| Background and Objective:Hearing loss has become a worldwide problem and affects more than 27 million patients in China mainland, Until now, the diagnosis of hearing loss has been typically done through examination in the hospital using standard pure tone audiometry. However, this method needs a sound booth and audiometric equipment and is expensive and not portable, precluding its application to limited conditions. It would be helpful to develop a portable and self-testing audiometer for timely diagnosis and medication schedule for patients suffering from hearing loss, especially for those who need long-term repeated hearing monitoring and those in remote area.In this study, a prototype of software-based, self-reported hearing monitoring system was developed and evaluated.Application of hypobaric chamber has treated many diseases for a long time, especially the literature was reported that hypobaric chamber for Meniere’s disease may be effective, illustrate the potential for pressure changes within inner ear disease. Some scholars have thought fluctuating low-frequency sensorineural hearing loss may be atypical Meniere’s disease in the early stage and both have cochlear hydrops in the common pathological basis. The research of hypobaric chamber for Meniere’s disease provides an idea for fluctuating low-frequency sensorineural hearing loss. This study formulates hypobaric chamber method and investigates its clinical effects for fluctuating low-frequency sensorineural hearing loss.Materials and Methods:Part one:The software-based self-testing system, written by using Microsoft Office Visio software, consisted of a notebook computer, an external sound card, and pair of 10-Ω insert earphones. The system could be used to test the hearing thresholds by patients themselves in an interactive manner through software. The reliability and validity of the system at octave frequencies of 250 Hz to 8000 Hz were analyzed in three series experiments. Thirty-seven normal hearing subjects (74 ears) were enrolled in experiment 1. Forty patients (80 ears) with sensorineural hearing loss (SNHL) participated in experiment 2. Thirteen normal hearing subjects (26 ears) and thirty-seven patients (74 ears) with SNHL were enrolled in experiment 3. In all experiments, pure tone audiometry in a sound booth was regarded as the golden standard. SPSS for Windows, version 17.0 (SPSS, Chicago, IL, USA), was used for statistical analysis. The paired t-test was used to compare the hearing thresholds between pure tone audiometry and software-based self-testing in experiment 1 and 2. In experiment 3, One-way analysis of variance (ANOVA) and post-hoc comparisons were used to compare the hearing thresholds among pure tone audiometry and two rounds of software-based self-tests. Linear correlation analysis was performed for the twice self-tests. The concordance was analyzed between the pure tone audiometry and self-testing using the Kappa method..P<0.05 was considered statistically significant.Part two:The change of the aircraft cabin pressure parameters was recorded. The effects of 7 healthy volunteers in hypobaric chamber were evaluated. The best hypobaric chamber method was formulated by using 4 different hypobaric chamber plans for volunteers with fluctuating low-frequency sensorineural hearing loss.20 cases with fluctuating low-frequency sensorineural hearing loss were included in the last study, which were treated by the best hypobaric chamber method, whose pure tone threshold and subjective symptoms degrees (ear stuffiness blocking, tinnitus, cranial tinnitus) were evaluated before and after exposed to hypobaric pressure in chamber.Results:Part one:Experiment 1& experiment 2:Hearing thresholds determined by two methods were not significantly different at frequencies of 250 Hz,500 Hz, or 8000Hz (P>0.05) but were significantly different at frequencies of 1000Hz,2000Hz, and 4000Hz (P<0.05), except for 1000Hz in right ear in experiment 2. Experiment 3: Hearing thresholds determined by pure tone audiometry and twice software-based self-tests were not significantly different at any frequencies (P>0.05). The overall sensitivity of the software-based self-testing method was 97.6%, and the specificity was 98.3%. The sensitivity was 97.6% and the specificity was 97% in SNHL. The software-based self-testing had significant concordance with pure tone audiometry (Kappa value=0.848, P<0.001).Part two:Taking off about 20 minutes relief to about 80 kPa atmospheric pressure, down about 30 minutes to normal atmospheric pressure level.5 cases of healthy volunteers without ear discomfort,2 cases appear earache in the pressurization period, relieve by themselves. The best treatment program had three cycles. In the first cycle, chamber pressure changed at the speed of 3m/s from normal atmospheric pressure up to 2.2km altitude, about 78.6kPa, maintain for 5min, then down to 1.1km at lm/s speed, about 89.6kPa. The cycle repeated twice. Finally, pressure returned to normal atmospheric pressure at the speed of 1m/s. All patients breathe pure oxygen continually with 2.5L/min flow rate when the atmospheric pressure is lower than 550m altitude, about 95.1kPa. Once every day, five times as a course of treatment. Patients with mild hearing loss were treated one course, and those with moderate hearing loss were treated two courses. There were two days rest between the two courses. All cases had no adverse reactions. Pure tone threshold showed that 60% improved in hearing, in which 7 cases were cured and 5 cases were improved. The difference of hearing efficacy between mild and moderate hearing loss groups was statistically significant (P<0.05). The total effective rate of ear stuffiness was 95%, in which 17 cases were cured and 2 cases improved. Total improved rate of tinnitus was 60%. Patients were followed up for 4 to 6 months. Only 1 case recurred with ear stuffiness after upper respiratory infection, and then he accepted repeat hypobaric chamber treatment and cured again.Conclusions:This portable hearing self-monitoring system based on a notebook personal computer is a reliable and sensitive method for hearing threshold assessment and monitoring. As a good non-invasive method, hypobaric chamber can be an additional choice to treat fluctuating low-frequency sensorineural hearing loss, in particular improve ear stuffiness significantly. |
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