Showing papers by "AG Armin Kohlrausch published in 2014"

Analysis of the soundscape in an intensive care unit based on the annotation of an audio recording.

Abstract: The acoustic environments in hospitals, particularly in intensive care units (ICUs), are characterized by frequent high-level sound events which may negatively affect patient outcome. Many studies performed acoustic surveys, but the measurement protocol was not always reported in detail, and the scope of analysis was limited by the selected mode of sound level meters. Fewer studies systematically investigated the noise sources in ICUs by employing an observer in the patient room, which may potentially bias the measurement. In the current study, the soundscape of an ICU was evaluated where acoustic parameters were extracted from a ∼67-h audio recording, and a selected 24-h recording was annotated off-line for a source-specific analysis. The results showed that the patient-involved noise accounted for 31% of the acoustic energy and 11% of the predicted loudness peaks (PLPs). Excluding the patient-involved noise, the remaining acoustic energy was attributed to staff members (57%), alarms (30%), and the operational noise of life-supporting devices (13%). Furthermore, the contribution of each noise category to the PLPs was found to be more uneven: Staff (92%), alarms (6%), and device noise (2%). The current study suggests that most of the noise sources in ICUs may be associated with modifiable human factors.

Noise pollution in the ICU: time to look into the mirror

Abstract: We read with interest the recent issue of Critical Care in which Darbyshire and Young [1] reported on noise levels in five different ICUs and demonstrated average sound pressure levels far above the World Health Organization recommended standard of 35 dB LAeq (A-weighted energy-equivalent sound pressure level in decibels). Although their article provides an interesting insight into the ICU soundscape, the authors did not attempt to investigate the sources of noise. In the literature, only few studies have performed an analysis of noise sources, using either questionnaires [2] or a human observer in the patient’s room [3–5]. Aiming to provide more insight into this matter, some of the authors recently performed an acoustic survey in an ICU room in order to determine which sources are responsible for the high noise levels, and details of this study were recently published [6]. Briefly, an audio recording was made by using a calibrated microphone in an ICU room at Jeroen Bosch Hospital for a duration of 67 hours. In addition to the analysis of various acoustic parameters, a 24-hour audio fragment was manually annotated by six research assistants. All sound events (n = 27,421) were identified by using 28 noise source labels, which were grouped into five noise categories. Acoustic analysis showed an average sound pressure level of 61 dB LAeq when the room was occupied. In agreement with the aforementioned study, the number of predicted loudness peaks was up to 90 per hour. Restorative periods were defined as periods of at least 5 minutes in which the sound pressure level relative to the background level did not exceed 17.7 dBA (A-weighted sound pressure level in decibels); only approximately 46% of the periods recorded at night were considered to be restorative, and the average duration of these restorative periods was approximately 13 minutes. Source-specific analysis revealed that, on average, noisy events related to staff activities (54 dB LAeq) occurred approximately 10 times per minute, staff speech (55 dB LAeq) occurred approximately 4 times per minute, and alarms (57 dB LAeq) also occurred approximately 4 times per minute. Further analyses showed that 57% of total acoustic energy and 92% of predicted loudness peaks could be attributed to the activities and speech of hospital personnel (Figure 1). We agree with Darbyshire and Young [1] that high sound pressure levels may have detrimental effects in the already vulnerable population of ICU patients. The aforementioned study demonstrates that more than half of all acoustic energy in an ICU is related to human activities and speech and therefore is potentially modifiable. Strategies involving the adaptation of human behavior therefore may prove to be very effective at reducing noise pollution in the ICU. Figure 1 The contribution of each noise category for (A) the acoustic energy and (B) the number of predicted loudness peaks. Noise generated by or involving patients is excluded. For more details, refer to [6].

Apparatus and method for acoustic alarm detection and validation

Abstract: The invention relates to an apparatus and method for use in detecting and validating acoustic alarms, and in particular relates to an apparatus and method for use in detecting and validating acoustic alarms generated by medical devices, such as patient monitoring devices.

Apparatus and method for improving the audibility of specific sounds to a user

Abstract: There is provided a method of operating a device to generate a target sound that is audible to a user of the device, the method comprising measuring background noise in an environment in which the device is located; using a perceptual loudness model to predict an audibility of the target sound to the user of the device based on the measured background noise; using the output of the perceptual loudness model to determine a gain value that is to be applied to a source signal used to generate the target sound in order to provide at least a desired level of audibility of the target sound to the user; applying the determined gain value to the source signal to produce a modified source signal; and generating the target sound using the modified source signal.

