Clinical Trial: Static Graviceptive Functions in Patients With Cervical Dystonia (CD)

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Experimental Pilot Trial Assessing Static Graviceptive Function in Patients With Cervical Dystonia

Brief Summary: The purpose of this experimental pilot study is to test the effect of normalization of the head position on the sense of balance at patients with cervical dystonia under routine botulinum toxin treatment.

Detailed Summary:

Background:

The pathophysiological mechanism of cervical dystonia remains unclear. Affection of static graviceptive function has been shown in these patients by measuring the Subjective Visual Vertical (SVV). Healthy subjects, tested with voluntary head tilt, would tilt SVV in the opposite direction of the head. (Müller "E" effect), whereas patients with cervical dystonia set SVV close to true upright with a minimal deviation toward head-tilt. The mechanism of this change in otolith activity in patients with cervical dystonia is still unknown. When treated with botulinum toxin, head deviation will be reversed during a period of approximate 6-9 weeks, with a first peak of action after approximate 3 weeks.

Aim

The aim of this study is to investigate the effect of normalization of the head position under routine intramuscular botulinum toxin application in the cervical muscles (screening, 3 weeks and 9 weeks after injection) on static graviceptive function in patients with cervical dystonia.

Rationale

To our knowledge, the effect of botulinum toxin therapy on static otolith function in patients with cervical dystonia has never been evaluated. This study may provide new informations on the neural plasticity of the vestibular system and may contribute to the understanding of pathophysiological mechanisms of cervical dystonia. Accordingly, it may help developing new treatment strategies for this disease.

Primary hypothesis

There is a difference of at least 6 degrees in subjective visual vertical of patients with CD tested in habitual head position at study inclusion an
Sponsor: Kirsten Elwischger

Current Primary Outcome:

  • Subjective visual vertical (SVV), measured in degree (°) [ Time Frame: screening ]
    Assessment: sitting upright in dark room, head is fixed using a head holder with a strap and a neck rest covering the occiput and posterior neck. For deviation of head (0°, 15° and 30° to the left and right side), head holder can be rotated about its midpoint. In front of patient (distance of 100 cm) is dim light bar, which can be rotated about its midpoint by means of an electronic motor and a remote control device. Patients adjust bar for parallel alignment with the perceived gravitational vertical. The operator tilts the bar in a random order 18° from the physical vertical.
  • SVV in degree (°) [ Time Frame: 3 weeks after screeening ]
    Assessment: sitting upright in dark room, head is fixed using a head holder with a strap and a neck rest covering the occiput and posterior neck. For deviation of head (0°, 15° and 30° to the left and right side), head holder can be rotated about its midpoint. In front of patient (distance of 100 cm) is dim light bar, which can be rotated about its midpoint by means of an electronic motor and a remote control device. Patients adjust bar for parallel alignment with the perceived gravitational vertical. The operator tilts the bar in a random order 18° from the physical vertical.
  • SVV in degree (°) [ Time Frame: 9 weeks after screening ]
    Assessment: sitting upright in dark room, head is fixed using a head holder with a strap and a neck rest covering the occiput and posterior neck. For deviation of head (0°, 15° and 30° to the left and right side), he

    Original Primary Outcome: Same as current

    Current Secondary Outcome:

    • Degree of head deviation (°) [ Time Frame: screening ]
      head deviation of patients group in relaxed posture, measured in degrees (°)
    • degree of head deviation (°) [ Time Frame: 3 weeks after screening ]
      head deviation of patients group in relaxed posture, measured in degrees (°)
    • degree of head deviation (°) [ Time Frame: 9 weeks after screening ]
      head deviation of patients group in relaxed posture, measured in degrees (°)


    Original Secondary Outcome: Same as current

    Information By: Medical University of Vienna

    Dates:
    Date Received: July 14, 2010
    Date Started: June 2010
    Date Completion:
    Last Updated: January 28, 2012
    Last Verified: January 2012