Changes in indicators of intonation structure of speech in occupational activity of air traffic control operators

Introduction.The study is aimed to determine possible use of vocal signal analysis for diagnosis of functional states in air traffic control operators, with justifying selection of informative parameters of intonation structure of speech.Materials and methods.Experiments on semi-natural simulator complex with participation of 16 air traffic male dispatchers modelled occupational activity of air traffic dispatcher with moderate (6 aircrafts controlled) and intense (7–12 aircrafts controlled) work load. Duration of simulated working shiftwas 6 hours. Registration covered characteristics of main vocal tone of the examinees, with calculation of 8 jitter-factors that portrayed mirco-changes of main vocal tone curve and 2 tremor indices disclosing periodic waves of 4–16 Hz in main vocal tone curve. Functional state of the dispatchers was assessed via cardiac rhythm parameters. Reliability and work capacity of the dispatchers corresponded to correct radio traffi c, changes in threshold of reception and transfer of aircrafts in number of allowable dangerous approach of aircrafts, time to detection of input aircraft’s deviation from preset flight line.Results and discussion.According to analysis of the experiments results, some parameters of the main vocal tone carried significant changes both in first (simulated moderate work load) and second (simulated intense work load) experimental series.The data obtained prove lower level of psychic regulation of the dispatchers’ occupational activity during 3rd to 5thhours of “working shift” in the first experimental series and from 2nd to 4thhours of the second experimental series, due to decreased psychophysiologic resources and developing fatigue.Conclusion.Studies of changes in indicators of intonation structure of speech in occupational activity of air traffic dispatchers demonstrated that using such indicators provides adequate diagnosis of the functional state. The most informative indicators are average value, histogram asymmetry and excessive frequency of main vocal tone, duration of pauses between words of the dispatchers’ commands and fi ft h jitter-factor.