Variability in non-invasive brain stimulation studies: reasons and results

Non-invasive brain stimulation techniques (NIBS), such as Theta Burst Stimulation (TBS), Paired Associative Stimulation (PAS) and transcranial Direct Current Stimulation (tDCS), are widely used to probe plasticity in the human motor cortex (M1). Although TBS, PAS and tDCS differ in terms of physiological mechanisms responsible for experimentally-induced cortical plasticity, they all share the ability to elicit long-term potentiation (LTP) and depression (LTD) in M1. However, NIBS techniques are all affected by relevant variability in intra- and inter-subject responses. A growing number of factors contributing to NIBS variability have been recently identified and reported. In this review, we have readdressed the issue of variability in human NIBS studies. We have first briefly discussed the physiological mechanisms responsible for TBS, PAS and tDCS-induced cortical plasticity. Then, we have provided statistical measures of intra- and inter-subject variability, as calculated in previous studies. Finally, we have reported in detail known sources of variability by categorizing them into physiological, technical and statistical factors. Improving knowledge about sources of variability could lead to relevant advances in designing new tailored NIBS protocols in physiological and pathological conditions

Distributed cortical structural properties contribute to motor cortical excitability and inhibition

The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license.[Abstract]: Introducción:The link between the local structure of the primary motor cortex and motor function has been well documented. However, motor function relies on a network of interconnected brain regions and the link between the structural properties characterizing these distributed brain networks and motor function remains poorly understood. Here, we examined whether distributed patterns of brain structure, extending beyond the primary motor cortex can help classify two forms of motor function: corticospinal excitability and intracortical inhibition. To this effect, we recorded high-resolution structural magnetic resonance imaging scans in 25 healthy volunteers. To measure corticospinal excitability and inhibition in the same volunteers we recorded motor evoked potentials (MEPs) elicited by single-pulse transcranial magnetic stimulation (TMS) and short-interval intracortical inhibition (SICI) in a separate session. Support vector machine (SVM) pattern classification was used to identify distributed multivoxel gray matter areas, which distinguished subjects who had lower and higher MEPs and SICIs. We found that MEP and SICI classification could be predicted based on a widely distributed, largely nonoverlapping pattern of voxels in the frontal, parietal, temporal, occipital and cerebellar regions. Thus, structural properties distributed over the brain beyond the primary motor cortex relate to motor function

Influence of situational variables on changes in direction of ball possession in football

[Resume]: Los objetivos de este estudio fueron (a) identificar como las variables situacionales afectan a los cambios de dirección de la circulación en fútbol; y (b) conocer la relación entre la observación externa del juego, interpretaciones de los jugadores e intención previa del entrenador de un equipo profesional de fútbol. Se visualizaron veinticinco partidos (n=25) correspondientes a la temporada 2016/2017. Las grabaciones de video de los partidos fueron analizadas y codificadas después de cada evento mediante metodología observacional. A través de la prueba no paramétrica de Kruskal-Wallis, se verificó como los cambios de dirección de la circulación del balón entre los tres carriles longitudinales están relacionados de manera estadísticamente significativa con el tiempo de posesión (H=64.046; p<.001) y el resultado parcial (H=17.095; p<0.05). El nivel del equipo adversario no ha resultado ser significativo. La regresión logística multinomial permitió verificar como a medida que aumenta la duración de la posesión, el equipo juega como local y/o ante equipos ubicados en la zona media de la tabla clasificatoria, se incrementan las probabilidades de realizar tres o más cambios de dirección de la circulación del balón (p < 0.05). Además, la interpretación de los jugadores no siempre está relacionada con la observación externa o intención previa del entrenador. Se espera que los resultados obtenidos ayuden a staff técnico y jugadores a entender las probabilidades de una gestión de la posesión del balón más eficiente en competición.[Abstract]: The aims of this study were (a) to identify how situational variables affect changes in the direction of ball circulation in football and (b) know the relationship between behaviors, players interpretations and the coach previous intention in the football team finishing situations. Twenty-five matches (n=25) were shown in the 2016/2017 season. The matches video recordings were analyzed and coded after each event using observational methodology. Through the nonparametric test of Kruskal-Wallis, it was verified how the changes of direction of the circulation of the ball are related in a statistically significant way with the time of possession (H=64.046; p <.001)and the partial result (H=17,095;p <0.05). Opposing team level has not been significant. The multinomial logisticregression allowed to verify that as the duration of possession increases, the team plays as a local player and/or before teams located in the middle zone of the qualifying table, the chances of making three or more direction ball possession changes are increased (p <0.05). In addition, players interpretation is not always related to the external observation or previous intention of the coach. The results obtained provide information related to potential bifurcation points that may emerge during the game. It is expected that the results obtained will help technical staff and players understand the probabilities of managing more efficiently ball possession in competition

