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Author Notes:

Correspondence: Donald L. Bliwise, Ph.D. Department of Neurology, Emory University School of Medicine, 1841 Clifton Road, Room 509, Atlanta, Georgia 30329, USA, 404-728-4751 (phone), 404-712-8145 (fax).

Please see publication for full list of author contributions.

Drs. Bliwise, Scullin, and Trotti had full access to all the data and they take responsibility for the integrity of the data.

We are appreciative of Anthony Wilson and Sophia Greer at Emory University who provided assistance in the collection and management of the data.

Dr. Bliwise is a consultant for Ferring Pharmaceuticals, Morehouse School of Medicine and the New England Research Institute; Dr. Scullin has no disclosures; and Dr. Trotti was previously a consultant for UCB Pharma.


Research Funding:

This work was supported by the United States National Institutes of Health (grant number R01 NS-050595 to D.L.B., F32 AG-041543 to M.K.S., KL2 RR-025009 to L.M.T., UL1 RR-025008 for the Atlanta Clinical and Translational Science Institute).

M.K.S. was partially supported by an Emory University Cottrell Fellowship.


  • Science & Technology
  • Life Sciences & Biomedicine
  • Clinical Neurology
  • Neurosciences & Neurology
  • dementia with Lewy bodies
  • fluctuations
  • cognition
  • alertness
  • digit span
  • DLB

Fluctuations in Cognition and Alertness Vary Independently in Dementia With Lewy Bodies


Journal Title:

Movement Disorders


Volume 29, Number 1


, Pages 83-89

Type of Work:

Article | Post-print: After Peer Review


Fluctuations in mental status are 1 of the core diagnostic criteria for dementia with Lewy bodies (DLB) and are thought to reflect variability in daytime alertness. Previous attempts to study fluctuations have been limited to caregiver reports, observer rating scales, short segments of electroencephalography, or motor-dependent, reaction time tests. Concordance among such measures is often poor, and fluctuations remain difficult to quantify. We compared fluctuations in cognition and alertness in patients with DLB (n=13) and idiopathic Parkinson's disease (PD) (n=64), a condition associated with deficits in daytime alertness. We systematically and repeatedly collected cognitive and physiologic measures during a 48-hour inpatient protocol in a sound-attenuated sleep laboratory in a geriatric hospital. Cognitive fluctuations were analyzed using coefficients of variation (COVs) derived from performance on a bedside examination familiar to clinicians (digit span). Alertness fluctuations were assessed objectively using COVs from the polysomnographically-based Maintenance of Wakefulness Test. Despite predictably lower mean digit span performances, DLB patients demonstrated significantly greater cognitive fluctuations than PD patients (P<0.001), even when groups were matched on general cognitive impairment. There were no group differences in alertness fluctuations, although DLB patients were less alert than PD patients not receiving dopaminergics. The prevailing assumption that fluctuations in cognition in DLB are reflected in fluctuations in daytime alertness was not supported by objective, physiological measurements. Fluctuating mental status in DLB patients can be detected with repeated administration of a simple bedside exam that can be adapted to a clinic setting.

Copyright information:

© 2013 Movement Disorder Society.

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