptoms of vertigo could predict the return to work. Recovery was followed through the reduction in spontaneous and head-shaking nystagmus, evaluated by Video-Frenzel examination, and by caloric response/asymmetry and spontaneous nystagmus, evaluated by bithermal binaural caloric testing. Information regarding employment, sick leave and subjective symptoms of vertigo was collected using a questionnaire. Twenty-seven patients with AUVL participated in a physiotherapy training programme, starting within 48 h of disease onset. Four assessments were performed: at disease onset, in the acute stage, and after one and six months. In most patients a very rapid cessation of spontaneous nystagmus could be observed (14/27 at a median time of two days after ...