Are false-positive rates leading to an overestimation of noise-induced hearing loss?

PURPOSE

To estimate false-positive rates for rules proposed to identify early noise-induced hearing loss (NIHL) using the presence of notches in audiograms.

METHOD

Audiograms collected from school-age children in a national survey of health and nutrition (the Third National Health and Nutrition Examination Survey [NHANES III]; National Center for Health Statistics, 1994) were examined using published rules for identifying noise notches at various pass-fail criteria. These results were compared with computer-simulated "flat" audiograms. The proportion of these identified as having a noise notch is an estimate of the false-positive rate for a particular rule.

RESULTS

Audiograms from the NHANES III for children 6-11 years of age yielded notched audiograms at rates consistent with simulations, suggesting that this group does not have significant NIHL. Further, pass-fail criteria for rules suggested by expert clinicians, applied to NHANES III audiometric data, yielded unacceptably high false-positive rates.

CONCLUSIONS

Computer simulations provide an effective method for estimating false-positive rates for protocols used to identify notched audiograms. Audiometric precision could possibly be improved by (a) eliminating systematic calibration errors, including a possible problem with reference levels for TDH-style earphones; (b) repeating and averaging threshold measurements; and (c) using earphones that yield lower variability for 6.0 and 8.0 kHz--2 frequencies critical for identifying noise notches.

A survey of environmental safety issues at 20 medical clinics

In the study described in this article, the authors performed safety walk-throughs or inspections for 20 clinics located both inside a major medical center clinic (onsite) and away from the main clinic site (offsite). A checklist was used to evaluate compliance with institutional, local, state, and federal guidelines and regulations. The results obtained at onsite clinics were compared with the results from offsite clinics. Findings suggested no overall difference in the number of yes (desirable) answers. A marginally significant difference, however, was observed between the onsite and offsite clinics with regard to knowledge of infection control and waste/infection control questions. The walk-throughs helped create an improved working relationship between clinic personnel and environmental safety personnel, allowed for correction of safety issues, enabled an informal training opportunity, and increased institutional compliance with guidelines and regulations.

Views of a Cal/OSHA Inspector

Retiring CAL/OSHA Industrial Hygienist and Senior Safety Engineer Jack Oudiz offers his thoughts in the nature of a voluntary "exit interview" on his years working for the agency and its performance in its mission.

Improving compliance with Occupational Safety and Health Administration standards

Health care facilities can be dangerous places. The mission of the Occupational Safety and Health Administration (OSHA) is to improve the safety of the American workplace by developing and implementing standards that prevent occupational injury, illness, and death. Perioperative services are performed in environments where exposure to bloodborne pathogens is a daily occurrence, making implementation and compliance with OSHA standards very important. Employees and employers must remain current with workplace safety requirements, including use of personal protective equipment. This article presents implications of the OSHA standards for employers, educators, and employees.

Statistical methods for establishing equivalency of several sampling devices

The problem of comparing several alternate sampling devices to the Occupational Safety and Health Administration (OSHA) standard, or the comparison of several sampling devices among themselves, is considered. A test based on the OSHA criterion that states that "90% of the readings of the sampling device should be within +/- 25% of the readings obtained by the standard" is developed. Type I error rates and powers of the test are studied using Monte Carlo simulation. The study indicates that the proposed test is quite satisfactory for applications. The method is illustrated using a simulated data set.