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1.
BMC Geriatr ; 24(1): 545, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38914987

RESUMO

BACKGROUND: Late-life depression (LLD) is a prevalent neuropsychiatric disorder in the older population. While LLD exhibits high mortality rates, depressive symptoms in older adults are often masked by physical health conditions. In younger adults, depression is associated with deficits in pupil light reflex and eye blink rate, suggesting the potential use of these responses as biomarkers for LLD. METHODS: We conducted a study using video-based eye-tracking to investigate pupil and blink responses in LLD patients (n = 25), older (OLD) healthy controls (n = 29), and younger (YOUNG) healthy controls (n = 25). The aim was to determine whether there were alterations in pupil and blink responses in LLD compared to both OLD and YOUNG groups. RESULTS: LLD patients displayed significantly higher blink rates and dampened pupil constriction responses compared to OLD and YOUNG controls. While tonic pupil size in YOUNG differed from that of OLD, LLD patients did not exhibit a significant difference compared to OLD and YOUNG controls. GDS-15 scores in older adults correlated with light and darkness reflex response variability and blink rates. PHQ-15 scores showed a correlation with blink rates, while MoCA scores correlated with tonic pupil sizes. CONCLUSIONS: The findings demonstrate that LLD patients display altered pupil and blink behavior compared to OLD and YOUNG controls. These altered responses correlated differently with the severity of depressive, somatic, and cognitive symptoms, indicating their potential as objective biomarkers for LLD.


Assuntos
Piscadela , Depressão , Reflexo Pupilar , Humanos , Masculino , Idoso , Feminino , Piscadela/fisiologia , Reflexo Pupilar/fisiologia , Depressão/fisiopatologia , Depressão/psicologia , Idoso de 80 Anos ou mais , Pessoa de Meia-Idade , Adulto , Pupila/fisiologia , Escuridão , Adulto Jovem , Luz
2.
Muscle Nerve ; 70(2): 279-283, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38837459

RESUMO

INTRODUCTION/AIMS: Paired-pulse stimulation provides clinically useful information regarding sensory inhibition. When supraorbital nerve stimulation is repeated within a short interval, the response to the second stimulation is reduced to varying degrees. This magnitude of change in stimulation response can be monitored by electromyogram (EMG) or by mechanomyogram (MMG) as in this report. MMG has some advantages such as being less time consuming and lacking stimulus artifact. We compared the use of MMG and EMG to validate MMG as an effective method of assessing blink reflex paired-pulse inhibition. METHODS: Eight volunteers participated. Participants received electrical stimulation to the supraorbital nerve of each side. A paired-pulse paradigm was employed, varying the conditioning-test interval between 5 and 800 ms. The R1 component of the induced blink reflex was simultaneously recorded by EMG using a pair of electrodes placed on the lower eyelid and by MMG using an accelerometer placed between the electrodes. RESULTS: The correlation coefficient of the R1 amplitude between MMG and EMG of the grand-averaged waveforms was 0.99. The average participant r value was .91 (range .76-.99). Similar analyses were performed for the amplitude variation of the second response relative to the first response. Results correlated well, yielding r values of .97 and .86 for the grand-averaged waveform and the average for each subject. DISCUSSION: The present results demonstrate that MMG could be an alternative to EMG in assessing paired-pulse inhibition of the electrical blink reflex R1 component.


Assuntos
Piscadela , Estimulação Elétrica , Eletromiografia , Humanos , Piscadela/fisiologia , Masculino , Adulto , Feminino , Estimulação Elétrica/métodos , Eletromiografia/métodos , Adulto Jovem , Miografia/métodos , Inibição Neural/fisiologia
3.
Schizophr Res ; 269: 9-17, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38703519

RESUMO

BACKGROUND: 22q11.2 deletion syndrome (22q11DS) is one of the most robust genetic predictors of psychosis and other psychiatric illnesses. In this study, we examined 22q11DS subjects' acoustic startle responses (ASRs), which putatively index psychosis risk. Latency of the ASR is a presumptive marker of neural processing speed and is prolonged (slower) in schizophrenia. ASR measures correlate with increased psychosis risk, depend on glutamate and dopamine receptor signaling, and could serve as translational biomarkers in interventions for groups at high psychosis risk. METHODS: Startle magnitude, latency, and prepulse inhibition were assessed with a standard acoustic startle paradigm in 31 individuals with 22q11.2DS and 32 healthy comparison (HC) subjects. Surface electrodes placed on participants' orbicularis oculi recorded the electromyographic signal in ASR eyeblinks. Individuals without measurable startle blinks in the initial habituation block were classified as non-startlers. RESULTS: Across the startle session, the ASR magnitude was significantly lower in 22q11DS subjects than HCs because a significantly higher proportion of 22q11DS subjects were non-startlers. Latency of the ASR to pulse-alone stimuli was significantly slower in 22q11DS than HC subjects. Due to the overall lower 22q11DS startle response frequency and magnitudes prepulse inhibition could not be analyzed. CONCLUSIONS: Reduced magnitude and slow latency of 22q11DS subjects' responses suggest reduced central nervous system and neuronal responsiveness. These findings are consistent with significant cognitive impairments observed in 22q11DS subjects. Further research is needed to untangle the connections among basic neurotransmission dysfunction, psychophysiological responsiveness, and cognitive impairment.


