Background: Together with visual information, awareness of limb position and movement is essential for limb coordination. A proprioceptive deficit has been demonstrated in a number of rheumatological disorders. There is a lack of a portable device for measuring hand proprioception in the field.
Methods: A compact portable device for measuring joint position sense in the metacarpophalangeal joint of the index finger of either hand was constructed. This device was manually operated and required the subject to match the position of the hidden finger with a surface-mounted silhouette. Reliability studies were performed over three consecutive days in 12 normal volunteers.
Results: Intrasubject variability [95% confidence interval (CI)] was 0.86 degrees (0.04-1.76) between days 1 and 2, and 1.23 degrees (1.04-3.50) between days 2 and 3. The intraclass correlation coefficient (95% CI) between all 3 days was 0.92 (0.85-0.96). Average proprioceptive error (95% CI) in the sample population was 5.72 degrees (1.23-10.2) over the 3 days. This value was 5.94 degrees , 5.79 degrees and 5.42 degrees on days 1, 2 and 3, respectively. No difference was found between sexes but dominant hands gave smaller errors (mean dominant error 5.11 degrees , mean non-dominant error 6.35 degrees ; t = -3.4, P = 0.002).
Conclusions: This report describes a new portable device for measuring proprioception in the hand. Reproducibility was shown to be good on an individual and group basis. These results are promising and warrant larger age- and sex-related studies. The ease and portability of the device make it ideal for use in epidemiological studies of rheumatological disorders involving the hands, including joint hypermobility.