OBJECTIVE To investigate the differences in audiological characteristics and speech recognition rates between vestibular schwannoma(VS)patients presenting with sudden sensorineural hearing loss(SSNHL)as first symptom and patients with idiopathic sudden deafness(ISD),in order to provide a reference for clinical diagnosis and differential diagnosis.METHODS A retrospective analysis was conducted on 60 patients with VS presenting as SSNHL(VS group),and 60 patients with unilateral ISD(SD group).Pure-tone thresholds,audiogram configurations,and speech recognition scores were compared between the two groups.Statistical analyses were performed using t-test,Mann-Whitney U test,and chi-square test.RESULTS Hearing loss in the VS group was mainly distributed in the moderate to profound range,and the proportion of descending-type audiograms was significantly higher than that in the SD group(χ2=13.97,P=0.002 9).In contrast,the SD group was predominantly characterized by mild to moderate hearing loss and flat-type audiograms.Regarding speech recognition,the VS group showed significantly poorer monosyllabic recognition(38.6%±40.4%)and sentence recognition(53.4%±42.0%)compared with the SD group(59.0%±37.8%,75.8%±36.0%,P<0.01).Notably,some VS patients exhibited complete loss of speech recognition even before the pure-tone average reached the level of total deafness.CONCLUSION VS patients presenting with SSNHL showed significant differences in audiogram configurations and speech recognition compared with those with ISD.A marked decline in speech recognition,combined with a typical descending-type audiogram,may serve as important clinical indicators,suggesting that early imaging examinations should be performed to confirm the diagnosis.

To study alkaloid constituents in Corydalis decumbens,thirteen compounds were isolated from 95％ ethanol extracts of Corydalis decumbens (Thunb) Pers.by silica gel,RP-C1s,Sephadex LH-20 column chromatographer,recry stallization,thin-layer chromatography and HPLC.Their structures were elucidated on the basis of spectral data combined with physiochemical properties as tetrahydropalmatine (1),oxyhydrastinine (2),doryanine (3),palmatine (4),bicuculline (5),canadine (6),tetrahydrocoptisine(7),corydaldine (8),epicorynoxidine (9),N-methylcorydaldine (10),(+)-corlumine (11),N-methyl-6,7-dimethoxyisoquinolone (12) and oxysanguinarine (13).Compounds 2,3,6,7,and 9-13 were isolated from this plant for the first time.In addition,compounds 2,3,and 9-13 were obtained firstly from this genus.Pharmacological experiments showed that tetrahydropalmatine (1) might have analgesic or sedative effects,and the bicuculline (5) could probably induce epilepsy.