Noise exposure: a continuous dilemma of the industrial environments and modern world.

Noise exposure has long been known to be a risk factor for hearing loss. Noise-induced hearing loss (NIHL) is one of the most common occupational diseases worldwide; 49% of male miners by the age of 50 and 70% of them by the age of 60 have hearing loss.1 Currently, NIHL is not considered only an occupational disease; the non-occupational forms of the disease are on the rise. Leisure-time noise and exposure to the noise exceeding a certain level can lead to the NIHL. Overstimulation of the outer hair cells (OHCs) increases the risk of NIHL. There are two types of NIHL: “acoustic trauma” that refers to the sudden exposure to a high-intensity sound, e.g., gunfire or explosions, which may lead to permanent cochlear damage; and NIHL secondary to the chronic exposure to loud noises like that mostly happen in industrial and occupational settings. NIHL generally presents with bilateral high-frequency sensorineural hearing loss that has a characteristic first notch at 4 kHz on the audiogram.2 Continuation of the exposure will give rise to worsening of the hearing loss and involvement of other frequencies.3 Patients with NIHL may have tinnitus—one of the most disturbing and debilitating symptoms. Tinnitus can affects all aspects of the life. In 16% to 21% of adults it occurs at some points in their lifetime.4 Approximately 2% of people have decreased quality of life due to chronic tinnitus.5 Tinnitus has no exteriorization; thus, it has no definite classification, nor is there any standard algorithm for its management. The complex and lengthy medical treatment programs for tinnitus that are not successful most of the time, make physicians to often use other therapeutic approaches. And, that is why the management of tinnitus is costly and in most instances, discouraging. In this issue of The IJOEM, Raghunath G, et al, show that chronic exposure to noise does affect the vestibular system and can cause minimal elusive symptoms.6 Therefore, noise not only affect hearing but can also harm the vestibular system. Sound levels ≥100 dB SPL can produce saccular stimulation that in turn results in balance problem.6 In a study in Taiwan, patients with chronic NIHL also complained of vestibular symptoms.7 People are not equally susceptible to the harmful effects of noise. Therefore, identification of susceptible individuals to arrange things so that they are not exposed to loud noise in workplaces as much as possible, is of paramount importance. Audiologists and otolaryngologists should therefore pay more attention to preventing occupational noise exposure. M Amirabadi