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Brainstem trigeminal-hypoglossal reflexes (THRs), also known as the jaw-tongue reflexes, coordinate the position of the tongue in the mouth in relation to the jaw movement during oromotor behaviors such as mastication, swallowing, vocalization, and breathing. Their use in brainstem surgery however, has never been assessed in spite of its potential benefit possibly due to the lack of a methodology to elicit these reflexes under general anesthesia.We proposed a technique to elicit the THRs during total intravenous anesthesia (TIVA) consisting on a V3 infrazygomatic train stimulation paradigm and recording from the Styloglossus (31 patients) and the Genioglossus (21 patients) muscles to elicit long latency responses.The THR was successfully recorded using the V3 stimulation point in 82.1% of patients, of which 96.9% presented a response on the Styloglossus muscle (Jaw-opening reflex) while 0.06% presented a response on the Genioglossus muscle instead (Jaw-closing reflex).The THRs can be successfully recorded in surgery under general anaesthesia with the predominant reflex seen being the jaw-opening reflex.We provide a novel method to elicit the THRs during general anesthesia, which could be of aid in brainstem surgery.

Study Design Retrospective cohort study. Objectives Intraoperative neurophysiological monitoring (IONM) is widely used in spinal neurosurgery, particularly for intramedullary tumours. However, its validity in intradural extramedullary (IDEM) spinal tumours is less clearly defined, this being the focus of this study. Methods We compared outcomes for patients that underwent resection of IDEM tumours with and without IONM between 2010 and 2020. Primary outcomes were postoperative American Spinal Injury Association (ASIA) scores. Other factors assessed were use of intraoperative ultrasound, drain placement, postoperative complications, postoperative Eastern Cooperative Oncology Group (ECOG) score, extent of resection, length of hospital stay, discharge location and recurrence. Results 163 patients were included, 71 patients in the IONM group and 92 in the non-IONM group. No significant differences were noted in baseline demographics. For preoperative ASIA D patients, 44.0% remained ASIA D and 49.9% improved to ASIA E in the IONM group, compared to 39.7% and 30.2% respectively in the non-IONM group. For preoperative ASIA E patients, 50.3% remained ASIA E and 44.0% deteriorated to ASIA D in the IONM group, compared to 30.2% and 39.7% respectively in the non-IONM group (all other patients deteriorated further). Length of inpatient stay was significantly shorter in the IONM group ( P = .043). There were no significant differences in extent of resection, postoperative complications, discharge location or tumour recurrence. Conclusions Research focusing on the use of IONM in IDEM tumour surgery remains scarce. Our study supports the use of IONM during surgical excision of IDEM tumours.

Objective To correlate intraoperative changes of the laryngeal adductor reflex (LAR), alone or in combination with corticobulbar motor evoked potential of vocal muscles (vocal-CoMEPs), with postoperative laryngeal function after posterior fossa and brainstem surgery. Methods We monitored 53 patients during cerebellar-pontine angle and brainstem surgeries. Vocal-CoMEPs and LAR were recorded from an endotracheal tube with imbedded electrodes or hook-wires electrodes. A LAR significant change (LAR-SC) defined as ≥ 50% amplitude decrement or loss, was classified as either transient or permanent injury to the vagus or medullary pathways by the end of the surgery. Results All patients with permanent LAR loss (n = 5) or LAR-SC (n = 3), developed postoperative laryngeal dysfunction such as aspiration/pneumonia and permanent swallowing deficits (5.6%). Vocal-CoMEP findings refined postoperative vocal motor dysfunction. All seven patients with transient LAR-SC or loss, reverted by changing the surgical approach, did not present permanent deficits. Conclusions Permanent LAR-SCs or loss correlated with postoperative laryngeal dysfunction and predicted motor and sensory dysfunction of the vagus nerve and reflexive medullary pathways. In contrast, a LAR-SC or loss, averted by a timely surgical adjustment, prevented irreversible damage. Significance Monitoring of the LAR, with vocal-CoMEPs, may enhance safety to resect complex posterior fossa and brainstem lesions.

