Assessment of Audio-Tactile Sensory Substitution Training in Participants with Profound Deafness Using the Event-Related Potential Technique.

This paper examines the application of electroencephalogram-based methods to assess the effects of audio-tactile substitution training in young, profoundly deaf (PD) participants, with the aim of analyzing the neural mechanisms associated with vibrotactile complex sound discrimination. Electrical brain activity reflects dynamic neural changes, and the temporal precision of event-related potentials (ERPs) has proven to be key in studying time-locked processes while performing behavioral tasks that involve attention and working memory. The current protocol was designed to study electrophysiological activity in PD subjects while they performed a continuous performance task (CPT) using complex-sound stimuli, consisting of five different animal sounds delivered through a portable stimulator system worn on the right index finger. As a repeated-measures design, electroencephalogram (EEG) recordings in standard conditions were performed before and after a brief training program (five 1 h sessions over 15 days), followed by offline artifact correction and epoch averaging, to obtain individual and grand-mean waveforms. Behavioral results show a significant improvement in discrimination and a more robust P3-like centroparietal positive waveform for the target stimuli after training. In this protocol, ERPs contribute to the further understanding of learning-related neural changes in PD subjects associated with audio-tactile discrimination of complex sounds.

Type 1 diabetes affects the brain functional connectivity underlying working memory processing.

Visuospatial working memory (VSWM) deficits have been demonstrated to occur during the development of type-1-diabetes (T1D). Despite confirming the early appearance of distinct task-related brain activation patterns in T1D patients compared to healthy controls, the effect of VSWM load on functional brain connectivity during task performance is still unknown. Using electroencephalographic methods, the present study evaluated this topic in clinically well-controlled T1D young patients and healthy individuals, while they performed a VSWM task with different memory load levels during two main VSWM processing phases: encoding and maintenance. The results showed a significantly lower number of correct responses and longer reaction times in T1D while performing the task. Besides, higher and progressively increasing functional connectivity indices were found for T1D patients in response to cumulative degrees of VSWM load, from the beginning of the VSWM encoding phase, without notably affecting the VSWM maintenance phase. In contrast, healthy controls managed to solve the task, showing lower functional brain connectivity during the initial VSWM processing steps with more gradual task-related adjustments. Present results suggest that T1D patients anticipate high VSWM load demands by early recruiting supplementary processing resources as the probable expression of a more inefficient, though paradoxically better adjusted to task demands cognitive strategy.

Quantitative EEG measures in profoundly deaf and normal hearing individuals while performing a vibrotactile temporal discrimination task.

Challenges in early oral language acquisition in profoundly deaf individuals have an impact on cognitive neurodevelopment. This has led to the exploration of alternative sound perception methods involving training of vibrotactile discrimination of sounds within the language spectrum. In particular, stimulus duration plays an important role in linguistic categorical perception. We comparatively evaluated vibrotactile temporal discrimination of sound and how specific training can modify the underlying electrical brain activity. Fifteen profoundly deaf (PD) and 15 normal-hearing (NH) subjects performed a vibrotactile oddball task with simultaneous EEG recording, before and after a short training period (5 one-hour sessions; in 2.5-3 weeks). The stimuli consisted of 700 Hz pure-tones with different duration (target: long 500 ms; non-target: short 250 ms). The sound-wave stimuli were delivered by a small device worn on the right index finger. A similar behavioral training effect was observed in both groups showing significant improvement in sound-duration discrimination. However, quantitative EEG measurements reveal distinct neurophysiological patterns characterized by higher and more diffuse delta band magnitudes in the PD group, together with a generalized decrement in absolute power in both groups that might reflect a facilitating process associated to learning. Furthermore, training-related changes were found in the beta-band in NH. Findings suggest PD have different cognitive adaptive mechanisms which are not a mere amplification effect due to greater cortical excitability.

Sustained attention in schoolchildren with type-1 diabetes. A quantitative EEG study.

OBJECTIVE: Type-1 diabetes (T1D) is a disruptive metabolic disease that has an impact on neurodevelopment through its effects on the structure and function of the brain. One of the cognitive domains affected by T1D is sustained attention. The aim of this study was to analyze this process in children with T1D and compare their results to those of healthy controls. METHODS: Seventeen T1D children attending regular primary school and a similar group of healthy children matched by gender, age, handedness, and educational level were evaluated while identifying happy faces in a Go-NoGo task presented visually with simultaneous electrophysiological recording. RESULTS: Behavioral performance in the two groups was similar but, the T1D children showed greater prefrontal and frontoparietal spectral power in the theta and alpha bands, compared to controls. Distinct patterns of theta lateralization between groups were also observed, with a negative correlation between frontal power magnitudes in delta and theta and glycated hemoglobin levels. CONCLUSIONS: These results seem to reflect the early deleterious effects of T1D on neurodevelopment, which affects mainly attention allocation processes and the neurofunctional substrates that underlie them. SIGNIFICANCE: This phenomenon emphasizes the need for studies on neural-specific targets in which T1D affects neurodevelopment.

