Gravity-Dependent Modulation of Downbeat Nystagmus and Subjective Visual Vertical in the Roll Plane.

Downbeat nystagmus (DBN) is the most common form of acquired central vestibular nystagmus. Gravity perception in patients with DBN has previously been investigated by means of subjective visual straight ahead (SVA) and subjective visual vertical (SVV) in the pitch and roll planes only during whole-body tilts. To our knowledge, the effect of head tilt in the roll plane on the SVV and on DBN has not yet been systematically studied in patients. In this study, we investigated static and dynamic graviceptive function in the roll-plane in patients with DBN (patients) and healthy-controls (controls) by assessment of the Subjective Visual Vertical (SVV) and the modulation of slow-phase-velocity (SPV) of DBN. SPV of DBN and SVV were tested at different head-on trunk-tilt positions in the roll-plane (0°,30° clockwise (cw) and 30° counterclockwise (ccw)) in 26 patients suffering from DBN and 13 controls. In patients, SPV of DBN did not show significant modulations at different head-tilt angles in the roll-plane. SVV ratings did not differ significantly between DBN patients vs. controls, however patients with DBN exhibited a higher variability in mean SVV estimates than controls. Our results show that the DBN does not exhibit any modulation in the roll-plane, in contrast to the pitch-plane. Furthermore, patients with DBN show a higher uncertainty in the perception of verticality in the roll-plane in form of a higher variability of responses.

Seasonality of benign paroxysmal positional vertigo : A retrospective study from Central Europe.

BACKGROUND: Although benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo in clinical practice, factors influencing the pathophysiology remain not fully understood. OBJECTIVE: Here we aim to investigate possible seasonal influences on the occurrence of BPPV in Vienna, a city located in a Central European country with pronounced seasonal fluctuations. METHODS: We retrospectively investigated data from 503 patients presenting with BPPV to the outpatient clinics of the Medical University of Vienna between 2007 and 2012. Analyses included age, gender, type of BPPV, seasonal assignment, as well as daylight hours and the temperature in Vienna at symptom onset. RESULTS: Out of 503 patients (159 male, 344 female, ratio 1:2.2; mean age 60 ± 15.80 years), most patients presented with posterior (89.7%) and left-sided (43.1%) BPPV. There was a significant seasonal difference (χ2 p = 0.036) with the majority of symptoms occurring in winter seasons (n = 142), followed by springtime (n = 139). Symptom onset did not correlate with the average temperature (p = 0.24) but on the other hand very well with daylight hours (p < 0.05), which ranged from 8.4 h per day in December, to an average of 15.6 h in July. CONCLUSION: Our results show a seasonal accumulation of BPPV during winter and springtime, which is in line with previous studies from other climatic zones, suggesting an association of this seasonality with varying vitamin D levels.

Cupulolithiasis as an Alternative Mechanism for Pseudo-spontaneous Nystagmus in Horizontal Canal Benign Paroxysmal Positional Vertigo.

Benign paroxysmal positional vertigo of the horizontal semicircular canal may present a differential diagnostic challenge. In addition to the classical positional nystagmus, a persistent nystagmus in a seated position occasionally occurs, so-called pseudo-spontaneous nystagmus (PSN), which can be mistaken for a central or peripheral spontaneous nystagmus. We report a case with cupulolithiasis of the horizontal semicircular canal presenting with horizontal PSN in a sitting position, with implications for a new pathomechanism of PSN.

Ocular Motor Abnormalities in Anti-IgLON5 Disease.

Objective: Anti-IgLON5 disease forms an interface between neuroinflammation and neurodegeneration and includes clinical phenotypes that are often similar to those of neurodegenerative diseases. An early diagnosis of patients with anti-IgLON5 disease and differentiation from neurodegenerative diseases is necessary and may have therapeutic implications. Methods: In our small sample size study we investigated oculomotor function as a differentiating factor between anti-IgLON5 disease and neurodegenerative disorders. We examined ocular motor and vestibular function in four patients suffering from anti-IgLON5 disease using video-oculography (VOG) and a computer-controlled rotational chair system (sampling rate 60 Hz) and compared the data with those from ten age-matched patients suffering from progressive supranuclear palsy (PSP) and healthy controls (CON). Results: Patients suffering from anti-IgLON5 disease differed from PSP most strikingly in terms of saccade velocity and accuracy, the presence of square wave jerks (SWJ) (anti-IgLON5 0/4 vs. PSP 9/10) and the clinical finding of supranuclear gaze palsy (anti-IgLON5 1/4). The presence of nystagmus, analysis of smooth pursuit eye movements, VOR and VOR suppression was reliable to differentiate between the two disease entities. Clear differences in all parameters, although not always significant, were found between all patients and CON. Discussion: We conclude that the use of VOG as a tool for clinical neurophysiological assessment can be helpful in differentiating between patients with PSP and patients with anti-IgLON5 disease. VOG could have particular value in patients with suspected PSP and lack of typical Parkinson's characteristics. future trials are indispensable to assess the potential of oculomotor function as a biomarker in anti-IgLON5 disease.

