Erica E. Ryherd

Characterizing noise and perceived work environment in a neurological intensive care unit

The hospital sound environment is complex. Alarms, medical equipment, activities, and ventilation generate noise that may present occupational problems as well as hinder recovery among patients. In this study, sound measurements and occupant evaluations were conducted in a neurological intensive care unit. Staff completed questionnaires regarding psychological and physiological reactions to the sound environment. A-weighted equivalent, minimum, and maximum (L(Aeq),L(AFMin),L(AFMax)) and C-weighted peak (L(CPeak)) sound pressure levels were measured over five days at patient and staff locations. Acoustical descriptors that may be explored further were investigated, including level distributions, restorative periods, and spectral content. Measurements near the patients showed average L(Aeq) values of 53-58 dB. The mean length of restorative periods (L(Aeq) below 50 dB for more than 5 min) was 9 and 13 min for day and night, respectively. Ninety percent of the time, the L(AFMax) levels exceeded 50 dB and L(CPeak) exceeded 70 dB. Dosimeters worn by the staff revealed higher noise levels. Personnel perceived the noise as contributing to stress symptoms. Compared to the majority of previous studies, this study provides a more thorough description of intensive care noise and aids in understanding how the sound environment may be disruptive to occupants.

Implications of human performance and perception under tonal noise conditions on indoor noise criteria

This research investigated differences in task performance and perception under six non-time-varying ventilation-type background noise spectra with differing tonality. The results were related to five indoor noise criteria systems: noise criteria, balanced noise criteria, room criteria, room criteria mark II, and the A-weighted equivalent sound pressure level (L(Aeq)). These criteria systems are commonly used in the U.S. building industry, but concerns exist over whether they are appropriate for all noise situations. Thirty test subjects completed three types of performance tasks (typing, reasoning, and math) and answered questions about their perception of the indoor environment under each noise condition. Results showed that performance scores did not change significantly across the six noise conditions, but there were differences in subjective perception. For example, perception trends for tonality, annoyance, and distraction changed based on the frequency and prominence of discrete tones in noise. However, these perceptual changes were not fully reflected in the criteria level or spectral quality ratings. Additionally, task performance was related to subjective perception but not to criteria level predictions. As a result, the authors suggest that the current criteria should be modified to account for the frequency and prominence of tones in background noise.

Evaluating the Hospital Soundscape

cular arousal, extended hospital stay, and increased dosages of pain medication due to excessive noise levels have also been documented in patient studies. Decreased healing is another potential concern as a few studies on animals have revealed that noise exposure may slow wound healing. Furthermore, increased sound absorption that tends to make speech more intelligible and lower background noise levels has been linked to improved sleep in an experimental study, a reduction in cardiovascular arousals, and decreased incidence of re-hospitalization. Speech interference and increased medical errors are two additional potentially hazardous effects of hospital noise that could have obvious negative implications for patient safety. Indeed, there is a growing body of research on pharmaceutical name recognition in noise similar to that found in hospitals. The impact of the hospital soundscape on staff members is also a concern. Statistics indicate that 14 million people are employed in the U.S. healthcare industry, with 4.9 million of them working specifically in hospitals. Therefore, the quality of this occupational environment affects a large segment of the population. There is some evidence that overall levels of hospital noise may contribute to stress and burnout, a serious concern given the current nursing shortage throughout the U.S. Other studies suggest that the acoustical environment contributes to decreased short-term memory, decreased mental efficiency, and decreased ability to aurally distinguish critical physiological functions such as heart and lung sounds. Some studies indicate that orthopedic staff may be at risk for noise-induced hearing loss. Increased sound absorption has been shown to correlate with improvement in the staff psychosocial environment and improved perception of the soundscape (i.e., increased satisfaction with the overall noise level).

Effects of exposure duration and type of task on subjective performance and perception in noise

The influences of exposure time and the types of tasks on human perception and task performance have been investigated under a variety of noise conditions with differing level, spectral content, and behavior over time. Ten test subjects each completed 38 hours of testing over multiple days. Subjects were exposed to each of six background noise conditions over 20, 40, 80, and 240 minute trials. During the trials, subjects completed three types of performance tasks (typing, grammatical reasoning, and math tests) and answered questions about their perception of the indoor environment. Results indicate that the different exposure lengths used in this study did not have a significant effect on performance scores. Some influence of exposure time on subjective perception was observed, however; shorter time lengths combined with back to back exposures led to greater differentiation in perception. Significant differences in task performance between the different noise conditions were not observed, but differences in perception were found. Additionally, task performance was related to subjective perception; if subjects perceived the noise to be more tonal, they performed worse on all tasks. The performance results were not always negatively influenced by unfavorable quality perceptions, though. For example, as subjects perceived noise to be more roaring in this study, their typing scores decreased but reasoning and math scores improved.

