Screening tool shows promise for Parkinson’s sleep disturbance

By Lucy Piper, Senior medwireNews Reporter

Researchers have developed a sleep questionnaire for screening the range of sleep disturbances experienced by patients with Parkinson’s disease (PD).

They say that the Neurodegenerative Disease Sleep Questionnaire (NDSQ) could have advantages over existing questionnaires, as it focuses on five components of sleep disturbance instead of just one, and that its use could avoid the costs associated with polysomnography.

Donald Bliwise (Emory University School of Medicine, Atlanta, Georgia, USA) and fellow researchers administered the 12-item NDSQ, along with the Epworth Sleepiness Scale (ESS), to 145 patients with idiopathic PD.

Principal component analysis identified five separate components – sleep quality, nocturia, dreams/nightmares, restless legs symptoms, and sleep-disordered breathing – that together explained 70.2% of the total variance.

The researchers note in the Journal of the Neurological Sciences that the sleep quality component comprised primarily sleep maintenance difficulties, and to a lesser extent sleep initiation difficulties.

Sleep initiation loaded most strongly onto the sleep quality component but there was some overlap with the restless legs symptoms factor, which the researchers say is likely to be due to restless leg syndrome stopping people from being able to get to sleep.

Vivid dreams/nightmares were a distinct component and their clinical relevance may be related to the presence of rapid eye movement sleep behavior disorder, pharmacologic treatment, psychiatric comorbidity, or even narcolepsy, says the team.

Nocturia, which is often not incorporated into sleep questionnaires, despite being a major issue for patients with neurodegenerative conditions, including PD, was also a valid component.

“The omission of a nocturia assessment from typical sleep questionnaires may be important not only because it assesses a different component than other sleep questions… but also because nocturia is associated with increased risk for falls and worsened health-related quality of life,” comment Bliwise and colleagues.

They believe that “when combined with the ESS, the 12 items inquired about here provide a very quick overview of what issues may be problematic for PD patients and their caregivers.”

The researchers point out that the scale needs to undergo test-retest reliability evaluations and be trialed in patients with other neurologic conditions.

“However, based on the component structure that was revealed by principal component analysis, the NDSQ appears to be a valid and efficient metric for assessing sleep disturbances in patients with neurodegenerative disease, in this case those with PD,” they conclude.

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