The cut off points of 90th percentile of acoustic reflex thresholds were determined in the normal and sensory hearing loss.All subjects had measurable hearing(ANSI-1969≤110 dBHL) in three frequencies of 500,1000 and 2000Hz.

While hearing loss was more than 55dB, The cut off point was higher in studies that NR responses was included.

In cases that hearing loss was less than 75dB, 90th percentile can be used in diganosis of retrochochlear lesions.Since Acoustic reflexes are absent in both mentioned pathologies in greater amount of hearing loss,It would be less efficient in diffrential diganisis of cochlear and retrochochlear lesions to use acoustic reflex thresholds under the mentioned circumstances.

Background: Fanconi anemia (FA) is an autosomal recessive genetic disorder wich characterized by progressive pancytopenia, multiple congenital anomalies,  increased susceptibility to acute myelogenous leukemia and epithelial cancers specially in head and neck and GUT. Characteristic feature of FA include short stature, café-au-laitspots, small eyes, mental retardation, skeletal and ear anomalies.
Case: A 23-year-old man who was a known case of FA since he was ten reffered to audiology clinic because of severe hearing loss. His initial diagnosis was pneumonia. Audilogic evaluation revealed  bilateral profound hearing loss.
Conclusion: One of the anomalies in FA are  ear anomalies. These included conductive haering loss, external auditory canal stenosis and auricular malformation and progressive sensoryneural hearing loss. In this report external auditory canal and tympanic membrane were normal. The result of tympanometry were type An and audiometry were bilateral profound hearing loss that is a rare finding  in FA patient.