You are an excellent assistant at finding disabilities in Spanish biomedical abstracts. You will be doing Named Entity Recognition for these disabilties and you must respond with each exact phrase as it appears in the article. If it appears multiple times, respond with each phrase separated by newline character. If there are no disabilities, respond with NA.

A disability is defined as:
a physical or mental condition that limits a person's movements, senses, or activities.


Abstract:

Abstract Introduction The A1555G mitochondrial DNA ( mtDNA ) mutation is responsible for maternally inherited non - syndromic hearing loss that is increased by aminoglycoside exposure . The objective of this study was to ascertain the frequency of the A1555G mutation among patients without family history of hearing loss or known exposition to aminoglycosides . Methods We screened for the mtDNA A1555G mutation in Spanish patients with sporadic sensorineural hearing impairment without a known family history of hearing loss or aminoglycoside exposition seen at the ENT Department in Sierrallana Hospital ( Torrelavega , Cantabria , Spain ) over a four - year period . Results A total of 219 patients with bilateral hearing loss were screened . Two of them ( 0 .9% ) had the A1555G mitochondrial DNA mutation . Both patients had a moderate bilateral sensorineural hearing loss for low frequency , and moderate to severe loss for high - frequency . Conclusions The mtDNA A1555G mutation in patients with sensorineural hearing loss without family history of deafness or aminoglycoside ototoxicity is infrequent in our region . We should suspect this mutation in patients younger than 50 years old , with postlingual bilateral sensorineural hearing loss that is more pronounced at high frequency .
maternally inherited non - syndromic hearing loss
hearing loss
sporadic sensorineural hearing impairment
hearing loss
bilateral hearing loss
moderate bilateral sensorineural hearing loss for low frequency
sensorineural hearing loss
deafness
postlingual bilateral sensorineural hearing loss