Russian doctor Vitutas Kisilius indicated that one of the causes of tinnitus is stress and sleep disturbance. Vitutas Kisilius, a specialist in audiology and ENT at the "Sverzhivsky" Clinical Research Institute of the Russian Ministry of Health, stated: "Increased stress, sleep disorders, eating disorders, and insomnia all lead to excessive nervous tension, which may result in the onset of tinnitus." According to the specialist, sometimes patients are less concerned about hearing loss than they are about the emergence of tinnitus. He added: "There are various medical terms, such as noise, whistle, squeak, and ringing, but this often manifests more prominently in stress, sleep disorders, and eating disorders that may occur in large cities, as well as insomnia, which causes excessive nervous tension that sometimes triggers tinnitus."