Sound isolation and music on the comfort of mechanically ventilated critical patients.

OBJECTIVES: To assess the effect of sound isolation versus music on the comfort of mechanically ventilated patients admitted to the intensive care unit (ICU) as a combined measurement of the hypnotic level, the level of sedation and the alteration of behaviour because of pain. INTRODUCTION: Patients admitted to the ICU who require mechanical ventilation are surrounded by an ambient noise level ranging from 60 to 90 dB, well above the 40 dB recommended by the World Health Organization (WHO). METHODS: This was a randomized crossover clinical trial. Group A: sound isolation (1 h) followed by music (1 h); Group B: music (1 h) followed by sound isolation (1 h). Interventions were administered using noise-cancelling headphones. The hypnotic level, the level of sedation and the alteration of behaviour because of pain was assessed using the bispectral index (BIS), the Ramsay scale and the behavioural pain scale (BPS), respectively. Statistical analysis of correlated data was performed using a generalized estimating equations (GEE) model. RESULTS: Of 130 patients assessed for eligibility, 82 were randomized to Groups A (n = 40) or B (n = 42). Mean age was 69 years (SD = 14), and 77·3% were men. A decrease of 4-5 points out of 100 during sound isolation and music therapy was recorded in BIS in both groups; the differences were not statistically significant compared with baseline scores. Likewise, no differences were observed in the scores obtained in the Ramsay scale and BPS. CONCLUSIONS: Sound isolation and music intervention did not modify the comfort or physiological variables of mechanically ventilated critical patients from their respective baseline values. RELEVANCE TO CLINICAL PRACTICE: Music and sound isolation are potential strategies that could be used in nursing care to provide comfort to critical patients. Further studies should be undertaken to define the role of these new approaches and determine which groups of patients can benefit most from music or sound isolation.

Development and validation of a spectro-temporal processing test for cochlear-implant listeners.

Psychophysical tests of spectro-temporal resolution may aid the evaluation of methods for improving hearing by cochlear implant (CI) listeners. Here the STRIPES (Spectro-Temporal Ripple for Investigating Processor EffectivenesS) test is described and validated. Like speech, the test requires both spectral and temporal processing to perform well. Listeners discriminate between complexes of sine sweeps which increase or decrease in frequency; difficulty is controlled by changing the stimulus spectro-temporal density. Care was taken to minimize extraneous cues, forcing listeners to perform the task only on the direction of the sweeps. Vocoder simulations with normal hearing listeners showed that the STRIPES test was sensitive to the number of channels and temporal information fidelity. An evaluation with CI listeners compared a standard processing strategy with one having very wide filters, thereby spectrally blurring the stimulus. Psychometric functions were monotonic for both strategies and five of six participants performed better with the standard strategy. An adaptive procedure revealed significant differences, all in favour of the standard strategy, at the individual listener level for six of eight CI listeners. Subsequent measures validated a faster version of the test, and showed that STRIPES could be performed by recently implanted listeners having no experience of psychophysical testing.

Evaluation of Noise Reduction Algorithms in Hearing Aids for Multiple Signals From Equal or Different Directions.

One objective way to evaluate the effect of noise reduction algorithms in hearing aids is to measure the increase in signal-to-noise-ratio (SNR). To this end, Hagerman and Olofsson presented a method where multiple recordings take place and the phase of one signal is inverted between the measurements. This phase inversion method allows one to separate signal and noise at the output of the hearing aid so that the increase in SNR can be evaluated. However, only two signals can be distinguished, for example, speech and noise. As many realistic situations include more than two signals, we extend the method to an arbitrary number of signals. Two different approaches are discussed. For the first one, groups of the signals are created and presented in such a way that the basic phase inversion method can be used. The second, more efficient approach defines a linear system of equations considering all signals. As the robustness of this approach depends on the structure of the system matrix, the design of this matrix is described in detail. To prove the concept, the proposed efficient method was applied to a setup in which nine different signals were presented by eight loudspeakers, and an analysis of errors was performed. With this setup, a state-of-the-art hearing aid was analyzed for four different settings, that is, with the digital noise reduction or the directional microphones turned on or off. As a result, the SNRs for all directions can be investigated individually.

The insomnia of Franz Kafka.