Pulse-synchronous torsional nystagmus.

Purely torsional spontaneous nystagmus almost always has a central vestibular cause. We describe a man with spontaneous pulse-synchronous torsional nystagmus in which the clockwise component corresponded to his pulse upswing, in keeping with a peripheral vestibular cause; following imaging we diagnosed left-sided superior canal dehiscence syndrome. Identifying pulse synchronicity of spontaneous nystagmus may help to distinguish central from peripheral vestibular torsional nystagmus, and is readily confirmed at the bedside using Frenzel's glasses and a pulse oximeter.

Assessment of Static Graviceptive Perception in the Roll-Plane using the Subjective Visual Vertical Paradigm.

Vestibular disorders are among the most common syndromes in medicine. In recent years, new vestibular diagnostic systems have been introduced that allow the examination of all semicircular canals in the clinical setting. Assessment methods of the otolithic system, which is responsible for the perception of linear acceleration and perception of gravity, are far less in clinical use. There are several experimental approaches for measuring the perception of gravity. The most frequently used method is the determination of the subjective visual vertical. This is usually measured with the head in an upright position. We present here an assessment method for testing otolith function in the roll plane. The subjective visual vertical is measured in the head upright position as well as with head inclination of ± 15° and ± 30° in the roll plane. This extended functional paradigm is an easy-to-perform clinical test of otolith function and ensures increased information content for the detection of impaired graviceptive perception.

Slowed vertical saccades as a hallmark of hereditary spastic paraplegia type 7.

Anecdotal oculomotor disturbances have been described in spastic paraplegia type 7 (SPG7). We investigated oculomotor and vestibular dysfunction in five patients with genetically verified SPG7. All five patients exhibited significantly slower velocities of vertical saccades compared to controls, but significantly faster than in progressive supranuclear palsy, with upward saccades being particularly affected. Horizontal saccades, cerebellar oculomotor markers, and vestibuloocular reflex seem to be variably affected. Thus, albeit subclinical in some cases, slowing of the vertical saccades may belong to the phenotype of SPG7 and may serve as a valuable biomarker for differentiation from spastic ataxias and atypical parkinsonism.

7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia.

Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders.

Neuromagnetic cortical activation during initiation of optokinetic nystagmus: an MEG pilot study.

PURPOSE: To investigate the spatiotemporal evolution of cortical activation during the initiation of optokinetic nystagmus using magnetoencephalography. BACKGROUND: Previous imaging studies of optokinetic nystagmus in humans using positron emission tomography and functional magnetic resonance imaging discovered activation of a large set of cortical and subcortical structures during steady-state optokinetic stimulation, but did not provide information on the temporal dynamics of the initial response. Imaging studies have shown that cortical areas responsible for vision in occipital and temporo-occipital areas are involved, i.e. cortical areas control optokinetic stimulation in humans. Magnetoencephalography provides measures that reflect neural ensemble activity in the millisecond time scale, allowing the identification of early cortical components of visuomotor integration. DESIGN/METHODS: We studied neuromagnetic cortical responses during the initiation of optokinetic nystagmus in 6 right-handed healthy subjects. Neuromagnetic activity was recorded with a whole-head magnetoencephalograph, consisting of 143 planar gradiometers. RESULTS: The mean (±SD) latency between stimulus onset and initiation of optokinetic nystagmus was 177.7 ± 59 ms. Initiation of optokinetic nystagmus evoked an early component in the primary visual cortex starting at 40-90 ms prior to the onset of the slow phase of nystagmus. Almost simultaneously an overlapping second component occurred bilaterally in the temporo-occipital area (visual motion areas), pronounced in the right hemisphere, starting at 10-60 ms prior to the slow-phase onset. Both components showed long-duration activity lasting for up to 100 ms after slow-phase onset. CONCLUSIONS: Our findings suggest that the initiation of optokinetic nystagmus induces early cortical activation in the occipital cortex and almost simultaneously bilaterally in the temporo-occipital cortex. These cortical regions might represent essential areas for the monitoring of retinal slip.

