Two Measures of Tactile Acuity in CRPS Type I Patients


This study aims to investigate whether two different measures of tactile acuity lead to comparable results in patients diagnosed with CRPS Type I of the upper extremity. Additionally patients with a neuropathy of the median nerve and healthy controls are included.

Full Title of Study: “Comparison of Two Measures of Tactile Acuity in CRPS Type I Patients , Patients With a Neuropathy of the Median Nerve and Healthy Controls.”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Non-Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Basic Science
    • Masking: None (Open Label)
  • Study Primary Completion Date: September 2013


  • Other: Tactile acuity measured by 2PD and the GOT
    • For a detailed description of the methods see “outcome measures”

Arms, Groups and Cohorts

  • Experimental: CRPS Type I
    • Patients diagnosed with complex regional pain syndrome type I of the upper limb
  • Active Comparator: Median Nerve Neuropathy
    • Patients diagnosed with a neuropathy of the median nerve of the upper limb.
  • Active Comparator: Healthy Controls
    • Healthy adult persons.

Clinical Trial Outcome Measures

Primary Measures

  • tactile acuity as measured by 2-point-discrimination
    • Time Frame: unique measurement of maximal one hour duration
    • Thresholds on the tip of the index finger of boths hands are assessed using the method of constant stimuli. One single needle and seven pairs of needles with different spacings are tested in randomized order. After each presentation, the subject has to report the sensation of one or two needles by answering immediately “one” or “two.” Each distance is presented eight times resulting in 64 single decisions. The summed responses are plotted against distance as a psychometric function for absolute threshold and get fitted by a binary logistic regression. Thresholds are taken from the fit at the distance at which 50% correct answers are given
  • tactile acuity as measured by the Grating Orientation Task (GOT)
    • Time Frame: unique measurement of maximal half an hour duration
    • Stimuli are taken from a set of dome-shaped plastic gratings with equal groove and ridge widths. Gratings are applied to the immobilized distal fingerpad of the index finger of boths hand with the ridges oriented either along or across the long axis of the finger in randomized sequences of the two alternatives. Subjects have to report the orientation of the gratings as “along” or “across”. The largest groove widths in the set is 6mm, the minimal width is 0.5mm. Thresholds were taken from the groove width at which the performance was 75% correct. Unless the performance is exactly 75% for a particular grating, interpolation between gratings spanning the 75% correct responses ared used

Participating in This Clinical Trial

Inclusion Criteria

  • Patients diagnosed with CRPS Type I according to the "Budapest Criteria" – Patients diagnosed with a neuropathy of the median nerve – Healthy Controls,matched in age and gender to both patient cohorts Exclusion Criteria:

  • intolerable hyperalgesia – lesions at the fingertips – high grade digit contracture – central neurologic disorders – psychiatric disorders

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 75 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Ruhr University of Bochum
  • Provider of Information About this Clinical Study
    • Principal Investigator: Christoph Maier, Prof. Dr., Prof. Dr. med Christoph Maier, Head Dep. of Pain Medicine – Ruhr University of Bochum
  • Overall Official(s)
    • Christoph Maier, Prof. Dr., Study Chair, Ruhr University Bochum
  • Overall Contact(s)
    • Christoph Maier, Prof. Dr., +49 2343023402,

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