Stress effects of personal control over hospital noise

Hospital critical care unit (CCU) sounds, instruction in personal control over noise, and stress were studied in 105 female volunteers attempting to sleep overnight in a simulated hospital environment. Subjects were randomly assigned to three groups--instruction in personal control over noise, no instruction in personal control over noise, or a quiet condition. The two noise conditions heard audiotaped recorded playback of CCU nighttime sounds. The subjects with instruction in personal control received directions for using a sound conditioner to block out unwanted sounds. This intervention failed to result in less stress. The results of group comparisons provided strong support for a causal relationship between CCU sounds and greater subjective stress (p less than .000) but not for physiological stress measured by urinary epinephrine. As predicted, scores for sensitivity of the person to noise were positively correlated with scores for noise-induced subjective stress (r = .226, p less than .05). Hierarchical multiple regression revealed that CCU sound levels independently accounted for 54% (p less than .001) and sensitivity to noise for 5% (p less than .01) of the variance in subjective stress.