Evaluation of nonnociceptive sensation in patients with congenital insensitivity to pain with anhidrosis

Abstract

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare, autosomal recessive disorder characterized by lack of pain and thermal sensation, anhidrosis, thermodysregulation, and mental retardation. Although nonnociceptive sensation, which is mediated by large-caliber myelinated Abeta fibers, is reported to be normal in CIPA patients, precise clinical assessments of this type of sensation have yet to be performed. The aim of this study was to evaluate peripheral sensory nerve function, including senses of touch/pressure, vibration, joint position, and two-point discrimination, in patients with CIPA by basic clinical neurological examination. We examined touch/pressure sense, deep senses (vibration, joint proprioception), and two-point discrimination in 12 patients with CIPA (six males and six females aged 11-44) and 12 age- and sex-matched healthy controls. Touch/pressure sense was examined with Semmes-Weinstein monofilaments, vibration sense with a tuning fork, and two-point discrimination with a vernier caliper. Joint proprioception was assessed through subject recognition of passive movement of the great toe. Perception thresholds of touch/pressure, vibration, and two-point discrimination were significantly higher (p < 0.05), and proprioception sensitivity was significantly lower (p < 0.05) in CIPA patients than in the healthy controls. Our findings suggest that CIPA patients suffer from more widespread disturbances of sensation than has been previously recognized. Impairment may not be restricted to the types of sensation conducted by peripheral sensory Adelta and C fibers.