Search

Background: Idiopathic REM sleep behavior disorder (iRBD) is a prodromal marker of the alpha-synucleinopathies, in which autonomic nervous system (ANS) involvement may occur. We aimed to characterize the presence and severity of subjective and objective ANS dysfunction in iRBD and assess its capacity to predict short-term clinical progression to a synucleinopathy. Methods: Prospective study of patients with polysomnography-confirmed iRBD in whom symptomatic ANS involvement was assessed using the Composite Autonomic Symptom Score (COMPASS-31) and objective dysfunction with the Composite Autonomic Severity Score (CASS). Baseline ANS data were compared between those who later developed a synucleinopathy and those who did not. Results: We evaluated 25 subjects with iRBD without risk factors for autonomic neuropathy and at least 6 months of follow-up (mean: 19 months). At the end of the study, seven (28%) patients developed a synucleinopathy, namely Parkinson's disease (n = 5) and dementia with Lewy bodies (n = 2). 73.7% of patients had COMPASS-31 scores above the normal cut-off, while no score differences regarding phenoconversion status were observed. At baseline, 85.7% of the subjects who phenoconverted exhibited at least one abnormal result in the CASS score, compared to 38.9% of subjects who remained disease-free (p = 0.035). Adrenergic dysfunction evaluated by an impaired overshoot in Valsalva phase IV and by pressure recovery time was associated with the development of overt synucleinopathy (p = 0.032 and 0.033, respectively). Conclusion: Symptomatic and subclinical ANS dysfunctions are common in iRBD. ANS dysfunction affecting mainly the adrenergic system seems to be a short-term risk for the development of a synucleinopathy. [ABSTRACT FROM AUTHOR]

Neonates with critical congenital heart disease (cCHD) undergo a complicated transition to ex-utero life. However, continuous monitoring of autonomic tone using heart rate variability is currently lacking. We retrieved continuous electrocardiograms from the time of admission or from 10 days prior to surgery for neonates with dextro-transposition of the great arteries (d-TGA) and hypoplastic left heart syndrome (HLHS). Beat-to-beat intervals (RRi) were calculated and divided into 10-min epochs. Spectral metrics, including low-frequency (LF) and high-frequency (HF) powers, as well as detrended fluctuation analysis metrics (α S , α L , RM S S , and RM S L), were computed for RRi within each epoch and averaged over 24 h. The relationship between RRi metrics and time to surgery was analyzed using linear mixed-effects models, adjusting for prenatal and postnatal factors. The study included 10 neonates with HLHS and 23 with d-TGA. RRi metrics were available for 110 days. In the unadjusted models, LF power (Estimate: −4.4× 10 − 3 , P = 0.02), HF power (−4.1 x 10 − 2 , 5 x 10 − 5), RM S S (−3.7 x 10 − 4 , 8.7 x 10 − 3), and RM S L (−1.4× 10 − 3 , 0.02) were all negatively associated with time to surgery, with HF power showing the strongest association. After adjusting for covariates, HF power retained its significant negative association with time (−0.04, P = 0.03). The cCHD diagnosis did not significantly influence RRi metrics. In neonates with cCHD, there is a progressive decline in autonomic function leading up to surgery. RRi metrics may serve as valuable indicators of deteriorating physiology in these patients. • Heart rate variability (HRV) progressively decreases during the preoperative period • The cCHD diagnosis does not impact HRV changes during the preoperative period • High-frequency power showed the strongest trend among other HRV metrics considered [ABSTRACT FROM AUTHOR]

Background and Purpose: Patients with postural tachycardia syndrome report position-dependent visual symptoms. Despite their impact on daily life, these symptoms have remained largely unexplored in research. The aim of this study was to investigate the nature of visual symptoms in postural tachycardia syndrome and possible underlying pathophysiological mechanisms., Methods: Fifteen patients with postural tachycardia syndrome and 15 healthy controls were included in the study. Through a comprehensive array of measurements, including haemodynamics, subjective symptom assessments, eye movement tracking and pupil diameter analysis, participants were assessed during free image exploration in both supine and 60° head-up tilt positions., Results: During head-up tilt, patients showed a decreased number and duration of fixations, as well as a decreased number, peak velocity and amplitude of saccades compared to the supine position and the control group. This reduction in visual exploration occurred primarily in the peripheral field of view and coincided with the occurrence of subjective visual symptoms. No significant differences in the saccade main sequence were observed between the two groups in either body position., Conclusions: Patients with postural tachycardia syndrome have a reduced exploration of the peripheral field of view when in an upright body position, potentially leading to tunnel vision. Since the normality of the saccade main sequence in patients combined with the focus on the centre of the field of view and the lower saccade amplitudes points to an intact brainstem function, the decrease in peripheral visual exploration may be attributed to a position-dependent dysfunction of the frontal eye field., (© 2024 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)