Pavel Prado

San Sebastián University | USS · Escuela de Fonoadiologia

The sensorimotor adaptation process is crucial for maintaining oral communication. Recent studies have shown that individuals with non-phonotraumatic vocal hyperfunction (NPVH) experience difficulties in sensorimotor adaptation when speaking in noise (known as the Lombard effect). However, the role of auditory and somatosensory feedback in the dyna...

Background Structural income inequality – the uneven income distribution across regions or countries – could affect brain structure and function, beyond individual differences. However, the impact of structural income inequality on the brain dynamics and the roles of demographics and cognition in these associations remains unexplored. Methods Here...

Brain clocks, which quantify discrepancies between brain age and chronological age, hold promise for understanding brain health and disease. However, the impact of diversity (including geographical, socioeconomic, sociodemographic, sex and neurodegeneration) on the brain-age gap is unknown. We analyzed datasets from 5,306 participants across 15 cou...

Ketamine is a dissociative anesthetic that induces a shift in global consciousness states and related brain dynamics. Portable low-density EEG systems could be used to monitor these effects. However, previous evidence is almost null and lacks adequate methods to address global dynamics with a small number of electrodes. This study delves into brain...

Brain clocks, which quantify discrepancies between brain age and chronological age, hold promise for understanding brain health and disease. However, the impact of multimodal diversity (geographical, socioeconomic, sociodemographic, sex, neurodegeneration) on the brain age gap (BAG) is unknown. Here, we analyzed datasets from 5,306 participants acr...

INTRODUCTION Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) lack mechanistic biophysical modeling in diverse, underrepresented populations. Electroencephalography (EEG) is a high temporal resolution, cost‐effective technique for studying dementia globally, but lacks mechanistic models and produces non‐replicable res...

Methods In a double-blinded cross-over design, 30 adults (mean age = 25.57, SD = 3.74; all male) were administered racemic ketamine and compared against saline infusion as a control. Both task-driven (auditory oddball paradigm) and resting-state EEG were recorded. HOI were computed using advanced multivariate information theory tools, allowing us t...

Background Abnormal gamma oscillations (γ) have been systematically reported in preclinical animal models of Alzheimer’s disease (AD) and human AD patients. However, little is known about the underlying mechanisms, non‐linear dynamics, and high‐order interactions of γ in dementia. Method To bridge this gap, we combined EEG and fMRI with three nove...

Background Neuroimaging biomarkers are intensively investigated in Alzheimer disease (AD) and the behavioral variant frontotemporal dementia (bvFTD). However, advanced ND biomarkers (i.e., PET and plasma) are expensive or not widely available/validated in underrepresented regions. EEG emerges as a promising alternative, due to its low‐cost, non‐inv...

The Latin American Brain Health Institute (BrainLat) has released a unique multimodal neuroimaging dataset of 780 participants from Latin American. The dataset includes 530 patients with neurodegenerative diseases such as Alzheimer’s disease (AD), behavioral variant frontotemporal dementia (bvFTD), multiple sclerosis (MS), Parkinson’s disease (PD),...

High-altitude hypoxia triggers brain function changes reminiscent of those in healthy aging and Alzheimer's disease, compromising cognition and executive functions. Our study sought to validate high-altitude hypoxia as a model for assessing brain activity disruptions akin to aging. We collected EEG data from sixteen healthy volunteers during acute...

Introduction: Harmonization protocols that address batch effects and cross-site methodological differences in multi-center studies are critical for strengthening electroencephalography (EEG) signatures of functional connectivity (FC) as potential dementia biomarkers. Methods: We implemented an automatic processing pipeline incorporating electrod...

The neurocomputational model ‘Directions into Velocities of Articulators’ (DIVA) was developed to account for various aspects of normal and disordered speech production and acquisition. The neural substrates of DIVA were established through functional magnetic resonance imaging (fMRI), providing physiological validation of the model. This study int...

