Noise characterization of “effective quiet” areas on a U.S. Navy aircraft carrier

The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (L_eq) measurements were collected during flight operations (L_{eq (flt ops)}), non-flight operations (L_{eq (non-flt ops)}), and over 24-hr periods (L_{eq (24-hr)}). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH^®) Threshold Limit Value (TLV^®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The L_eq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between L_{eq (flt ops)}, L_{eq (non-flt ops)}, and L_{eq (24-hr)} and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) L_{eq (24-hr)}: 70.8–105.4 dBA; (2) L_{eq (flt ops)}: 70–101.2 dBA; and (3) L_{eq (non-flt ops)}: 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean L_eqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The L_eqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.     

Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.     

Sensory evoked potentials in patients with Rett syndrome through the lens of animal studies: Systematic review

ObjectiveSystematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations).MethodsPubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards.ResultsERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients.ConclusionsWhile there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms.SignificanceThe review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology.     

钨针电刀在耳内镜鼓膜修补手术中的应用

目的探讨钨针电刀在耳内镜鼓膜修补手术中的应用。方法选取2018年8月-2019年8月住院行耳内镜鼓膜修补的患者85例。其中采用外耳道皮瓣刀行外耳道内切口的40例为对照组,采用钨针电刀行外耳道内切口的45例为观察组,对比分析两组患者手术中和手术后效果。结果观察组比较对照组切口时间短、切口出血量少、术中镜头擦拭次数少、术中止血海绵粒使用量小,两组差别具有统计学意义(t=-13.6、-9.0、-7.6、-12.8、P<0.05);两组患者在术后愈合时间,外耳道狭窄程度方面差别不大,无统计学意义。观察组缺点是电刀使用过程中会产生烟雾,需要助手辅助吸引烟雾。结论钨针电刀小巧灵活,精细准确,具有减少切口出血,缩短手术时间的优点,适合在耳内镜外耳道手术中推广应用。     

内听动脉闭塞综合征的临床与发病机理

目的：探讨内听动脉闭塞综合征的临床与发病机理。方法：分析24例患者年龄、性别及所伴发疾病如高血压病、糖尿病、冠心痛及椎-基底动脉供血不足等。结果：50岁以上，有高血压病、冠心病、糖尿病、椎-基底动脉供血不足者内听动脉闭塞发病明显增加。结论：高血压病、冠心病、糖尿病、椎基底动脉供血不足是内听动脉闭塞综合征的主要危险因素。     

听觉诱发电位指数、脑电双频指数对异丙酚麻醉下患者术中体动反应的预测

目的评价听觉诱发电位指数(AAI)、脑电双频指数(BIS)预测异丙酚麻醉下患者术中体动反应的可能性。方法择期行妇科手术全麻患者28例,ASAⅠ或Ⅱ级,年龄24-62岁,体重46- 71 kg,术前2 h口服咪达唑仑10 mg,入室后以血浆靶浓度3．5μg/ml靶控输注异丙酚、静脉注射芬太尼2μg／kg及维库溴铵0．1 mg／kg麻醉诱导,气管插管后,调整异丙酚血浆靶浓度维持BIS 40-60。切皮后不再追加肌松剂,观察患者术中头面部及四肢的体动反应,记录体动反应发生前、后2min内BIS、AAI的最大值(BISmax、AAImax)及此时段内BIS>75、AAI>40的次数及出现时间。记录术中当BIS>75、AAI>40时前、后2 min内有无体动反应发生及发生时间。结果12例出现体动反应,体动前、后2 min内BISmax为63±16(4例BIS>75,33．3％),AAImax为48±11(12例AAI>40,100％)。麻醉维持过程中,出现14次BIS>75,并发体动反应4次(28．5％),BIS反应时间较体动时间滞后(84±19)s;出现AAI>40者28次,并发体动者12次(42．8％),AAI反应时间较体动时间滞后(13±3)s。结论异丙酚麻醉下BIS、AAI反应时间较体动发生时间滞后,不能预测术中体动反应的发生。     

Investigation of hearing loss in patients with acute brucellosis by standard and high-frequency audiometry

This study aimed to determine the effect of acute brucellosis on the auditory system. Forty-two patients with acute brucellosis were evaluated clinically, and with serological and audiological tests, before and after treatment. Hearing threshold averages were calculated at 11 different frequencies (250-8000 Hz) of the auditory airway, and statistical analysis was performed. The average hearing thresholds were > 20 dB, with standard audiometry at 6000-8000 Hz, and < 20 dB at all other frequencies. After treatment, the average auditory threshold decreased to < 20 dB at 6000-8000 Hz (p < 0.0001). Pure-tone hearing thresholds were improved at all frequencies after treatment, with statistically significant differences at all frequencies except 12,000, 14,000 and 16 000 Hz (p < 0.05). There was no permanent hearing loss caused by acute brucellosis, and hearing thresholds were restored after treatment. It was concluded that acute brucellosis affects the auditory system, especially at high frequencies, and that patients with all forms of brucellosis should be evaluated for hearing loss.     

Needle electromyography

Physiologic assessment of diseases of the motor unit from the anterior horn cells to the muscles relies on a combination of needle electromyography (EMG) and nerve conduction studies (NCS). Both require a unique combination of knowledge of peripheral nervous system anatomy, physiology, pathophysiology, diseases, techniques, and electricity is necessary. Successful, high‐quality, reproducible EMG depends on the skills of a clinician in patient interaction during the physical insertion and movement of the needle while recording the electrical signals. These must be combined with the skill of analyzing electric signals recorded from muscle by auditory pattern recognition and semiquantitation. 10 , 52 This monograph reviews the techniques of needle EMG and waveform analysis and describes the types of EMG waveforms recorded during needle EMG. © 2009 Wiley Periodicals, Inc. Muscle Nerve 39: 244–270, 2009     

兔内听动脉阻断与听觉改变的关系

目的 探讨实验性内听动脉阻断与术后听力改变的关系及术中听觉监控的方法。方法 实验兔乙状窦后进路暴露小脑桥脑角，下压小脑暴露内听道及第Ⅷ神经复合体，分辨出内听动脉，予阻断不同时间，分别行蜗神经直接复合动作电位(DCAP)和畸变产物耳声发射记录(DPOAE)。结果对照组DCAPN1波潜伏期值无明显改变。内耳血供阻断10s和30s组在压迫开始后3min，DCAPN1波潜伏期值均恢复为初始值。内耳血供阻断1min组在压迫开始后3h，DCAPN1波潜伏期值未恢复为初始值假手术组DPOAE幅值无明显改变，内耳血供阻断10s、30s对DPOAE幅值无影响，内耳血供阻断1min使得DPOAE幅值下降结论兔内耳血供阻断1min可能造成兔听觉不可逆损伤。DCAP、DPOAE能有效、持续地监控内耳血供阻断，是耳神经外科手术中实用的听觉监测手段。     

脑瘫患儿脑干听觉诱发电位研究

本文采用日本光电公司生产的 MEB-5304K 诱发电位测定仪,对101名6月-14岁脑瘫患儿和40名正常儿测定了脑干听觉诱发电位(BAEP)。结果表明:给予80dBNHL,20Hz 刺激时 BAEP 异常率为45.54%,随刺激强度减小及刺激重复率增加,BAEP 阳性率提高。BAEP 改变与病情、病型及并发症有关。为脑瘫的发病机理及病理生理学研究提供神经电生理学依据。对脑瘫合并听力障碍者有助于及早选用助听装置,解决其听力障碍问题。