João Lemos

João Lemos
Coimbra University Hospital Centre

PhD

About

51
Publications
4,720
Reads
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396
Citations
Citations since 2017
35 Research Items
343 Citations
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2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080

Publications

Publications (51)
Article
Introduction and objectives acute vestibular syndrome is a diagnostic challenge, requiring a rapid and precise diagnosis to take therapeutic actions. Truncal ataxia, inability to sit still, and Babinski flexor dysergy were evaluated. Material anf methods: 52 patients with central pathology (stroke in aica and pica territory) and vestibular neuritis...
Article
Full-text available
Introduction Oculopalatal tremor (OPT) is a late manifestation of a Guillain-Mollaret triangle lesion. Memantine has been shown to improve nystagmus in OPT, but its long-term efficacy and putative distinct effects on each plane of nystagmus and on associated phenomena (e.g., gravity perception) are largely unknown. Methods We conducted a 6-month o...
Article
Full-text available
Purpose of review Central positional nystagmus (CPN) is attributed to disease affecting the central vestibulo-cerebellar pathways. It can be associated with prominent vertigo, oscillopsia, and dysautonomia. Its treatment highly depends on the etiology, and response is fairly heterogenous. This review presents a critical appraisal of CPN therapies....
Conference Paper
Full-text available
This paper is about the use of vestibulospinal signs in AVS demonstrated that severe ataxia l and that when the patient is unable to maintain seated the cause is always central
Article
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Clinically, central positional nystagmus (CPN) is often suspected when atypical forms of its peripheral counterpart, i.e., benign paroxysmal positional vertigo (BPPV), are observed, namely a linear horizontal nystagmus as in horizontal canal BPPV or a downwardly and torsionally beating nystagmus as in anterior canal BPPV. Pathophysiologically, CPN...
Article
Full-text available
Paroxysmal positional vertigo is a frequent cause for consultation. When approaching these patients, we try to differentiate central from peripheral causes, but sometimes we find manifestations that generate diagnostic doubts. In this review, we address atypical paroxysmal positional vertigo, reviewing the literature on the subject and giving a pro...
Article
Introduction: Cognitive impairment and retinal atrophy have been proposed as two potential markers of neurodegeneration in multiple sclerosis (MS). We aimed at assessing the relation between peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell layer (mGCL) atrophy and cognitive performance in early MS. Methods: This is a mul...
Article
Purpose of review: Major therapeutic advances have been made in patients with episodic and progressive cerebellar ataxias, downbeat nystagmus and some vestibular disorders. We provide an update review on this subject highlighting important research findings from the last two years. Recent findings: Recently, the use of omaveloxolone for 2 years...
Article
Cerebral venous thrombosis (CVT) can rarely present with acute ipsilateral cochlear and/or vestibular loss, to date always in the absence of a clear local otogenic process evidenced by magnetic resonance imaging (MRI). This association has been putatively attributed to inner ear anoxia due to blockage of inner ear venous drainage. We present a nonr...
Article
Full-text available
While dynamic ocular motor abnormalities (e.g., gaze-evoked nystagmus (GEN), low optokinetic nystagmus (OKN), pursuit and vestibulo-ocular reflex (VOR) gains, and dysmetric saccades) have been shown to be potential biomarkers in spinocerebellar ataxia type 3 (SCA3), the value of static abnormalities (e.g., convergent [esodeviation] and divergent st...
Article
Full-text available
Significance The association between molecular and functional brain plasticities in health and disease remains an outstanding research challenge. Functional up-regulation of postsynaptic D2 receptors has been documented in PD while its significance at the neural activity level has never been identified. Here we provide a link between synaptic plast...
Article
Full-text available
Mumps is an infectious disease caused by a paramyxovirus. It can involve several organs in the acute stage of the infection, including central nervous system. (Rubin et al., 2015) [1] Neurological complications in the post-infectious period are also described, one of which is acute disseminated encephalomyelitis (ADEM). (Jonhson et al., 2004) [2] W...
