Heart Rate Variability in Duchenne Muscular Dystrophy During Computer Task

Study Overview
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Brief Summary
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HRV is attained using a Polar RS800CX. Then, evaluated through linear, non-linear and chaotic global techniques (CGT). Forty-five male subjects were included in the DMD group and age-matched with forty-five in the healthy Typical Development (TD) control group. They were assessed for twenty minutes at rest sitting, and then five minutes whilst performing the maze task on a computer.

Detailed Description
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This is a cross-sectional study, where HR was recorded beat-to-beat (RR intervals) using the portable Polar RS800CX HR monitor (Polar Electro, Finland). HR was recorded before the onset and at the end of the five minutes of the computer maze paradigm task. The subjects were seated in a standard chair (walkers, TD group and DMD) or in their own wheelchair (non-walkers, DMD group), the Polar watch was positioned on the wrist. The analysis of HRV was possible through the recording of RR interval in two periods: the period of twenty minutes at seated rest, and then during the computer task for five minutes. The computer task used a maze paradigm with one correct pathway that could be negotiated and ultimately solved. All participants were positioned comfortably and an evaluator responsible for instruction and annotation of data. Each individual was instructed to walk the correct path with the digital character pawn (pointed on the screen by the evaluator) to the exit of the maze identified by an x (pointed on the screen by the evaluator). It was provided for the subjects, who used the arrow buttons on the keyboard, identified by up, down, right and left, using the dominant hand, with the arrows moving through a 20 x 20 cm maze. Participants were requested to complete the maze as fast as possible. HRV analysis followed the guidelines published by the Task Force of the European Society of Cardiology and North American Society of Pacing and Electrophysiology. The RR intervals were recorded, and then were downloaded to the Polar Precision Performance program (v.3.0). This software enabled the visualization of HR and the extraction of a cardiac period (RR intervals series; the variation of beat-to-beat interval in milliseconds) file in .txt format. For analysis of HRV data at rest, we analyzed 1000 consecutive RR intervals, and for HRV analysis for the computational task, the number of consecutive RR intervals obtained was exactly 256 RR intervals. Digital filtering complemented by manual filtering was performed to eliminate artifacts and only series with greater than 95% of sinus beats were included in the study. HRV analysis was undertaken through linear, non-linear and chaotic global techniques (CGT).

Official Title
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Computational Task in Duchenne Muscular Dystrophy: Involvement of Cardiac Autonomic Regulation.

Conditions
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Duchenne Muscular Dystrophy

Intervention / Treatment
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* Behavioral: Duchenne Muscular Dystrophy group
* Behavioral: Typical Development group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: DMD diagnoses was based on molecular methods and/or muscular protein expression. TD age-matched with DMD. Exclusion Criteria: subjects with severely dilated myocardium. subjects with other associated diseases. individuals with inability to understand task instructions.

Ages Eligible for Study
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Minimum Age: 9 Years
Maximum Age: 21 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Duchenne Muscular Dystrophy group<br>Forty-five male subjects were included in the Duchenne Muscular Dystrophy (DMD) group and they were assessed for twenty minutes at rest sitting, and then five minutes whilst performing the maze task on a computer. | Behavioral: Duchenne Muscular Dystrophy group<br>* Assessment of heart rate variability at rest and during computational task in people with Duchenne muscular dystrophy<br>|
| Typical Development group<br>Forty-five male subjects were included in the healthy Typical Development (TD) control group and they were assessed for twenty minutes at rest sitting, and then five minutes whilst performing the maze task on a computer | Behavioral: Typical Development group<br>* Assessment of heart rate variability at rest and during computational task in people with typical Development<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart Rate Variability behavior during computational task | Linear, non-linear and complexity indices of heart rate variability will be assessed at rest and during computational task, in order to analyse it's behavior. | 1 day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Heart rate variability, Duchenne muscular dystrophy, Typically developed, Autonomic nervous system, Chaotic global techniques