OBJECTIVE: To characterize the insomnia suffered by Franz Kafka (1883-1924), one of the most important literary figures of the 20th century. METHODS: We read Kafka's diaries and private correspondence to his fiancée, friends, editors and relatives looking for references to his insomnia. RESULTS: We found 292 references to insomnia indicating that Kafka suffered from chronic insomnia disorder that originated from and was maintained by the following predisposing and precipitating factors: (1) a complex personality predisposing to an increased arousal level, (2) intrusive thoughts and ruminations at bedtime, (3) excessive worrying about sleep loss and its daytime consequences, and (4) an extraordinary intolerance to noise. Since he could not sleep at night and felt the necessity to compose his literary works in an absolutely quiet environment, Kafka deliberately changed his sleep-wake schedule so he could write at night and nap in the afternoon. These maladaptive sleep habits perpetuated his insomnia and led to chronic sleep deprivation resulting in fatigue, lack of concentration and sleep-related auditory, tactile and visual hallucinations. Kafka sought help in alternative medicine however this was ineffective in improving his insomnia. CONCLUSIONS: Kafka suffered from chronic insomnia disorder and had inadequate sleep hygiene resulting in chronic sleep deprivation. These sleep problems impaired Kafka's quality of life.

Combined exposure to carbon disulfide and low-frequency noise reversibly affects vestibular function.

Chronic occupational exposure to carbon disulfide (CS2) has debilitating motor and sensory effects in humans, which can increase the risk of falls. Although no mention of vestibulotoxic effects is contained in the literature, epidemiological and experimental data suggest that CS2 could cause low-frequency hearing loss when associated with noise exposure. Low-frequency noise might also perturb the peripheral balance receptor through an as-yet unclear mechanism. Here, we studied how exposure to a low-frequency noise combined with 250-ppm CS2 affected balance in rats. Vestibular function was tested based on post-rotary nystagmus recorded by a video-oculography system. These measurements were completed by behavioral tests and analysis of the cerebellum to measure expression levels for gene expression associated with neurotoxicity. Assays were performed prior to and following a 4-week exposure, and again after a 4-week recovery period. Functional measurements were completed by histological analyses of the peripheral organs.Nystagmus was unaltered by exposure to noise alone, while CS2 alone caused a moderate 19% decrease of the saccade number. In contrast, coexposure to 250-ppm CS2 and low-frequency noise decreased both saccade number and duration by 33% and 34%, respectively. After four weeks, recovery was only partial but measures were not significantly different from pre-exposure values. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis of cerebellar tissue revealed a slight but significant modification in expression levels for two genes linked to neurotoxicity in CS2-exposed animals. However, neither histopathological changes to the peripheral receptor nor behavioral differences were observed. Based on all these results, we propose that the effects of CS2 were due to reversible neurochemical disturbance of the efferent pathways managing post-rotatory nystagmus. Because the nervous structures involving the vestibular function appear particularly sensitive to CS2, post-rotary nystagmus could be used as an early, non-invasive measurement to diagnose CS2 intoxication as part of an occupational conservation program.

Impact of SNR, masker type and noise reduction processing on sentence recognition performance and listening effort as indicated by the pupil dilation response.

Recent studies have shown that activating the noise reduction scheme in hearing aids results in a smaller peak pupil dilation (PPD), indicating reduced listening effort, at 50% and 95% correct sentence recognition with a 4-talker masker. The objective of this study was to measure the effect of the noise reduction scheme (on or off) on PPD and sentence recognition across a wide range of signal-to-noise ratios (SNRs) from +16 dB to -12 dB and two masker types (4-talker and stationary noise). Relatively low PPDs were observed at very low (-12 dB) and very high (+16 dB to +8 dB) SNRs presumably due to 'giving up' and 'easy listening', respectively. The maximum PPD was observed with SNRs at approximately 50% correct sentence recognition. Sentence recognition with both masker types was significantly improved by the noise reduction scheme, which corresponds to the shift in performance from SNR function at approximately 5 dB toward a lower SNR. This intelligibility effect was accompanied by a corresponding effect on the PPD, shifting the peak by approximately 4 dB toward a lower SNR. In addition, with the 4-talker masker, when the noise reduction scheme was active, the PPD was smaller overall than that when the scheme was inactive. We conclude that with the 4-talker masker, noise reduction scheme processing provides a listening effort benefit in addition to any effect associated with improved intelligibility. Thus, the effect of the noise reduction scheme on listening effort incorporates more than can be explained by intelligibility alone, emphasizing the potential importance of measuring listening effort in addition to traditional speech reception measures.

