Design Rationale and Performance Evaluation of the Wavelet Health Wristband: Benchtop Validation of a Wrist-Worn Physiological Signal Recorder

Background

Wearable and connected health devices along with the recent advances in mobile and cloud computing provide a continuous, convenient-to-patient, and scalable way to collect personal health data remotely. The Wavelet Health platform and the Wavelet wristband have been developed to capture multiple physiological signals and to derive biometrics from these signals, including resting heart rate (HR), heart rate variability (HRV), and respiration rate (RR).

Objective

This study aimed to evaluate the accuracy of the biometric estimates and signal quality of the wristband.

Methods

Measurements collected from 35 subjects using the Wavelet wristband were compared with simultaneously recorded electrocardiogram and spirometry measurements.

Results

The HR, HRV SD of normal-to-normal intervals, HRV root mean square of successive differences, and RR estimates matched within 0.7 beats per minute (SD 0.9), 7 milliseconds (SD 10), 11 milliseconds (SD 12), and 1 breaths per minute (SD 1) mean absolute deviation of the reference measurements, respectively. The quality of the raw plethysmography signal collected by the wristband, as determined by the harmonic-to-noise ratio, was comparable with that obtained from measurements from a finger-clip plethysmography device.

Conclusions

The accuracy of the biometric estimates and high signal quality indicate that the wristband photoplethysmography device is suitable for performing pulse wave analysis and measuring vital signs.

Vincristine treatment of acute lymphoblastic leukemia induces transient autonomic cardioneuropathy

Reduced respiratory sinus arrhythmia, measured as heart rate variability, is a reliable indicator of autonomic nervous dysfunction, reflecting a damage in vagal cardiac control. The authors studied the heart rate variability (HRV) of nine children treated for acute lymphoblastic leukemia during the different phases of cytostatic treatment utilizing heart rate processing techniques with a computer. The indices of HRV as well as the spectral components of heart rate were examined with special relation to vincristine administration. The heart rate variability was significantly reduced during the vincristine induction phases as compared to the consolidation and maintenance phases without vincristine administration. In particular, the respiratory components of the HRV during deep breathing tests were significantly reduced during vincristine treatment. The authors conclude that the measurement of the HRV is a suitable method for monitoring transient autonomic neuropathy, which these results show to be a frequent complication of vincristine treatment.