This paper presents diagnostic criteria for persistent postural-perceptual dizziness (PPPD) to be included in the International Classification of Vestibular Disorders (ICVD). The term PPPD is new, ...but the disorder is not. Its diagnostic criteria were derived by expert consensus from an exhaustive review of 30 years of research on phobic postural vertigo, space-motion discomfort, visual vertigo, and chronic subjective dizziness. PPPD manifests with one or more symptoms of dizziness, unsteadiness, or non-spinning vertigo that are present on most days for three months or more and are exacerbated by upright posture, active or passive movement, and exposure to moving or complex visual stimuli. PPPD may be precipitated by conditions that disrupt balance or cause vertigo, unsteadiness, or dizziness, including peripheral or central vestibular disorders, other medical illnesses, or psychological distress. PPPD may be present alone or co-exist with other conditions. Possible subtypes await future identification and validation. The pathophysiologic processes underlying PPPD are not fully known. Emerging research suggests that it may arise from functional changes in postural control mechanisms, multi-sensory information processing, or cortical integration of spatial orientation and threat assessment. Thus, PPPD is classified as a chronic functional vestibular disorder. It is not a structural or psychiatric condition.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The influence of anxiety on ocular motor control and gaze has received less research attention than its effects on postural control and locomotion. This review summarizes research on trait anxiety, ...state anxiety, anxiety disorders, ocular motor reflexes, and gaze. It applies these findings to clinical problems of visually induced unsteadiness and dizziness (VUD, also known as visual vertigo), fear of falling (FoF), and chronic subjective dizziness (CSD).
Humans are inherently more sensitive to vertical heights than horizontal distances. Vertical height intolerance is reported by one-quarter to one-third of the general population. Humans also possess a gaze bias toward potentially threatening stimuli in the visual field, more prominent in individuals with higher versus lower trait anxiety and increased by state anxiety. This bias may drive hypervigilance-avoidance gaze patterns in patients with social anxiety disorder and specific phobias. Trait and state anxiety also appear to adversely affect gaze control, reducing gaze stability on visual targets. This may be one mechanism underlying persistent VUD and visual symptoms of CSD. Anxiety-related gaze diversion may increase gait instability in patients with FoF.
Anxiety affects ocular motor reflexes and gaze control in ways that may contribute to clinically significant visual and visual-vestibular syndromes.
Classifications and definitions are essential to facilitate communication; promote accurate diagnostic criteria; develop, test, and use effective therapies; and specify knowledge gaps. This article ...describes the development of the International Classification of Vestibular Disorders (ICVD) initiative. It describes its history, scope, and goals. The Bárány Society has played a central role in organizing the ICVD by establishing internal development processes and outreach to other scientific societies. The ICVD is organized in four layers. The current focus is on disorders with a high epidemiologic importance, such as Menière disease, benign paroxysmal positional vertigo, vestibular migraine, and behavioral aspects of vestibular disorders.
Symptomatic recovery after acute vestibular neuritis (VN) is variable, with around 50% of patients reporting long term vestibular symptoms; hence, it is essential to identify factors related to poor ...clinical outcome. Here we investigated whether excessive reliance on visual input for spatial orientation (visual dependence) was associated with long term vestibular symptoms following acute VN. Twenty-eight patients with VN and 25 normal control subjects were included. Patients were enrolled at least 6 months after acute illness. Recovery status was not a criterion for study entry, allowing recruitment of patients with a full range of persistent symptoms. We measured visual dependence with a laptop-based Rod-and-Disk Test and severity of symptoms with the Dizziness Handicap Inventory (DHI). The third of patients showing the worst clinical outcomes (mean DHI score 36-80) had significantly greater visual dependence than normal subjects (6.35° error vs. 3.39° respectively, p = 0.03). Asymptomatic patients and those with minor residual symptoms did not differ from controls. Visual dependence was associated with high levels of persistent vestibular symptoms after acute VN. Over-reliance on visual information for spatial orientation is one characteristic of poorly recovered vestibular neuritis patients. The finding may be clinically useful given that visual dependence may be modified through rehabilitation desensitization techniques.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study used resting state functional magnetic resonance imaging (rsfMRI) to investigate whole brain networks in patients with persistent postural perceptual dizziness (PPPD). We compared rsfMRI ...data from 38 patients with PPPD and 38 healthy controls using whole brain and region of interest analyses. We examined correlations among connectivity and clinical variables and tested the ability of a machine learning algorithm to classify subjects using rsfMRI results. Patients with PPPD showed: (a) increased connectivity of subcallosal cortex with left superior lateral occipital cortex and left middle frontal gyrus, (b) decreased connectivity of left hippocampus with bilateral central opercular cortices, left posterior opercular cortex, right insular cortex and cerebellum, and (c) decreased connectivity between right nucleus accumbens and anterior left temporal fusiform cortex. After controlling for anxiety and depression as covariates, patients with PPPD still showed decreased connectivity between left hippocampus and right inferior frontal gyrus, bilateral temporal lobes, bilateral insular cortices, bilateral central opercular cortex, left parietal opercular cortex, bilateral occipital lobes and cerebellum (bilateral lobules VI and V, and left I–IV). Dizziness handicap, anxiety, and depression correlated with connectivity in clinically meaningful brain regions. The machine learning algorithm correctly classified patients and controls with a sensitivity of 78.4%, specificity of 76.9%, and area under the curve = 0.88 using 11 connectivity parameters. Patients with PPPD showed reduced connectivity among the areas involved in multisensory vestibular processing and spatial cognition, but increased connectivity in networks linking visual and emotional processing. Connectivity patterns may become an imaging biomarker of PPPD.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Persistent postural-perceptual dizziness (PPPD) is a common functional vestibular disorder characterized by persistent symptoms of non-vertiginous dizziness and unsteadiness that are exacerbated by ...upright posture, self-motion, and exposure to complex or moving visual stimuli. Recent physiologic and neuroimaging data suggest that greater reliance on visual cues for postural control (as opposed to vestibular cues-a phenomenon termed visual dependence) and dysfunction in central visuo-vestibular networks may be important pathophysiologic mechanisms underlying PPPD. Dysfunctions are thought to involve insular regions that encode recognition of the visual effects of motion in the gravitational field.