Evaluation of a multi-channel algorithm for reducing transient sounds.

OBJECTIVE: The objective was to evaluate and select appropriate parameters for a multi-channel transient reduction (MCTR) algorithm for detecting and attenuating transient sounds in speech. DESIGN: In each trial, the same sentence was played twice. A transient sound was presented in both sentences, but its level varied across the two depending on whether or not it had been processed by the MCTR and on the "strength" of the processing. The participant indicated their preference for which one was better and by how much in terms of the balance between the annoyance produced by the transient and the audibility of the transient (they were told that the transient should still be audible). STUDY SAMPLE: Twenty English-speaking participants were tested, 10 with normal hearing and 10 with mild-to-moderate hearing-impairment. Frequency-dependent linear amplification was provided for the latter. RESULTS: The results for both participant groups indicated that sounds processed using the MCTR were preferred over the unprocessed sounds. For the hearing-impaired participants, the medium and strong settings of the MCTR were preferred over the weak setting. CONCLUSIONS: The medium and strong settings of the MCTR reduced the annoyance produced by the transients while maintaining their audibility.

Evaluation of combined dynamic compression and single channel noise reduction for hearing aid applications.

OBJECTIVE: Single-channel noise reduction (SCNR) and dynamic range compression (DRC) are important elements in hearing aids. Only relatively few studies have addressed interaction effects and typically used real hearing aids with limited knowledge about the integrated algorithms. Here the potential benefit of different combinations and integration of SCNR and DRC was systematically assessed. DESIGN: Ten different systems combining SCNR and DRC were implemented, including five serial arrangements, a parallel and two multiplicative approaches. In an instrumental evaluation, signal-to-noise ratio (SNR) improvement and spectral contrast enhancement (SCE) were assessed. Quality ratings at 0 and +6 dB SNR, and speech reception thresholds (SRTs) in noise were measured using stationary and babble noise. STUDY SAMPLE: Thirteen young normal-hearing (NH) listeners and 12 hearing-impaired (HI) listeners participated. RESULTS: In line with an increased segmental SNR and spectral contrast compared to a serial concatenation, the parallel approach significantly reduced the perceived noise annoyance for both subject groups. The proposed multiplicative approaches could partly counteract increased speech distortions introduced by DRC and achieved the best overall quality for the HI listeners. CONCLUSIONS: For high SNRs well above the individual SRT, the specific combination of SCNR and DRC is perceptually relevant and the integrative approaches were preferred.

Listening to Relaxing Music Improves Physiological Responses in Premature Infants: A Randomized Controlled Trial.

BACKGROUND: Premature infants are exposed to high levels of noise in the neonatal intensive care unit (NICU). PURPOSE: This study evaluated the effect of a relaxing music therapy intervention composed by artificial intelligence on respiratory rate, systolic and diastolic blood pressure, and heart rate. METHODS: A double-blind, randomized, controlled trial was conducted in the NICUs of 2 general public hospitals in Andalusia, Spain. Participants were 17 healthy premature infants, randomly allocated to the intervention group or the control group (silence) at a 1:1 ratio. To be included in the study, the subjects were to be 32 to 36 weeks of gestation at birth (M= 32.33; SD = 1.79) and passed a hearing screening test satisfactorily. The intervention lasted 20 minutes, 3 times a day for 3 consecutive days, while infants were in the incubator. Infants' heart rate, respiratory rate, and blood pressure were assessed before and after each intervention session. RESULTS: After each session, the respiratory rate decreased in the experimental group (main between-groups effect (F1,13 = 6.73, P = .022, ηpartial = 0.34). Across the sessions, the heart rate increased in the control group (main between-groups effect, F1,11 = 5.09, P = .045, ηpartial = 0.32). IMPLICATIONS FOR RESEARCH: Future studies can use this music intervention to assess its potential effects in premature infants. IMPLICATIONS FOR PRACTICE: Nurses can apply the relaxing music intervention presented in this study to ameliorate the impact of the stressful environment on premature infants.

The relation between psychoacoustical factors and annoyance under different noise reduction conditions for railway noise.

