The Physical Performance Test measured physical function in elderly outpatients
ACP J Club. 1991 Mar-Apr;114:53. doi:10.7326/ACPJC-1991-114-2-053
Reuben DB, Siu AL. An objective measure of physical function of elderly outpatients. The Physical Performance Test. J Am Geriatr Soc. 1990;38:1105-12.
To report the development and validation of a direct-observation instrument for measuring physical performance capabilities of elderly persons.
Test construction was followed by reliability and validity testing, through comparing the scores of elderly persons on the Physical Performance Test (PPT) with their reported capacities and with their scores on other measures of physical functioning.
6 hospital or community-based geriatrics practices.
183 (mean age 79 y, 71% women) patients were selected, at random from 1 site, and by their own choice from the other sites. All participants were required to be > 65 years of age, except the 21 patients with Parkinson disease. Patients were excluded if they could not speak English, could not complete a 10-minute questionnaire, or had dementia or acute physical or psychiatric illness. 106 patients completed a 9-item PPT, and 179 completed a 7-item version.
Description of test and criterion standard
The PPT was designed to assess strength, mobility, dexterity, and stamina through direct observation of the elderly person's performance of specified activities, including writing a sentence, picking up a penny from the floor, and walking 20 meters. The test was administered by an observer according to a protocol. PPT scores were compared with a self-report questionnaire on functional status and health and with other self- or proxy-reported measures of functional status.
Main outcome measure
PPT scores were the sum of the 5-point scales for each of the items, varying from "most capable or fastest" to "unable to do."
Over 80% of patients reported that they were independent in each of the basic activities of daily living. There was ≥ 90% agreement between self-reported and observed ability to complete PPT activities. Inter-rater reliability on the 9-item and 7-item scales was high. Correlations of these scales with 3 self-reported measures of basic activities were 0.50 to 0.80 and with the Tinetti gait score, were 0.78 and 0.69.
The Physical Performance Test, as an instrument of direct observation, was a reliable and valid method of quantifying physical performance status in elderly persons. Its clinical and research value will need to be determined.
Source of funding: National Institute on Aging Academic Award.
Address for article reprint: Dr. D.B. Reuben, UCLA School of Medicine, 32-144 CHS, 10833 Le Conte Avenue, Los Angeles, CA 90024-1687, USA.
This study is a valuable contribution to the growing body of knowledge on performance testing of function. The authors are accurate in stating there are no other multidimensional, valid, reliable, and easily administered and scored direct-observation tests of function.
Three issues were not addressed by the authors, and one other issue, although mentioned in the article, has not been investigated. First, test-retest reliability and a potential practice effect were not evaluated. Second, the potential effects of sensory loss (visual and hearing impairment) and limited education (illiteracy) were not evaluated (1). Third, the framing of the instructions to study subjects was not adequately described: Were subjects aware they were being timed? Were they told to complete the tasks as fast as they could or as carefully and accurately as they could?* Finally, predictive validity has apparently not yet been evaluated. This study represents preliminary work. It should not be used in clinical decision making until it is tested in other populations and until its predictive validity is determined.
Thomas V. Jones, MD, MPH
University of North CarolinaChapel Hill, North Carolina, USA
*In response, Dr. Reuben states that patients were instructed to complete the tasks at their usual pace and in their usual manner and were informed that they were being timed— The Editor
**This study was updated in 1992. Reuben and colleagues compared the PTT with the Katz, Spector and Rosaw-Breslau and the Mini-Mental State exam. After 22 months, the 7-item PTT predicted death or nursing home placement. Clinical usefulness remains to be proven.