Nociceptive two-point discrimination acuity and body representation failure in polyneuropathy

Author(s)

Steenken, Livia ; Conde, Rodrigo M. ; Mueller, Julia K. ; Escolano-Lozano, Fabiola ; Birklein, Frank ; Dimova, Violeta

• Document type: Journal article
• Source: SCANDINAVIAN JOURNAL OF PAIN; v. 23, n. 1, p. 10-pg., 2022-08-04.

Abstract

Objectives: Although patients' complaints suggest polyneuropathy (PNP) and neuropathic pain, routine investigations do not always support the diagnosis. Assessing two-point-pain discrimination thresholds (2ptDT) and quantify body representation disturbances might be useful to close this diagnostic gap. Methods: Pinprick pain and laser-heat pain perception thresholds and 2ptDT on hands, forearms, lower legs and feet were obtained in 20 PNP patients (mean age: 57.6 +/- 13.9) and 20 healthy subjects (mean age: 50.6 +/- 4.7 years). Body representation disturbances were assessed by self-estimating feet size and the Bath CRPS body perception disturbances questionnaire adapted for PNP. Results: Pain perception thresholds and laser-heat pain 2ptDT were unaltered, but patients had higher pinprick pain 2ptDT then the healthy subjects. The 2ptDT for pinprick at the hands discriminate best between groups (U-test; p=0.001). Furthermore, patients estimated their feet longer than they are. In subsequent multivariate discriminant analyses, 2ptDT for pinprick pain at the hands, 2ptDT for laser-heat pain and the perception thresholds for laser-heat pain at the feet classified 85% of PNP vs. HC correctly. The combination of 2ptDT for pinprick pain at the hands, pinprick pain perception thresholds at the calves and foot length estimation differentiates painful vs. non-painful PNPs correctly in 90% of the cases. Conclusions: Testing 2ptDT for painful pinprick stimuli at the hands and asking for foot length estimation might add to diagnostic accuracy in painful PNP. (AU)

• FAPESP's process: 15/25893-3 - Spatial acuity for pain and its relationship with somatic sensory and autonomic measures in small fiber neuropathy
• Grantee: Rodrigo Melo Conde
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate