Detection and analysis of gastrointestinal sounds in normal and small bowel obstructed rats

This study is aimed at detecting gastrointestinal sounds (GIS) and correlating their characteristics with gastrointestinal (GI) conditions. The central hypotheses are that GIS generation depends on the motility patterns and the mechanical properties of the gut, and that changes in those result in measurable differences in GIS. An animal model which included both healthy rats and those with small bowel obstruction (SBO) was developed. The acoustic bursts, of GIS were detected by amplitude thresholding the signal envelope. Three methods of envelope estimation were proposed and evaluated. Envelope estimation using a Hilbert transform was found to produce the best results in the current application. The duration and dominant frequency of each detected GIS event was estimated and clear differences between healthy and diseased rats were discovered. In the control state, GIS events were found to consistently be of relatively short duration (3–65ms). Although the majority of events in the SBO state had similar short duration, infrequent longer events were also detected and appeared to be pathognomonic. Long duration events (>100 ms) occurred in each of seven obstructed, but in none of 14 non-obstructed, cases (p<0.001). It is concluded that GIS analysis may prove useful in the non-invasive, rapid, and accurate diagnosis of SBO.     

京剧嗓音的声学分析及音域特征

目的　从声学角度客观地检测京剧的嗓音特征 ,为京剧演唱者嗓音的训练和保护提供参考。方法　对 73名 1 6～ 5 7岁不同行当的专业京剧演员或学员 ,利用Dr Speech计算机频谱分析系统对元音 /a/、/i/歌唱舒适音和唱段进行声学参数的检测和分析。结果　各行当元音 /a/、/i/歌唱舒适音的基频 (fundamentalfrequency,F0 )分别是 :丑角 (2 72 6± 42 0 )Hz( x±s ,下同 )、(30 4 2± 2 2 1 )Hz;小生 (499 3± 34 0 )Hz,(485 4± 1 8 7)Hz;老生 (335 6± 6 0 0 )Hz,(31 7 9± 45 1 )Hz ;花脸 (31 9 0±6 1 3)Hz,(34 0 1± 6 8 8)Hz;老旦 (42 7 6± 47 2 )Hz,(437 7± 45 8)Hz ;花旦 (5 35 8± 48 8)Hz,(5 6 1 6± 2 9 2 )Hz ;青衣 (5 48 0± 6 9 5 )Hz,(5 43 5± 79 3)Hz;其它声学参数 :频率微扰 (pitchperiodperturbation,或Jitter)、振幅微扰 (amplitudeperturbation ,或Shimmer)和声门噪声能量 (也称标准化噪声能量级 ,normalizednoiseenergy ,NNE)均在软件提供的正常值范围内 ;京剧演员歌唱音域的跨度为 1 7～ 2 8个八度 ,最低音和多数最高音均比西洋唱法的高音声部相应的值高。结论　京剧嗓音有着独特的声学特征 ;结果对其嗓音的训练和保护有一定的临床参考     

成人女性嗓音障碍的客观多参数分析

目的：探讨嗓音客观多参数分析与主观听感知评估的相关性，建立嗓音客观多参数评估模型，实现嗓音评估的客观化和数据化。方法：声音样本采自83例嗓音障碍患者和40例嗓音正常者，全部受试者均为女性。客观检测采用Dr．Speech Science for Windows嗓音评估软件，在长元音/α：/上测试下列参数：基频、基频微扰(jitter)、振幅微扰(shimmer)、基频标准差、基频震颤、振幅震颤、标准化噪声能量(NNE)、谐噪比(HNR)、信噪比和最大发声时间(MPT)。主观听感知评估参数采用日本言语音声学会声音嘶哑评估GRBAS系统中的总嘶哑度，4级评估标准。结果：应用逐步判别分析方法，建立了5个参数(MPT、jitter、NNE、HNR和shimmer)的嗓音客观评估模型。客观评估结果与主观评估结果的一致性达到79．8％。结论：嗓音的客观评估是多参数的；嗓音的客观多参数评估模型与主观听感知结果有较好的一致性。     

An Analysis of the Acoustic Input Impedance of the Ear

Ear canal acoustics was examined using a one-dimensional lossy transmission line with a distributed load impedance to model the ear. The acoustic input impedance of the ear was derived from sound pressure measurements in the ear canal of healthy human ears. A nonlinear least squares fit of the model to data generated estimates for ear canal radius, ear canal length, and quantified the resistance that would produce transmission losses. Derivation of ear canal radius has application to quantifying the impedance mismatch at the eardrum between the ear canal and the middle ear. The length of the ear canal was found, in general, to be longer than the length derived from the one-quarter wavelength standing wave frequency, consistent with the middle ear being mass-controlled at the standing wave frequency. Viscothermal losses in the ear canal, in some cases, may exceed that attributable to a smooth rigid wall. Resistance in the middle ear was found to contribute significantly to the total resistance. In effect, this analysis “reverse engineers” physical parameters of the ear from sound pressure measurements in the ear canal.     

Proficiency in English sentence stress production by Cantonese speakers who speak English as a second language (ESL)

The present study examined English sentence stress produced by native Cantonese speakers who were speaking English as a second language (ESL). Cantonese ESL speakers' proficiency in English stress production as perceived by English-speaking listeners was also studied. Acoustical parameters associated with sentence stress including fundamental frequency (F0), vowel duration, and intensity were measured from the English sentences produced by 40 Cantonese ESL speakers. Data were compared with those obtained from 40 native speakers of American English. The speech samples were also judged by eight naïve listeners who were native speakers of American English for placement, degree, and naturalness of stress. Results showed that Cantonese ESL speakers were able to use F0, vowel duration, and intensity to differentiate sentence stress patterns. Yet, both female and male Cantonese ESL speakers exhibited consistently higher F0 in stressed words than English speakers. Overall, Cantonese ESL speakers were found to be proficient in using duration and intensity to signal sentence stress, in a way comparable with English speakers. In addition, F0 and intensity were found to correlate closely with perceptual judgement and the degree of stress with the naturalness of stress.     

Validation of the optimal site in the neck region for detecting swallowing sounds

Recently, the swallowing sound has been used to detect swallowing events non‐invasively. A previous study, using an accelerometer, showed that the site over the lateral border of the trachea immediately inferior to the cricoid cartilage was the optimal site for detecting swallowing sounds. However, the optimal site for detection of the swallowing sound using a microphone remains undetermined. To validate the optimal site in the neck region for detecting swallowing sounds. Fourteen healthy subjects (mean age, 27·6 ± 2·2 years; seven male and seven female) participated in this study. Twenty condenser microphones were attached to 20 sites on the left neck surface to detect swallowing sounds. Participants were instructed to swallow five different stimuli three times as follows: Resting saliva, 1 and 5 mL of Japanese tea, and 1 and 5 mL of yoghurt. Mean relative peak intensity was used to indicate the magnitude of the swallowing sound. Sound spectrograms were used to illustrate differences in the properties of swallowing sounds. Mean relative peak intensity number was highest in sites at the inferior border of the mandible just above the sternocleidomastoid muscle (site 11) and sites over the lateral border of the trachea immediately inferior to the cricoid cartilage (site 8). Comparison of spectrograms showed a greater density distribution of higher frequency components at site 11 compared with site 8. These results indicate that the inferior border of the mandible just above the sternocleidomastoid muscle is the optimal site for the detection of swallowing sounds.     

Acoustic Cues for Sound Source Distance and Azimuth in Rabbits, a Racquetball and a Rigid Spherical Model

There are numerous studies measuring the transfer functions representing signal transformation between a source and each ear canal, i.e., the head-related transfer functions (HRTFs), for various species. However, only a handful of these address the effects of sound source distance on HRTFs. This is the first study of HRTFs in the rabbit where the emphasis is on the effects of sound source distance and azimuth on HRTFs. With the rabbit placed in an anechoic chamber, we made acoustic measurements with miniature microphones placed deep in each ear canal to a sound source at different positions (10–160 cm distance, ±150° azimuth). The sound was a logarithmically swept broadband chirp. For comparisons, we also obtained the HRTFs from a racquetball and a computational model for a rigid sphere. We found that (1) the spectral shape of the HRTF in each ear changed with sound source location; (2) interaural level difference (ILD) increased with decreasing distance and with increasing frequency. Furthermore, ILDs can be substantial even at low frequencies when distance is close; and (3) interaural time difference (ITD) decreased with decreasing distance and generally increased with decreasing frequency. The observations in the rabbit were reproduced, in general, by those in the racquetball, albeit greater in magnitude in the rabbit. In the sphere model, the results were partly similar and partly different than those in the racquetball and the rabbit. These findings refute the common notions that ILD is negligible at low frequencies and that ITD is constant across frequency. These misconceptions became evident when distance-dependent changes were examined.     

全口义齿腭皱对语音恢复的作用

目的:研究金属基托全口义齿腭皱对修复后辅音声学特征的影响。方法:30例无牙颌患者分别戴入光滑面金属基托全口义齿(第一组)和有腭皱金属基托全口义齿(第二组),应用Minispeech lab测量并分析患者在初戴前,初戴时,初戴后1周、2周、4周、8周时汉语拼音/j/、/q/的第二强频区(F2)值、带宽(B2)值和嗓音起始时间(V.O.T.)。结果:第一组中,与初戴前相比,/j/、/q/的F2值从初戴后2周开始差异有统计学意义(P<0.05),/j/的B2值在初戴后8周,/q/的B2值在初戴后4周差异有统计学意义(P<0.05);第二组中,与初戴前相比,/j/、/q/的F2值从初戴后1周开始差异有统计学意义(P<0.05),/j/的B2值从初戴后2周开始,/q/的B2值从初戴后4周开始差异有统计学意义(P<0.05)。结论:金属基托全口义齿的腭皱能够缩短金属基托全口义齿初戴后患者语音恢复的时间。     

动态喉镜下嗓音声学测试的研究进展

嗓声学临床检测分为依赖于主观的听觉能力检测和客观性声学检测。两种检测方式所产生的检测效果有所区别,在很长时间一段时间内,由于先进诊断方式的缺乏,对于嗓音学的测试往往主要依靠主观检查。而主观检查靠测试者工作经验、主观感受等进行,虽可获得一定诊断价值,但仍有进步的空间。由此可见,嗓音检测很大程度上满足了嗓音医学发展的客观需求。伴随多媒体技术的快速发展,嗓音检测技术被逐渐应用于临床,为临床诊断提供客观参考依据。本研究检测和分析各种参数,对嗓音声学评价提供客观参考,先将其综述如下。