The A-weighted sound pressure level (SPL) is commonly used to assess the effect of noise reduction measures on noise-induced annoyance. While for road traffic noise loudness seems to be a better descriptor of annoyance, for railway noise a systematic investigation seems to be lacking. Thus, in this study, the relation between annoyance and perceptually motivated descriptors was investigated for various conditions of binaural recordings of pass-bys of cargo and passenger trains. The conditions included free field and spectral mitigations caused by a 4 m high noise barrier, a 1 m high noise barrier close to the track, and rail dampers. Forty listeners performed a free magnitude estimation of annoyance for different presentation levels and the ratings were fit to various models. Further, level changes required to evoke a noticeable change in annoyance (annoyance thresholds) were acquired. The models based on the A-weighted SPL explained the ratings and thresholds better when the reduction measure was explicitly provided as a parameter. However, the optimal models were loudness-level-based models, which were able to better describe the annoyance, even independently of the reduction measure. Both experiments underline the effectiveness of loudness when describing the annoyance in the area of railway noise reduction.

The Influence of Noise Reduction on Speech Intelligibility, Response Times to Speech, and Perceived Listening Effort in Normal-Hearing Listeners.

Single-microphone noise reduction leads to subjective benefit, but not to objective improvements in speech intelligibility. We investigated whether response times (RTs) provide an objective measure of the benefit of noise reduction and whether the effect of noise reduction is reflected in rated listening effort. Twelve normal-hearing participants listened to digit triplets that were either unprocessed or processed with one of two noise-reduction algorithms: an ideal binary mask (IBM) and a more realistic minimum mean square error estimator (MMSE). For each of these three processing conditions, we measured (a) speech intelligibility, (b) RTs on two different tasks (identification of the last digit and arithmetic summation of the first and last digit), and (c) subjective listening effort ratings. All measurements were performed at four signal-to-noise ratios (SNRs): -5, 0, +5, and +∞ dB. Speech intelligibility was high (>97% correct) for all conditions. A significant decrease in response time, relative to the unprocessed condition, was found for both IBM and MMSE for the arithmetic but not the identification task. Listening effort ratings were significantly lower for IBM than for MMSE and unprocessed speech in noise. We conclude that RT for an arithmetic task can provide an objective measure of the benefit of noise reduction. For young normal-hearing listeners, both ideal and realistic noise reduction can reduce RTs at SNRs where speech intelligibility is close to 100%. Ideal noise reduction can also reduce perceived listening effort.

Factors Affecting Acoustics and Speech Intelligibility in the Operating Room: Size Matters.

INTRODUCTION: Noise in health care settings has increased since 1960 and represents a significant source of dissatisfaction among staff and patients and risk to patient safety. Operating rooms (ORs) in which effective communication is crucial are particularly noisy. Speech intelligibility is impacted by noise, room architecture, and acoustics. For example, sound reverberation time (RT60) increases with room size, which can negatively impact intelligibility, while room objects are hypothesized to have the opposite effect. We explored these relationships by investigating room construction and acoustics of the surgical suites at our institution. METHODS: We studied our ORs during times of nonuse. Room dimensions were measured to calculate room volumes (VR). Room content was assessed by estimating size and assigning items into 5 volume categories to arrive at an adjusted room content volume (VC) metric. Psychoacoustic analyses were performed by playing sweep tones from a speaker and recording the impulse responses (ie, resulting sound fields) from 3 locations in each room. The recordings were used to calculate 6 psychoacoustic indices of intelligibility. Multiple linear regression was performed using VR and VC as predictor variables and each intelligibility index as an outcome variable. RESULTS: A total of 40 ORs were studied. The surgical suites were characterized by a large degree of construction and surface finish heterogeneity and varied in size from 71.2 to 196.4 m (average VR = 131.1 [34.2] m). An insignificant correlation was observed between VR and VC (Pearson correlation = 0.223, P = .166). Multiple linear regression model fits and ß coefficients for VR were highly significant for each of the intelligibility indices and were best for RT60 (R = 0.666, F(2, 37) = 39.9, P < .0001). For Dmax (maximum distance where there is <15% loss of consonant articulation), both VR and VC ß coefficients were significant. For RT60 and Dmax, after controlling for VC, partial correlations were 0.825 (P < .0001) and 0.718 (P < .0001), respectively, while after controlling for VR, partial correlations were -0.322 (P = .169) and 0.381 (P < .05), respectively. CONCLUSIONS: Our results suggest that the size and contents of an OR can predict a range of psychoacoustic indices of speech intelligibility. Specifically, increasing OR size correlated with worse speech intelligibility, while increasing amounts of OR contents correlated with improved speech intelligibility. This study provides valuable descriptive data and a predictive method for identifying existing ORs that may benefit from acoustic modifiers (eg, sound absorption panels). Additionally, it suggests that room dimensions and projected clinical use should be considered during the design phase of OR suites to optimize acoustic performance.

