Mismatch negativity in auditory neuropathy patients

Mismatch negativity [MMN] is a negative component in the auditory event-related potential. There has been increased interest in using the MMN as a clinical diagnostic tool because it might provide an objective neural measure of auditory discriminability. Auditory neuropathy [AN] is characterized by a paradoxical absence of auditory brainstem evoked potentials with presence of otoacoustic emissions, in patients whose pure-tone thresholds were slightly elevated. The present study was designed to investigate the detectability of MMN in cochlear hearing loss and AN patients and to test the effectiveness of MMN as an indicator of auditory discrimination at cortical level, particularly in patients with AN, if any. This study consisted of sixty subjects divided into three groups: [Group 1] 20 AN patients, [group 2] 20 patients with bilateral moderate SNHL of cochlear origin and [group 3] 20 normal peripheral hearing subjects. All participants were submitted to: full medical history, otoscopy, basic audiological evaluation. TEOAEs, ABR for neuro otologic diagnosis and MMN testing. The results of the present study demonstrated that SNHL had a significant impact on the timing of the brain processes involved in the detection and discrimination of stimuli. Moreover, no significant differences were found between AN patients and patients with cochlear hearing loss as far as MMN latencies

Type I tympanoplasty with tragal composite cartilage graft: inlay technique

Myringoplasty technique includes either an underlay or an only approaches using temporalis fascia or perichondrium as a graft material. Roland Eavy in 1998 descriped a transcanal cartilage butterfly inlay tympanoplasty technique in nine children under general anesthesia This technique was established to be successful to close ear drum perforations, easy and rapid with no external canal incisions. The aim of this study was to obtain our results with this technique. Tragal cartilage with double layer of perichondrium was used to close small to medium sized drum perforations in 30 adult patients with unilateral inactive chronic suppurative otitis media .The study was conducted in the period between February 2000 to October 2002.We evaluated the take rate and hearing improvement. The take rate was 100% at a follow up period of an average 18 months and all cartilage grafts were dry and intact at the last follow up period. All cases showed hearing improvement in. their audiometric results