The role of physical environment on student health and education in green schools

Abstract The role of physical school environment on student health and education is becoming better understood. A growing body of literature indicates that improved physical environments in schools (e.g., indoor air quality, lighting, and acoustic conditions) can enhance student health outcomes. In parallel, the green building movement centers around designing buildings, including schools, that are more sustainable to decrease energy consumption, minimize environmental impact, and create healthier spaces for occupants. This paper synthesizes the findings from both green design studies and school outcomes studies to provide a systematic evaluation of the potential impacts of green school design features on student health outcomes. Three inter-related topics are covered in detail: (i) overview of the “green” concept, including existing guidelines for “greening” schools, attitudes toward green schools, and condition of the physical environments in non-green schools; (ii) potential effects of the physical environment on school children, including documentation of national statistics and summary of findings from school research studies; (iii) synthesis of findings, including a discussion of the knowledge gaps in the field of green school research and conclusions.

Environmental Variables That Influence Patient Satisfaction: A Review of the Literature

Patient’s perception of care—referred to as patient satisfaction—is of great interest in the healthcare industry, as it becomes more directly tied to the revenue of the health system providers. The perception of care has now become important in addition to the actual health outcome of the patient. The known influencers for the patient perception of care are the patient’s own characteristics as well as the quality of service received. In patient surveys, the physical environment is noted as important for being clean and quiet but is not considered a critical part of patient satisfaction or other health outcomes. Patient perception of care is currently measured as patient satisfaction, a systematic collection of perceptions of social interactions from an individual person as well as their interaction with the environment. This exploration of the literature intends to explore the rigorous, statistically tested research conducted that has a spatial predictor variable and a health or behavior outcome, with the intent to begin to further test the relationships of these variables in the future studies. This literature review uses the patient satisfaction framework of components of influence and identifies at least 10 known spatial environmental variables that have been shown to have a direct connection to the health and behavior outcome of a patient. The results show that there are certain features of the spatial layout and environmental design in hospital or work settings that influence outcomes and should be noted in the future research.

Hospital noise and staff performance

Hospitals are often noisy and not conducive to staff performance. Indeed, many staff believe that noise negatively affects their professional performance, quality of work, and ability to concentrate and communicate. Research shows that increased stress and annoyance, increased rates of burnout, and reduced occupational health are a few of the possible effects of hospital noise on staff. However, only a few hospital studies have directly linked noise to job performance. Results show that noise and distractions can potentially deteriorate mental efficiency and short-term memory and increase errors, but other studies have shown no significant effects. Alarm fatigue is also of concern, as staff may tune out, silence, or disable alarms because they are desensitized or exhausted by them. This paper will discuss what is currently known about hospital noise and staff performance and what questions remain. On-going studies relating the sound environment to staff performance in medical simulations will also be high...

Relating the hospital sound environment to occupant psychological and physiological response

Examining the relationship between specific acoustical characteristics of noise and occupant response is a fundamental step in determining the current hospital soundscape. Hospitals should be conducive to patient recovery and safety as well as employee health and productivity. Therefore, the sound environment that occupants are exposed to should be attended to from a health standpoint. Previous research on hospital patients has indicated negative effects of hospital sounds such as sleep disturbance, cardiovascular response, increased incidence of rehospitalization, extended hospital stay, and increased dosages of pain medication. There is some evidence that overall levels of hospital noise may impact staff mental efficiency, short‐term memory and stress. A series of studies are currently being conducted by the authors to evaluate the modern hospital soundscape and the associated psycho‐physiological responses of occupants, incorporating both quantitative and qualitative approaches. One phase in which deta...

Prescribing healthy hospital soundscapes

In The Effects of Noise on Man, Karl Kryter emphasized that human reaction to sound is quantitatively related to the physical nature of sounds. He specified five unwanted characteristics of sound: “(a) the masking of unwanted sounds, particularly speech, (b) auditory fatigue and damage to hearing, (c) excessive loudness, (d) some general quality of bothersomeness or noisiness, and (e) startle.” Hospital soundscapes have been shown to demonstrate all five characteristics in one fashion or another. Some unwanted effects of sound have also been shown, such as fragmented sleep and recuperation, cardiovascular response, pain and intensive care delirium—however, few studies have been able to causally link sounds to patient outcomes and few examine detailed characteristics other than loudness. This paper will summarize what we know about noise in hospitals and the health effects on occupants, including highlights from the Healthcare Acoustics Research Team (HART) body of research. Results will be used to identif...

Influence of a wearer’s voice on noise dosimeter measurements

In recent years, interest in personal noise exposure has expanded beyond a workplace safety measure to become an effective means of investigating physiological effects of the acoustic environment on an individual. This work investigates the effects of the wearers voice as a possible dominant sound source on body-mounted noise dosimeters and develops methods to improve the application of dosimeter measurements in medium-level noise environments. Subjects experienced a controlled set of acoustic conditions while wearing a dosimeter. In each condition, sound pressure levels were recorded with and without the subject speaking controlled phrases. Three experimental variables were considered-room type, noise type, and noise level. All three variables had a statistically significant effect upon the contribution of speech to a dosimeter measurement; for example, noise level was shown to cause a change in speech contribution by as much as 5.5 dB between sequential levels. Based upon the analysis, a method of predicting the decibel contribution of a wearers voice was developed. The results of this study can be used to estimate the effect of a wearers voice on dosimeter measurements in medium-level noise environments.