Transsulcal minimally invasive parafasicular (TsMIP) approaches to brain tumor resection use tubular retractors to minimize iatrogenic brain injury. Dynamic cortical and subcortical continuous neurophysiological mapping facilitates safer resection of motor-eloquent tumors.To describe a new technique to address the challenge of combining TsMIP with tubular retractors and dynamic subcortical mapping using a single electrified stimulating microdebrider instrument.We adapted the NICO Myriad microdebrider with continuous monopolar stimulation electrification using high-frequency stimulation with the train-of-5 technique. We performed continuous subcortical mapping using this device and compared it with standard dynamic monopolar subcortical mapping using a suction stimulation device. We found no significant difference in recorded stimulation response.Using a single operating instrument that provides synchronous tumor resection and monopolar subcortical mapping with the NICO Brainpath tubular retractor, we observed increased degrees of movement, faster surgical resection times with an enlarged working channel down the retractor, and improved safety because the stimulating probe sits 2 mm deep to the resection window.We show that the adapted device is reliable and provides similar stimulation response as conventional subcortical mapping. We advocate the use of our adapted microdebrider in TsMIP tubular retractor approaches.

Contingency data was retrospectively collected to evaluate the historical and current ability to provide multimodality intraoperative neurophysiological monitoring during carotid endarterectomy under two conditions: total intravenous anaesthesia (TIVA) and low dose halogenated anaesthesia (SEVO). 229 patients were monitored during carotid endarterectomy procedures under general anaesthesia between 2012 and 2020. 121 Patients were monitored with SEVO at a minimum alveolar concentration less than 0.7 and 108 were monitored using TIVA, according to common anaesthetic practice standards in our hospital across the years. Multimodality IONM was established with electroencephalography, somatosensory evoked potentials and motor evoked potentials. As compared to TIVA, patients monitored with SEVO showed significantly higher motor evoked potential thresholds (313.52 ± 77.74 SEVO and 218.93 V ± 103.2 V TIVA p

To investigate changes in tremor severity over repeated spiral drawings to assess whether learning deficits can be evaluated directly in a limb in essential tremor (ET). A motor learning deficit in ET, possibly mediated by cerebellar pathways, has been established in eye-blink conditioning studies, but not paradigms measuring from an affected, tremulous limb. Computerized spiral analysis captures multiple characteristics of Archimedean spirals and quantifies performance through calculated indices. Sequential spiral drawing has recently been suggested to demonstrate improvement across trials among ET subjects. One hundred and sixty-one ET and 80 age-matched control subjects drew 10 consecutive spirals on a digitizing tablet. Degree of severity (DoS), a weighted, computational score of spiral execution that takes into account spiral shape and line smoothness, previously validated against a clinical rating scale, was calculated in both groups. Tremor amplitude (Ampl), an independent index of tremor size, measured in centimeters, was also calculated. Changes in DoS and Ampl across trials were assessed using linear regression with slope evaluations. Both groups demonstrated improvement in DoS across trials, but with less improvement in the ET group compared to controls. Ampl demonstrated a tendency to worsen across trials in ET subjects. ET subjects demonstrated less improvement than controls when drawing sequential spirals, suggesting a possible motor learning deficit in ET, here captured in an affected limb. DoS improved independently of Ampl, showing that DoS and Ampl are separable motor physiologic components in ET that may be independently mediated.

Objective An intriguing electrophysiological feature of patients with Huntington’s disease (HD) is the delayed latency and decreased amplitude of somatosensory long-latency evoked potentials (LLeps). We investigated whether such dysfunction was associated with delayed conscious perception of the sensory stimulus. Methods Sixteen HD patients and 16 control subjects faced a computer screen showing the Libet’s clock ( Libet et al., 1983 ). In Rest trials, subjects had to memorize the position of the clock handle at perception of either electrical or thermal stimuli (AW). In React, additionally, they were asked to make a fist with their right hand, in a simple reaction time task (SRT). LLseps were recorded from Cz in both conditions. Results LLeps negative peak latency (N2) and SRT were abnormally delayed in patients in all conditions. AW was only abnormally prolonged in the React condition but the time difference between AW and the negative peak of the LLeps was not different in the two groups. There was a significant negative correlation between SRT and AW or LLeps amplitude in patients but not in healthy subjects. Conclusion Our HD patients did not show abnormalities in conscious perception of sensory stimuli but their LLeps abnormalities were more marked when they had to react. This is compatible with failure to detect stimulus salience rather than with a cognitive defect. Significance HD patients at early stages of the disease have preserved subjective perception of sensation but faulty sensorimotor integration.

