Calculating Heart Rate Variability from ECG Data from Youth with Cerebral Palsy During Active Video Game Sessions

Summary

This protocol describes a method for calculating Heart Rate Variability (HRV) from electrocardiogram (ECG) waveforms. Waveforms from continuous heart rate (HR) recordings during active video game (AVG) sessions were used to measure the aerobic performance of youth with cerebral palsy (CP).

Abstract

The aim of this study was to generate a method for calculating heart rate variability (HRV) from electrocardiogram (ECG) waveforms. The waveforms were recorded by a HR monitor that participants (youth with cerebral palsy (CP)) wore during active video game (AVG) sessions. The AVG sessions were designed to promote physical activity and fitness (aerobic performance) in participants. The goal was to evaluate the feasibility of AVGs as a physical therapy (PT) intervention strategy. The maximum HR (mHR) was determined for each participant and the Target Heart Rate Zone (THRZ) was calculated for each of three exercise phases in the 20 min AVG session: (warm-up at 40-60% mHR, conditioning at 60-80% mHR, and cool down at 40-60% mHR). Each participant played three 20 min games during the AVG session. All games were played while sitting on a bench because many youth with CP cannot stand for extended periods of time. Each game condition differed with participants using hand icons only, hand and feet icons together or feet icons only to collect objects. The objective of the game (called KOLLECT) is to collect objects to gain points and avoid hazards to not lose points. Hazards were used in the warm-up and cool down phases only to promote slower, controlled movement to maintain HR in the target heart rate zone (THRZ). There were no hazards in the conditioning phase to promote higher levels and more intense physical activity. Analytic methods were used to generate HRV (selected time-domain and frequency-domain measures) from ECG data to examine aerobic workload. Recent applications of HRV indicate that short-term measurements (5 min bouts) are appropriate and that HRV biofeedback may help improve symptoms and the quality of life in a variety of health conditions. Although HR is a well-accepted clinical measure to examine aerobic performance and intensity in PT interventions, HRV may provide information of the autonomic system functions, recovery and adaptation during AVG sessions.

Introduction

Cerebral palsy (CP) is the most common physical disability of childhood¹. CP is caused by a neurologic insult to the developing brain and is associated with motor impairments such as muscle weakness, spasticity, deconditioning, and decreased motor control and balance^2,3. CP is a non-progressive condition but with age, children become less physically active and more sedentary compared to their peers with typical development (TD) mostly because of the increased demands of growth on their compromised neuromuscular and musculoskeletal systems⁴.

Protocol

  Institutional Review Board approval was obtained. All youth provided written assent and parents provided consent prior to participation.

1. AVG data collection sessions

1. The AVG game session
   1. In this study, have youth with CP participate in an AVG session which is comprised of three 20 min games. See Table 5 for Youth Demographics. It was expected that a total of 30 games would be played; however, 29 games were completed because one subject only played 2 games in his AVG session.
   2. Have the subjects wear a HR monitor throughout the session to record HR and ECG responses.
   3. In the AVG session, have youth....

Results

This method provides data for use in analyzing the effect that a newly developed method has on the subject's Heart Rate Variability (HRV). It does this by locating the R portion of the QRS waveform of a subject's ECG data, as shown in Figure 6, and by calculating various HRV values from it. If the HR monitor is making proper contact with the subject, the data will be uniform, substantially reducing the need for corrections (as seen in Fig.......

Discussion

Ten youth with CP participated in this study (mean + SD) [ age (yrs) = 15.53 ± 3.57 ; height (cm) 154.8 ± 12.6; weight (kg) 50.69 ± 11.1; body mass index (BMI) 50.46 ± 29.2; mHR 9 bpm) = 186.8 ± 12.4]. Please see Table 5 for patient demographics.

There are some considerations for use of HR monitors and the associated measures of HR and HRV which relate to modifications and troubleshooting. Two issues that are apparent, regardless of the technology empl.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
BioHarness Bluetooth Module (Electronics sensor)	Zephyr	9800.0189	Detects Heart Rate, Resiration Rate, Posture, and Skin Temperature.
BioHarness Chest Strap	Zephyr	9600.0189, 9600.0190	Sizes Small XS-M, Large M-XL
BioHarness Charge Cradle & USB Cable	Zephyr	9600.0257	Used to Transfer Data from the Module to a Computer for Analysis.
BioHarness Echo Gateway	Zephyr	9600.0254	Allows for Realtime Viewing of Subject's Heart Rate.
MATLAB R2016a	Mathworks	1.7.0_.60	Used for All Programming.