Environmental conditions and performance outcomes: a preliminary report of implications for patient outcomes

Whereas a host of studies have established various forms of experimental bias, few clinical investigations have examined the relationship of the behavior of the observer or examiner to a subject's physical performance.

To measure the grip strength of volunteers in 2 distinct clinical "environments."

Twenty subjects were randomized in a crossover design to undergo grip strength testing in positive and negative environments as created by the distinctly different behavioral/communication approaches of the research staff. Each subject underwent 4 consecutive trials in both settings.

A paired t- test was conducted to determine if the contrasting environments impacted the volunteer's performance. Eight of the 10 subjects demonstrated a significantly stronger grip in the positive environment. One subject's grip remained essentially unchanged and one subject provided a slightly higher performance in the negative setting.

The study suggests that clinical environmental conditions influence the physical performance of a grip strength maneuver. Thus, it seems probable that clinical or experimental settings may affect diagnostic test results and/or functional outcome.