Joanna Aftyka
supervisor: Jan Żebrowski
An ischemic stroke is a neurological condition that results in severe narrowing or blockage of the blood supply to the brain. The brain fragment affected by an ischemic stroke is not supplied with oxygen and nutrients. As a consequence, certain parts of the brain die. In the initial stage of a stroke, it is difficult to determine the patient's further prognosis for the future. Currently, there is no indicator that would indicate the prognosis of a particular patient in the future.
The purpose of this work is to find an indicator that predicts the clinical progression of patients in the acute phase of stroke.
Symbolic dynamics methods have been used since the end of the 1990s. They have evolved over the years. In this paper, I proposed my own modification of the symbolic dynamics method for the assessment of nocturnal heart rate variability records. In my research, I change each RR interval into one of the 4 available symbols {0, 1, 2, 3} and then analyze the lengths of the longest words that are sequences of identical symbols. I notice statistically significant differences in the length of the longest words in the group of people who had clinical progression during hospitalization after ischemic stroke vs. people without deteriorating health. The presented results are a proposal for the creation of a new indicator that would fill the information gap in the health status of a patient in a post-stroke treatment unit.