One study made in Germany by Charité – Univeritätsmedizin Berlin found that almost all the tinnitus patients had a hearing loss. Of the 531 tinnitus patients tested, 441 (83%) had a hearing loss in the upper frequencies corresponding to a noise-induced hearing loss. 84 patients (15.8%) had a hearing loss in all frequencies. Only 6 tinnitus patients did not have a hearing loss when measured.
Of the 441 patients with tinnitus, 72.3% (319 patients) had pure tone tinnitus. 27.7% (122 patients) had a noise tinnitus. 53% had bilateral tinnitus and 47% had unilateral tinnitus.
The data was obtained from 531 tinnitus patients admitted to a 7-day multimodal tinnitus therapy.
Another study found that 72.1% of the patients in the study with sensorineural hearing loss also had a high-pitched tinnitus. Of those who had a high-frequency sensorineural hearing loss, 88.4% had a high-pitched tinnitus.
Among the 312 persons in the study with tinnitus, 63.1% (197 persons) had a hearing deficit, while 36.9% (115 persons) had normal hearing.
Among those who had both tinnitus and hearing loss, 74.6% had a sensorineural hearing loss, 10.7% had a conductive hearing loss and 14.7% had a mixed hearing loss. Of those who had a sensorineural hearing loss, 58.5% (147 people) had a high frequency hearing loss, 11.6% had a low frequency hearing loss and 29.9% had a flat hearing loss.
The hearing loss among the tinnitus patients was mild in 58.9% of the cases, 22.3% had a moderate hearing loss, 15.7% had a severe hearing loss and 3.1% had a profound hearing loss
The study was conducted by the Audiology Section of the Department of Bio-technology of Palermo University in Italy and consisted of 312 persons aged from 21 to 83.
The first study “The more the Worse: The grade of Noise-Induced Hearing Loss associates with the Severity of Tinnitus” was published in International Journal of Environmental Research and Public Health in 2010.
The second study “Assessing audiological, pathophysiological and psychological variables in tinnitus patients with or without tinnitus” was published in European Archives of Oto-Rhino-Laryngoly in 2010.
Sources: www.ncbi.nlm.nih.gov and SpringerLink