Two-point discrimination (TPD) is a tool broadly used in clinical practice.

Two-point discrimination (TPD) is a tool broadly used in clinical practice. 

Decreased tactile acuity and cortical reorganization have been observed in several neurological diseases and chronic pain statessuch as CRPS, phantom limb pain, chronic back pain and painful OA. TPD is used to assess tactile acuity, which is considered as a clinical sign of cortical changes. Besides its frequent use, the reliability and precision of the measurements have not been determined. 

The intra- and inter-rater reliability, bias and variability of TPD was measured at the back, neck, hand and foot of 28 healthy participants, measured by 28 clinicians (physiotherapists). Clinicians received training in the use of mechanical callipers and followed a standardized protocol. 

The results indicate good intra-rater reliability, which mean that the reliability of TPD point in individual clinicians is reliable for the neck, back, hand and foot using callipers. TPD measures assessed by different clinicians were only reliable for the neck and foot Due to the large variability, caution should be taken when interpreting changes in tactile acuity in individual patients, especially when measures are taken by more than one clinician. Clinical experience did not seem to have an effect on TPD measures. > From: Catley et al., Rheumatology (2013) (Epub ahead of print). All rights reserved to the British Society of Rheumatology.