Several sleep disorders associated with neurologic disease can negatively impact mood, cognitive functioning, and quality of life. Such sleep disorders include rapid eye movement (REM) sleep behavior disorder (RBD), periodic limb movements during sleep (PLMS), restless legs syndrome (RLS), sleepwalking (SW), obstructive sleep apnea (OSA), sleep related leg cramps (SRLC), and insomnia. These disorders are treatable and such treatment often results in improved quality of life and improved management of the coexisting neurologic disorder. Hence there is an increasing interest in identifying and treating patients with these conditions.
Current practice in the assessment of sleep disorders involves the clinical interview of patients and their bed partners, physical examination, and in those suspected to have certain sleep disorders, polysomnography (PSG). The history and examination usually require 30–60 minutes for a sleep medicine clinician to complete. PSG is clearly necessary for establishing the diagnosis of RBD, OSA, and PLMS, but the procedure requires appropriate monitoring equipment, including time synchronized video recordings, specially trained technologists, bed availability in a sleep laboratory, and clinicians who can interpret the data. The procedure is costly (>$1000 per study at most centers for a clinical PSG), especially for patients with limited insurance coverage. Subjects must be willing and able to sleep in a sleep laboratory and undergo monitoring. Some patients with coexisting neurologic disorders are too cognitively or physically impaired to tolerate and undergo an adequate study, are too uncooperative to permit all monitoring equipment to remain in place, are at risk for falls during the night, or are institutionalized. While home monitoring may be appropriate for the diagnosis of uncomplicated OSA in some patients, RBD and PLMS cannot be accurately assessed in this way. For clinical and especially research purposes, it would be desirable to screen for the presence of key sleep disorders, using a validated measure, by querying the bed partners of patients who are cognitively impaired, severely disabled or deceased, with PSG remaining as the gold standard for confirming their presence and determining their severity. Seeing how impractical it is to perform PSGs in large numbers of subjects in epidemiologic sleep disorder studies, using a simple, short, reliable, and accurate measure to screen for the presence of various sleep disorders would be highly valuable.
These issues led us to develop the Mayo Sleep Questionnaire (MSQ) in 2001, which is a 16-item measure that poses questions about RBD, PLMS, RLS, SW, OSA, and SRLC. The primary goal of this measure was to assess RBD with adequate sensitivity and specificity. There were two versions initially developed—one completed by the patient and one completed by his/her bed partner/informant. Our early pilot data using the MSQ through 2002 [1
], in which responses on the MSQ were compared with the findings on PSG, indicated that the sensitivity and specificity were higher for the bed partner/informant version compared to the patient version, regardless of whether the patient was cognitively impaired or not. Since 2002, we have therefore only used the bed partner/informant version of the MSQ. The MSQ was designed to be used for clinical and research purposes in a variety of settings, such as a Behavioral Neurology Clinic (which involves patients with cognitive/behavioral changes), a Movement Disorder Clinic (which involves patients with parkinsonism and other movement disorders), a Sleep Disorders Center, a research program involving community-dwelling nondemented aged individuals, and a research program involving individuals with normal cognition, mild cognitive impairment, dementia, or parkinsonism. The pilot data were collected on individuals evaluated in a Behavioral Neurology Clinic and Sleep Disorders Center [1
]. In this paper, we report validation data on the MSQ compared to PSG focused on RBD. Validation of the MSQ compared to PSG-confirmed data regarding PLMS and OSA, and also MSQ data compared to established clinical diagnostic criteria for RLS, SW, and SRLC, are presented as supplemental data
. Because of the relevance of RBD pertaining to aging and neurodegenerative disease, the sample includes normal control subjects and patients with cognitive impairment and/or parkinsonism who are participants in the Mayo Alzheimer’s Disease Research Center at Mayo Clinic Rochester or Mayo Clinic Jacksonville.