Type 1 diabetes and working memory processing of emotional faces.

Several executive functions decline with the development of type-1 diabetes (T1D), particularly working memory (WM). In adults, WM ensures efficient cognitive processing by focusing on task-relevant information while suppressing distractors. It has been well documented that WM can be influenced by emotional stimuli, which may facilitate the retention of information, interfere with uptake, or even affect its capacity. We evaluated the effect of T1D on visual WM processing using emotional faces as stimuli, in young patients with satisfactory clinical evolution, and matched controls without T1D. All subjects performed a 2-back task detecting facial identity using neutral, happy or fearful faces in a block design for fMRI. Behavioral performance was similar with the exception that patients responded significantly slower. Most importantly, between-group differences were found in patterns of brain activation. In comparison, more widespread brain activation -predominantly prefrontal- was found in the participants with T1D when processing neutral faces, while a decrease was observed when processing happy and fearful ones. Statistical contrasts demonstrated significantly-different activation patterns between groups when processing emotional faces, as controls exhibited greater activation in the cuneus, posterior cortex and parahippocampal gyrus, while the patients showed greater activation in the prefrontal structures. Results may reflect compensatory efforts made to minimize the deleterious effects of disease development on attention allocation processes and the operational efficiency of WM. The results suggest that emotional parameters should be periodically assessed in individuals with T1D in order to anticipate the emergence of attention and WM impairment.

Dataset on the EEG time-frequency representation in children with different levels of mathematical achievement.

This article presents the data related to the research paper entitled "The analysis of EEG coherence reflects middle childhood differences in mathematical achievement" (González-Garrido et al., 2018). The dataset is derived from the electroencephalographic (EEG) records registered from a total of 60 8-9-years-old children with different math skill levels (High: HA, Average: AA, and Low Achievement: LA) while performing a symbolic magnitude comparison task. The average brain patterns are shown through Time-Frequency Representations (TFR) for each group, and also grand-mean amplitudes within specific EEG epochs in a 19-electrode array are provided. Making this information publicly available for further analyses could significantly contribute to a better understanding on how math achievement in children associates with cognitive processing strategies.

Complex systems representing effective connectivity in patients with Type One diabetes mellitus.

BACKGROUND: Type 1 diabetes mellitus (T1D) affects the entire cellular network of the organism. Some patients develop cognitive disturbances due to the disease, but several authors have suggested that the brain develops compensatory mechanisms to minimize or prevent neuropsychological decline. The present study aimed to assess the effective connectivity underlying visuospatial working memory performance in young adults diagnosed with T1D using neuroimaging techniques (fMRI). METHODS: Fifteen T1D right-handed, young adults with sustained metabolic clinical stability and a control group matched by age, sex, and educational level voluntarily participated. All participants performed 2 visuospatial working memory tasks using a block design within an MRI scanner. Regions of interest and their signal values were obtained. Effective connectivity-by means of structural equations models-was evaluated for each group and task through maximum likelihood estimation, and the model with the best fit was chosen in each case. RESULTS: Compared to the control group, the patient group showed a significant reduction in brain activity in the two estimated networks (one for each group and task). The models of effective connectivity showed greater brain connectivity in healthy individuals, as well as a more complex network. T1D patients showed a pattern of connectivity mainly involving the cerebellum and the red nucleus. In contrast, the control group showed a connectivity network predominantly involving brain areas that are typically activated while individuals are performing working memory tasks. CONCLUSION: Our results suggest a specific effective connectivity between the cerebellum and the red nucleus in T1D patients during working memory tasks, probably reflecting a compensatory mechanism to fulfill task demands.

Is sex an influential factor in type-1 diabetes neurofunctional development? A preliminary study.

The aim of the study was to evaluate the neurofunctional effect of gender in Type-1 Diabetes Mellitus (T1DM) patients during a Visual Spatial Working Memory (VSWM) task. The study included 28 participants with ages ranging from 17-28 years. Fourteen well-controlled T1DM patients (7 female) and 14 controls matched by age, sex, and education level were scanned performing a block-design VSWM paradigm. Behavioral descriptive analyses and mean comparisons were done, and between-group and condition functional activation patterns were also compared. Whole-brain cumulative BOLD signal (CumBS), voxel-wise BOLD level frequency, Euclidean distance, and divergence indices were also calculated. There were no significant differences between or within-group sex differences for correct responses and reaction times. Functional activation analyses showed that females had activation in more brain regions, and with larger clusters of cortical activations than males. Furthermore, BOLD activation was higher in males. Despite the preliminary nature of the present study given the relatively small sample size, current results acknowledge for the first time that sex might contribute to differences in functional activation in T1DM patients. Findings suggest that sex differences should be considered when studying T1DM-disease development.