Article
Full-text available
Upward and downward bias of eye movement signals in the semicircular canals (SCC)- and/or otolith-related central pathways have been proposed to explain the occurrence of vertical nystagmus (downbeat nystagmus [DBN] and upbeat nystagmus [UBN]) and its frequent modulation with head position. Video-head impulse test (VHIT), usually performed in uprig...
Article
Objective: Presumed microvascular ischemia is the most frequent cause of ocular motor palsy (OMP). Ischemic stroke incidence after an episode of microvascular OMP (mOMP) is not established, contrasting with other common vascular conditions, such as lacunar ischemic stroke (LS). We sought to compare the incidence of subsequent ischemic stroke betwe...
Article
Objective: To evaluate the utility of positional testing in peripheral and central acute vestibular syndrome (pAVS, cAVS, respectively). Study design: Prospective; observational. Setting: Tertiary referral center. Patients: Consecutive AVS patients. Interventions: Video-oculography in upright, supine and head hanging positions at presentat...
Article
In Reply We appreciate Dr Bhatti's interest in our article¹ and thoughtful comments. Defining skew deviation merely by nonconformity to fourth nerve palsy (4NP) and presumed posterior fossa localization, while practical, would decrease case ascertainment by potentially including partial third nerve palsy (which would show vertical misalignment, pre...
Article
Full-text available
Purpose Chronic relapsing inflammatory optic neuropathy (CRION) is a type of idiopathic recurrent optic neuritis that responds to systemic corticosteroids and relapses on steroid withdrawal or dose reduction. Central serous chorioretinopathy (CSCR) is often associated with glucocorticoid therapy. This paper aims to highlight CSCR as a cause of visu...
Article
Ocular neuromyotonia is a rare, albeit treatable, ocular motor disorder, characterised by recurrent brief episodes of diplopia due to tonic extraocular muscle contraction. Ephaptic transmission in a chronically damaged ocular motor nerve is the possible underlying mechanism. It usually improves with carbamazepine. A 53-year-old woman presented with...
Article
Importance Accurate clinical differentiation between skew deviation and fourth nerve palsy (4NP) is critical in the acute and subacute settings. Objective To determine the sensitivity and specificity of the upright-supine test to detect vertical misalignment changes using different head positions for the diagnosis of acute or subacute skew deviati...
Article
An immune attack by anti-glutamic acid decarboxylase (GAD) antibodies is believed to cause a deficiency in gamma-aminobutyric acid-mediated neurotransmission in the cerebellum. This, in turn, leads to several eye movement disorders, including spontaneous downbeat (DBN) and periodic alternating nystagmus. We describe a 68-year-old diabetic woman wit...
Presentation
The use of dalfampridine in central paroxysmal positioning nystagmus caused by non-cerebellar lesions
Article
Background/aims: Neurodegeneration with brain iron accumulation (NBIA) type I is a rare disease that can be divided into a classical or atypical variant, according to age of onset and clinical pattern. Neuro-ophthalmological involvement has been documented in the classical variant but only anecdotically in the atypical variant. We sought to descri...
Article
Progressive supranuclear palsy (PSP) is a neurodegenerative disorder showing predominant brainstem involvement, characterized by marked slowing of rapid eye movements (saccades), particularly along the vertical plane. While the contribution of the brainstem damage for the saccadic disturbance in PSP has been extensively studied, much less is known...
Thesis
Full-text available
The study of eye movements has been extensively used to gain insight into the pathophysiology of neurodegenerative disorders, over the last 60 years. Among these, Parkinson’s disease (PD) and progressive supranuclear palsy (PSP) stand out as a classical example of a clinical disorder where ocular motor examination can not only aid in the diagnosis,...
Article
Full-text available
Over the last two decades, functional magnetic resonance imaging (fMRI) has become a powerful research method to investigate cortical visual plasticity. Abnormal fMRI response patterns have been occasionally detected in the visually deprived cortex of patients with bilateral retinal diseases. Controversy remains whether these observations indicate...
