ABSTRACT
Objective To study the distribution of cochlear dead regions in the cochlea with sensorineural hearing loss (SNHL),and to investigate the effects of cochlear dead regions on speech recognition.Methods A total of 41 SNHL patients (81 ears) were divided into the cochlear dead region group (35 ears) and the group without cochlear dead regions (46 ears) by using threshold equalizing noise test (TEN test).Then we used speech recognition threshold (SRT) and speech discrimination score (SDS) tests to study the distribution of cochlear dead regions and to investigate the effects of cochlear dead regions on speech recognition.Results There were 41 cases (81 ears) sensorineural hearing loss patients and 43.21％ (35/81) were found to have the cochlear dead regions.The cochlear dead region detection rate for patients with mild SNHL was 0(0/11);in patients with moderate SNHL,the cochlear dead region detection rate was 24.1％ (7/29);in patients with severe SNHL the cochlear dead region detection rate was 66.7％ (24/36);the cochlear dead regions of profound SNHL patients were 80.0％ (4/5) respestively.The existence of the cochlear dead regions was significantly correlated with the degree of hearing loss (P＜0.05).The proportion of high frequency cochlear dead regions (16 ears)was much higher than that of the low frequency cochlear dead regions(8 ears).There was no significant reduction of SRT and SDS between high and low cochlear dead regions groups(P＞0.05).The SRT and SDS of the patients with cochlear dead regions were 61.63± 16.76 dB,86.35％±12.03％.The SRT and SDS of the patient with no cochlear dead regions were 75.54 ± 9.56 dB and 64.97％±20.84％.Theresults showed a significant (P＜0.05) reduction of SRT and SDS between the patient with cochlear dead regions and the patient with no cochlear dead regions.Conclusion The greater the degree of hearing loss is,the higher possibility of the existence of cochlear dead regions there is.Cochlear dead regions are common in high frequencies than in low frequencies.The speech recognition ability can be affected.
ABSTRACT
Objective To investigate the clinical features,etiology,diagnosis and treatment of acute auditory agnosia.Methods We studied the clinical manifestation,diagnosis and treatment of acute auditory agnosia in a patient in our hospital.Results A 28 year oldyoung woman visited our department because she suffered from the tinnitus for 7 days and she could not distinguish the semantics for 1 day.There were no other abnormal symptoms in the central and peripheral nervous system on admission.Audiological testing showed normal,language testing showed that the speech discrimination score was zero.MRI showed extensive damage to temporal lope.MR spectroscopy revealed increased lactate and reduced N-acetyl aspartate.Acute auditory agnosia resulted from mitochondrial myopathy was considered.After symptomatic treatment,the symptoms were significantly improved.Molecular genetics examination showed the A3243G mtDNA mutation,further confirmed the diagnosis of mitochondrial encephalomyopathy with lactic acidosis and stroke like episodes (MELAS) syndrome.Conclusion Acute auditory agnosia and acute tinnitus can be the first symptoms in MELAS,thus,MELAS should be suspected in patients with acute auditory agnosia,acute tinnitus,sudden hearing loss in children and youth.Imaging examination plays an important role in the etiological diagnosis of acute auditory agnosia.