Assuntos
Piscadela , Síndrome de DiGeorge , Inibição Pré-Pulso , Reflexo de Sobressalto , Humanos , Masculino , Feminino , Reflexo de Sobressalto/fisiologia , Adulto , Adolescente , Adulto Jovem , Síndrome de DiGeorge/fisiopatologia , Inibição Pré-Pulso/fisiologia , Piscadela/fisiologia , Tempo de Reação/fisiologia , Eletromiografia , Estimulação Acústica
4.
Curr Eye Res ; 49(7): 691-697, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38717137

RESUMO

PURPOSE: The study aimed to investigate the factors associated with anterior location of Marx's line in ocular surface and living habits, especially in tear film. MATERIALS AND METHODS: This cross-sectional study enlisted 483 participants with meibomian gland dysfunction, who were divided into two groups: 160 participants with mild anterior location of Marx's line and 323 participants with moderate-to-severe anterior location. Participants completed a survey of demographic characteristics (sex, age, length of visual terminal use, sleep duration, skin property), and the Ocular Surface Disease Index and Standard Patient Evaluation of Eye Dryness questionnaires. They also underwent slit-lamp examinations of the lids, and measurements of non-invasive tear break up time, tear meniscus height, fluorescein tear break up time, lipid layer thickness, partial blink rate, lid wiper epitheliopathy, and meibomian gland dropout. RESULTS: The tear meniscus height (mild:0.21(0.18-0.25), moderate-to-severe:0.19(0.16-0.23), p = 0.004), fluorescein tear break up time(mild:3(2-4),moderate to severe:2(1-3), p = 0.000), max LLT(mild:87(62-100), moderate-to-severe:99(69-100), p = 0.04), average LLT(mild:64.5(47.5-96.75), moderate-to-severe:74(53-100), p = 0.012), min LLT(mild:52(38-75), moderate-to-severe:59(41-85), p = 0.029) differed significantly between mild and moderate-to-severe anterior location of Marx's line, and associated to the anterior location of Marx's line(r=-0.134, p = 0.03; r=-0.194, p = 0.000; r = 0.093, p = 0.041; r = 0.119, p = 0.009; r = 0.105, p = 0.022) However, no statistical significance was observed in the OSDI, SPEED, partial blink rate, non-invasive tear breakup time, lipid layer thickness, meibomian gland dropout and lid wiper epitheliopathy(p > 0.05). Meanwhile, in the demographic characteristics, statistically significant correlations were associated with skin property(r = 0.154, p = 0.001) and sleep duration(r=-0.124, p = 0.006), but not with age, sex, and the length of visual terminal use (p > 0.05). CONCLUSIONS: Lower TMH and shorter TBUT positively correlated with anterior location of the Marx's line, and were risk factors. Meanwhile, participants with oily skin and shorter sleep duration were more likely to exhibit anterior location of Marx's line.


Assuntos
Disfunção da Glândula Tarsal , Glândulas Tarsais , Lágrimas , Humanos , Estudos Transversais , Masculino , Feminino , Lágrimas/metabolismo , Lágrimas/fisiologia , Pessoa de Meia-Idade , Glândulas Tarsais/diagnóstico por imagem , Glândulas Tarsais/metabolismo , Glândulas Tarsais/patologia , Adulto , Disfunção da Glândula Tarsal/diagnóstico , Disfunção da Glândula Tarsal/metabolismo , Disfunção da Glândula Tarsal/fisiopatologia , Inquéritos e Questionários , Piscadela/fisiologia , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/metabolismo , Síndromes do Olho Seco/fisiopatologia , Idoso , Fatores de Risco
5.
Ophthalmic Plast Reconstr Surg ; 40(3): 336-339, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38738711