Gait pattern and cognitive performance during treadmill walking in Parkinson disease

[Abstract] Objective: The aim of this study was to explore whether attentional demands are involved in gait improvements in Parkinson disease (PD) patients when they walk on a treadmill. Design: Nineteen individuals with idiopathic PD and 19 age-matched healthy controls participated in this study. Participants walked on a treadmill and on overground under single task (walk only) and dual task (walk performing a simultaneous cognitive task) conditions. The dual-task paradigm was used to reveal the attention allocation behavior. Gait pattern and cognitive performance was measured. Results: The PD group showed reduced gait variability when walking on a treadmill in comparison with overground. However, this reduction did not deteriorate during the dual task. Moreover, there were no differences in the cognitive performance between treadmill and overground walking. Conclusions: This study does not support the proposition attentional resource allocation as a possible mechanism for the treadmill-associated gait improvements observed in PD.Ministerio de Ciencia e Innovación; DEP2011-2246

Chronic functional adaptations induced by the application of transcranial direct current stimulation combined with exercise programs: A systematic review of randomized controlled trials

This work was supported by the Spanish Ministry of Science, Innovation, and Universities under Grant (PID2021-128204OA-I00-AEI/FEDER, UE)[Abstract]: The present systematic review aimed to determine the chronic effects of the combination of transcranial direct current stimulation (tDCS) and exercise on motor function and performance outcomes. We performed a systematic literature review in the databases MEDLINE and Web of Science. Only randomized control trials that measured the chronic effect of combining exercise (comprising gross motor tasks) with tDCS during at least five sessions and measured any type of motor function or performance outcome were included. A total of 22 interventions met the inclusion criteria. Only outcomes related to motor function or performance were collected. Studies were divided into three groups: (a) healthy population (n = 4), (b) neurological disorder population (n = 14), and (c) musculoskeletal disorder population (n = 4). The studies exhibited considerable variability in terms of tDCS protocols, exercise programs, and outcome measures. Chronic use of tDCS in combination with strength training does not enhance motor function in healthy adults. In neurological disorders, the results suggest no additive effect if the exercise program includes the movements pretending to be improved (i.e., tested). However, although evidence is scarce, tDCS may enhance exercise-induced adaptations in musculoskeletal conditions characterized by pain as a limiting factor of motor function.Xunta de Galicia, Universidade da Coruna/CISUG ; (ED431B 2021/28

The effects of auditory startle and nonstartle stimuli on step initiation in Parkinson's disease

[Abstract] Background. Auditory external cues enhance step initiation in Parkinson's disease (PD) patients. We wanted to explore whether a startle reaction has a comparable effect on step initiation in PD. Methods. Thirteen PD patients and 13 aged-matched controls participated in this study. Electromyography pattern and onset toe-off time during a step initiation task were recorded in response to three different stimuli: a visual imperative stimulus; visual stimulus simultaneous with a nonstartle auditory stimulus and with a startle auditory stimulus. Results. In all subjects, onset of tibialis anterior was faster in the startle auditory condition, compared with the nonstartle auditory condition. However, in the patient group, there was no difference in onset of soleus and toe-off between the startle and nonstartle conditions. Conclusions. Startle reaction in PD patients demonstrates a disordered coupling between the anticipatory postural adjustments that initiate the weight shift and the movement to initiate toe-off during step initiation.Ministerio de Ciencia e Innovación; PSI2008-0317

Is babesiosis a rare zoonosis in Spain? Its impact on the Spanish Health System over 23 years

Background: Babesiosis is a zoonosis caused by an intraerythrocytic protozoan of the genus Babesia and transmitted mainly by ticks of the Ixodes spp. complex. There is no comprehensive global incidence in the literature, although the United States, Europe and Asia are considered to be endemic areas. In Europe, the percentage of ticks infected with Babesia spp. ranges from 0.78% to 51.78%. The incidence of babesiosis in hospitalized patients in Spain is 2.35 cases per 10,000,000 inhabitants/year. The mortality rate is estimated to be approximately 9% in hospitalized patients but can reach 20% if the disease is transmitted by transfusion. Objective: To analyze the epidemiological impact of inpatients diagnosed with babesiosis on the National Health System (NHS) of Spain between 1997 and 2019. Methodology: A retrospective longitudinal descriptive study that included inpatients diagnosed with babesiosis [ICD-9-CM code 088.82, ICD-10 code B60.0, cases ap2016-2019] in public Spanish NHS hospitals between 1 January 1997 and 31 December 2019 was developed. Data were obtained from the minimum basic dataset (CMBD in Spanish), which was provided by the Ministerio de Sanidad, Servicios Sociales e Igualdad after the receipt of a duly substantiated request and the signing of a confidentiality agreement. Main findings: Twenty-nine inpatients diagnosed with babesiosis were identified in Spain between 1997 and 2019 (IR: 0.28 cases/10,000,000 person-years). A total of 82.8% of the cases were men from urban areas who were approximately 46 years old. The rate of primary diagnoses was 55.2% and the number of readmissions was 79.3%. The mean hospital stay was 20.3±19.2 days, with an estimated cost of €186,925.66. Two patients, both with secondary diagnoses of babesiosis, died in our study. Conclusions: Human babesiosis is still a rare zoonosis in Spain, with an incidence rate that has been increasing over the years. Most cases occurred in middle-aged men from urban areas between summer and autumn. The Castilla-La-Mancha and Extremadura regions recorded the highest number of cases. Given the low rate of primary diagnoses (55.2%) and the high number of readmissions (79.3%), a low clinical suspicion is likely. There was a 6.9% mortality in our study. Both patients who died were patients with secondary diagnoses of the disease