Although social functioning relies on working memory, whether a social-specific mechanism exists remains unclear. This undermines the characterization of neurodegenerative conditions with both working memory and social deficits. We assessed working memory domain-specificity across behavioral, electrophysiological, and neuroimaging dimensions in 245...

The treatment of neurodegenerative diseases is hindered by lack of interventions capable of steering multimodal whole-brain dynamics towards patterns indicative of preserved brain health. To address this problem, we combined deep learning with a model capable of reproducing whole-brain functional connectivity in patients diagnosed with Alzheimer's...

Multicentric initiatives based on high-density electroencephalography (hd-EEG) are urgently needed for classification and characterization of diseases subtypes in diverse and low-resource settings. These initiatives are, however, not without challenges, with sources of variability arising from differing data acquisition and harmonization methods, m...

Healthy brain dynamics can be understood as the emergence of a complex system far from thermodynamic equilibrium. Brain dynamics are temporally irreversible and thus establish a preferred direction in time (i.e., arrow of time). However, little is known about how the time-reversal symmetry of spontaneous brain activity is affected by Alzheimer's di...

Brain functional connectivity in dementia has been assessed with dissimilar EEG connectivity metrics and estimation procedures, thereby increasing results' heterogeneity. In this scenario, joint analyses integrating information from different metrics may allow for a more comprehensive characterization of brain functional interactions in different d...

The value of Electroencephalography (EEG) to unveil pathophysiological signatures in neurodegenerative diseases that cause dementia has been recently highlighted. To grant EEG tools the necessary validity, reliability, and scalability to support the diagnosis of dementia globally, efforts will need to integrate knowledge developed by EEG labs acros...

Brain functional connectivity analyses derived from electroencephalography (EEG) provides relevant information for classification of dementia subtypes. The predictive strength of classification tools can be benefit from integrative, multi‐feature analysis of EEG which result in composite metric of functional connectivity. Additionally, significant...

Brain functional networks have been traditionally studied considering only interactions between pairs of regions, neglecting the richer information encoded in higher orders of interactions. In consequence, most of the connectivity studies in neurodegeneration and dementia use standard pairwise metrics. Here, we developed a genuine high-order functi...

Purpose This study aims to describe variations in acoustic and electroencephalography measures when speaking in the presence of background noise (Lombard effect) in participants with typical voice and normal hearing. Method Twenty-one participants with typical voices and normal hearing uttered simple vocal tasks in three sequential background condi...

The treatment of neurodegenerative diseases is hindered by lack of interventions capable of steering multimodal whole-brain dynamics towards patterns indicative of preserved brain health. To address this problem, we combined deep learning with a model capable of reproducing whole-brain functional connectivity in patients diagnosed with Alzheimer's...

Purpose This exploratory study aims to investigate variations in voice production in the presence of background noise (Lombard effect) in individuals with nonphonotraumatic vocal hyperfunction (NPVH) and individuals with typical voices using acoustic, aerodynamic, and vocal fold vibratory measures of phonatory function. Method Nineteen participant...

Neural entrainment, the synchronization of brain oscillations to the frequency of an external stimuli, is a key mechanism that shapes perceptual and cognitive processes. Objective . Using simulations, we investigated the dynamics of neural entrainment, particularly the period following the end of the stimulation, since the persistence (reverberatio...

Background The predictive coding theory of allostatic interoceptive load states that brain networks mediating autonomic regulation and interoceptive-exteroceptive balance regulate the internal milieu to anticipate future needs and environmental demands. These functions seems to be distinctly compromised in behavioral variant frontotemporal dementia...

The proposal to use brain connectivity as a biomarker for dementia phenotyping can be potentiated by conducting large-scale multicentric studies using high-density electroencephalography (hd- EEG). Nevertheless, several barriers preclude the development of a systematic “ConnEEGtome” in dementia research. Here we review critical sources of variabili...

The entrainment (synchronization) of brain oscillations to the frequency of sensory stimuli is a key mechanism that shapes perceptual and cognitive processes, such that atypical neural entrainment leads to neuro-psychological deficits. Objective We investigated the dynamic of neural entrainment. Particular attention was paid to the oscillatory beh...