Acoustically absorbing room divider

Abstract: A room divider ( 100 ) for dividing a room into two sub-portions (R 1 , R 2 ) and for attenuating sound (S 1 , S 2 ) travelling between the two sub-portions is provided. The room divider comprises hollow cylindrical elements ( 110 ) arranged periodically for dividing the room into the two sub-portions. At least some of the hollow cylindrical elements have a cylindrical shell ( 111 ) with at least one slit ( 112 ) extending in an axial direction ( 120 ) of the shell. The shell extends continuously along the perimeter of the corresponding hollow cylindrical element from one side ( 113 ) of the at least one slit to another side ( 114 ) of the at least one slit. Each of the at least one slit faces in a local elongation direction ( 130 ) of the room divider for increasing acoustic symmetry with respect to the two sub-portions. The use of destructive interference and resonance to attenuate sound allows for a less bulky/heavy acoustically absorbing room divider.

Data-Driven Modeling of the Spatial Sound Experience

Abstract: Since the evaluation of audio systems or processing schemes is time-consuming and resource-expensive, alternative objective evaluation methods attracted considerable research interests. However, current perceptual models are not yet capable of replacing a human listener especially when the test stimulus is complex, for example, a sound scene consisting of time-varying multiple acoustic images. This paper describes a data-driven approach to develop a model to predict the subjective evaluation of complex acoustic scenes, where the extensive set of listening test results collected in the latest MPEG-H 3D audio initiative was used as training data. The results showed that a few selected outputs of various auditory models may be a useful set of features, where linear regression and multilayer perceptron models reasonably predicted the overall distribution of listening test scores, estimating both mean and variance.

Trends of the acoustic condition in an intensive care unit based on a long-term measurement

Abstract: Noise levels in hospitals, especially in intensive care units (ICUs), are often very high, potentially influencing the patients’ well-being and recovery processes, where the undesirable acoustic environment is also considered to be one of the risk factors contributing to ICU delirium. In the current study, a continuous measurement was taken for 3 months in 8 single-bed patient rooms in an ICU, of which the results were analyzed in synchrony with the admission of 106 patients. On average, the A-weighted energy-equivalent sound pressure level (LAeq) in patient rooms varied significantly with the time of day (p < 0.001), but was not dependent on the day of week (p = 0.448). Furthermore, analysis of noise levels in occupied versus unoccupied rooms indicated the dominance of room-internal sources in the former and room-external sources in the latter periods. During the first four days of patients’ ICU stay, the acoustic condition improved slightly from day 1 to day 2, but the noise level rebounded from day 2, ...

Limited effect of binaural modulation on monaural modulation sensitivity

Abstract: Speech can be degraded by the presence of interfering speech sources in daily life. The auditory system, however, shows great resilience towards these adverse conditions, and the spatial separation between two talkers is known to be beneficial. Within such acoustical settings, there is a possible interaction between the target speech modulations and spatial cues, which are important for speech intelligibility and for the spatial benefit of speech intelligibility, respectively. This study investigates the interaction between such cues with synthetic stimuli. Using a broadband noise stimulus that alternates periodically between two values of interaural time differences (ITD), we can show that listeners are able to accurately lateralize very brief noise segments of only 7.5 ms at the target ITD location and are able to discriminate between different binaural modulation rates. A primary question of this study was to determine the influence of this binaural modulation on the ability of listeners to detect a diotic amplitude modulation (AM). By imposing an AM envelope onto the binaural modulation, the interference of the binaural modulation on the ability to detect a diotic AM was investigated. Although AM detection thresholds were statistically significantly higher when the binaural modulation was present, thresholds were increased by only 1.7 dB. In a separate study, the ability to detect a binaural modulation in the presence of a diotic AM was tested. Across the population of listeners, nearly a doubling of the segment length needed to detect the binaural modulation was observed when an interfering, diotic AM was present. The weak interaction between the rapid interaural switching and AM detection could provide insight into how binaural and monaural processing mechanisms interact and aid in speech reception as a function of talker separation.

Object opinion registering device for guiding a person in a decision making situation

Abstract: The present invention relates to an object opinion registering device (20) for guiding a person in a decision making situation involving one or more physical objects (10A-10F), the object opinion registering device (20) being arranged to register opinion indications of each of the one or more physical objects (10A-10F), and the object opinion registering device comprising a controller (26) arranged to control at least one object indicator (30) arranged to physically highlight a physical object (10B), among the one or more physical objects (10A-10F), based on registered opinion indications of each of the one or more physical objects (10A-10F).

Analysis of the acoustic environment in an ICU using patient information as a covariate

Abstract: Noise levels in ICUs are often very high, potentially affecting patient health outcome, which are also considered to be among the risk factors contributing to ICU delirium [1]. In the current study, multivariate linear regression models were established to relate the acoustic data to the indicators of patient status.