Neurophysics Assessment of the Muscle Bioenergy Generated by Transcranial Magnetic Stimulation.

The content of the rectified motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) has ambiguously been assessed without the precision that energy calculation deserves. This fact has misled data interpretation and misguided biomedical interventions. To definitively fill the gap that exits in the neurophysics processing of these signals, we computed, in Walls ( W ^ ), the bioenergy within the rectified MEP recorded from the human first digitorum index (FDI) muscle at rest and under isometric contraction. We also gauged the biowork exerted by this muscle. Here we show that bioenergy and biowork can accurately and successfully be assessed, validated, and determined in W ^ from MEP signals induced by TMS, regardless of knowing the mathematical expression of the function of the signal. Our novel neurophysics approach represents a dramatic paradigm shift in analysis and interpretation of the content of the MEP and will give a true meaning to the content of rectified signals. Importantly, this innovative approach allowed unveiling that women exerted more bioenergy than men at the magnetic stimulations used in this study. Revisitation of conclusions drawn from studies published elsewhere assessing rectified EMG signals that have used ambiguous units is strongly recommended.

The Three Nociceptive Responses of the Orbicularis Oculi Reflex in Alzheimer's Disease: State of the Evidence and Meta-analysis.

There is an emerging belief that electrically elicited blink reflexes (BR) may distinguish Alzheimer's disease (AD) from other disorders characterized by memory dysfunction. To qualitatively and quantitatively distinguish the effects that electrical stimulation has over the blink reflex (eBR) recorded from patients with AD and healthy controls (HCs), we did a systematic review of the literature, and conducted a meta-analysis. Following our selected criteria, 94 AD patients and 97 HCs were identified from articles published in English between 1950 and 2017. Although the 3 responses (R1, R2 and R3) of the eBR were studied in a number of patients, only the R2 response was quantified in all studies. Thresholds and stimulation intensities parameters were found to be used in a miscellaneous form, and the majority of times, such parameters deviated from validated guidelines. The stimulation frequencies used to elicit the BR responses ranged between 0.14 and 0.2 Hz. These frequencies favored HCs compared with AD patients (odds ratio = 1.08; 95% CI = 0.30-1.85), I2 = 0% [P = .99]; Q = 271.89 [df = 7, P < .000]). Egger's regression test suggested publication bias (intercept = 32.38; 95% CI = -8.98 to -3.2; P = .001). Our results unveiled key shortcomings in the data reported; such shortcomings need to be corrected in future AD research looking for obtaining more reliable and reproducible eBR studies; otherwise, interventions may be misleading.

Key Aspects in Foramen Magnum Meningiomas: From Old Neuroanatomical Conceptions to Current Far Lateral Neurosurgical Intervention.

Foramen magnum meningiomas represent a challenge for neurosurgeons. These tumors require careful surgical manipulation as they are often located in proximity to critical neurovascular structures and the cranial nerves. The far lateral approach is considered the safest neurosurgical approach for excising foramen magnum lesions. It facilitates the access to the anterior foramen magnum and reduces the retraction of vital structures. We describe key historical, epidemiological, genetic, epigenetic, clinical, and neurosurgical aspects of foramen magnum meningiomas. We emphasize the far lateral approach for lesions arising in the foramen magnum, as well as the most appropriate patient positioning for such approach. Caring for these aspects will be rewarded with the best perioperative neurosurgical outcomes.

A new neurometric dissection of the area-under-curve-associated jiggle of the motor evoked potential induced by transcranial magnetic stimulation.

OBJECTIVE: The jiggle of the motor evoked potential (MEP) induced by transcranial magnetic stimulation (TMS) depends on a number of factors including the assessment of this stochastic signal by the method known as area under curve (AUC). We aim to ascertain the MEP findings assessed by the AUC method obtained from individuals affected by lesions at different levels of the neuroaxis. METHODS: We systematically search and critically appraise the scientific reports publishing on the MEP obtained from individuals with hypo- or hyperkinetic disorders of the neural system, and dissect the neurophysical assessment of the obtained data. To accomplish this, we used the instruments named to as U-Pen Instrument for Neurometric Evaluation Uncommonly and Rarely Obtained from NeuroSignals 1.0 (UPINEURON 1.0), and the Quality of Assessment Statistics Index (QuASI). RESULTS: The MEP differences found by the classical peak-to-peak method decreased or disappeared when the AUC was used. The opposite was also true (Kappa=<0.00). The internal consistency of the UPINEURON was 0.88. The mean of the UPINEURON 1.0 indicator was 34.8 (range=16-50), and the mean of the QuASI scores was 56.5 (range 30-80). Spearman correlation between UPINEURON 1.0 and QuASI was 0.513. CONCLUSIONS: The MEP jiggle found in individuals with disordered neural function is not a "minor" factor; it is beyond the underlying neural condition, sample size, type of coils, and number of trials, among other variables. The use of the novel indicators introduced in this investigation will help to improve the analysis of the AUC of neural signals. They may also lead to the reconsideration of current practices.