RESUMO

PURPOSE: To investigate the relationship between the kinematics of spontaneous blinks and the anterior area of the levator palpebrae superioris muscle in patients with Graves orbitopathy (GO). METHODS: This is a case-control study. The authors measured the margin reflex distance of the upper eyelid (margin reflex distance 1), the kinematics of spontaneous blinks, and the anterior area of levator palpebrae superioris muscle in CT coronal scans of patients with Graves upper eyelid retraction (GO) and a control group. The eye with the greatest margin reflex distance 1 was selected for analysis in each group. RESULTS: A total of 68 participants were included, with 36 in the GO group and 32 in the control group. In the GO group, the mean margin reflex distance 1 measured 6.5 mm, while in the control group, it was 3.9 mm. Almost all parameters related to the closing phase of spontaneous blinking activity, including amplitude, velocity, blinking rate, and interblink time, did not differ between the two groups. However, the effectiveness of the blink's amplitude (ratio of blink amplitude to margin reflex distance 1) and the main sequence (relationship between amplitude and velocity) were significantly reduced in the GO group compared with the control group. The area of the levator palpebrae superioris muscle was significantly larger in GO than in controls, with 71.4% of patients' muscles outside of the maximum range of the controls. CONCLUSIONS: In patients with GO, there is a reduction in blinking effectiveness, also known as blink lagophthalmos, which is a factor in the common occurrence of ocular surface symptoms. The increase in velocity with amplitude is also reduced in GO.


Assuntos
Piscadela , Pálpebras , Oftalmopatia de Graves , Músculos Oculomotores , Humanos , Piscadela/fisiologia , Feminino , Oftalmopatia de Graves/fisiopatologia , Oftalmopatia de Graves/complicações , Oftalmopatia de Graves/diagnóstico , Masculino , Pessoa de Meia-Idade , Músculos Oculomotores/fisiopatologia , Adulto , Estudos de Casos e Controles , Pálpebras/fisiopatologia , Doenças Palpebrais/fisiopatologia , Doenças Palpebrais/diagnóstico , Idoso , Tomografia Computadorizada por Raios X , Lagoftalmia
6.
World Neurosurg ; 187: e759-e768, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38705267

RESUMO

BACKGROUND: Blink reflex (BR) is an oligosynaptic reflex that involves the ophthalmic branch of the trigeminal nerve (TN), ipsilateral main sensory and trigeminospinal nuclei, bilateral facial nuclei, and the facial nerves (FNs). Theoretically, as BR tests the function of both TN and FNs simultaneously, it is an ideal tool for monitoring the status of TN and FNs during skull base surgeries. Nevertheless, it has been used only recently in surgeries as the use of anesthesia limits its use. METHODS: For this systematic review, 2 authors input the search terms [(Blink Reflex) AND (Intraoperative Neuromonitoring OR Neuro Intraoperative Monitoring OR Intraoperative OR NIOM OR IONM) AND (skull base surgery OR Facial Nerve OR Trigeminal Nerve OR Microvascular Decompression OR Hemifacial Spasm)] in MEDLINE through its PubMed interface and other search engines. Articles that fulfilled the inclusion and exclusion criteria were obtained and scrutinized. RESULTS: Seven observational articles with a total of 437 participants were included. All 5 studies that described the use of BR in FN surgery noted that intraoperative BR is beneficial, safe, sensitive, specific, and predictive of outcomes, while 2 articles describing patients with trigeminal neuralgia recommended use of BR in microvascular decompression of TN. CONCLUSIONS: Intraoperative BR is a sensitive, specific, and safe monitoring technique that has good predictability of facial paresis and paresthesia among patients undergoing MVD for trigeminal neuralgia and primary hemifacial spasm and patients undergoing cerebellopontine angle tumor resection.


Assuntos
Piscadela , Nervo Facial , Base do Crânio , Nervo Trigêmeo , Humanos , Piscadela/fisiologia , Nervo Facial/fisiopatologia , Nervo Trigêmeo/cirurgia , Base do Crânio/cirurgia , Prognóstico , Monitorização Neurofisiológica Intraoperatória/métodos , Procedimentos Neurocirúrgicos/métodos , Cirurgia de Descompressão Microvascular/métodos , Monitorização Intraoperatória/métodos , Neuralgia do Trigêmeo/cirurgia , Espasmo Hemifacial/cirurgia , Espasmo Hemifacial/fisiopatologia
7.
Behav Res Ther ; 178: 104555, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38718630

