Abstract

The development of hand-held auditory screening devices has led to increased hearing screening by physicians. Ambient noise levels were assessed in examination rooms of 20 physician offices. Measurements provided Ln, Leq, Lmax, and octave band data for specialty types: pediatrics, internal medicine, family practice and otolaryngology. Such data should not replace the need for individually monitoring potential screening sites.

Ambient Noise Levels have been reported for a variety of medical care environments including nursery, surgical and acute care hospital areas (Aitken, 1982; Falk, & Woods, 1973; Long, Lucev, & Philip, 1980). The purpose of this investigation was to measure typical background noise levels in physician office examination rooms. Though such data do not replace the need to monitor individual sites contemplated for hearing screening, it was felt general data descending this environment would be useful.

Methods

Measurements were made in 20 separate physician offices in the Salt Lake City area. Five offices from each of the following specialties were chosen: pediatrics, internal medicine, family practice, and otolaryngology. After visually inspecting each office, a room was chosen for measurement which was felt to have the same general noise characteristics as the examination rooms being used that day. The room chosen was either an adjacent examination room or an office of similar size. The door was kept shut in order to simulate conditions under which a physician would likely examine patients. Among the 20 practices were represented most of the various office arrangements, that is, small or large free standing clinics containing several offices, clinics within hospitals. and single offices within separate buildings.

Instrumentation and Testing Protocol

Measurements were performed on a day having typical patient load during peak office hours. Noise samples were made utilizing a sound level meter interfaced with a microcomputer (Larson-Davis 800 B sound level meter with Bruel & Kjaer 4132 pressure microphone: Hewlett Packard 71B microcomputer). using two environmental noise programs ("ENVN" and ""SPAN"), Larson-Davis. Inc, Provo. UT) two separate 20 minute octave band analyses centered at 500, 1000, 2000, and 4000 Hz were made in each office. Each analysis consisted of 40 spectrum scans with each scan sampling 2 sec per frequency. In addition. following each octave band, analysis a 2 hour statistical sample was taken providing L90, L50, Leq, Lmax. These Ln values represent dB(A) sound level exceeded for 90%, 50%, and 10% of the sampling period. Data for each office, therefore., consisted of two 20 minute octave band analyses and two 2 hour statistical noise measurements

Results

Table I shows mean, standard deviation, and range of octave band data for each office type and the total sample. Table 2 shows mean, standard deviation, and range of Ln, Leq, Lmax, for each office type and the sample as a whole. In order to relate the data to suitability for screening with standard audiometric equipment, comparison may be made to previously published noise criteria. For example, in the 1985 "Guidelines for Identification Audiometrv," ASHA proposed the following octave band noise levels for screening at 20 dB HL for 500, 1000,2000, and 4000 Hz, respectively: 41.5, 49.5,54.5, and 62.0 (dB SPL re:20uPa) (assuming screening conducted on an ear covered with an earphone mounted in MX-41/AR cushion)([American Speech-Language-Hearing Association, 1985). These criteria were arrived at by adding the chosen screening level (20 dB HL) to the already existing ANSI standards for ambient noise necessary for testing to 0 dB HL: 21.5, 29.5, 34.5, 42.0 (500 to 4K Hz, db SPL re: 20uPa) (ANSI S3.1 - 1977). In other words, if screening is performed at 20 dB HL, then 20 dB more noise is allowable at each octave band than necessary for testing at 0 dB HL. Similarly, criteria for other screening levels may be arrived at by adding the desired screening level to the ANSI specified levels. Accordingly, the levels shown in Table 3 are obtained as octave band noise criteria (500 to 4000 Hz) for screening at 15, 20, and 25 dB HL according to the ASHA rationale. (Again, these values assume the noise attenuation properties of an MX-41/AR cushion.) Comparing the measured data with these criteria results in Table 4 which shows the number and percentage of offices whose characteristics would allow screening at 15, 20, and 25 dB HL at the various frequencies using standard audiometric equipment.

