Validating a New Writer s Cramp Scale

Overview

Background: \- People with writer s cramp develop tightness in arm muscles and abnormal hand posture when writing, which makes writing difficult or impossible. At present, there is no suitable rating scale to measure the symptoms of or disability associated with writer s cramp. Researchers want to videotape people performing simple writing tasks. They will then compare the performance of people with writer s cramp on these tasks to those of people without writer s cramp. This information will help develop a rating scale to evaluate writer s cramp. Objectives: \- To develop a new rating scale for writer s cramp. Eligibility: \- Individuals at least 18 years of age who have writer s cramp. Design: * Participants will be screened with a physical exam and medical history. * Participants will have one outpatient study visit that will last about 3 hours. * Participants will perform tasks related to writing, such as writing passages and drawing spirals and loops. They will be videotaped during these tasks. They will repeat some of the writing tasks three more times; on paper attached to a writing tablet, directly on the writing tablet, and on a computer tablet. * The angles made by the joints will be measured at rest not while writing healthy volunteers.

Objective: Writer s cramp (WC) causes significant discomfort and disability to those afflicted by this condition. Studies on WC have been hampered by the lack of objective, validated rating scales. In this study, we will test and validate new instruments to rate WC; the WC impairment scale (WCIS) and a new disability scale (WCDS).We will also collect exploratory data about biomechanics of the hand. Study population: The study population will consist of 20 subjects. Ten patients with WC and 10 age and handedness matched HVs will constitute the study population. Design: 10 patients with WC and 10 age- and handedness-matched HV will be videotaped while writing. The WCIS scores will be given to each subject by four blinded raters (Drs. Mark Hallett, Barbara Karp, Katherine Alter, and Camilo Toro) based on the videos. The patients will complete the WCDS. In addition, each individual will be asked to repeat some basic elements of the scale while writing on the screen of a tablet PC, and on the surface of a detached digitizing tablet in order to generate high temporal and spatial resolution pen tip position samples for further numerical analyses and scoring. The biomechanics of the hand will be measured using a published scale. Outcome measures: Using the WCIS, inter and intra-rater reliability, internal consistency (Cronbach s alpha) face validity, and reproducibility will be measured in addition to other secondary outcomes. The ease of use by the raters will be assessed for each subject. Reproducibility of writing on tablet, writing on paper placed on a writing tablet, and writing on a tablet PC will be assessed. Finally, biomechanics of the hands of patients with WC will be compared with those of the unaffected healthy volunteers.