The analysis of EEG coherence reflects middle childhood differences in mathematical achievement.

Symbolic numerical magnitude processing is crucial to arithmetic development, and it is thought to be supported by the functional activation of several brain-interconnected structures. In this context, EEG beta oscillations have been recently associated with attention and working memory processing that underlie math achievement. Due to that EEG coherence represents a useful measure of brain functional connectivity, we aimed to contrast the EEG coherence in forty 8-to-9-year-old children with different math skill levels (High: HA, and Low achievement: LA) according to their arithmetic scores in the Fourth Edition of the Wide Range Achievement Test (WRAT-4) while performing a symbolic magnitude comparison task (i.e. determining which of two numbers is numerically larger). The analysis showed significantly greater coherence over the right hemisphere in the two groups, but with a distinctive connectivity pattern. Whereas functional connectivity in the HA group was predominant in parietal areas, especially involving beta frequencies, the LA group showed more extensive frontoparietal relationships, with higher participation of delta, theta and alpha band frequencies, along with a distinct time-frequency domain expression. The results seem to reflect that lower math achievements in children mainly associate with cognitive processing steps beyond stimulus encoding, along with the need of further attentional resources and cognitive control than their peers, suggesting a lower degree of numerical processing automation.

Effect of verbal task complexity in a working memory paradigm in patients with type 1 diabetes. A fMRI study.

Type 1 diabetes (T1D) is commonly diagnosed in childhood and adolescence, and the developing brain has to cope with its deleterious effects. Although brain adaptation to the disease may not result in evident cognitive dysfunction, the effects of T1D on neurodevelopment could alter the pattern of BOLD fMRI activation. The aim of this study was to explore the neural BOLD activation pattern in patients with T1D versus that of healthy matched controls while performing two visuospatial working memory tasks, which included a pair of assignments administered through a block design. In the first task (condition A), the subjects were shown a trial sequence of 3 or 4 white squares positioned pseudorandomly around a fixation point on a black background. After a fixed delay, a second corresponding sequence of 3 or 4 red squares was shown that either resembled (direct, 50%) or differed from (50%) the previous stimulation order. The subjects were required to press one button if the two spatial sequences were identical or a second button if they were not. In condition B, the participants had to determine whether the second sequence of red squares appeared in inverse order (inverse, 50%) or not (50%) and respond by pressing a button. If the latter sequence followed an order distinct from the inverse sequence, the subjects were instructed to press a different button. Sixteen patients with normal IQ and without diabetes complications and 16 healthy control subjects participated in the study. In the behavioral analysis, there were no significant differences between the groups in the pure visuo-spatial task, but the patients with diabetes exhibited poorer performance in the task with verbal stimuli (p < .001). However, fMRI analyses revealed that the patients with T1D showed significantly increased activation in the prefrontal inferior cortex, subcortical regions and the cerebellum (in general p < .001). These different activation patterns could be due to adaptive compensation mechanisms that are devoted to improving efficiency while solving more complex cognitive tasks.

Electrophysiological dynamic brain connectivity during symbolic magnitude comparison in children with different mathematics achievement levels.

Children with mathematical difficulties usually have an impaired ability to process symbolic representations. Functional MRI methods have suggested that early frontoparietal connectivity can predict mathematic achievements; however, the study of brain connectivity during numerical processing remains unexplored. With the aim of evaluating this in children with different math proficiencies, we selected a sample of 40 children divided into two groups [high achievement (HA) and low achievement (LA)] according to their arithmetic scores in the Wide Range Achievement Test, 4th ed.. Participants performed a symbolic magnitude comparison task (i.e. determining which of two numbers is numerically larger), with simultaneous electrophysiological recording. Partial directed coherence and graph theory methods were used to estimate and depict frontoparietal connectivity in both groups. The behavioral measures showed that children with LA performed significantly slower and less accurately than their peers in the HA group. Significantly higher frontocentral connectivity was found in LA compared with HA; however, when the connectivity analysis was restricted to parietal locations, no relevant group differences were observed. These findings seem to support the notion that LA children require greater memory and attentional efforts to meet task demands, probably affecting early stages of symbolic comparison.

Type 1 Diabetes Modifies Brain Activation in Young Patients While Performing Visuospatial Working Memory Tasks.

