Speech Intelligibility and Cognition: Are Inpatients Impaired by Noise?

Study Objectives:

• 1. To examine the extent to which noise typical of nursing units reduces speech intelligibility in acutely ill hospitalized patients
• 2. To examine the extent to which noise typical of nursing units impairs recall in acutely ill hospitalized patients
• 3. To quantify severity of reduced performance associated with age, familiarity with the healthcare setting, hearing and health status.

Plan:

One hundred and twenty inpatients from the four medical/surgical nursing units at the Portland VA Medical Center, 60 with normal hearing and 60 with hearing impairment will be recruited to participate in the study. Following assessment to ascertain eligibility and obtaining informed consent, patients will be tested in a sound booth housed at the National Center for Rehabilitative Auditory Research (NCRAR). Designed so that each patient serves as his or her own control, we can accommodate considerable baseline variability between patients without adversely affecting required sample size. Patients' performance in speech intelligibility and recall tests will be measured using a constant level of speech, in controlled environments of no noise (baseline), white noise, hospital noise and hospital noise with speech, all delivered via headphones in pseudo-random order. Performance will be measured in each type of noise at decibel levels equivalent to those currently experienced on nursing units and at lower levels that prior studies have shown are more conducive to effective communication

By selecting measures that are particularly relevant to the safe care of hospitalized patients, and that have been studied extensively in healthy populations in highly controlled conditions, we expect to find compelling and unambiguous evidence that hospitalized patients correctly hear and recall very little of what is said to them during their hospitalizations. The majority of hospitalized patients stay on acute care nursing units during most or all of their hospitalizations, making this an appropriate population to study in the context of their responses to the noises typical in these environments. Perhaps most importantly, this study will heighten awareness of health-care personnel to the levels of impairment suffered by their patients - both in their ability to correctly interpret speech and to recall it - in the typical noisy environments of nursing units.