RESUMO

Although observational fear learning has been implicated in the development of phobic-related fears, studies investigating observational learning of fear of bodily symptoms remain scarce. Therefore, the aim of the present study was to investigate whether fear in response to bodily symptoms can be acquired simply by observing a fearful reaction to provocation of aversive bodily symptoms in others. Forty healthy participants underwent an observational fear conditioning paradigm consisting of two phases. In the first phase, participants observed a demonstrator reacting to an aversive bodily symptom provocation (unconditioned stimulus or US, i.e., labored breathing) paired with one conditioned stimulus (CS+) but not with the other one (CS-, both CSs were geometric symbols presented on a screen the demonstrator was watching). In the second phase, participants were directly presented with the same conditioned stimuli, but in the absence of the US. Our results revealed enhanced conditioned fear responses in the beginning of the second phase to the CS + as compared to CS-, as indexed by greater skin conductance and subjective fear responses, as well as greater potentiation of startle eyeblink responses to the CS + as compared to the ITI. Taken together, these findings implicate that fear of bodily symptoms can be learned through observation of others, that is, without first-hand experience of bodily threat.


Assuntos
Condicionamento Clássico , Medo , Resposta Galvânica da Pele , Reflexo de Sobressalto , Humanos , Medo/psicologia , Feminino , Masculino , Condicionamento Clássico/fisiologia , Reflexo de Sobressalto/fisiologia , Adulto Jovem , Resposta Galvânica da Pele/fisiologia , Adulto , Adolescente , Piscadela/fisiologia
8.
Transl Vis Sci Technol ; 13(5): 2, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38696181

RESUMO

Purpose: Currently, no solution exists to restore natural eyelid kinematics for patients with complete eyelid paralysis due to loss of function of both the levator palpebrae superioris and orbicularis oculi. These rare cases are prone to complications of chronic exposure keratopathy which may lead to corneal blindness. We hypothesized that magnetic force could be used to fully automate eyelid movement in these cases through the use of eyelid-attached magnets and a spectacle-mounted magnet driven by a programmable motor (motorized magnetic levator prosthesis [MMLP]). Methods: To test this hypothesis and establish proof of concept, we performed a finite element analysis (FEA) for a prototype MMLP to check the eyelid-opening force generated by the device and verified the results with experimental measurements in a volunteer with total bidirectional eyelid paralysis. The subject was then fitted with a prototype to check the performance of the device and its success. Results: With MMLP, eye opening was restored to near normal, and blinking was fully automated in close synchrony with the motor-driven polarity reversal, with full closure on the blink. The device was well tolerated, and the participant was pleased with the comfort and performance. Conclusions: FEA simulation results conformed to the experimentally observed trend, further supporting the proof of concept and design parameters. This is the first viable approach in human patients with proof of concept for complete reanimation of a bidirectionally paretic eyelid. Further study is warranted to refine the prototype and determine the feasibility and safety of prolonged use. Translational Relevance: This is first proof of concept for our device for total bidirectional eyelid paralysis.


Assuntos
Piscadela , Pálpebras , Estudo de Prova de Conceito , Humanos , Piscadela/fisiologia , Pálpebras/fisiopatologia , Doenças Palpebrais/fisiopatologia , Doenças Palpebrais/terapia , Músculos Oculomotores/fisiopatologia , Análise de Elementos Finitos , Fenômenos Biomecânicos , Próteses e Implantes , Desenho de Prótese , Imãs , Masculino
9.
Proc Natl Acad Sci U S A ; 121(15): e2310291121, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38564641

RESUMO

Humans blink their eyes frequently during normal viewing, more often than it seems necessary for keeping the cornea well lubricated. Since the closure of the eyelid disrupts the image on the retina, eye blinks are commonly assumed to be detrimental to visual processing. However, blinks also provide luminance transients rich in spatial information to neural pathways highly sensitive to temporal changes. Here, we report that the luminance modulations from blinks enhance visual sensitivity. By coupling high-resolution eye tracking in human observers with modeling of blink transients and spectral analysis of visual input signals, we show that blinking increases the power of retinal stimulation and that this effect significantly enhances visibility despite the time lost in exposure to the external scene. We further show that, as predicted from the spectral content of input signals, this enhancement is selective for stimuli at low spatial frequencies and occurs irrespective of whether the luminance transients are actively generated or passively experienced. These findings indicate that, like eye movements, blinking acts as a computational component of a visual processing strategy that uses motor behavior to reformat spatial information into the temporal domain.


