Feasibility of a new free mobility procedure to evaluate the function of the autonomic nervous system in patients with syncope

Abstract

to propose a new test to evaluate the autonomic nervous system in patients with syncope: Multimodal Monitoring for Diagnosis of Dysautonomia (MMDD). We included 21 patients with syncope (16 female, 6 male, mean age 43.5 years) and 21 with no-syncope subjects (15 female, 7 male, mean age 45.1 years) to perform a test of nine 2-min stages: four while resting and four during active testing of autonomic response. transcranial-Doppler, electrocardiogram, and photoplethysmography blood pressure pulse-to-pulse monitoring, allow registering six variables from the Middle cerebral Artery and four from the Cardiovascular System. We analyze each variable's mean differences in each stage and its change when they pass from one stage to another with the t and Z tests. to understand the significance of the change, we use a logistic regression model for a certain subgroup of variables. Since we have a small dataset, we use the bootstrap technique to infer the general behavior that characterizes a syncope. Our data confirm differences between syncope and non-syncope patients during MMDD stress stages 2, 4, 6 and 8. Bootstrap and multivariate logistic regression allow us to identify which sets of variables in each of these stages of the MMDD are sufficiently sensitive to recognizing syncope. MMDD protocol can recognize a syncope patient with some confidence by detecting subtle changes in the autonomic nervous system. this protocol encourages us to continue to study the effectiveness of MMDD protocol allowing a new approach to future research. Dysautonomia, defined as changes in the functioning of the autonomic nervous system that negatively affect health status, has manifestations ranging from symptoms located in some part of the body or transient and occasional episodes of neurally mediated hypotension to progressive neurodegenerative diseases 1. Syncope, the most common event to translate dysautonomia, is defined as a state of transient loss of consciousness of rapid onset, short duration, and spontaneous recovery due to a transitory state of cerebral hypoperfusion that leaves no neurological sequelae 2,3. In the Framingham study, at least 3% of men and 3.5% of women between 30 and 62 years old, had an episode of syncope through 26 years follow-up 4. In 50% of the cases, the clinical history allows us to identify the causes of syncope 5 ; however, in the rest, diagnosis of the primary and less understood forms of syncope are elusive 6. The phenomenon of syncope occurs because of a state of transient global cerebral hypoperfusion that, independently of the mechanism that initiates it, responds to a decrease in the activity of vasoconstrictor neurons and an increase in the parasympathetic activity of cardiomotor neurons 7. Due to its complexity, we find several proposals to evaluate the Autonomic Nervous System (ANS) in patients with syncope, most of which study the reactivity of the heart and blood pressure in response to maneuvers such as Valsalva, deep breathing, isometric hand contraction with a dynamometer, orthostatism test, ...

Diagnostic Features and Potential Applications of PPG Signal in Healthcare: A Systematic Review

“…There is a direct relationship between the PPG signal and human lungs and heart, and this relation is already used clinically. There is also an indirect relation between PPG and the human brain that is mainly used in observational studies [ 37 , 38 ]. The PPG signal might reflect other body organs’ status, but the question remains, is this relation reliable enough for diagnosing purposes?…”

“…An article by Aileni et al [ 37 ] studied the correlations between biomedical signals (including PPG) that measure the electrical activity in the brain. Kawachi et al [ 38 ] also proposed a new protocol to monitor the autonomic nervous system in patients with syncope that includes PPG.…”

“… Venn diagram representing an overview of the PPG healthcare applications [ 5 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 37 , 38 , 40 , 41 , 42 , 43 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , <...>…”