Introduction Vocal Hyperfunction (VH) refers to excessive perilaryngeal musculoskeletal activity . A recent framework proposes two subtypes of VH depending on the presence or absence of vocal fold tissue lesion, i.e., phonotraumatic VH (PVH) and non-phonotraumatic VH (NPVH). Previous studies using auditory feedback perturbation with pitch shift pa...

Objective: The envelope following response (EFR) is a clinically relevant evoked potential, reflecting the synchronization of the auditory pathway to the temporal envelope of sounds. Since there is no standard analysis of this potential, we here aim at contrasting the relative accuracy of known time-frequency methods and new strategies for the rel...

Introducción. La comprensión del lenguaje está determinada por diversos procesos, entre los que se encuentra el reconocimiento léxico. Según el modelo conexionista, este reconocimiento se genera por activación mediante el emparejamiento de la información acumulada y por la inhibición de las entradas léxicas que compiten por activación. Objetivo. D...

Neural entrainment is the synchronization of neural activity to the frequency of repetitive external stimuli, which can be observed as an increase in the electroencephalogram (EEG) power spectrum at the driving frequency, -also known as the steady-state response. Although it has been systematically reported that the entrained EEG oscillation persis...

The envelope following response (EFR) is a scalp-recorded evoked potential elicited by carrier tones or noise, modulated in amplitude with a continuous sweep of modulation frequencies. This non-stationary response reflects the phase-locked neural activity of the auditory pathway to the temporal envelope of sounds and has been commonly assessed by f...

Entrainment persists after the stimulation ends. Duration of the persistence depends on the phase at the time the stimulus is removed.

Objectives: To determine whether the neural entrainment is sustained once the periodic stimulus has been removed. To investigate the neural generators involved in the persistence of the entrainment.

Removal of artifacts induced by muscle activity is crucial for analysis of the electroencephalogram (EEG), and continues to be a challenge in experiments where the subject may speak, change facial expressions, or move. Ensemble empirical mode decomposition with canonical correlation analysis (EEMD-CCA) has been proven to be an efficient method for...

The amplitude of auditory steady-state responses (ASSRs) generated in the brainstem of rats exponentially decreases over the sequential averaging of EEG epochs. This behavior is partially due to the adaptation of the ASSR induced by the continuous and monotonous stimulation. In this study, we analyzed the potential clinical relevance of the ASSR ad...

Auditory steady-state responses (ASSRs) are brain oscillations locked to the periodic properties of acoustic stimuli. Audiological tests based on the acquisition of ASSR are useful for estimating the hearing sensitivity, mainly because multiple hearing frequencies can be simultaneously assessed, and the auditory response can be objectively detected...

Auditory steady-state responses (ASSRs) are brain oscillations locked to the periodic properties of acoustic stimuli. Audiological tests based on the acquisition of ASSR are useful for estimating the hearing sensitivity, mainly because multiple hearing frequencies can be simultaneously assessed, and the auditory response can be objectively detected...

The amplitude of the auditory steady-state responses (ASSRs) generated in the brainstem exponentially decreases over the averaging of subsequent EEG epochs. This behavior is partially due to the adaptation of the auditory response to the continuous and monotonous stimulation. We analyzed the potential clinical relevance of the ASSR adaptation. Spec...

ne of the most common yet least understood hyperfunctional voice disorders is muscle tension dysphonia (MTD). The etiology of MTD remains unclear, but most MTD patients report having to produce an overly increased vocal effort under noisy environments. This an unconscious response, called the Lombard effect (LE), where subjects increase vocal loudn...

Mutations in human connexin (Cx) genes have been related to diseases, which we termed connexinopathies. Such hereditary disorders include nonsyndromic or syndromic deafness (Cx26, Cx30), Charcot Marie Tooth disease (Cx32), occulodentodigital dysplasia and cardiopathies (Cx43), and cataracts (Cx46, Cx50). Despite the clinical phenotypes of connexino...