To investigate changes in tremor severity over repeated spiral drawings to assess whether learning deficits can be evaluated directly in a limb in essential tremor (ET). A motor learning deficit in ET, possibly mediated by cerebellar pathways, has been established in eye-blink conditioning studies, but not paradigms measuring from an affected, tremulous limb. Computerized spiral analysis captures multiple characteristics of Archimedean spirals and quantifies performance through calculated indices. Sequential spiral drawing has recently been suggested to demonstrate improvement across trials among ET subjects. One hundred and sixty-one ET and 80 age-matched control subjects drew 10 consecutive spirals on a digitizing tablet. Degree of severity (DoS), a weighted, computational score of spiral execution that takes into account spiral shape and line smoothness, previously validated against a clinical rating scale, was calculated in both groups. Tremor amplitude (Ampl), an independent index of tremor size, measured in centimeters, was also calculated. Changes in DoS and Ampl across trials were assessed using linear regression with slope evaluations. Both groups demonstrated improvement in DoS across trials, but with less improvement in the ET group compared to controls. Ampl demonstrated a tendency to worsen across trials in ET subjects. ET subjects demonstrated less improvement than controls when drawing sequential spirals, suggesting a possible motor learning deficit in ET, here captured in an affected limb. DoS improved independently of Ampl, showing that DoS and Ampl are separable motor physiologic components in ET that may be independently mediated.

Introduction Objective measures for detection and quantification of dystonic movements may guide both diagnosis and clinical monitoring. Digitized spiral analysis is a non-invasive method used to assess upper limb motor control in movement disorders and may have utility in dystonia. We aimed to determine if digitized spiral analysis can distinguish dystonia subjects from controls, and evaluated correlation with a validated clinical rating scale. Methods Kinematic, dynamic, and spatial attributes of Archimedean spirals drawn with an inking pen on a digitizing tablet were compared for participants with brachial dystonia and either Tor1A (DYT1) (n = 15) or THAP1 (DYT6) mutations (n = 12) and age and gender matched controls (n = 27) using Receiver Operator Characteristics (ROC) analysis. Spiral indices including an overall degree of severity (DoS) were also calculated and correlated with clinical severity ratings as measured by the Burke-Fahn-Marsden scale. Results Dystonia spirals had significantly higher severity scores as well as higher measures of spiral irregularity compared to controls. ROC analysis demonstrated that the DoS score had good discriminative ability to distinguish dystonia spirals from controls, with an Area Under the Curve (AUC) of 0.87. Measures of spiral irregularity correlated with validated clinical rates of dystonia severity in the analyzed arm, with one particular index, Residue of Theta vs R, showing the highest correlation (r = 0.55, p = 0.005). Conclusion Digitized spiral analysis may be a promising non-invasive method to objectively quantify brachial dystonia. It may also be a useful way to monitor subtle changes in dystonia severity over time not captured with current clinical rating scales.

The perirhinal cortex (PRh) is a key region downstream of auditory cortex (ACx) that processes familiarity linked mnemonic signaling. In gerbils, ACx-driven EPSPs recorded in PRh neurons are largely shunted by GABAergic inhibition (Kotak et al., 2015, Frontiers in Neural Circuits, 9). To determine whether inhibitory shunting prevents the induction of excitatory long-term potentiation (e-LTP), we stimulated ACx-recipient PRh in a brain slice preparation using theta burst stimulation (TBS). Under control conditions, without GABA blockers, the majority of PRh neurons exhibited long-term depression. A very low concentration of bicuculline increased EPSP amplitude, but under this condition TBS did not significantly increase e-LTP induction. Since PRh synaptic inhibition included a GABAB receptor-mediated component, we added a GABAB receptor antagonist. When both GABAA and GABAB receptors were blocked, TBS reliably induced e-LTP in a majority of PRh neurons. We conclude that GABAergic transmission is a vital mechanism regulating e-LTP induction in the PRh, and may be associated with auditory learning.