Summary

It would appear that the ambient noise levels of the physicians' offices surveyed here are sufficiently low to allow screening at 20 dB HL at frequencies of 1000, 2000, and 4000 Hz. If these measurements represent typical offices, it is probably not advisable to screen at 500 Hz since average noise levels at that frequency often exceed maximum allowable limits. This is especially true when using non-typical (hand-held) devices for which sound attenuating characteristics have not been identified. The subject of hearing screening by physicians raises many questions both scientific and philosophical beyond the scope of this study. The reader is referred to the following publications for excellent information on specific screening recommendations and procedures (American Speech-Language-Hearing
Association, 1985; Barrett, 1985). General data of this nature should not be viewed as replacing the need for individual noise monitoring of potential hearing screening sites. Rather, it is hoped this data may be of benefit in the understanding of the general noise characteristics of this environment.

Table 1.  Octave band measure (dB SPL) for various types (N=20)
Frequency (Hz)	500	1000	2000	4000
Pediatric
Mean	40.6	38.6	37.9	38.7
Standard Deviation	4.3	4.7	8.1	9.2
Range	36.5-47.1	31.6-42.0	27.5-49.4	25.9-50.6
Family Practice
Mean	39.4	36.8	37.9	38.7
Standard Deviation	5.7	7.3	9.1	9.4
Range	35.0-47.7	27.5-47.4	24.9-46.5	24.4-42.8
Internal Medicine
Mean	35.8	32.1	26.0	23.3
Standard Deviation	5.2	3.5	4.1	2.7
Range	26.9-40.3	28.3-37.3	18.9-29.1	19.8-25.5
ENT
Mean	42.1	37.1	32.5	28.9
Standard Deviation	3.0	5.2	11.0	5.6
Range	38.9-45.6	30.6-43.6	14.1-42.9	23.0-37.1
Total
Mean	39.5	36.2	32.4	30.8
Standard Deviation	4.9	5.5	8.9	8.8
Range	26.9-47.7	27.5-47.4	14.1-49.5	19.8-50.6

Table 2.  Statistically sampled noise measures for various office types (N=20)
	Leq	L10	L50	L90	Lmax
Pediatric
Mean	46.8	48.2	42.1	38.5	69.8
Standard Deviation	6.4	5.8	8.7	10.3	5.8
Range	38.4-55.0	40.0-55.0	31.0-55.0	26.5-55.0	63.0-75.0
Family Practice
Mean	42.5	43.4	37.4	34.0	66.2
Standard Deviation	5.2	4.6	4.5	5.8	7.4
Range	37.9-50.2	39.5-50.5	33.5-43.0	27.0-42.5	59.3-76.0
Internal Medicine
Mean	43.2	43.1	35.4	32.6	69.2
Standard Deviation	6.5	5.9	5.5	5.8	6.3
Range	34.6-49.5	35.0-49.5	28.0-41.0	26.0-38.5	61.0-76.0
ENT
Mean	44.1	43.8	38.4	34.8	69.4
Standard Deviation	4.6	4.8	5.4	6.2	3.7
Range	39.3-51.4	40.0-52.0	35.0-48.0	28.0-45.0	66.0-75.0
Total
Mean	44.2	44.6	38.3	35.0	68.7
Standard Deviation	5.5	5.3	6.2	7.0	5.7
Range	34.6-55.0	35.0-55.0	28.0-55.0	26.0-55.0	59.0-76.0

Table 3.  Octave band noise criteria (dB SPL re:Pa) for screening 25 dB HL (adapted ASHA, 1985)
Frequency (Hz)	500	1000	2000	4000
15	36.5	44.5	49.5	57
20	41.5	49.5	54.5	62
25	46.5	54.5	59.5	67.0

References

- Aitken RJ. Quantitative noise analysis in a modern hospital. Arch Environ Health 1982:37(G),361-364.
- American Speech-Language-Hearing Association Guidelines for Identification Audiometry. Asha 1985(May):49-52, cont. 40. American National Standards Institute, American National Standard.
- Criteria for Permissible Ambient Noise during Audiometric Testing. ANSI S3.1-1977, New York.
- AudioScope Operating Instructions.Welch-Allyn, Skanaeteles Falls, NY.
- Garret K. Hearing and immittance screening of school-age children. In Katz J, Ed. Handbook of Clinical Audiology, 3rd ed. Baltimore: Williams&Wilkins, 1985:621-641.
- Falk SA and Woods NF. Hospital noise--Levels and potential health. N Engl JMed 1973;289(15):774-781.
- Long JG, Lucey JF, and Philip AGS. Noise and Hposemia in the intensive care nursery. Pediatrics 1980;65:143-145.

Article and study by Lynn S. Alvord, PhD