Noise may be defined simply as “unwanted sound” [1]. The World Health Organization (WHO) recommends that the average background noise in hospitals should not exceed 30 A weighted decibels (dB [A]), and that peaks during the night-time should be less than 40 dB(A) [1]. Noise in hospitals and particularly in intensive care units (ICUs), frequently exceeds these values [2]–[4]. The United States Environmental Protection Agency in fact defines noise as “any sound that may produce an undesired physiological or psychological effect in an individual or group”. Noise affects both staff and patients. It may impede concentration and cognitive function [5, 6]. It interferes with effective communication and may thus increase the risk of accidents [5, 7]. The critically ill are particularly sensitive to the disruption of sleep by noise [8]. In addition, and especially for the elderly and hard of hearing, noise may hinder communication and impair understanding of their environment. It may also potentially contribute to the abnormal thought processes and behavior associated with ICU delirium [9].