Objectives: To revise the static and dynamic normative values for the two-point discrimination test and to examine its applicability and validity in patients with a polyneuropathy.
Methods: Two-point discrimination threshold values were assessed in 427 healthy controls and 99 patients mildly affected by a polyneuropathy. The controls were divided into seven age groups ranging from 20-29, 30-39,…, up to 80 years and older; each group consisted of at least 30 men and 30 women. Two-point discrimination examination took place under standardised conditions on the index finger. Correlation studies were performed between the obtained scores and the values derived from the Weinstein-Enhanced-Sensory-Test (WEST) and the arm-grade of the Overall Disability SumScore (ODSS) in the patients group (validity studies). Finally, the sensitivity to detect patients mildly affected by a polyneuropathy was evaluated for static and dynamic assessments.
Results: There was a significant age dependent increase of the two-point discrimination values. No significant gender difference was found. The dynamic threshold values were lower compared with the static scores. The obtained two-point discrimination values were significantly correlated with the arm-grade of the ODSS (static values: r=0.33, p=0.04; dynamic values: r=0.37, p=0.02) and the scores of the WEST in patients (static values: r=0.58, p=0.0001; dynamic values: r=0.55, p=0.0002). The sensitivity for the static and dynamic threshold values was 28% and 33%, respectively.
Conclusion: This study provides age-related normative two-point discrimination threshold values using a two-point discriminator (an aesthesiometer). This easily applicable instrument could be used as part of a more extensive neurological sensory evaluation.