The origins of vestibular science.

The vestibular system conveys information about body motion and gravity. It was one of the first sensory systems to emerge in evolution; however, it was also the last to be discovered. The causal relationship between diseases of the ear and the symptom of vertigo was not recognized until the mid-19th century. Only a few years later, the basic principle of semicircular canal function was elucidated almost simultaneously by three scientists with completely different backgrounds. This historical review describes the major milestones in the discoveries of the anatomy and the physiology of the vestibular system that paved the way for the establishment of neurotology as a clinical subspecialty.

Neural and mental hierarchies.

The history of the sciences of the human brain and mind has been characterized from the beginning by two parallel traditions. The prevailing theory that still influences the way current neuroimaging techniques interpret brain function, can be traced back to classical localizational theories, which in turn go back to early phrenological theories. The other approach has its origins in the hierarchical neurological theories of Hughlings-Jackson, which have been influenced by the philosophical conceptions of Herbert Spencer. Another hallmark of the hierarchical tradition, which is also inherent to psychoanalytic metapsychology, is its deeply evolutionary perspective by taking both ontogenetic and phylogenetic trajectories into consideration. This article provides an outline on hierarchical concepts in brain and mind sciences, which contrast with current cognitivistic and non-hierarchical theories in the neurosciences.

Migraine and vertigo--a prospective diary study.

The objective of the study was to examine migrainous vertigo prospectively by means of a diary. We included 146 patients with at least one migraine attack per month. All patients underwent a semistructured interview, completed questionnaires on depression, anxiety and quality of sleep and kept a diary covering detailed information on headache, vertigo and dizziness over a period of 30 days. A completed diary was returned by 116 patients (79.5%). Based on the diary migrainous vertigo (MV) was diagnosed in 18 patients (15.5%) and non-migrainous vertigo or dizziness (non-MV) in 35 patients (30.2%). MV was present on 65 of 3477 patient days (1.9%) and non-MV on 145 days (4.2%). MV occurred more often on days with headache (P < 0.001). Its median duration was 3 h and it lasted longer on days with headache than on days without headache (P < 0.001). The most prominent specific feature of MV was head motion intolerance. Patients with MV showed anxiety more often (P < 0.001) and tended to have worse quality of sleep and higher depression scores. In conclusion, vertigo and dizziness are frequent symptoms in migraineurs. The 1-month prevalence of MV is 16% and that of non-MV 30% in patients with at least one migraine attack per month. Frequency of MV is higher and duration longer on days with headache. MV is a risk factor for co-morbid anxiety.

Panic attacks in an individual with bilateral selective lesions of the amygdala.

OBJECTIVE: To describe the unique case of a patient with panic attacks and bilateral selective amygdala lesions due to Urbach-Wiethe disease. DESIGN: Case report. SETTING: Epilepsy Monitoring Unit, Medical University of Vienna. Patient A 38-year-old man with Urbach-Wiethe disease developed spontaneous panic attacks and depressive mood, which ceased after antidepressive treatment. INTERVENTIONS: Video electroencephalography monitoring, magnetic resonance imaging, and neuropsychological testing. RESULTS: Extended video electroencephalography monitoring excluded an epileptic etiology of the panic attacks. Results of cranial magnetic resonance imaging showed bilateral selective calcifications of the whole amygdaloid complex. Neuropsychological testing revealed selective memory impairment of autobiographic episodes with preserved memory for autobiographic facts. CONCLUSIONS: Our findings indicate that the occurrence of panic attacks does not critically depend on the integrity of the amygdala. Furthermore, the neuropsychological findings in our patient suggest that the amygdala represents an essential neural substrate for the processing of episodic autobiographic memories.

Covered versus bare self-expanding stents for endovascular treatment of carotid artery stenosis: a stopped randomized trial.