In recent years, increasing attention has been paid to the effects of Type 1 Diabetes (T1D) on cognitive functions. T1D onset usually occurs during childhood, so it is possible that the brain could be affected during neurodevelopment. We selected young patients of normal intelligence with T1D onset during neurodevelopment, no complications from diabetes, and adequate glycemic control. The purpose of this study was to compare the neural BOLD activation pattern in a group of patients with T1D versus healthy control subjects while performing a visuospatial working memory task. Sixteen patients and 16 matched healthy control subjects participated. There was no significant statistical difference in behavioral performance between the groups, but, in accordance with our hypothesis, results showed distinct brain activation patterns. Control subjects presented the expected activations related to the task, whereas the patients had greater activation in the prefrontal inferior cortex, basal ganglia, posterior cerebellum, and substantia nigra. These different patterns could be due to compensation mechanisms that allow them to maintain a behavioral performance similar to that of control subjects.

La distimia en el contexto clínico / Dysthymia in the Clinical Context

La distimia se define como un trastorno afectivo crónico que persiste por lo menos dos años en adultos y un a ño en adolescentes y niños. Según el DSM IV-TR, se clasifica en dos subtipos: la distimia de inicio temprano, antes de los 21 años, y la de inicio tardío después de los 21 años. Generalmente antes de los 21 años se puede observar trastornos de conducta, déficit de atención e hiperactividad y algunos síntomas vegetativos. Es importante distinguir tempranamente la distimia de otros tipos de depresión, a fin de brindar un tratamiento oportuno que atenúe el impacto continuo de síntomas caracterizados por pobre conciencia del estado de ánimo, pensamiento negativo, baja autoestima y anergia, lo que deteriora progresivamente la calidad de vida. La etiología es compleja y multifactorial, dados los variados mecanismos biológicos, psicológicos y sociales involucrados. Varias hipótesis tratan de explicar la etiología de la distimia; destacan la hipótesis genética que incluye además factores ambientales y la hipótesis aminérgica, que apunta a una deficiencia de serotonina, noradrenalina y dopamina en el sistema nervioso central. Desde nuestro punto de vista, no se puede concebir la distimia como un simple trastorno depresivo leve; es una entidad diferente caracterizada por un trastorno depresivo crónico que puede persistir toda la vida, con importantes repercusiones en la calidad de vida, tanto del sujeto que la padece como de sus familiares.

Dysthymia is defined as a chronic mood disorder that persists for at least two years in adults, and one year in adolescents and children. According to DSM IV-TR, Dysthymia is classified into two subtypes: early-onset, when it begins before 21 years-old, and late onset Dysthymia, when it starts after this age. Before age 21, symptoms of conduct disorder, attention deficit disorder and hyperactivity with a few vegetative symptoms are usually present. It is important to distinguish it from other types of depression, as earlier as possible. This would allow providing these patients with the appropriate treatment to attenuate the impact of symptoms, such as poor awareness of self-mood, negative thinking, low self-esteem, and low energy for social and family activities, which progressively deteriorate their life quality. The etiology of Dysthymia is complex and multifactorial, given the various biological, psychological and social factors involved. Several hypotheses attempt to explain the etiology of Dysthymia, highlighting the genetic hypothesis, which also includes environmental factors, and an aminergic hypothesis suggesting a deficiency in serotonin, norepinephrine and dopamine in the central nervous system. From our point of view, dysthymia cannot be conceived as a simple mild depressive disorder. It is a distinct entity, characterized by a chronic depressive disorder which could persist throughout life, with important repercussions on the life quality of both patients and families.

[Dysthymia in the Clinical Context]. / La distimia en el contexto clínico.

Dysthymia is defined as a chronic mood disorder that persists for at least two years in adults, and one year in adolescents and children. According to DSM IV-TR, Dysthymia is classified into two subtypes: early-onset, when it begins before 21 years-old, and late onset Dysthymia, when it starts after this age. Before age 21, symptoms of conduct disorder, attention deficit disorder and hyperactivity with a few vegetative symptoms are usually present. It is important to distinguish it from other types of depression, as earlier as possible. This would allow providing these patients with the appropriate treatment to attenuate the impact of symptoms, such as poor awareness of self-mood, negative thinking, low self-esteem, and low energy for social and family activities, which progressively deteriorate their life quality. The etiology of Dysthymia is complex and multifactorial, given the various biological, psychological and social factors involved. Several hypotheses attempt to explain the etiology of Dysthymia, highlighting the genetic hypothesis, which also includes environmental factors, and an aminergic hypothesis suggesting a deficiency in serotonin, norepinephrine and dopamine in the central nervous system. From our point of view, dysthymia cannot be conceived as a simple mild depressive disorder. It is a distinct entity, characterized by a chronic depressive disorder which could persist throughout life, with important repercussions on the life quality of both patients and families.