Depressed baroreflex sensitivity from spontaneous oscillations of heart rate and blood pressure in SCA1 and SCA2

Abstract

| INTRODUC TI ONSpinocerebellar ataxia (SCA) type 1 and 2 are dominantly inherited neurodegenerative disorders. These SCA subtypes are two of the most widely prevalent SCAs worldwide with a similar pattern found in India as well. SCA1 and SCA2 are caused by the abnormal expansion of CAG trinucleotide repeats in ATXN1 and ATXN2 genes, respectively. This results in progressive neuronal loss in the cerebellum along with certain cortical and subcortical brain regions in SCA subtypes 1,2 which subsequently leads to widespread clinical manifestations. Motor symptoms of SCA comprise cerebellar ataxia, peripheral neuropathy, ophthalmoplegia, pyramidal and extrapyramidal signs. 3 Furthermore, symptoms of autonomic dysfunction have also been observed in SCA patients. Thus, the evaluation of autonomic profile in SCA subtypes has an extensive clinical value. Objectives: To assess the time and frequency domain measures of cardiac autonomic activity/tone in patients of genetically defined spinocerebellar ataxia (SCA) types 1 and 2, as well as to decipher the probable associations among the cardiovascular autonomic parameters and genetic and clinical characteristics. Materials and methods:Simultaneous 5-min recording of RR interval (RRI) and blood pressure (BP) for the calculation of heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were performed in genotypically confirmed SCA1 (n = 31) and SCA2 (n = 40) patients and healthy controls (n = 40).Additionally, the International Cooperative Ataxia Rating Scale (ICARS) was used for scoring of clinical severity in SCA patients.Results: Time and frequency domain parameters of HRV, BPV and BRS were depressed in SCA1 and SCA2 subtypes as compared to controls, although there was no statistically significant difference in autonomic tone between the two SCA subtypes.On correlation analysis, autonomic tone parameters were found to be associated with the clinical and genetic features of the SCA subtypes. Also, ICARS was associated with the genotype (CAG repeat length) in SCA2 patents. Conclusions:Cardiac autonomic tone is depressed in both SCA1 and 2 as compared to healthy controls while the two SCA subtypes do not differ in terms of autonomic tone. Also, a typical association exists between disease characteristics and autonomic indices. K E Y W O R D Sbaroreflex sensitivity, blood pressure variability, cardiac autonomic activity/tone, heart rate variability, spinocerebellar ataxia

Beat-to-beat blood pressure variability in patients with obstructive sleep apnea

“…A higher cuff BP most likely reflects white-coat hypertension. 30,87 This white-coat hypertension appeared to have been present only when a research team member took a manual reading, as opposed to when the researcher was standing close to the participant while the automated process was performed for the CNAP calibration (Figure 1, "CNAP initialization"). Another possible source of difference is that the brachial cuff measure was taken earlier in the visit while seated at a desk, whereas the CNAP measures were made after more than 10 minutes being seated with back support (Figure 1).…”

“…25,29 We can obtain measures reflecting blood flow regulation by the autonomic nervous system as HRV from a continuous electrocardiogram (ECG). 17,[30][31][32][33][34] HRV can be calculated as power in frequency bands, and a ratio of low frequency power termed sympathetic-tovagal ratio is an indirect measure of sympathetic activation. 35,36 However, while HRV is widely used and simply interpreted, there are limitations, which are well addressed in the literature.…”

Measurement of High-School Students’ Trait Math Anxiety Using Neurophysiological Recordings During Math Exam

“…Although data from the non-significant time bins could serve to highlight the functional importance of these significant time points, ideally it is expected to have a baseline period beyond the anticipation and exam periods. Third, while the present study only used a simple correlational analysis to investigate the neurophysiological signature for MA, a deeper understanding of the underlying mechanisms of MA could benefit from the use of more advanced analytical methods, such as modeling the temporal characteristics of the neurophysiological signals by autoregression [67], exploring the spectral information of these neurophysiological signals [68]- [70], etc. Last but not least, our findings might be limited by the relatively smalle sample size (due to feasibility concerns) and the biased distribution of the math performance of the volunteers towards the highperforming ends.…”

Brain-heart Connections in Spinocerebellar Ataxia: Role of Central

“…On the other hand, literature suggested 60% dysautonomia in SCA patients [10][11][12]. We have also reported autonomic dysfunction in SCA patients [13,14]. We more intrigued to know about the structural atrophy goes hand in hand with the loss of functional attributes of autonomic regulation in SCA patients.…”