Assuntos
Piscadela , Movimentos Oculares , Humanos , Estimulação Luminosa , Percepção Visual/fisiologia , Visão Ocular
10.
Biomed Eng Online ; 23(1): 43, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38654246

RESUMO

We developed a video-based tool to quantitatively assess the Glabellar Tap Reflex (GTR) in patients with idiopathic Parkinson's disease (iPD) as well as healthy age-matched participants. We also video-graphically assessed the effect of dopaminergic medication on the GTR in iPD patients, as well as the frequency and blinking duration of reflex and non-reflex blinks. The Glabellar Tap Reflex is a clinical sign seen in patients e.g. suffering from iPD. Reliable tools to quantify this sign are lacking. METHODS: We recorded the GTR in 11 iPD patients and 12 healthy controls (HC) with a consumer-grade camera at a framerate of at least 180 images/s. In these videos, reflex and non-reflex blinks were analyzed for blink count and blinking duration in an automated fashion. RESULTS: With our setup, the GTR can be extracted from high-framerate cameras using landmarks of the MediaPipe face algorithm. iPD patients did not habituate to the GTR; dopaminergic medication did not alter that response. iPD patients' non-reflex blinks were higher in frequency and higher in blinking duration (width at half prominence); dopaminergic medication decreased the median frequency (Before medication-HC: p < 0.001, After medication-HC: p = 0.0026) and decreased the median blinking duration (Before medication-HC: p = 0.8594, After medication-HC: p = 0.6943)-both in the direction of HC. CONCLUSION: We developed a quantitative, video-based tool to assess the GTR and other blinking-specific parameters in HC and iPD patients. Further studies could compare the video data to electromyogram (EMG) data for accuracy and comparability, as well as evaluate the specificity of the GTR in patients with other neurodegenerative disorders, in whom the GTR can also be present. SIGNIFICANCE: The video-based detection of the blinking parameters allows for unobtrusive measurement in patients, a safer and more comfortable option.


Assuntos
Piscadela , Doença de Parkinson , Gravação em Vídeo , Humanos , Doença de Parkinson/fisiopatologia , Doença de Parkinson/tratamento farmacológico , Masculino , Feminino , Idoso , Pessoa de Meia-Idade , Processamento de Imagem Assistida por Computador/métodos , Estudos de Casos e Controles
11.
PLoS Comput Biol ; 20(4): e1011277, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38574161

RESUMO

According to the motor learning theory by Albus and Ito, synaptic depression at the parallel fibre to Purkinje cells synapse (pf-PC) is the main substrate responsible for learning sensorimotor contingencies under climbing fibre control. However, recent experimental evidence challenges this relatively monopolistic view of cerebellar learning. Bidirectional plasticity appears crucial for learning, in which different microzones can undergo opposite changes of synaptic strength (e.g. downbound microzones-more likely depression, upbound microzones-more likely potentiation), and multiple forms of plasticity have been identified, distributed over different cerebellar circuit synapses. Here, we have simulated classical eyeblink conditioning (CEBC) using an advanced spiking cerebellar model embedding downbound and upbound modules that are subject to multiple plasticity rules. Simulations indicate that synaptic plasticity regulates the cascade of precise spiking patterns spreading throughout the cerebellar cortex and cerebellar nuclei. CEBC was supported by plasticity at the pf-PC synapses as well as at the synapses of the molecular layer interneurons (MLIs), but only the combined switch-off of both sites of plasticity compromised learning significantly. By differentially engaging climbing fibre information and related forms of synaptic plasticity, both microzones contributed to generate a well-timed conditioned response, but it was the downbound module that played the major role in this process. The outcomes of our simulations closely align with the behavioural and electrophysiological phenotypes of mutant mice suffering from cell-specific mutations that affect processing of their PC and/or MLI synapses. Our data highlight that a synergy of bidirectional plasticity rules distributed across the cerebellum can facilitate finetuning of adaptive associative behaviours at a high spatiotemporal resolution.


Assuntos
Cerebelo , Simulação por Computador , Condicionamento Palpebral , Modelos Neurológicos , Plasticidade Neuronal , Plasticidade Neuronal/fisiologia , Animais , Cerebelo/fisiologia , Condicionamento Palpebral/fisiologia , Células de Purkinje/fisiologia , Piscadela/fisiologia , Condicionamento Clássico/fisiologia , Sinapses/fisiologia , Biologia Computacional , Camundongos , Córtex Cerebelar/fisiologia
12.
eNeuro ; 11(4)2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38627063

RESUMO

Trace eyeblink conditioning (TEBC) has been widely used to study associative learning in both animals and humans. In this paradigm, conditioned responses (CRs) to conditioned stimuli (CS) serve as a measure for retrieving learned associations between the CS and the unconditioned stimuli (US) within a trial. Memory consolidation, that is, learning over time, can be quantified as an increase in the proportion of CRs across training sessions. However, how hippocampal oscillations differentiate between successful memory retrieval within a session and consolidation across TEBC training sessions remains unknown. To address this question, we recorded local field potentials (LFPs) from the rat dorsal hippocampus during TEBC and investigated hippocampal oscillation dynamics associated with these two functions. We show that transient broadband responses to the CS were correlated with memory consolidation, as indexed by an increase in CRs across TEBC sessions. In contrast, induced alpha (8-10 Hz) and beta (16-20 Hz) band responses were correlated with the successful retrieval of the CS-US association within a session, as indexed by the difference in trials with and without CR.