We tested for altered activity in vestibular and visual cortices during self-motion simulation obtained
a visual virtual-reality rollercoaster stimulation using functional magnetic resonance imaging in 15 patients with PPPD and 15 healthy controls (HCs). We compared between groups differences in brain responses to simulated displacements in vertical vs horizontal directions and correlated the difference in directional responses with dizziness handicap in patients with PPPD.
HCs showed increased activity in the anterior bank of the central insular sulcus during vertical relative to horizontal motion, which was not seen in patients with PPPD. However, for the same comparison, dizziness handicap correlated positively with activity in the visual cortex (V1, V2, and V3) in patients with PPPD.
We provide novel insight into the pathophysiologic mechanisms underlying PPPD, including functional alterations in brain processes that affect balance control and reweighting of space-motion inputs to favor visual cues. For patients with PPPD, difficulties using visual data to discern the effects of gravity on self-motion may adversely affect balance control, particularly for individuals who simultaneously rely too heavily on visual stimuli. In addition, increased activity in the visual cortex, which correlated with severity of dizziness handicap, may be a neural correlate of visual dependence.
Utilizing spectroscopic observations taken for the VIMOS Ultra-Deep Survey (VUDS), new observations from Keck/DEIMOS, and publicly available observations of large samples of star-forming galaxies, we ...report here on the relationship between the star-formation rate (SFR) and the local environment (
δ
gal
) of galaxies in the early universe (2 <
z
< 5). Unlike what is observed at lower redshifts (
z
≲ 2), we observe a definite, nearly monotonic increase in the average SFR with increasing galaxy overdensity over more than an order of magnitude in
δ
gal
. The robustness of this trend is quantified by accounting for both uncertainties in our measurements and galaxy populations that are either underrepresented or not present in our sample (e.g., extremely dusty star-forming and quiescent galaxies), and we find that the trend remains significant under all circumstances. This trend appears to be primarily driven by the fractional increase of galaxies in high-density environments that are more massive in their stellar content and are forming stars at a higher rate than their less massive counterparts. We find that, even after stellar mass effects are accounted for, there remains a weak but significant SFR–
δ
gal
trend in our sample implying that additional environmentally related processes are helping to drive this trend. We also find clear evidence that the average SFR of galaxies in the densest environments increases with increasing redshift. These results lend themselves to a picture in which massive gas-rich galaxies coalesce into proto-cluster environments at
z
≳ 3, interact with other galaxies or with a forming large-scale medium, subsequently using or losing most of their gas in the process, and begin to seed the nascent red sequence that is present in clusters at slightly lower redshifts.
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FMFMET, NUK, UL, UM, UPUK
Functional neurological disorder is common in neurological practice. A new approach to the positive diagnosis of this disorder focuses on recognisable patterns of genuinely experienced symptoms and ...signs that show variability within the same task and between different tasks over time. Psychological stressors are common risk factors for functional neurological disorder, but are often absent. Four entities—functional seizures, functional movement disorders, persistent perceptual postural dizziness, and functional cognitive disorder—show similarities in aetiology and pathophysiology and are variants of a disorder at the interface between neurology and psychiatry. All four entities have distinctive features and can be diagnosed with the support of clinical neurophysiological studies and other biomarkers. The pathophysiology of functional neurological disorder includes overactivity of the limbic system, the development of an internal symptom model as part of a predictive coding framework, and dysfunction of brain networks that gives movement the sense of voluntariness. Evidence supports tailored multidisciplinary treatment that can involve physical and psychological therapy approaches.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Functional dizziness is the new term for somatoform or psychogenic dizziness. The aim of this study is to review arguments for the new nomenclature, clinical features, possible pathomechanisms, and ...comorbidities of functional dizziness.
The prevalence of functional dizziness as a primary cause of vestibular symptoms amounts to 10% in neuro-otology centers. Rates of psychiatric comorbidity in patients with structural vestibular syndromes are much higher with nearly 50% and with highest rates in patients with vestibular migraine, vestibular paroxysmia, and Ménière's disease. Pathophysiologic processes seem to include precipitating events that trigger anxiety-related changes in postural strategies with an increased attention to head and body motion and a cocontraction of leg muscles. Personality traits with high levels of neuroticism and low levels of extraversion appear as risk factors for anxiety and depressive disorders and increased morbidity in functional disorders.
Correct and early diagnosis of functional dizziness, as primary cause or secondary disorder after a structural vestibular syndrome, is very important to prevent further chronification and enable adequate treatment. Treatment plans that include patient education, vestibular rehabilitation, cognitive and behavioral therapies, and medications substantially reduce morbidity and offer the potential for sustained remission when applied systematically.
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