Lincoln Gray

Changing levels of quiet in an intensive care nursery

OBJECTIVES: To document low sound levels, the range and pattern of levels, and the relative effects of operational (staff and equipment generated) and facility (building generated) noise on the acoustic environment of a level III nursery.STUDY DESIGN: A quasi-experimental, prospective, longitudinal study of one bed space. Operational noise was reduced through staff behavior change while facility noise was reduced through renovation.RESULTS: Initial noise levels were typical of those in the literature and in recently measured nurseries. About 80% of sound levels were between 62 and 70 dBA. The lowest levels (Lmin) were 60 to 65 dBA. After staff behavior change, Lmin was about 56 dBA although the highest levels (Lmax) remained at 78 to 100 dBA. Levels following renovation were reduced to Lmins of 47 to 51 dBA and Lmaxs of 68 to 84 dBA, perceived as three or four times quieter than initially.CONCLUSIONS: Staff behavior as well as the acoustical characteristics of the facility determine the levels of noise and quiet in an intensive care nursery.

Perception of speech and nonspeech stimuli by children with and without reading disability and attention deficit hyperactivity disorder

The auditory temporal deficit hypothesis predicts that children with reading disability (RD) will exhibit deficits in the perception of speech and nonspeech acoustic stimuli in discrimination and temporal ordering tasks when the interstimulus interval (ISI) is short. Initial studies testing this hypothesis did not account for the potential presence of attention deficit hyperactivity disorder (ADHD). Temporal order judgment and discrimination tasks were administered to children with (1) RD/no-ADHD (n=38), (2) ADHD (n=29), (3) RD and ADHD (RD/ADHD; n=32), and (4) no impairment (NI; n=43). Contrary to predictions, children with RD showed no specific sensitivity to ISI and performed worse relative to children without RD on speech but not nonspeech tasks. Relationships between perceptual tasks and phonological processing measures were stronger and more consistent for speech than nonspeech stimuli. These results were independent of the presence of ADHD and suggest that children with RD have a deficit in phoneme perception that correlates with reading and phonological processing ability. (c) 2002 Elsevier Science (USA).

Measuring Sound in Hospital Nurseries

This article provides practical advice on how to document sound levels in a nursery: How do you use sound-level meters, noise dosimeters, and spectrum analyzers? Where is the best position for microphones in a sound survey? How do you present results to nursery staff? The goal is to provide informal instruction on how to use these devices and interpret their measurements. The intended audience is medical personnel, not engineers. A companion article in this issue provides background on the technical aspects of sound measurement. There is an appendix with hints about finding help and purchasing equipment.This article provides practical advice on how to document sound levels in a nursery: How do you use sound-level meters, noise dosimeters, and spectrum analyzers? Where is the best position for microphones in a sound survey? How do you present results to nursery staff? The goal is to provide informal instruction on how to use these devices and interpret their measurements. The intended audience is medical personnel, not engineers. A companion article in this issue provides background on the technical aspects of sound measurement. There is an appendix with hints about finding help and purchasing equipment.

Properties of sound.

Basic concepts about sound exposure are reviewed without extensive reliance on the technical details of physical acoustics or psychoacoustics. The frequencies and intensities of sounds that might be encountered in a hospital nursery are described. Examples of the nonlinear properties of sound levels are provided. The complexities of adding and subtracting decibels are discussed. Some important noise standards are reviewed, along with an explanation of why some sounds might be more annoying than others. A companion article in this issue gives practical information on how to make sound-level measurements.Basic concepts about sound exposure are reviewed without extensive reliance on the technical details of physical acoustics or psychoacoustics. The frequencies and intensities of sounds that might be encountered in a hospital nursery are described. Examples of the nonlinear properties of sound levels are provided. The complexities of adding and subtracting decibels are discussed. Some important noise standards are reviewed, along with an explanation of why some sounds might be more annoying than others. A companion article in this issue gives practical information on how to make sound-level measurements.

Dissociation of sensitivity and response bias in children with attention deficit/hyperactivity disorder during central auditory masking.

