Application of a Digital Head-Posture Measuring System in Children

PURPOSE: To report the repeatability of a digital head-posture measuring system when used to record anomalous head postures in children. DESIGN: Prospective study and clinical laboratory investigation. METHODS: Using a digital head-posture measuring system, we measured 36 different anomalous head postures in 27 children with infantile nystagmus syndrome. Repeatability values and 95% limits of repeatability of measurements were generated for anomalous head postures. RESULTS: Among the 27 children, 3 had 2 head postures (right and left head turns) in 2 different directions; 6 had 2-dimensional head postures that were considered 2 different head postures; and 18 had a 1-dimensional head posture. There were 5 chin-up or chin-down postures, 23 head-turn postures, and 8 head-tilt postures in a total of 36 anomalous head postures. The repeatability value for all anomalous head postures was less than 10 degrees. Ninety-five percent limits of repeatability yielded ranges of less than 10 degrees for all anomalous head postures. CONCLUSIONS: The digital head-posture measuring system is a valid and reliable device for measuring 3-dimensional head postures in children with nystagmus. (Am J Ophthalmol 2011;151:66-70. (C) 2011 by Elsevier Inc. All rights reserved.)