ABSTRACT
Purpose
to investigate the existence of an association between Heart Rate Variability (HRV) and hearing sensitivity in healthy children in the first year of life, using the RMSSD (Root Mean Square of Successive Differences) and SD1 (Poincaré plot standard deviation perpendicular to the line of identity) indices.
Methods
this is a methodological study with evaluation of 20 children divided into two groups: 10 children without hearing loss (G1) and 10 children with hearing loss, regardless of type and/or degree (G2). The click stimulus was presented at intensities of 30-60 dB nHL. To capture the HRV, a Polar RS800CX heart monitor was used, with a sample rate of 1.000 Hz. Stable sets with 60 R-R intervals were selected and only those with more than 95% sinus beats were included. The analysis of the 2-way repeated measures ANOVA test was used to evaluate the effects of acoustic stimulation on the RMSSD and SD1 indices, in silence and in the presence of the click stimulus, in groups G1 and G2. The factor analysis was applied to evaluate the indices with the factors sex, tested ear, behavioral state of the child and test period.
Results
there were no significant differences for the RMSSD and SD1 indices, in silence and in the presence of the click stimulus, in groups G1 and G2, and between both groups. There was no interaction between the HRV indices, and all the analyzed confounders.
Conclusion
there was no association between HRV and hearing sensitivity, so the HRV researched with click stimulus at intensities of 30-60 dB nHL was not effective to identify children with hearing loss in the first year of life, through the RMSSD and SD1 indices.
Keywords:
Autonomic nervous system; Acoustic stimulation; Hearing; Hearing loss; Child