Search

In 2019, we highlighted the disparities in scientific production between high-income countries (HICs) and low- to middle-income countries (LMICs) by emphasizing how scientific research was underrepresented in the latter. The present study aimed to investigate research productivity in neurosurgery of low-income countries (LICs) and LMICs for the years 2018-2020 and to compare it with the results of our previous study for 2015-2017.We performed a retrospective bibliometric analysis using PubMed and Scopus databases to record all the reports published in 2018-2020 by investigators affiliated with neurosurgical departments in LICs and LMICs. The attribution of the study to LMICs was based on the presence of either the first author or the majority of authors.Our systematic search identified 486 studies reported by LICs and LMICs for full text examination in 12 journals. These articles represent 4.9% of all published neurosurgical articles, compared with 4.5% in the 2015-2017 study. India remained the country with the highest contribution, with a 17.1% increase in reports. Other countries, such as Nigeria and Philippines, also show an increased percentage of reports (from 0.9% to 3.7% and from 0.6% to 2.1%, respectively).There is growing consensus in the neurosurgical scientific community that the dissemination and analysis of epidemiologic and clinical data from developing countries can provide guidelines and practical suggestions worldwide. However, our study shows that the number of neurosurgical articles published by low-income countries in 2018-2020 remained at approximately 5% of the total, resulting in a negative impact on the process of globalization.

An inverted U-shape relationship between cognitive performance and indoor temperature with best performance peaking at 21.6 °C was previously described. Little is known on classroom temperature reduction effects on cognitive performances and cardiac autonomic profile, during the cold season. Fifteen students underwent electrocardiogram recording during a lecture in two days in December when classroom temperatures were set as neutral (NEUTRAL, 20-22 °C) and cool (COOL, 16-18 °C). Cognitive performance (memory, verbal ability, reasoning, overall cognitive C-score) was assessed by Cambridge Brain Science cognitive evaluation tool. Cardiac autonomic control was evaluated via the analysis of spontaneous fluctuations of heart period, as the temporal distance between two successive R-wave peaks (RR). Spectral analysis provided the power in the high frequency (HF, 0.15-0.40 Hz) and low frequency (LF, 0.04-0.15 Hz) bands of RR variability. Sympatho-vagal interaction was assessed by LF to HF ratio (LF/HF). Symbolic analysis provided the fraction of RR patterns composed by three heart periods with no variation (0 V%) and two variations (2 V%), taken as markers of cardiac sympathetic and vagal modulations, respectively. The students' thermal comfort was assessed during NEUTRAL and COOL trials. Classroom temperatures were 21.5 ± 0.8 °C and 18.4 ± 0.4 °C during NEUTRAL and COOL. Memory, verbal ability, C-Score were greater during COOL (13.01 ± 3.43, 12.32 ± 2.58, 14.29 ± 2.90) compared to NEUTRAL (9.98 ± 2.26, p = 0.002; 8.57 ± 1.07, p = 0.001 and 10.35 ± 3.20, p = 0.001). LF/HF (2.4 ± 1.7) and 0 V% (23.2 ± 11.1%) were lower during COOL compared to NEUTRAL (3.7 ± 2.8, p = 0.042; 28.1 ± 12.2.1%, p = 0.031). During COOL, 2 V% was greater (30.5 ± 10.9%) compared to NEUTRAL (26.2 ± 11.3, p = 0.047). The students' thermal comfort was slightly reduced during COOL compared to NEUTRAL trial. During cold season, a better cognitive performance was obtained in a cooler indoor setting enabling therefore energy saving too.

The effect of classroom temperature reduction on cognitive performance and cardiac autonomic control were assessed in 12 healthy undergraduate students during a 2-hour lasting lecture. In all subjects ECG was continuously recorded by a portable device when classroom temperature was “neutral” $(22.4\pm 0.1^{\circ}\mathrm{C}$ , Day1) and “cool” $(18.4^{\circ}\mathrm{C}\pm 0.3^{\circ}\mathrm{C}$ , Day2). Symbolic analysis of RR variability provided the percentage of three heart period sequences with no significant change in RR interval (0V%) and with two significant variations (2UV%), reflecting cardiac sympathetic and vagal modulation, respectively. Students' cognitive performance was assessed at the end of each lecture by the Cambridge Brain Sciences cognitive evaluation tool. In Day2 the 0V% was greater and 2UV% was lower compared to Day1. Cognitive performance rated better in Day2 compared to Day1. Students' cognitive performance was improved and their cardiac sympathetic modulation was enhanced when the lecture was performed in a cooler environment.

Postural Tachycardia Syndrome (POTS) is a chronic disorder characterized by symptoms of orthostatic intolerance such as fatigue, lightheadedness, dizziness, palpitations, dyspnea, chest discomfort and remarkable tachycardia upon standing. Non-invasive transdermal vagal stimulators have been applied for the treatment of epilepsy, anxiety, depression, headache, and chronic pain syndromes. Anti-inflammatory and immunomodulating effects after transdermal vagal stimulation raised interest for applications in other diseases. Patients with sympathetic overactivity, reduced cardiac vagal drive and presence of systemic inflammation like POTS may benefit from tVNS. This article will address crucial methodological aspects of tVNS and provide preliminary results of its acute and chronic use in POTS, with regards to its potential effectiveness on autonomic symptoms reduction and heart rate modulation.