Sleep in the Intensive Care Unit: A Review.

Patients in the intensive care unit (ICU) are susceptible to sleep deprivation. Disrupted sleep is associated with increased morbidity and mortality in the critically ill patients. The etiology of sleep disruption is multifactorial. The article reviews the literature on sleep in the ICU, the effects of sleep deprivation, and strategies to promote sleep in the ICU. Until the impact of disrupted sleep is better explained, it is appropriate to provide critically ill patients with consolidated, restorative sleep.

[The analysis of acoustic activity unsynchronized with the stimulus with the use of TEOAE]. / Analiz akusticheskoi aktivnosti, ne sinkhronizirovannoi so stimulom, pri registratsii zaderzhannoi vyzvannoi otoakusticheskoi emissii.

The presence of ambient noise or the troubled child's behavior during the registration of transiently induced optoacoustic emission (TEOAE) can lead to false positive results at the first stage of hearing screening. The aim of this study is to evaluate the effectiveness of the noise reduction method based on weighted averaging of the data in the frequency and time slot, to check TEOAE, and to improve the effectiveness of universal hearing screening. Particular attention is paid to the analysis of the origin of noise recorded during the UAE. PATIENTS AND METHODS: We have developed a method of noise reduction, based on weighted averaging of the data in the frequency and time cells. In this study, 20 people were examined (9 adults and 11 children). TEOAE was performed using the probe of the ILO 288 instrument manufactured by Otodinamics Ltd. that was connected to the E-MU 0204 sound card. The probe microphone was connected through the preamplifier to one input channel of the sound card, and the second channel was used to receive a signal from the ECG and the respiration recorder. Thereafter, the data thus obtained were processed by several methods, including the method of averaging in the frequency and time slot designed to average a set of implementations that contain a noisy signal. The comparison of the results of the use of noise suppression method based on weighted averaging of the data in the frequency and time cells showed that it increases the accuracy of TEOAE. MAIN RESULTS: Our work suggests that the use of the noise suppression method based on weighted averaging of the data in the frequency and time cells, increases the accuracy of TEOAE. Similar results were obtained by the weighted averaging method.

Non-pharmacological interventions for assisting the induction of anaesthesia in children.

