DEVELOPMENT OF A COMPUTER AIDED SYSTEM FOR THE TREATMENT OF INSOMNIA BASED ON AUTOMOBILE ENGINE IN-CABIN ACOUSTIC NOISE

Abstract

This research is aimed at developing a computer aided system for treatment of insomnia based on automobile engine in-cabin acoustic noise. A conventional pharmacologic approach of using sleeping drug has been faulted because of its economic impact, adverse effect on patient and inefficacy of the drugs when used for a long time. This research looked into the use of non-pharmacologic treatment of insomnia with a focus on the use of sound therapy. From a hypothesis based on an observed phenomenon that for vehicles moving at high speed, the in-cabin acoustic noise made by the engine coupled with the inflow of fresh air into the vehicle emit some certain sound frequencies which induce sleep in the vehicle passengers. This is as a result of human brainwave response to some selected sound to induce sleep. Samples of in-cabin acoustic noise of a selected automobile were acquired using Infinix Smartphone Android Phone for different stages of motion: acceleration, constant speed and deceleration. The acquired samples were edited using cyberlink wave-editor 2 and MATLAB software to remove unwanted portion and to prepare the sample for investigation and analysis in order to determine their characteristics. Mathematical and statistical analysis were carried out on the edited noise samples which include waveform pattern, distribution function, Probability Density Function (PDF), autocorrelation, Power Spectral Density (PSD) and spectrograph. Appropriate power frequency models for each type of vehicle motion noise were developed from these analyses. A Graphical User Interface (GUI) using MATLAB software was developed. The GUI through the computer system is interconnected with a fan speed/air-flow control system which was developed to administer the acquired noise on insomnia patients. The GUI contains buttons to initiate the administration of the noise for each motion stage as desired by the user, and also to control the speed of the fan. The fan speed control system uses the audio signal amplitude from the Personal Computer (PC) to control the fan speed. The control system iiwas developed using discrete components and Integrated Circuit (I.C.) Amplifiers, and the fan used is a d.c. fan. The fan control system runs on an external 12V supply. The developed computer aided system was tested on healthy subjects and insomnia patients and its performance was observed and evaluated using questionnaire. Questionnaires were given to 10 (ten) subjects to record their responses to the therapy. The age of the subjects ranges from 5 years to 70 years. Six (6) males and four (4) females were administered and their sleeping periods were recorded. The results of the analyses showed that the acquired sound is stochastic in nature with low autocorrelation for all time lags. The Power Spectral Density and Spectrogram show that the strength of the noise is high at low frequencies than at high frequencies. Eight of the patients showed good response to the therapy while the remaining two participants find the sound unpleasant. 80% of the patients find the application of the sound improving their sleeping period and recommended it to be good.