Study of the Combined Effect of Stress Factor and Musical Signal on the Psychophysical State of Human
Authors: Pareniuk Anastasiia Volodymyrivna , Pareniuk Dmytro Volodymyrovych , Drozdenko Kateryna Serhiivna , Nayda Serhii Anatoliiovych 
Published: July 2021

Today the actual direction in psychoacoustics is the use of acoustic influences in order to correct the physiological, functional or psychological state of man. Various audio stimuli are used to achieve this goal, such as regulating heart rate, increasing the productivity of human work, improving mood and relieving depression.
To study the effectiveness of music therapy with the help of modern electroencephalographic complexes, an electroencephalogram (EEG) is recorded and analyzed. Changes in the state of the brain can be assessed by changes in the frequency components (rhythms) of the EEG.
Delta rhythm is registered during deep sleep, hyperventilation or anesthesia. The dominance of delta activity in adolescents and adults in the state of wakefulness is a sign of pathology. There is information that fluctuations in this rhythm can be identified in the EEG signal at rest under some forms of stress. The aim of this work is to analyze the ratio of the contribution of delta waves of the brain in its total activity in percentage when listening to low-frequency acoustic signals before and during the action of stressors.
The experiments were conducted on 5 people, of whom 2 were men and 3 – women, all of them aged 18-22 years. A total of 14 experiments were conducted - 7 in male and female groups. Electroencephalogram (EEG) registration took place in 16 leads. The composition “Demon Wings” by Bohren & der Club of Gore was used as a musical impact factor. Research was conducted in time periods before and during the increased study load, which is actually considered as a factor that causes an increase in psycho-emotional stress.
The results obtained in the periods before and during the influence of the stress factor are presented via the following data: mean values ​​of the comparative levels, differences in mean values and the probability of error of the delta rhythms in the two hemispheres of the brain in periods during the first and third minutes of the experiment. The probability of error of the assumption was determined via using Student's t-criterion.
Obtained results show that the average values ​​of the test groups under the influence of stress factor increased significantly relative to the values ​​obtained before this influence. In addition, if before the influence of stress factors there was a decrease in values ​​in the third minute of the experiment relative to the first, then after this effect, the values ​​did not vary. There is no statistically significant difference for the last two compared groups The data presented in the paper indicate that the level of delta rhythm increases significantly during the indirect influence of time-stretched stressors, despite the presence of another type of influence - acoustic, caused by a low-frequency music signal.
This rhythm is abnormal for the human body, which is in good spirits. That is why the presence of a high level of this rhythm can affect the accuracy of experiments that investigate the effect of a musical signal on the psycho-emotional state of a person, regardless of the nature of the impact and spectral characteristics of the musical signal.