Article
Saccadic behaviour ranges from reflexive (e.g., prosaccade) to goal oriented voluntary movements (e.g., antisaccade). Behavioural asymmetries between vertical and horizontal saccades have been described both in normal individuals (greater delay of vertical prosaccades) and in disease states such as Parkinson's disease (prosaccades are short and ant...
Article
The sensitivity of acetylcholine receptor (AChR) antibody testing is thought to be lower in ocular myasthenia gravis (OMG) compared with generalized disease, although estimates in small-scale studies vary. There is little information in the literature about the implications of AChR antibody levels and progression from OMG to generalized myasthenia...
Article
Neuro-ophthalmological emergencies constitute vision or life-threatening conditions if diagnosis and treatment are not promptly undertaken. Even with immediate therapy, these clinical entities carry a high rate of morbidity. They may present with diplopia, visual loss, and/or anisocoria. Arteritic anterior ischemic optic neuropathy is an ominous co...
Article
To calculate the rate and timing of conversion from ocular myasthenia gravis to generalized myasthenia gravis. Retrospective multicenter analysis. Patients included in the study were diagnosed with ocular myasthenia gravis without the presence of generalized disease at onset. We conducted a retrospective multicenter analysis. We reviewed charts of...
Conference Paper
Full-text available
This study intends to identify acoustic and phonetic characteristics of the speech of Parkinson’s Disease (PD) patients, usually manifesting hypokinetic dysarthria. A speech database has been collected from a control group and from a group of patients with similar PD severity, but with different degrees of hypokinetic dysarthria. First and second f...
Article
Purpose of review: This work reviews supranuclear ocular motor disorders, highlighting new data published during the past year. Recent findings: Perceptional adaptative mechanisms may explain recent research concerning the discrepancy between objective measurement of saccade abnormalities and their putative functional visual impairment. Eye move...
Article
We describe a patient with downbeat nystagmus (DBN) evoked only by eye closure. Brain and spinal cord magnetic resonance imaging revealed a T2 paramedian lesion in the left lower basis pontis and other white matter lesions consistent with multiple sclerosis. One potential mechanism for DBN in this case involves transverse ephaptic spread of excitat...
Article
While positional dizziness is most commonly related to peripheral vestibular disease, it may rarely be caused by a pontomedullary or vestibulocerebellar lesion. Three main clinical forms have been described: central positional nystagmus (CPN), central paroxysmal positional vertigo (CPPV), and rotational vertebral artery syndrome (RVAS). The first t...
Conference Paper
Full-text available
A prevalência da Perturbação de Tourette (PT) está estimada em 50/10000 na população geral. A doença envolve diversos tiques motores e pelo menos um tique vocal presentes por pelo menos um ano e surge antes dos 18 anos de idade. O curso caracteriza-se por períodos sucessivos de agravamento e atenuação relativa dos tiques. Na maioria dos casos obser...
Article
This article reviews and updates basic concepts, diagnosis and treatment of cyclotorsion. Cyclodeviation in congenital superior oblique palsy (SOP) seems to correlate with the extent of superior oblique muscle hypoplasia. Genetic polymorphisms such as PHOX2B polymorphism, considered to be risk factors for congenital fibrosis of the extraocular musc...
Article
This work reviews saccadic intrusions focusing on recent developments in pathophysiology and treatment. Saccadic intrusions have been recognized as features of oculomotor apraxia type 2 and neuromyelitis optica. Novel fixation instabilities have been identified such as 'staircase' square wave jerks, or the pervasive ocular microtremor seen in Parki...
Conference Paper
The aim of this work is to provide a Panoptic™ ophthalmoscope with digital data acquisition. In fact, most ophthalmoscopes used in daily clinical practice do not contain the data recording ability. Therefore, the main advantages of a digital ophthalmoscope are, among others, better quality data sharing, the possibility of exam's reassessment and im...

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