Publications by authors named "Adolfo Bronstein"

"Trying too hard" can interfere with skilled movement, such as sports and music playing. Postural control can similarly suffer when conscious attention is directed toward it ("conscious movement processing"; CMP). However, the neural mechanisms through which CMP influences balance remain poorly understood.

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Article Synopsis
  • Subjective dizziness, or idiopathic dizziness (ID), is a common issue in older adults, caused by difficulties in postural control and an unclear understanding of its mechanisms.
  • A study involving 30 patients with ID and 30 controls measured how they responded to platform movements, focusing on their body sway and perceptions of instability, while also considering psychological factors and brain health via MRIs.
  • Results indicated that patients with ID felt more unstable than controls despite similar levels of actual body sway, and their cautious stepping responses were linked to fears of falling and brain health issues.
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The cerebellum is important for motor adaptation. Lesions to the vestibulo-cerebellum selectively cause gait ataxia. Here we investigate how such damage affects locomotor adaptation when performing the 'broken escalator' paradigm.

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Introduction: Vertigo is a prevalent and burdensome symptom. More than 80% of patients with vertigo are primarily treated by their general practitioner (GP) and are never referred to a medical specialist. Despite this therapeutic responsibility, the GP's diagnostic toolkit has serious limitations.

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Background: Our sense of direction (SOD) ability relies on the sensory integration of both visual information and self-motion cues from the proprioceptive and vestibular systems. Here, we assess how dysfunction of the vestibular system impacts perceived SOD in varying vestibular disorders, and secondly, we explore the effects of dizziness, migraine and psychological symptoms on SOD ability in patient and control groups.

Methods: 87 patients with vestibular disorder and 69 control subjects were assessed with validated symptom and SOD questionnaires (Santa Barbara Sense of Direction scale and the Object Perspective test).

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The ability to adapt our locomotion in a feedforward (i.e., "predictive") manner is crucial for safe and efficient walking behavior.

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Purpose Of Review: To explore the differential diagnosis of posterior fossa transient ischemic attacks (TIA) associated with vertigo and/or imbalance.To review the contribution of cerebral small vessel (SVD) disease to balance dysfunction and dizziness in the elderly.

Main Findings: TIAs involving vestibular structures that mediate the vestibulo-ocular and vestibulospinal reflexes remain a diagnostic challenge because they overlap with causes of benign episodic vertigo.

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The alpha rhythm is a dominant electroencephalographic oscillation relevant to sensory-motor and cognitive function. Alpha oscillations are reactive, being for example enhanced by eye closure, and suppressed following eye opening. The determinants of inter-individual variability in reactivity in the alpha rhythm (e.

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Aims of the present article are: ) assessing vestibular contribution to spatial navigation, ) exploring how age, global positioning systems (GPS) use, and vestibular navigation contribute to subjective sense of direction (SOD), ) evaluating vestibular navigation in patients with lesions of the vestibular-cerebellum (patients with downbeat nystagmus, DBN) that could inform on the signals carried by vestibulo-cerebellar-cortical pathways. We applied two navigation tasks on a rotating chair in the dark: return-to-start (RTS), where subjects drive the chair back to the origin after discrete angular displacement stimuli (path reversal), and complete-the-circle (CTC) where subjects drive the chair on, all the way round to origin (path completion). We examined 24 normal controls (20-83 yr), five patients with DBN (62-77 yr) and, as proof of principle, two patients with early dementia (84 and 76 yr).

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This paper describes the Bárány Society Classification OverSight Committee (COSC) position on Cervical Dizziness, sometimes referred to as Cervical Vertigo. This involved an initial review by a group of experts across a broad range of fields, and then subsequent review by the Bárány Society COSC. Based upon the so far published literature, the Bárány Society COSC takes the view that the evidence supporting a mechanistic link between an illusory sensation of self-motion (i.

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One in three older people (>60 years) complain of dizziness which often remains unexplained despite specialist assessment. We investigated if dizziness was associated with vascular injury to white matter tracts relevant to balance or vestibular self-motion perception in sporadic cerebral small vessel disease (age-related microangiopathy). We prospectively recruited 38 vestibular clinic patients with idiopathic (unexplained) dizziness and 36 age-matched asymptomatic controls who underwent clinical, cognitive, balance, gait and vestibular assessments, and structural and diffusion brain MRI.

