Medium pain ratings of four distinct pain levels (A) VAS (B) PM.

<p>All comparisons between the pain intensities were significant (p ≤ 0.05) for VAS and PM. Bars depict average values and their S.E. Please note that for the VAS, ratings for medium- and high-pain levels do not change over time in contrast to PM values for the same pain levels (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051014#s2" target="_blank">Discussion</a>).</p

The Painmouse®.

<p>The measuring device connected to a hand-held portable computer.</p

Patients’ standardized mean PM ratings of the five different dressing change steps.

<p>Bars depict average values and their S.E.</p

A new tool for real-time pain assessment in experimental and clinical environments

Pain measurement largely depends on the ability to rate personal subjective pain. Nevertheless, pain scales can be difficult to use during medical procedures. We hypothesized that pain can be expressed intuitively and in real-time by squeezing a pressure sensitive device. We developed such a device called "Painmouse(®)" and tested it on healthy volunteers and patients in two separate studies: Sixteen male participants rated different painful heat stimuli via Painmouse(®) and a Visual Analog Scale (VAS). Retest was done one week later. Participants clearly distinguished four distinct pain levels using both methods. Values from the first and second sessions were comparable. Thereafter, we tested the Painmouse(®) by asking twelve female and male leg- ulcer patients to continuously squeeze it during the whole length of their wound-dressing change. Patients rated each step of dressing change on an 11-point numeric rating scale. Painmouse(®) ratings were highest for the wound cleaning and debridement step. Application of the new dressing was not evaluated as very painful. On the other hand, numeric scale ratings did not differentiate between dressing change steps. We conclude that the Painmouse(®) enables pain assessment even under difficult clinical circumstances, such as during a medical treatment in elderly patients