In a time-series, memory is a statistical feature that lasts for a period of time and distinguishes the time-series from a random, or memory-less, process. In the present study, the concept of "memory length" was used to define the time period, or scale over which rare events within a physiological time-series do not appear randomly. The method is based on inverse statistical analysis and provides empiric evidence that rare fluctuations in cardio-respiratory time-series are 'forgotten' quickly in healthy subjects while the memory for such events is significantly prolonged in pathological conditions such as asthma (respiratory time-series) and liver cirrhosis (heart-beat time-series). The memory length was significantly higher in patients with uncontrolled asthma compared to healthy volunteers. Likewise, it was significantly higher in patients with decompensated cirrhosis compared to those with compensated cirrhosis and healthy volunteers. We also observed that the cardio-respiratory system has simple low order dynamics and short memory around its average, and high order dynamics around rare fluctuations.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3764113PMC
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0072854PLOS

Publication Analysis

Top Keywords

physiological time-series
8
time-series memory
8
rare fluctuations
8
higher patients
8
healthy volunteers
8
order dynamics
8
time-series
7
quantifying memory
4
memory complex
4
complex physiological
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!