Assuntos
Condicionamento Palpebral , Hipocampo , Consolidação da Memória , Rememoração Mental , Ratos Long-Evans , Hipocampo/fisiologia , Masculino , Condicionamento Palpebral/fisiologia , Animais , Consolidação da Memória/fisiologia , Rememoração Mental/fisiologia , Aprendizagem por Associação/fisiologia , Ratos , Condicionamento Clássico/fisiologia , Piscadela/fisiologia
13.
Altern Lab Anim ; 52(3): 149-154, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38606566

RESUMO

In the cosmetics sector, many products such as shampoos have a probability of accidental ocular exposure during their routine use. One very specific safety parameter is the residence time of the substance on the corneal surface, as prolonged exposure may cause injury. In this study, we developed a system that simulates corneal exposure to blinking and tear flow, for comparing the corneal clearance times of viscous detergent formulations. The Ex Vivo Eye Irritation Test (EVEIT), which uses corneal explants from discarded rabbit eyes from an abattoir, was used as the basis for the new system. To simulate blinking, we developed a silicone wiping membrane to regularly move across the corneal surface, under conditions of constant addition and aspiration of fluid, to mimic tear flow. Six shampoo formulations were tested and were shown to differ widely in their corneal clearance time. Three groups could be identified according to the observed clearance times (fast, intermediate and slow); the reference shampoo had the shortest clearance time of all tested formulations. With this new system, it is now possible to investigate an important physicochemical parameter, i.e. corneal clearance time, for the consideration of ocular safety during the development of novel cosmetic formulations.


Assuntos
Piscadela , Córnea , Animais , Coelhos , Córnea/efeitos dos fármacos , Piscadela/efeitos dos fármacos , Alternativas aos Testes com Animais/métodos , Preparações para Cabelo , Lágrimas/efeitos dos fármacos
15.
Lab Chip ; 24(8): 2327-2334, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38563256

RESUMO

The eyes provide rich physiological information and offer diagnostic potential as a sensing site, and probing tear constituents via the wearable contact lens could be explored for healthcare monitoring. Herein, we propose a novel adhesive contrast contact lens platform that can split tear film by natural means of tear secretion and blinking. The adhesive contrast is realized by selective grafting of a lubricant onto a polydimethylsiloxane (PDMS)-based contact lens, leading to high pinning zones on a non-adhesive background. The difference in contact angle hysteresis facilitates the liquid splitting. Further, the method offers control over the droplet volume by controlling the zone dimension. The adhesive contrast contact lens is coupled with fluorescent spectroscopic as well as colorimetric techniques to realize its potential as a diagnostic platform. The adhesive contrast contact lens is exploited to detect the level of lactoferrin in tear by sensitizing split droplets with Tb3+ ions. The adhesive contrast contact lens integrated with a fluorescence spectrometer was able to detect the lactoferrin level up to a concentration of 0.25 mg mL-1. Additionally, a colorimetric detection based on the fluorescence of the lactoferrin-terbium complex is demonstrated for the measurement of lactoferrin, with a limit of detection in the physiological range up to 0.5 mg mL-1.


Assuntos
Lentes de Contato Hidrofílicas , Lactoferrina/análise , Olho , Lágrimas/química , Piscadela
16.
Sci Rep ; 14(1): 9794, 2024 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-38684721