BACKGROUND: Induction of general anaesthesia can be distressing for children. Non-pharmacological methods for reducing anxiety and improving co-operation may avoid the adverse effects of preoperative sedation. OBJECTIVES: To assess the effects of non-pharmacological interventions in assisting induction of anaesthesia in children by reducing their anxiety, distress or increasing their co-operation. SEARCH METHODS: In this updated review we searched CENTRAL (the Cochrane Library 2012, Issue 12) and searched the following databases from inception to 15 January 2013: MEDLINE, EMBASE, PsycINFO and Web of Science. We reran the search in August 2014. We will deal with the single study found to be of interest when we next update the review. SELECTION CRITERIA: We included randomized controlled trials of a non-pharmacological intervention implemented on the day of surgery or anaesthesia. DATA COLLECTION AND ANALYSIS: At least two review authors independently extracted data and assessed risk of bias in trials. MAIN RESULTS: We included 28 trials (2681 children) investigating 17 interventions of interest; all trials were conducted in high-income countries. Overall we judged the trials to be at high risk of bias. Except for parental acupuncture (graded low), all other GRADE assessments of the primary outcomes of comparisons were very low, indicating a high degree of uncertainty about the overall findings. Parental presence: In five trials (557 children), parental presence at induction of anaesthesia did not reduce child anxiety compared with not having a parent present (standardized mean difference (SMD) 0.03, 95% confidence interval (CI) -0.14 to 0.20). In a further three trials (267 children) where we were unable to pool results, we found no clear differences in child anxiety, whether a parent was present or not. In a single trial, child anxiety showed no significant difference whether one or two parents were present, although parental anxiety was significantly reduced when both parents were present at the induction. Parental presence was significantly less effective than sedative premedication in reducing children's anxiety at induction in three trials with 254 children (we could not pool results). Child interventions (passive): When a video of the child's choice was played during induction, children were significantly less anxious than controls (median difference modified Yale Preoperative Anxiety Scale (mYPAS) 31.2, 95% CI 27.1 to 33.3) in a trial of 91 children. In another trial of 120 children, co-operation at induction did not differ significantly when a video fairytale was played before induction. Children exposed to low sensory stimulation were significantly less anxious than control children on introduction of the anaesthesia mask and more likely to be co-operative during induction in one trial of 70 children. Music therapy did not show a significant effect on children's anxiety in another trial of 51 children. Child interventions (mask introduction): We found no significant differences between a mask exposure intervention and control in a single trial of 103 children for child anxiety (risk ratio (RR) 0.59, 95% CI 0.31 to 1.11) although children did demonstrate significantly better co-operation in the mask exposure group (RR 1.27, 95% CI 1.06 to 1.51). Child interventions (interactive): In a three-arm trial of 168 children, preparation with interactive computer packages (in addition to parental presence) was more effective than verbal preparation, although differences between computer and cartoon preparation were not significant, and neither was cartoon preparation when compared with verbal preparation. Children given video games before induction were significantly less anxious at induction than those in the control group (mYPAS mean difference (MD) -9.80, 95% CI -19.42 to -0.18) and also when compared with children who were sedated with midazolam (mYPAS MD -12.20, 95% CI -21.82 to -2.58) in a trial of 112 children. When compared with parental presence only, clowns or clown doctors significantly lessened children's anxiety in the operating/induction room (mYPAS MD -24.41, 95% CI -38.43 to -10.48; random-effects, I² 75%) in three trials with a total of 133 children. However, we saw no significant differences in child anxiety in the operating room between clowns/clown doctors and sedative premedication (mYPAS MD -9.67, 95% CI -21.14 to 1.80, random-effects, I² 66%; 2 trials of 93 children). In a trial of hypnotherapy versus sedative premedication in 50 children, there were no significant differences in children's anxiety at induction (RR 0.59, 95% CI 0.33 to 1.04). Parental interventions: Children of parents having acupuncture compared with parental sham acupuncture were less anxious during induction (mYPAS MD -17, 95% CI -30.51 to -3.49) and were more co-operative (RR 1.59, 95% CI 1.01 to 2.53) in a single trial of 67 children. Two trials with 191 parents assessed the effects of parental video viewing but did not report any of the review's prespecified primary outcomes. AUTHORS' CONCLUSIONS: This review shows that the presence of parents during induction of general anaesthesia does not diminish their child's anxiety. Potentially promising non-pharmacological interventions such as parental acupuncture; clowns/clown doctors; playing videos of the child's choice during induction; low sensory stimulation; and hand-held video games need further investigation in larger studies.

Do alumina matrix composite bearings decrease hip noises and bearing fractures at a minimum of 5 years after THA?

BACKGROUND: Ceramic-on-ceramic bearing couples are theoretically attractive in total hip arthroplasty (THA) because of low wear, but concerns regarding ceramic fracture and squeaking have arisen. Improved material properties of newer alumina matrix composite (AMC) materials, known as Delta ceramics, may reduce these risks. In addition, the use of thinner liners and larger femoral heads may be helpful clinically to lower the rate of dislocation. However, limited short-term clinical results are available and intermediate-term effects are unclear. QUESTIONS/PURPOSES: (1) What is the frequency of bearing-related complications (dissociation, fracture, and noise) with ceramic-on-ceramic AMC bearings in cementless THA? (2) What other complications arose in patients treated with these bearings? (3) What are the Harris hip scores (HHS) and survivorship free from reoperation and revision at a minimum of 5 years after cementless THA performed with AMC bearings? METHODS: Over a 9-month period in 2009, one surgeon performed 125 THAs, of which 100 (80% of the total) were performed with cementless, AMC bearings. During the period in question, the exclusion criteria for this implant were primary THAs with severe acetabular or femoral bone defect and revision THAs. Of these, 94 hips (95%) in 91 patients were available for analysis at a minimum of 5 years (range, 5-6 years), because five patients (six hips) had died. Mean age at the time of arthroplasty was 55 ± 14 years. Prostheses with an identical design and Biolox(®) Delta ceramics were used in all patients. Noise was classified into squeaking, clicking, grinding, and popping. Ceramic fracture, dislocation, and any other complications associated with the use of AMC ceramics were also investigated. Clinical evaluation included the modified HHS preoperatively and at each followup. Survivorship free from reoperation and revision was calculated using the Kaplan-Meier method. RESULTS: Of 91 patients, four developed bearing-related complications, including one with liner dissociation despite initial square seating and three with clicking. No patients had ceramic fractures. A single event of perioperative dislocation occurred in one patient and postoperative periprosthetic fracture occurred in two hips. Mean HHS improved from 56 to 93 points at the final followup (p < 0.001). Survivorship at 5 years free from reoperation and revision was 96.8% and 97.9%, respectively. CONCLUSIONS: Improved material properties combined with the possible use of larger diameter heads make AMC ceramics a promising alternative bearing option with seemingly comparable clinical outcomes reported by others with conventional ceramic bearings. Despite these encouraging results, however, meticulous technical precautions such as square seating and proper impaction in particular should be taken during liner insertion, because we did observe one liner dissociation and several patients with hip noises. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Sensitivity to Envelope Interaural Time Differences at High Modulation Rates.