The Effects of Startle and Non-Startle Auditory Stimuli on Wrist Flexion Movement in Parkinson's Disease

[Abstract] Startle stimuli lead to shorter reaction times in control subjects and Parkinson's disease (PD) patients. However, non-startle stimuli also enhance movement initiation in PD. We wanted to examine whether a startle-triggered movement would retain similar kinematic and EMG-related characteristics compared to one induced by a non-startle external cue in PD patients. In this study we investigated the electromyography pattern and the reaction time during a wrist flexion movement in response to three different stimuli: a visual imperative stimulus; visual stimulus simultaneous with a non-startle auditory stimulus and with a startle auditory stimulus. Ten PD patients and ten aged matched controls participated in this study. The reaction times were faster for startle and non-startle stimuli in comparison with the visual imperative stimulus, in both patients and control subjects. The startle cue induced a faster reaction than the non-startle cue. The electromyography pattern remained unchanged across the conditions. The results suggest that the startle reaction effect for upper limb movements are unimpaired in PD patients and has different characteristics than the effect of non-startle stimuli.Ministerio de Ciencia e Innovación; DEP2011-2246

Epidemiological assessment of 5598 brucellosis inpatients in Spain (1997-2015)

Brucellosis remains one of the main zoonoses worldwide. Epidemiological data on human brucellosis in Spain are scarce. The objective of this study was to assess the epidemiological characteristics of inpatient brucellosis in Spain between 1997 and 2015. A retrospective longitudinal descriptive study was performed. Data were requested from the Health Information Institute of the Ministry of Health and Equality, which provided us with the Minimum Basic Data Set of patients admitted to the National Health System. We also obtained data published in the System of Obligatory Notifiable Diseases. A total of 5598 cases were registered. The period incidence rate was 0.67 (95% CI 0.65?0.68) cases per 100 000 person-years. We observed a progressive decrease in the number of cases and annual incidence rates. A total of 3187 cases (56.9%) came from urban areas. The group most at risk comprised men around the fifth decade of life. The average (±S.D.) hospital stay was 12.6 days (±13.1). The overall lethality rate of the cohort was 1.5%. The number of inpatients diagnosed with brucellosis decreased exponentially. The group of patients with the highest risk of brucellosis in our study was males under 45 years of age and of urban origin. The lethality rate has reduced to minimum values. It is probable that hospital discharge records could be a good database for the epidemiological analysis of the hospital management of brucellosis and offer a better information collection system than the notifiable diseases system (EDO in Spanish)

Epidemiological Scenario of Q Fever Hospitalized Patients in the Spanish Health System: What's New

Objectives: The objective of this study was to assess the epidemiology and burden of Q fever (QF) in Spain. Methods: We designed a retrospective descriptive study using the minimum basic data set in patients admitted to hospitals of the National Health System between 1998 and 2015 with a diagnosis of Q fever (ICD-9: 083.0.). Results: We found 4214 hospitalized patients with a mean age (±SD) of 50.9±19.3 years. The male/female ratio was 3:1. The incidence rate was between 0.41 and 0.65 cases per 100,000 person-years over the 18-year period. The highest incidence of cases was from March to August (p=0.024). 21.1% patients had pneumonia, 17.5% had liver disease, and only 3.2% had endocarditis. The average hospital stay was 13.8 days (±12.8). A total of 117 (2.8%) patients died. The total mean cost of QF is approximately €154,232,779 (€36,600±139,422 per patient). Conclusions: QF is an important zoonosis in Spain with a stable incidence rate and high cost for hospitalization. Older patients have a more severe clinical picture and higher mortality, which can be decreased with early clinical suspicion