PURPOSE: To investigate whether filter-protected carotid artery stenting (CAS) using a covered self-expanding stent reduces the risk of cerebral embolization. METHODS: Fourteen asymptomatic patients (13 men; median age 77 years, IQR 73-83) were enrolled in a randomized pilot trial comparing the rates of cerebral microembolism during and after filter-protected CAS using either a self-expanding covered (n=8) or a bare (n=6) carotid stent. Transcranial Doppler (TCD) monitoring was done during and for 90 minutes after the procedure. Diffusion-weighted magnetic resonance imaging (DW-MRI) was performed before and 24 hours after CAS. Patients were followed for 6 months for neurological events and occurrence of restenosis. RESULTS: A significant reduction in ipsilateral microembolic signals by TCD was observed with the covered (median 1, IQR 0-4) versus the bare stent (median 6, IQR 3-8; p=0.043). Comparison of the preprocedural and 24-hour postprocedural DW-MRI images showed no new ipsilateral lesions but 1 new lesion in the contralateral hemisphere in the covered stent group, resulting in an overall 7% (95% CI 0%-20%) rate of new ischemic lesions. No neurological complications occurred up to 6 months. Restenosis (>70%) occurred in 3 (38%) of 8 patients with the covered versus none of the bare stents (p=0.21). The trial was stopped when the third restenosis of a covered stent was detected. CONCLUSION: Self-expanding covered stents potentially reduce the risk of cerebral microembolism during and after carotid stenting. However, the problem of in-stent restenosis has to be resolved before these devices can be considered for further investigation.

The personal and scientific feud between Ernst Brücke and Josef Hyrtl.

OBJECTIVE: To describe the events surrounding the personal and professional feud between Josef Hyrtl and Ernst Brücke and its impact on early investigations into the function of the semicircular canals of the inner ear. DATA SOURCES: Published data in scientific journals and news media, documents at the Vienna Institute for the History of Medicine, published personal letters, and an interview with Brücke's great-grandson, Dr. Thomas Brücke. CONCLUSION: Although Hyrtl was instrumental in recruiting Brücke to the University of Vienna, the two professors soon became embroiled in a feud that persisted throughout their academic careers. The difference in approach of these two giants in their field is well illustrated by their views on the function of the semicircular canals of the inner ear. Based on their shape, Hyrtl concluded that they were important for directional hearing, whereas based on animal experiments, Brücke concluded that they were sense organs for equilibrium.

FMRI reveals functional cortex in a case of inconclusive Wada testing.

OBJECTIVES: The intracarotid amobarbital test (Wada test) currently represents the gold standard for preoperative lateralization of hemispheric dominance. Here, we report an epileptic patient with a longstanding extended lesion of the left hemisphere showing absence of motor and speech dysfunction with left carotid amobarbital injection, but tetraplegia and speech arrest with right carotid injection interpreted as a neuroplastic shift of motor and language functions to the right hemisphere. In contrast to the Wada results, motor functional magnetic resonance imaging (fMRI) showed a strong left hemispheric activation with right hand movements. METHODS: Right and left hand motor fMRI was performed. FMRI results and neurophysiological information obtained by motor and sensory evoked potential measurements were compared with the Wada test results. RESULTS: Initial interpretation of neuroplastic shifts of intrinsic left hemisphere functions to the right brain was revised after fMRI results which were confirmed by motor and sensory evoked potentials. CONCLUSION: As motor inactivation usually is thought to be the most robust feature of the Wada test, this case demonstrates that fMRI may reveal residual functional cortex in cases of inconclusive Wada results.

Initiation of the human heave linear vestibulo-ocular reflex.

The linear vestibulo-ocular reflex (LVOR) was studied in eight normal human subjects of average age 24+/-5 years. Subjects underwent a sudden heave (mediolateral) translation delivered by a pneumatic servo-driven chair with a peak acceleration of 0.5 g while viewing earth-fixed targets at 15, 25, 50, and 200 cm. Stimuli were provided both with targets continuously visible or extinguished just prior to motion. Cancellation was tested using chair-fixed targets at each viewing distance. Eye movements were recorded using binocular magnetic search coils. Head translation was measured using a linear accelerometer attached to the upper teeth, to which also was attached a magnetic search coil verifying absence of head rotation. Vergence angles achieved by all subjects were appropriate to interpupillary distance and target distance. Heave translations evoked horizontal ocular rotations in the opposite direction following a brief latency. Latency of the LVOR was determined by automated algorithms based on identification of times when eye position and head acceleration exceeded three standard deviations (SDs) of baseline noise, and was corrected for differing transducer delays. Mean LVOR latency was 30+/-16 ms (mean +/- SD), range 12-53 ms. Slow phase LVOR amplitude was greater for near and less for more distant targets, although all observed responses were suboptimal. Measured 100 ms after head translation onset, mean response was 20% of ideal for the target at 15 cm, 22% at 25 cm, 31% at 50 cm, and 53% at 200 cm. Mean latency was significantly longer than the previously reported values for both the human angular VOR and the monkey LVOR, and had significant inverse correlation with response magnitude. The relatively longer latency of the human LVOR than angular VOR may be tailored to match human head movement dynamics.