Sensitivity to interaural time differences (ITDs) conveyed in the temporal fine structure of low-frequency tones and the modulated envelopes of high-frequency sounds are considered comparable, particularly for envelopes shaped to transmit similar fidelity of temporal information normally present for low-frequency sounds. Nevertheless, discrimination performance for envelope modulation rates above a few hundred Hertz is reported to be poor-to the point of discrimination thresholds being unattainable-compared with the much higher (>1,000 Hz) limit for low-frequency ITD sensitivity, suggesting the presence of a low-pass filter in the envelope domain. Further, performance for identical modulation rates appears to decline with increasing carrier frequency, supporting the view that the low-pass characteristics observed for envelope ITD processing is carrier-frequency dependent. Here, we assessed listeners' sensitivity to ITDs conveyed in pure tones and in the modulated envelopes of high-frequency tones. ITD discrimination for the modulated high-frequency tones was measured as a function of both modulation rate and carrier frequency. Some well-trained listeners appear able to discriminate ITDs extremely well, even at modulation rates well beyond 500 Hz, for 4-kHz carriers. For one listener, thresholds were even obtained for a modulation rate of 800 Hz. The highest modulation rate for which thresholds could be obtained declined with increasing carrier frequency for all listeners. At 10 kHz, the highest modulation rate at which thresholds could be obtained was 600 Hz. The upper limit of sensitivity to ITDs conveyed in the envelope of high-frequency modulated sounds appears to be higher than previously considered.

Effects of noise reduction on speech intelligibility, perceived listening effort, and personal preference in hearing-impaired listeners.

This study evaluates the perceptual effects of single-microphone noise reduction in hearing aids. Twenty subjects with moderate sensorineural hearing loss listened to speech in babble noise processed via noise reduction from three different linearly fitted hearing aids. Subjects performed (a) speech-intelligibility tests, (b) listening-effort ratings, and (c) paired-comparison ratings on noise annoyance, speech naturalness, and overall preference. The perceptual effects of noise reduction differ between hearing aids. The results agree well with those of normal-hearing listeners in a previous study. None of the noise-reduction algorithms improved speech intelligibility, but all reduced the annoyance of noise. The noise reduction that scored best with respect to noise annoyance and preference had the worst intelligibility scores. The trade-off between intelligibility and listening comfort shows that preference measurements might be useful in addition to intelligibility measurements in the selection of noise reduction. Additionally, this trade-off should be taken into consideration to create realistic expectations in hearing-aid users.

A practical application of Katharine Kolcaba's comfort theory to cardiac patients.

Nursing approaches to care as based on Katharine Kolcaba's (2003) middle range nursing theory of comfort are discussed in reference to patients' suffering from symptoms related to the discomfort from cardiac syndromes. The specific intervention of "quiet time" is described for its potential use within this population as a comfort measure that addresses Kolcaba's four contexts of comfort: physical, psychospiritual, environmental and sociocultural. Without realizing it, many nurses may practice within Kolcaba's theoretical framework to promote patient comfort. Explicit applications of comfort theory can benefit nursing practice. Using comfort theory in research can provide evidence for quiet time intervention with cardiac patients.