Normal Digit Tip Values for the Weinstein Enhanced Sensory Test Lisa A. Schulz, MS, OTRlL, CUT Departments of Hand Therapy and Orthopedics University of Massachusetts Medical Center Worcester, Massachusetts Richard W. Bohannon, EdD, PT, NCS University of Connecticut School of Allied Health Storrs, Connecticut William J. Morgan, MD Department of Orthopedics University of Massachusetts Medical Center Worcester, Massachusetts T he ability to feel with the fingertips is crit- ically important for many activities, from buttoning a button or threading a needle to using a hammer. This ability to perceive a stimulus, or sensibility, can be affected by any injury or illness affecting peripheral nerves. Often with progressive loss of sensibility, a concurrent loss of functional ability occurs. For example, patients with early car- pal tunnel syndrome may complain initially of dif- ficulty with writing for prolonged periods of time. As their symptoms worsen, they report that they drop items, stating that they "just loose their grip." Finally, the patients may be unable to button but- tons because they cannot feel them. Clinicians need to be able to accurately assess changes in sensation as they occur in order to provide appropriate treat- ment to patients and assess treatment effectiveness. The testing of sensibility appears at a cursory glance to be straightforward. If examined carefully, however, it becomes evident that sensibility testing is in fact a complex "art" rather than an exact sci- ence. In attempts to objectively measure specific nerve function, a variety of tools have been devel- oped. The Weinstein Enhanced Sensory Test (WEST) is such a tool, which has been developed to test cutaneous sensibility. The WEST is a nonin- vasive assessment of threshold of light touch. The roots of the WEST are found in work done by Max von Frey in the 1890s. 1 Based on observa- tions he developed a graded series of "sensory Correspondence and reprint requests to Lisa A. Schulz, MS, OTR/L, CHT, Department of Hand Therapy, University of Mas- sachusetts Medical Center, 55 Lake Avenue North, Worcester, MA01655. 200 JOURNAL OF HAND THERAPY ABSTRACT: The Weinstein Enhanced Sensory Test (WEST) is performed using a calibrated monofilament esthesiometer. This study was designed to establish normal values for the WEST when testing digit tip sensibility and to assess whether factors such as age, gender, and side affect normal WEST values. In order to establish normal values, the WEST was performed on 120 subjects who had no clinical evidence of peripheral neurop- athy or subjective changes in digit tip sensation. Subjects also completed a questionnaire and underwent neurometric testing of the median nerve and a brief clinical examination. The results of the study indicate that age had a significant effect on WEST values (p = 0.0002) and that there was an interaction effect for age and gender (p = 0.018). There are strong correlations be- tween the WEST values for individual digits for a given subject and between WEST and electroneurometer values. Normal val- ues for the WEST should be interpreted with regard to age and gender. These normal values (defined as the values for 80% of the population of each category) based on the sample used for this study are as follows: for men and women 55 years of age or younger, 0.035 g; for women older than 55 years, 0.15 g; for men older than 55 years, 0.385 g. J HAND THER 11:200-205, 1998. hairs" 40-100 I-Lm in diameter, which he used to determine light touch thresholds. His recom- mended series of hairs included child's hair, wom- an's hair, man's hair, and horse hair.2 In the 1960s a series of calibrated nylon filaments, based on the von Frey hairs, was developed by Semmes, Wein- stein, Ghent, and Teuber. These filaments are com- monly known as Semmes-Weinstein monofila- ments. The filaments are graded by filament thickness, stiffness, and length and were devised to be used quickly and easily, without the need for frequent recalibration.! Detection threshold, which is the boundary point at which a stimulus is re- ported as being felt half the time, is assessed with the monofilaments. Detection thresholds vary at different points on the body.3 The Semmes-Weinstein mono filaments test was designed to control the force of application of the stimulus and has been shown to be reproducible with repeated application of the stimulus, provided the monofilaments have been manufactured care- fully, to the correct filament length and diameter. 4 However, manufacturing variations, among other problems, can affect the consistency of the force ap- plied by the monofilaments. 1 Concerns about man- ufacturing consistency led to the development of the WEST. Unlike the Semmes-Weinstein monofilaments, the WEST is calibrated to indicate force application thresholds in milligrams. Studies have shown that the WEST provides the same thresholds as the Semmes-Weinstein monofilaments test. s Before the WEST can be widely used, norma- tive values for the test must be established. 6 These normal values represent an average of how a spe-