BACKGROUND: Poverty is associated with a great number of diseases, but the prevalence of vitamin D deficiency, secondary hyperparathyroidism and the potential association of osteoporosis, osteoporotic fractures and metabolic syndrome in this situation are less well known. OBJECTIVE: To evaluate the associations between poverty, bone density, fragility fractures and metabolic syndrome in a population of southern-European postmenopausal women. Also, to assess the potential role of vitamin D and PTH levels in these associations. METHOD: Cross sectional study, carried out in 1,250 postmenopausal Caucasian Spanish women. The socio-economic status of the participants was determined after a personal interview, according to the criteria of the Spanish Institute of Statistics. Participants were divided into two socioeconomic levels: low (poverty), and medium or high. The study protocol included a health questionnaire, a complete physical examination, lateral radiograph of the dorsal and lumbar spine, and measurement of bone mineral density (BMD) at the lumbar spine (L2-L4) and proximal femur. Fasting blood was obtained to measure 25 hydroxy-vitamin D (25-OHD), intact PTH, and selected biochemical variables. RESULTS: Low socioeconomic status was associated with 25-OHD insufficiency, higher values of PTH, higher bodyweight and body mass index (BMI), lower values of BMD at the lumbar spine and a higher prevalence of fragility fractures, both vertebral and non-vertebral. Poverty was also associated with higher prevalence of metabolic syndrome, but this association was driven mainly by the higher BMI and not by poverty itself. Both vitamin D insufficiency and elevated PTH were consistently related to poverty and osteoporotic fractures. CONCLUSIONS: Poor postmenopausal women in southern Europe have a high prevalence of metabolic syndrome and osteoporotic fractures. Poverty was associated with higher BMI and metabolic syndrome on the one hand and, on the other, with 25OHD insufficiency, higher PTH levels and osteoporosis. 25OHD insufficiency and/or secondary hyperparathyroidism do not have a significant influence on the presence of metabolic syndrome in this population. © 2012 Blackwell Publishing Ltd.

Resumen Fundamento Se ha descrito la existencia de deficiencia de vitamina D tanto en la poblacion general como en un gran numero de enfermedades. Sin embargo, se han publicado pocos estudios realizados en poblacion joven y sana en Espana. Teoricamente no deberia encontrarse deficiencia de vitamina D entre los estudiantes de Medicina de la Universidad de Las Palmas de Gran Canaria, porque disponen de todos los medios para evitarla. Objetivo Estimar la prevalencia de deficiencia de vitamina D en una poblacion de estudiantes de Medicina de ambos sexos de la Universidad de Las Palmas de Gran Canaria. Metodo Se estudiaron 103 alumnos de Medicina de ambos sexos de la Universidad de Las Palmas de Gran Canaria. A todos se les realizo un cuestionario y una exploracion fisica. Se determino la vitamina D 25-hidroxicolecalciferol (25-HCC), la hormona paratiroidea, varios marcadores bioquimicos de remodelado oseo y un estudio bioquimico general. Se estimo la densidad mineral osea por absorciometria radiologica dual en la columna lumbar y en la extremidad proximal del femur. Asimismo, se midieron los parametros ultrasonograficos en el calcaneo. Resultados Solo el 38,8% de los estudiantes de Medicina (el 42,1% de los varones y el 44,9% de las mujeres) presentaron niveles de 25-HCC superiores a 30 ng/dl tal y como se recomienda en la actualidad. Se observo deficiencia de vitamina D (menos de 20 ng/ml) en el 32,6% de los alumnos e insuficiencia (menos de 30 ng/ml) en el 28,6% de los estudiantes de Medicina de la Universidad de Las Palmas de Gran Canaria. Conclusiones Aunque los estudiantes de Medicina de las Isla Canarias disponen de las condiciones ideales para tener unos niveles optimos de vitamina D, casi dos tercios de ellos tienen valores de 25-HCC inferiores a 30 ng/ml.

Vitamin D deficiency has been described in many diseases and indeed in the general population. However fewer reports have been published in young and healthy people. Vitamin D deficiency should not be found in medical students of the Canary Islands, because they have all the resources to avoid it.To estimate the prevalence of vitamin D deficiency in a population of medical students of both gender from the University of Las Palmas de Gran Canaria.103 medical students of both genders from the University of Las Palmas de Gran Canaria. They completed a questionnaire and a physical examination. Vitamin D (25- hydroxycholecalciferol [25-HCC]), parathyroid hormone, biochemical markers of bone remodeling and a general biochemical study were performed. Bone mineral density was assessed by dual energy X-ray absorptiometry at the lumbar spine and the proximal femur. Quantitative ultrasounds parameters were measured at the calcaneus.Only 38.8% of the students of Medicine (42.1% of males and 44.9% of females) have 25-HCC values higher than 30 ng/dl as widely recommended nowadays. Vitamin D deficiency (20 ng/ml) is observed in 32.6% and vitamin D insufficiency (30 ng/ml) in 28.6% of the students of Medicine in Las Palmas de Gran Canaria.Although they have optimal conditions for having good levels of vitamin D, near two thirds of the medical students in the Canaries have low values of vitamin D.