Parkinson patients with REM disorder show worse cognitive function

By Reuters Staff

NEW YORK (Reuters Health) - Parkinson’s disease (PD) patients with REM sleep behavior disorder (RBD) have worse cognitive function than those without RBD, a new study shows.

“This patient subgroup and their caregivers should receive targeted medical attention to better detect and monitor impairment and to enable the development of management interventions for cognitive decline and its consequences,” Dr. Jean-Francois Gagnon of the University of Quebec at Montreal and colleagues conclude in their report, published online June 22 in Sleep.

In RBD, patients lose muscle atonia during REM, “resulting in undesirable motor activity during REM sleep as people ‘act out their dreams,’” the researchers explain. Up to 46% of PD patients have RBD. While RBD is known to be associated with dementia, they add, it is unclear whether patients with RBD have a unique cognitive profile.

To investigate, the researchers compared 53 PD patients with RBD, 40 PD patients without RBD, and 69 healthy subjects.

Patients with RBD were more likely to be men, were older, and had worse Mini Mental State Examination scores than patients without RBD. They also scored worse on several tests measuring attention, executive functions, episodic verbal learning and memory, and visuospatial ability, as well as tests of delayed recall and recognition of verbal information and language. However, cognitive function was similar for the PD patients without RBD and the healthy controls.

Sixty-six percent of the patients with RBD had mild cognitive impairment, versus 23% of the patients without RBD, while subjective cognitive decline was reported in 89% and 58%, respectively.

Among PD patients with RBD, men and those with onset of the sleep disorder before PD diagnosis had worse cognitive function.

“Future studies attempting to identify a distinct cognitive profile in PD with RBD should use a greater variety of tests to more deeply assess all the language components (i.e., naming, reading, writing, understanding, and pragmatism) and higher executive functions (i.e., planning, problem-solving) as well as procedural learning,” Dr. Gagnon and his team conclude.

SOURCE: http://bit.ly/2sqOAs3

Sleep 2017.

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