br Introduction Scales that measure symptoms

Introduction Scales that measure symptoms of narcolepsy emphasize rating clinical features of the disease such as excessive daytime sleepiness and cataplexy [1,2], but they may fail to capture the full functional impact of narcolepsy or its treatments. The Medical Outcomes Study Short Form-36 (SF-36) [3] has been used in patients with narcolepsy to characterize more fully the effect of the disease on physical and psychosocial spheres [4,5]. Another general health status measure, the Sickness Impact Profile (SIP) [6,7] has the potential to expand further our understanding of dysfunction in narcolepsy patients. The SIP was designed to assess functional status of patients with any chronic disease [6,7]. Its reliability and validity have been extensively studied in neurologic [8,9] and non-neurologic diseases [7,10], but not in patients with narcolepsy, to our knowledge. The SIP contains 136 items grouped in 12 categories and requires about 30min to complete. Each item describes a specific behavioral dysfunction, rather than a subjective self-evaluation. Patients are instructed to endorse only those items describing dysfunction due to their disease. Each item has a weight reflecting the relative severity of the dysfunction compared to other items [11]. The 12 category scores, expressed as percents, are the sum of the weighted scores for all the endorsed items in a particular category divided by the maximum score, which represents total dysfunction for that category. Some categories contribute to a physical dimension; some, to a psychosocial dimension; and some independent categories, to neither of these dimensions.
Materials and methods In the parent study, we attempted to identify all prevalent cases of physician-diagnosed narcolepsy who were 18 years and older and residing in King County, Washington as of July 1, 2001 [12]. Cases were recruited through multiple overlapping methods. For providers, we focused on clinicians working in sleep disorders centers but also contacted neurologists, family medicine physicians, psychiatrists, and ezh2 pathway clinics where patients without financial resources often receive care. For patients, presentations were made at support groups and other regional meetings. Pharmacists in King County agreed to include an information sheet about the study with all prescriptions relevant to narcolepsy. Multimedia advertisements and public service announcements were also used and linked to telephone and online contact information. Patients identified were contacted and asked to participate in an epidemiologic study. For those who provided written informed consent, trained professionals administered a structured interview. Consent to provide buccal specimens and to obtain medical records was also requested from each participant. A total of 425 patients were entered into the narcolepsy registry. Of these, 78 cases could not be located, 10 could not be interviewed due to language barriers or psychiatric illnesses, and 55 refused. Interviews were arranged for 282 cases, 279 of whom completed the interview and provided buccal specimens for deoxyribonucleic acid (DNA), which was tested for human leukocyte antigen (HLA) DQB1⁎0602 as detailed elsewhere [13]. The University of Washington Human Subjects Committee reviewed and approved the study.
Data collection Trained professionals administered in-person interviews to patients using a standardized questionnaire that included demographic information, the Epworth Sleepiness Scale (ESS) [1], and the Ullanlinna Narcolepsy Scale (UNS) [2]. We defined cataplexy as present if indicated by medical record review, self-reported cataplexy, or an affirmative response to questions about experiencing muscle weakness when telling or hearing a joke, or when laughing [14]. After the interview, the SIP was explained to the patient, who was given the choice of completing the SIP while the interviewer waited or to complete it at a later date and return it by mail. Of the 279 patients who participated in the study, the 226 (81%) who completed the SIP, the ESS, and the UNS are the focus of this report.