RESUMO

Face perception is a major topic in vision research. Most previous research has concentrated on (holistic) spatial representations of faces, often with static faces as stimuli. However, faces are highly dynamic stimuli containing important temporal information. How sensitive humans are regarding temporal information in dynamic faces is not well understood. Studies investigating temporal information in dynamic faces usually focus on the processing of emotional expressions. However, faces also contain relevant temporal information without any strong emotional expression. To investigate cues that modulate human sensitivity to temporal order, we utilized muted dynamic neutral face videos in two experiments. We varied the orientation of the faces (upright and inverted) and the presence/absence of eye blinks as partial dynamic cues. Participants viewed short, muted, monochromic videos of models vocalizing a widely known text (National Anthem). Videos were played either forward (in the correct temporal order) or backward. Participants were asked to determine the direction of the temporal order for each video, and (at the end of the experiment) whether they had understood the speech. We found that face orientation, and the presence/absence of an eye blink affected sensitivity, criterion (bias) and reaction time: Overall, sensitivity was higher for upright compared to inverted faces, and in the condition where an eye blink was present compared to the condition without an eye blink. Reaction times were mostly faster in the conditions with higher sensitivity. A bias to report inverted faces as 'backward' observed in Experiment I, where upright and inverted faces were presented randomly interleaved within each block, was absent when presenting upright and inverted faces in different blocks in Experiment II. Language comprehension results revealed that there was higher sensitivity when understanding the speech compared to not understanding the speech in both experiments. Taken together, our results showed higher sensitivity with upright compared to inverted faces, suggesting that the perception of dynamic, task-relevant information was superior with the canonical orientation of the faces. Furthermore, partial information coming from eye blinks, in addition to mouth movements, seemed to play a significant role in dynamic face perception, both when faces were presented upright and inverted. We suggest that studying the perception of facial dynamics beyond emotional expressions will help us to better understand the mechanisms underlying the temporal integration of facial information from different -partial and holistic- sources, and that our results show how different strategies, depending on the available information, are employed by human observers when judging the temporal order of faces.


Assuntos
Reconhecimento Facial , Humanos , Feminino , Masculino , Reconhecimento Facial/fisiologia , Adulto , Adulto Jovem , Tempo de Reação/fisiologia , Expressão Facial , Piscadela/fisiologia , Estimulação Luminosa/métodos , Emoções/fisiologia , Face/fisiologia , Sinais (Psicologia)
17.
Clin Neurophysiol ; 162: 165-173, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38642482

RESUMO

OBJECTIVE: The current study examined the efficacy of the facial corticobulbar motor evoked potentials (FCoMEPs) and blink reflex (BR) on predicting postoperative facial nerve function during cerebellopontine angle (CPA) tumor surgery. METHODS: Data from 110 patients who underwent CPA tumor resection with intraoperative FCoMEPs and BR monitoring were retrospectively reviewed. The association between the amplitude reduction ratios of FCoMEPs and BR at the end of surgery and postoperative facial nerve function was determined. Subsequently, the optimal threshold of FCoMEPs and BR for predicting postoperative facial nerve dysfunction were determined by receiver operating characteristic curve analysis. RESULTS: Valid BR was record in 103 of 110 patients, whereas only 43 patients successfully recorded FCoMEP in orbicularis oculi muscle. A reduction over 50.3% in FCoMEP (O. oris) amplitude was identified as a predictor of postoperative facial nerve dysfunction (sensitivity, 77.1%; specificity, 83.6%). BR was another independent predictor of postoperative facial nerve deficit with excellent predictive performance, especially eyelid closure function. Its optimal cut-off value for predicting long-term postoperative eyelid closure dysfunction was was 51.0% (sensitivity, 94.4%; specificity, 94.4%). CONCLUSIONS: BR can compensate for the deficiencies of the FCoMEPs. The combination of BR and FCoMEPs can be used in CPA tumor surgery. SIGNIFICANCE: The study first proposed an optimal cut-off value of BR amplitude deterioration (50.0%) for predicting postoperative eyelid closure deficits in patients undergoing CPA tumor surgery.


Assuntos
Piscadela , Potencial Evocado Motor , Humanos , Masculino , Feminino , Piscadela/fisiologia , Pessoa de Meia-Idade , Adulto , Potencial Evocado Motor/fisiologia , Idoso , Estudos Retrospectivos , Nervo Facial/fisiopatologia , Valor Preditivo dos Testes , Ângulo Cerebelopontino/cirurgia , Ângulo Cerebelopontino/fisiopatologia , Adulto Jovem , Neuroma Acústico/cirurgia , Neuroma Acústico/fisiopatologia , Monitorização Neurofisiológica Intraoperatória/métodos , Adolescente , Neoplasias Cerebelares/cirurgia , Neoplasias Cerebelares/fisiopatologia , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/diagnóstico
18.
IEEE Trans Vis Comput Graph ; 30(5): 2077-2086, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38437077