The study of the temporal processing of acoustic signals by the auditory system becomes increasingly important for the development of new strategies for diagnosis and treatment of people who are deaf or hearing impaired. In this work we evaluated different methodologies ─chirp analyzer (AFM), short time Fourier transform (TFTC) and continuous wav...

Generation of the auditory steady state responses (ASSR) is commonly explained by the linear combination of random background noise activity and the stationary response. Based on this model, the decrease of amplitude that occurs over the sequential averaging of epochs of the raw data has been exclusively linked to the cancelation of noise. Neverthe...

Aminoglycosides are efficient antimicrobials commonly used in clinical practice. Their effects on the cells of the organ of Corti and the spiral ganglion neurons have been extensively studied. However, there are only a few reports concerning aminoglycoside-induced morphological changes on the stria vascularis. The purpose of this study was to descr...

The study of temporal processing of acoustic sig-nals by the auditory system becomes increasingly important for the development of new strategies for diagnosis and treat-ment of people who are deaf or hearing impaired. Objectives: To evaluate three time-frequency methods (Short Time Fouri-er Transform, Morlet Wavelet Transform, and a newly pro-pose...

The maturation pattern of the envelope following response (EFR) was described using rats as an experimental model. EFRs were recorded in animals at different postnatal ages (15, 20, 25, 35, and 70 postnatal days) in response to broadband noise (BBN) and tones of 8000 and 4000 Hz modulated in amplitude using a continuous sweep of modulation frequenc...

The purpose of this study is to better characterize the hematological, biochemical, respiratory, cardiovascular and electroneurophysiological parameters in young adult Cercopithecus aethiops sabaeus of both sexes. The rhesus and cynomolgus monkeys are widely used as experimental primate models. However, only few articles have been published testing...

Deafness is one of the most widespread disabilities in the world. Its most frequent cause is death of cochlear hair cells (located in the organ of Corti), which induces degeneration of spiral ganglion neurons and their peripheral processes innervating the organ of Corti. In a previous light microscopy study using a rat model of ototoxicity, a loss...

La sordera es una de las discapacidades más comunes mundialmente, con una incidencia en Cuba de 2,1 por cada 1 000 habitantes. La mayoría de las sorderas son de origen sensorineural, debido a la muerte de las células ciliadas cocleares, localizadas en el órgano de Corti, lo que conduce a la degeneración de las neuronas del ganglio espiral. En un tr...

We investigated the effect of pulse duration (PD) and interphase-gap (IPG) on the electrically-evoked auditory brain stem response (EABR) and viiith nerve compound action potential (ECAP) of deafened guinea pigs in order to test the hypothesis that the extent of change in these neural responses is affected by the histological status of the auditory...

Los implantes cocleares (IC) son dispositivos que permiten la recuperación de la audición en individuos que padecen de sordera sensorial u otro tipo de sordera que tenga su origen en el órgano receptor auditivo, ya que sustituyen el papel desempeñado por las células ciliadas. Sin embargo, el hecho de que las prótesis cocleares utilicen estímulos el...

Resumen Introducci ón : En este trabajo se estudian las células tipo I del ganglio espiral (GE) de la cóclea. Adem ás de ser las m ás susceptibles al dañ o, constituyen el 95% de la población celular, por lo que son decisivas en la aplicación de los implantes cocleares. En un estudio previo al microscopio óptico, desde la segunda semana de sordera...

Damage induced by ototoxic therapeutic drugs is among the main causes of auditive losses in humans. The objective of this work was to explore the temporal dynamics of an ototoxic treatment with kanamycin and furosemide on the cytoarchitecture of the organ of Corti and the spiral ganglion in adult rats. Cochlear sections from deaf rats (removed at 2...

A pesar de la comprobada ototoxicidad de los aminoglucósidos, éstos continúan empleándose frecuentemente en la clínica por su alta efectividad bactericida [1-3]. El dominio de modelos de ototoxicidad constituye un arma potente para las investigaciones que se imponen ante el desarrollo de nuevos enfoques para aliviar o resolver la sordera. El objeti...