Forty-three children (ages 7.0-14.5 years old) with and without attention deficit/hyperactivity disorder (ADHD), combined type had thresholds for detection of a 500-Hz pure tone estimated with and without a noise masker in the contralateral ear. The ear receiving the signal in the masked condition was varied randomly. A single-interval maximum-likelihood method estimated thresholds and false-alarm rate. Whereas the increase in threshold in children with ADHD in the presence of contralateral masking was comparable with controls, the increase in false-alarm rate was significantly greater. This dissociation between changes in sensitivity and response bias in the presence of masking noise supports suggestions that children with ADHD have difficulty inhibiting maladaptive responses and indicates that this deficit is quantifiable using psychoacoustic methods.

Ear advantage in dichotic listening after correction for early congenital hearing loss

Twelve patients who had undergone surgical correction for either unilateral or bilateral congenital hearing loss were given a postoperative dichotic listening test for consonant vowel-consonant (CVC) words. Four normal hearing control subjects were also tested. Patients were first given a test of subjective loudness, and the level of presentation of stimuli in the atretic ear was adjusted accordingly. In the dichotic condition all controls exhibited a right ear advantage, and all unilateral atresia patients showed an ear advantage favouring the non-atretic ear. Patients with bilateral atresia essentially exhibited no ear advantage. Patients had the same error rate as controls in the dichotic condition, which suggests that ear advantage was not due to increased errors in the atretic ear. For patients there was a significant relationship between ear advantage and both preoperative interaural asymmetry in hearing loss and age at operation. Results suggest that a sensitive and critical period for development of the ear is complete by 5 years of age. Results also suggest some limited ability to adjust to permanent change in stimulation levels until, but not after, puberty.

Pressed scar tissue for tympanic membrane grafting in revision tympanoplasty.

OBJECTIVE Compare the efficacy of pressed scar tissue grafts to standard fascia and areolar tissue grafts for use in tympanoplasty. STUDY DESIGN A retrospective review of a prospective computerized database of tympanoplasty and mastoid surgeries at an academic, tertiary care practice was performed. Search parameters were set to find all patients who underwent tympanoplasty with or without mastoidectomy with use of various grafting materials for repair of tympanic membrane perforation from 1996 to 2002. All ages were included. Patients with cholesteatoma at the time of surgery were excluded. The short-term graft take rate was evaluated at 30 to 90 days to identify any differences in results using the standard fascia and areolar grafts vs. pressed scar tissue grafts. Other parameters that may have an influence on outcome were analyzed including mastoidectomy, infection, perforation size, perforation location, age of patient, primary vs. revision surgery, number of previous surgeries, postauricular vs. transcanal approaches, and medial vs. lateral grafting techniques. Hearing results were analyzed to see whether the use of scar tissue grafts resulted in equivalent outcomes compared to standard graft materials. RESULTS: There were no statistically significant differences in short-term tympanic membrane closure rates in subjects undergoing surgery using standard fascia/areolar tissue grafts and pressed scar tissue grafts. Hearing results were also statistically equivalent regardless of graft material used. The only parameter that was somewhat associated with successful closure of tympanic perforation was use of the postauricular approach compared to the transcanal approach. CONCLUSIONS Pressed scar tissue grafts are as efficacious as standard fascia and areolar tissue grafts when used to repair tympanic membrane perforations. Pressed scar tissue graft can be used successfully in cases such as revision tympanoplasty when standard tissue grafts are not available or difficult to obtain. EBM rating: B-3.

The paperless essay: One way to teach writing and computer skills in medical school

We designed an assignment for first-year medical students that included instruction in writing and in computer use, two important subjects that are usually neglected in the traditional curriculum. As part of a neuroscience course, students wrote an essay using a word processor and submitted it to the instructor via the campus computer network. If requested by the instructor, the students submitted a revision of their essays without a grade penalty. As a result of completing the assignment, students learned the importance of revision and were stimulated to learn more about computers. With only slight modification of medical school courses, faculty can place more emphasis on writing skills and computer literacy.