RESUMO

Eye tracking has shown great promise in many scientific fields and daily applications, ranging from the early detection of mental health disorders to foveated rendering in virtual reality (VR). These applications all call for a robust system for high-frequency near-eye movement sensing and analysis in high precision, which cannot be guaranteed by the existing eye tracking solutions with CCD/CMOS cameras. To bridge the gap, in this paper, we propose Swift-Eye, an offline precise and robust pupil estimation and tracking framework to support high-frequency near-eye movement analysis, especially when the pupil region is partially occluded. Swift-Eye is built upon the emerging event cameras to capture the high-speed movement of eyes in high temporal resolution. Then, a series of bespoke components are designed to generate high-quality near-eye movement video at a high frame rate over kilohertz and deal with the occlusion over the pupil caused by involuntary eye blinks. According to our extensive evaluations on EV-Eye, a large-scale public dataset for eye tracking using event cameras, Swift-Eye shows high robustness against significant occlusion. It can improve the IoU and F1-score of the pupil estimation by 20% and 12.5% respectively, compared with the second-best competing approach, when over 80% of the pupil region is occluded by the eyelid. Lastly, it provides continuous and smooth traces of pupils in extremely high temporal resolution and can support high-frequency eye movement analysis and a number of potential applications, such as mental health diagnosis, behaviour-brain association, etc. The implementation details and source codes can be found at https://github.com/ztysdu/Swift-Eye.


Assuntos
Algoritmos , Movimentos Oculares , Gráficos por Computador , Piscadela , Pupila
19.
J Neural Eng ; 21(2)2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38507808

RESUMO

Facial paralysis is the inability to move facial muscles thereby impairing the ability to blink and make facial expressions. Depending on the localization of the nerve malfunction it is subcategorised into central or peripheral and is usually unilateral. This leads to health deficits stemming from corneal dryness and social ostracization.Objective: Electrical stimulation shows promise as a method through which to restore the blink function and as a result improve eye health. However, it is unknown whether a real-time, myoelectrically controlled, neurostimulating device can be used as assistance to this pathological condition.Approach: We developed NEURO-BLINK, a wearable robotic system, that can detect the volitional healthy contralateral blink through electromyography and electrically stimulate the impaired subcutaneous facial nerve and orbicularis oculi muscle to compensate for lost blink function. Alongside the system, we developed a method to evaluate optimal electrode placement through the relationship between blink amplitude and injected charge.Main results: Ten patients with unilateral facial palsy were enrolled in the NEURO-BLINK study, with eight completing testing under two conditions. (1) where the stimulation was cued with an auditory signal (i.e. paced controlled) and (2) synchronized with the natural blink (i.e. myoelectrically controlled). In both scenarios, overall eye closure (distance between eyelids) and cornea coverage measured with high FPS video were found to significantly improve when measured in real-time, while no significant clinical changes were found immediately after use.Significance: This work takes steps towards the development of a portable medical device for blink restoration and facial stimulation which has the potential to improve long-term ocular health.


Assuntos
Paralisia Facial , Humanos , Biônica , Piscadela , Pálpebras/inervação , Nervo Facial
20.
Clin Neurophysiol ; 161: 17-26, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38432185

RESUMO

OBJECTIVE: Both blinking and walking are altered in Parkinson's disease and both motor outputs have been shown to be linked in healthy subjects. Additionally, studies suggest an involvement of basal ganglia activity and striatal dopamine in blink generation. We investigated the role of the basal ganglia circuitry on spontaneous blinking and if this role is dependent on movement state and striatal dopamine. METHODS: We analysed subthalamic nucleus (STN) activity in seven chronically implanted patients for deep brain stimulation (DBS) with respect to blinks and movement state (resting state and unperturbed walking). Neurophysiological recordings were combined with individual molecular brain imaging assessing the dopamine reuptake transporter (DAT) density for the left and right striatum separately. RESULTS: We found a significantly higher blink rate during walking compared to resting. The blink rate during walking positively correlated with the DAT density of the left caudate nucleus. During walking only, spontaneous blinking was followed by an increase in the right STN beta power and a bilateral subthalamic phase reset in the low frequencies. The right STN blink-related beta power modulation correlated negatively with the DAT density of the contralateral putamen. The left STN blink-related beta power correlated with the DAT density of the putamen in the less dopamine-depleted hemisphere. Both correlations were specific to the walking condition and to beta power following a blink. CONCLUSION: Our findings show that spontaneous blinking is related to striatal dopamine and has a frequency specific deployment in the STN. This correlation depends on the current movement state such as walking. SIGNIFICANCE: This work indicates that subcortical activity following a motor event as well as the relationship between dopamine and motor events can be dependent on the motor state. Accordingly, disease related changes in brain activity should be assessed during natural movement.


Assuntos
Ritmo beta , Piscadela , Estimulação Encefálica Profunda , Doença de Parkinson , Núcleo Subtalâmico , Caminhada , Humanos , Núcleo Subtalâmico/fisiopatologia , Doença de Parkinson/fisiopatologia , Doença de Parkinson/terapia , Masculino , Pessoa de Meia-Idade , Caminhada/fisiologia , Feminino , Piscadela/fisiologia , Idoso , Ritmo beta/fisiologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo
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