Review of psychology, Vol. 11 No. 1-2, 2004.
Original scientific paper
How do sound rhythms affect heartbeat: Comparison of linear and non-linear analyses of R-R intervals
Pavle Valerjev
Nataša Šimić
Abstract
A 2x3 within groups experiment with two levels of sound intensity and three levels of tempo of sound rhythm was conducted. Eleven psychology students participated in the study. SMI index, 1/f spectra slopes and some non-linear analyses parameters - correlation dimension and largest Lyapunov exponents - were used. Decrease in SMI indexes in low and medium spectral bands occurred with more intensive sound rhythms as a function of rhythm tempo increase which may point to increased stress and mental load. Spectral analysis showed no clear interference between sound and cardiac rhythm. Changes in 1/f spectra slopes were similar to those of SMI indexes. A decrease in correlation dimension for more intensive rhythms points to decrease of series dimensionality which is probably the result of domination of non-linear factors determining dynamic system. More evidence for such an interpretation was indicated by decrease in system predictability when exposed to sound rhythms, as shown by an increase in Lyapunov exponents.
Keywords
non-linear analyses; chaos; sound rhythms; heartbeat variability; Lyapunov exponent
Hrčak ID:
1982
URI
Publication date:
22.1.2005.
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