◆ SpookStack

Approved For Release AW03469/H16[EB1A-RDP96-00788R001300020001-6 ST-CS-01-169-72 July 1972 Under daily six hour exposure to noise of 110-112 db for five days, the changes increased from day to day: fatigue, headache and general malaise. After the third day the symptoms did not disappear by the beginning of the following work day. With noise of 118-120 db, a single exposure elicited the same changes as at lower levels, but the degree of expression increased significantly and the aftereffects lasted longer. Especially strong reactions were observed in three and six hour exposures. All volunteers complained of noise and ringing in the ears, general fatigue and heaviness of the head. In some subjects, paleness of the skin, involuntary twitching of face muscles, apathy or irritability, perspiration, or tremors of the eyelids and fingers appeared. One general observation of considera- ble significance was that the effects of prolonged noise exposure are cumulative. 7. (U) Mikhaylova and Byshevskiy report that 2000 Hz for various periods of time (from 30 minutes to 10 days) on exposed rats may contribute to inhibition of the anticoagulation process (272). Further studies on rats exposed to 2000 Hz for various time limits showed a reduced transketolase activity (273). 8. (U) Yuganov et al (274) have suggested that there be a standardi- zation for admissible limits for high intensity sound. The effect exerted on humans by noise of 114-116 and 125-126 db with an acoustic energy of 500 Hz was studied. The auditory thresholds, blood pressure values and time of response to light stimuli were measured. Sixty-four healthy male test subjects were used in 152 experimen's. Adverse changes in the acoustic analyzer, cardiovascular system and locomotor analyzer were detected during an exposure to 125-126 db noise. Taking into account the changes in the thresholds of skin vibrosensitivity when the ear was protected, it is concluded that the skin becomes a second gauge for acoustic energy beginning with 125-126 db. Noise of 114-116 db is considered admissible during powered stages of spaceflight. SECTION IV - ULTRASONIC NOLSE 1. (U) Various psychological effects to exposure to ultrasound (greater than 20,000 Hz) has been reported in the Soviet literature. Mel'kumova and Koroleva (275) reported psychological-subjective findings based on ¢linical observations of 104 individuals exposed to ultrasound in an industrial environment. The main complaints of the examinees were headache, extremely pronounced fatigability, tiredness and a general weakness. The onset of fatigue in most of the subjects began as early as two to three hours after starting work with simultaneous development of headache, with the latter 96 UNCLASSIFIED