Multiple Sclerosis: A Better Tool for Measuring Sleep Quality

Multiple sclerosis (MS) patients have new ways to self-report outcome measures for sleep and sleepiness. The new scales were developed by Roger Mills, PhD, of the Lancashire Teaching Hospitals NHS Foundations Trust, Department of Neurology in Lancashire, UK, and colleagues. A paper describing their work was published in the Multiple Sclerosis Journal -- Experimental, Translational and Clinical recently.

The researchers say, “Despite the importance of sleep disturbance in MS, there is currently no MS-specific scale for measuring sleepiness or quality of nocturnal sleep.” They go on to say that when instruments not specifically designed for people with neurological problems are used, the results must be viewed cautiously. They go on to say, “During the construction of the Neurological Fatigue Index for MS (NFI-MS), two such sleep-related scales were identified -- a relief by diurnal sleep or rest scale and an abnormal nocturnal sleep scale -- but it was concluded that further development of these was required.”

The objective of the current paper was to take those two scales further. They say, “with the objective of achieving high psychometric validity, including fit to the Rasch measurement model.”

The work was done in several stages: the qualitative phase, in which 40 subjects were interviewed; the main data sample, which included data from 722 individuals who had received packs of surveys; the qualitative analysis; and the psychometric analyses.

The authors say, “a suite of short, simple, patient-based, MS-specific self-report scales was developed which measured diurnal sleepiness, non-restorative nocturnal sleep and fragmented nocturnal sleep.” These scales met the Rasch analysis, which is required by the US Food and Drug Administration’s guidelines for patient-reported outcome measures. Furthermore, the researchers say, “The scales provided valid measurement for patients of any age, sex, disease type, and disability level.” They are called, collectively, the Neurological Sleep Index for MS.

“It is intended that the suite of scales will allow sophisticated interrogation of the relationships between sleep dysfunction and other clinical features of MS at both an individual and population-based level,” conclude the researchers.

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