哮喘联盟

摘要
   背景：近期研究显示，采用音频记录对咳嗽进行客观性定量，是一种新方法，有助于了解咳嗽，并对其治疗进行评价。目前，人工咳嗽计数是对咳嗽进行定量的最为准确的手段。然而，人工咳嗽计数的需求量太大，这就要求在计数前减少记录的长度，同时能够保留计数期间的咳嗽信息。本试验针对此要求设计一种算法，并研究该算法的可行性。
   方法：入选20名受试者（5名健康吸烟者和非吸烟者；5名慢性咳嗽患者；5名慢性阻塞性肺疾病患者和5名哮喘患者），采用门诊记录系统拟合并记录24 h。产生的记录被分为间隔15 min的节段，并进行计数。采用中位频率和音频信号能量，去除各节段的非活动音频，对剩下的文件进行重新计数。
   结果：剩下的节段平均长度为13.9 s（IQR：56.4 s），平均24 h记录长度为62.4 min（IQR：100.4）。平均每小时0次咳嗽被去除(IQR 0.0-0.2) ，剩下的咳嗽计数变异与人工咳嗽计数相当。哮喘患者出现的错误最多，但也仅每小时漏掉1.0%的咳嗽。
   结论：这些结果显示，采用平均音频频率检测信号活动的系统，能显著减少记录的长度，但不会显著影响咳嗽计数。

                                                                                           (林江涛 审校)
                                                        Cough. 2012 Dec 12;8(1):12. [Epub ahead of print]
 

Data reduction for cough studies using distribution of audio frequency content.

Barton A, Gaydecki P, Holt K, Smith JA.

Abstract
ABSTRACT: BACKGROUND: Recent studies suggest that objectively quantifying coughing in audio recordings offers a novel means to understand coughing and assess treatments. Currently, manual cough counting is the most accurate method for quantifying coughing. However, the demand of manually counting cough records is substantial, demonstrating a need to reduce record lengths prior to counting whilst preserving the coughs within them. This study tested the performance of an algorithm developed for this purpose.
METHODS: 20 subjects were recruited (5 healthy smokers and non-smokers, 5 chronic cough, 5 chronic obstructive pulmonary disease and 5 asthma), fitted with an ambulatory recording system and recorded for 24 hours. The recordings produced were divided into 15 min segments and counted. Periods of inactive audio in each segment were removed using the median frequency and power of the audio signal and the resulting files re-counted.
RESULTS: The median resultant segment length was 13.9 s (IQR 56.4 s) and median 24 hr recording length 62.4 min (IQR 100.4). A median of 0.0 coughs/h (IQR 0.0-0.2) were erroneously removed and the variability in the resultant cough counts was comparable to that between manual cough counts. The largest error was seen in asthmatic patients, but still only 1.0% coughs/h were missed.
CONCLUSIONS: These data show that a system which measures signal activity using the median audio frequency can substantially reduce record lengths without significantly compromising the coughs contained within them.

Cough. 2012 Dec 12;8(1):12. [Epub ahead of print]