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When given a series of sinusoidal oscillations in which the two hemicycles have equal amplitude but asymmetric velocity, healthy subjects lose perception of the slower hemicycle (SHC), reporting a drift towards the faster hemicycle (FHC). This response is not reflected in the vestibular-ocular reflex, suggesting that the adaptation is of higher order. This study aimed to define EEG correlates of this adaptive response.

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Area OP2 in the posterior peri-sylvian cortex has been proposed to be the core human vestibular cortex. We investigated the functional anatomy of OP2 and adjacent areas (OP2+) using spatially constrained independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data from the Human Connectome Project. Ten ICA-derived subregions were identified.

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To orientate in space, the brain must integrate sensory information that encodes the position of the body with the visual cues from the surrounding environment. In this process, the extent of reliance on visual information is known as the visual dependence. Here, we asked whether the relative positions of the head and body can modulate such visual dependence (VD).

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Background: Modulation of postural control strategies and heightened perceptual ratings of instability when exposed to postural threats, illustrates the association between anxiety and postural control.

Research Question: Here we test whether modulating prior expectations can engender postural-related anxiety which, in turn, may impair postural control and dissociate the well-established relationship between sway and subjective instability.

Methods: We modulated expectations of the difficulty posed by an upcoming postural task via priming.

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The vestibular system facilitates gaze and postural stability via the vestibulo-ocular (VOR) and vestibulo-spinal reflexes, respectively. Cortical and perceptual mechanisms can modulate long-duration VOR responses, but little is known about whether high-order neural phenomena can modulate short-latency vestibulo-spinal responses. Here, we investigate this by assessing click-evoked cervical vestibular myogenic-evoked potentials (VEMPS) during visual roll motion that elicited an illusionary sensation of self-motion (i.

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Article Synopsis
  • About one-third of patients with polyneuropathy are undiagnosed and categorized as having chronic idiopathic axonal polyneuropathy, a slowly progressive condition of unknown cause.
  • A study examining 225 patients identified that 34% of those with sensory neuropathy had biallelic RFC1 expansions, suggesting a possible connection between RFC1 mutations and this type of neuropathy.
  • Most RFC1-positive patients experienced isolated sensory neuropathy with varying degrees of sensory impairment, while many previously received incorrect diagnoses such as Sjögren's syndrome or chronic inflammatory demyelinating polyneuropathy.
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Background: Magnetic Resonance Imaging (MRI) scanning can induce psychological effects. No studies have investigated the role of magnetic vestibular stimulation (MVS) in 3TMRI scanner-induced psychological reactions.

Objective: To assess depersonalization/derealization (DD), state anxiety and motion-perception in a 3TMRI scanner, acutely and long-term.

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The virtual practice has made major advances in the way that we care for patients in the modern era. The culture of virtual practice, consulting, and telemedicine, which had started several years ago, took an accelerated leap as humankind was challenged by the novel coronavirus pandemic (COVID19). The social distancing measures and lockdowns imposed in many countries left medical care providers with limited options in evaluating ambulatory patients, pushing the rapid transition to assessments via virtual platforms.

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Walking onto a stationary platform that had been previously experienced as moving generates a locomotor after-effect-the so-called 'broken escalator' phenomenon. The motor responses that occur during locomotor after-effects have been mapped theoretically using a hierarchal Bayesian model of brain function that takes into account current sensory information that is weighted according to prior contextually-relevant experiences; these in turn inform automatic motor responses. Here, we use the broken escalator phenomenon to explore motor learning in patients with functional gait disorders and probe whether abnormal postural mechanisms override ascending sensory information and conscious intention, leading to maladaptive and disabling gait abnormalities.

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Background: Although vestibular lesions degrade postural control we do not know the relative contributions of the magnitude of the vestibular loss and subjective vestibular symptoms to locomotor adaptation.

Objective: To study how dizzy symptoms interfere with adaptive locomotor learning.

Methods: We examined patients with contrasting peripheral vestibular deficits, vestibular neuritis in the chronic stable phase (n = 20) and strongly symptomatic unilateral Meniere's disease (n = 15), compared to age-matched healthy controls (n = 15).

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Article Synopsis
  • Ataxia is a condition that makes people feel unbalanced and dizzy, leading to falls, and is a major reason for disability related to the nervous system.
  • Researchers found a specific genetic change in a gene called RFC1 that causes a type of ataxia known as CANVAS, which affects movement and balance, especially in older people.
  • In a study of 100 people with this genetic change, symptoms often started around age 60, with many experiencing a cough and balance problems, and over time, some needed walking aids or wheelchairs.
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