نوع مقاله : مقاله پژوهشی
1 کمیته پژوهشی دانشجویان. دانشجوی کارشناسی ارشد شنواییشناسی، دانشگاه علوم پزشکی شهید بهشتی، تهران، ایران
2 مربی گروه شنوایی شناسی، دانشکده علوم توانبخشی، دانشگاه علوم پزشکی شهید بهشتی، تهران، ایران
3 کارشناس ارشد آمار زیستی، دانشکده علوم توانبخشی، دانشگاه علوم پزشکی شهید بهشتی، تهران، ایران
عنوان مقاله [English]
Background and Aim: Hearing loss is one of the most common disorders in the elderly people. Sensory neural hearing loss mostly results from outer and inner hair cell damages in cochlea. The area wherein inner hair cells or auditory nerve fibers are inactive is named Dead Region (DR) or Cochlear dead Region (CDR). Many studies have investigated DR at high frequencies in sloping or sharply sloping audiograms, but few studies have investigated flat audiograms. Hence, the aim of the present study was to investigate the prevalence of DR in hearing impaired adults with mild to severe flat sensory neural hearing loss.
Materials and Methods: In the current descriptive-analytical study, 30 elderly people (60 ears) aged 65 years and above, with bilateral mild to severe flat sensory neural hearing loss were tested for DR at frequencies from 0.5 to 4 kHz using the threshold equalizing noise (HL) test. Based on the hearing thresholds, participants were divided into three groups of mild, moderate, and severe hearing loss.
Results: The prevalence of DR at 2 kHz, 3 kHz, and 4 kHz were significantly higher than DR at frequencies below 2 kHz (p<0.05). With increasing the amount of hearing loss, the number of DR increased. As a result, the difference between prevalence of DR in severe hearing loss and the other two groups was statistically significant (p<0.05).
Conclusion: The results indicated a relatively high prevalence of dead regions in the elderly with severe degree of hearing loss (60-80dBHL) and at high frequencies. Furthermore, with increasing frequency, the number of dead regions increased correspondingly.