Neurotripanosomiasis americana: aspectos clínicos de un problema básico / Neurological effects of American trypanosomyiasis: clinical aspects

Trypanosoma cruzi es el agente causal de la enfermedad de Chagas, patología que afecta principalmente estructuras cardiacas e intestinales. Sin embargo, las complicaciones neurológicas no han sido adecuadamente identificadas y estudiadas en Colombia, a pesar de existir allí áreas geográficas que presentan prevalencias de infección iguales o mayores de las informadas en otras latitudes, en donde se le ha dado una mayor atención a este tipo de complicaciones, desde hace ya varios años. Realizamos un metanálisis cualitativo sobre el tema, en la base de datos PubMed, en el motor de búsqueda Altavista y en las revistas colombianas indexadas por Colciencias, así como en tres libros que trataban el tópico de manera específica. Usamos las palabras claves: Trypanosoma, Chagas' disease, nervous system, spinal cord, central nervous system, peripheral nervous system, neuromuscular junction, autonomic nervous system, muscle, muscle disorders, neuromuscular disease, neuromuscular disorders, synapticopathies y dysautonomia. Como criterio de inclusión se debía haber realizado e informado la prueba de ELISA, inmunofluorescencia indirecta, presencia de parasitemia o presencia de parásitos en los tejidos, dependiendo de si se trataba de un estudio clínico-serológico o histopatólogico. No tuvimos en cuenta como criterio de inclusión la realización de la prueba de reacción en cadena de la polimerasa, dado que sólo hasta épocas recientes se introdujo esta técnica en el estudio de esta patología en Colombia. Encontramos 116 manuscritos con los términos antes descritos; éstos incluían artículos originales, revisiones, informe de casos, editoriales y comunicaciones breves, así como conferencias y capítulos de libros que cumplieron con los requisitos planteados. En ellos se apreció claramente cómo la enfermedad de Chagas afecta todos los niveles del sistema nervioso central, periférico y autonómico, siendo este último sistema el que se ha estudiado con mayor profundidad en nuestro país. Consideramos que el compromiso neurosistémico producido por T. cruzi debe ser evaluado de una manera más profunda a partir de la fecha, dado que muchos de los pacientes pueden estar siendo diagnosticados, tratados y seguidos como portadores de enfermedades 'idiopáticas'. Dichas patologías pueden llegar a convertirse en una seria amenaza para la salud de muchos colombianos si no se toman las medidas de prevención y control adecuadas. Por tanto, es necesario que...

[Neurological effects of American trypanosomyiasis: clinical aspects]. / Neurotripanosomiasis americana: aspectos clínicos de un problema básico.

Trypanosoma cruzi, causative agent of Chagas disease, affects not only cardiac and intestinal structures but also neurological structures. A high prevalence of T. cruzi infection occurs in Colombia, prompting the present study. First, a qualitative metaanalysis was undertaken using the PubMed database, the electronic internet engine Altavista, Colombian journals indexed by Colciencias, and three relevant textbooks. The following key words were used: Trypanosoma, Chagas disease, nervous system, spinal cord, central nervous system, peripheral nervous system, neuromuscular junction, autonomic nervous system, muscle, muscle disorders, neuromuscular disease, neuromuscular disorders, synapticopathies and dysautonomia. The documents analyzed numbered 116 and included original papers, reviews, case reports, editorials, brief communications, conferences and book chapters. At minimum, each document included data involving ELISA testing, indirect immunofluorescense, or parasitemia levels in the clinical, serological or histopathological studies. Polymerase chain reaction (PCR) studies were not included because of the recent introduction of PCR as a confirmatory technique for Chagas disease in Colombia. Chagas disease affects the central, the peripheral and the autonomic nervous system in humans, although its effects on the antonomic system is most commonly investigated in Colombia. Neurological lesions must be evaluated carefully, because patients may be misdiagnosed and treated as carriers of 'idiopathic' diseases. Neurological pathologies poses a serious threat in Colombia due to the prevalence of Chagas disease.