Transcranial doppler to measure cerebral blood flow in delirium superimposed on Dementia. A cohort study

Gideon A. Caplan*, ZhongZheng Lan, Lyndal Newton, Tasha Kvelde, Catherine McVeigh, Mark A. Hill

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Objective: Delirium superimposed on dementia (DSD) is frequently not diagnosed, at great cost. Both delirium and dementia are associated with cerebral hypoperfusion. A switch to anaerobic glycolysis in the central nervous system during delirium compared to Alzheimer's dementia (AD) suggests greater hypoperfusion in DSD. The main aims of this study were to investigate whether cerebral hypoperfusion could differentiate DSD from related entities, and the characteristics of that hypoperfusion. Methods: Prospective cohort study of 44 Geriatric Medicine patients in 4 groups: (1) delirium, no history of dementia; (2) DSD; (3) acute illness without delirium or dementia; and (4) AD, no delirium. We measured CBF using transcranial Doppler to assess flow velocity (FV) and pulsatility index in the middle cerebral artery (MCA). Results: DSD has lower FV than either AD or delirium alone, or acute illness (28.2 ± 4.7 vs AD: 41.3 ±15.7; P = .040; vs delirium 37.7 ± 8.2; P =.009; vs acute illness 43.0 ± 8.3; P <.001). A mean MCA FV cut-off of 32.25 cm/s diagnoses DSD with a sensitivity of 0.875 and specificity of 0.788, area under the curve 0.884; P = .001. Resolution of delirium improves FV (. P = .005). FV correlates with delirium severity (delirium index R = -0.39; P = .009) and dementia (Mini-Mental State Examination, R = 0.33; P = .029, and Informant Questionnaire on Cognitive Decline in the Elderly, R = -0.41; P = .005). Conclusions: Transcranial Doppler is a potential diagnostic and monitoring test for DSD. Correlation with clinical indicators of delirium suggests pathophysiological significance.

Original languageEnglish
Pages (from-to)355–360
Number of pages6
JournalJournal of the American Medical Directors Association
Issue number5
Publication statusPublished - May 2014
Externally publishedYes


  • Alzheimer's disease
  • Assessment of cognitive disorders/dementia
  • Delirium
  • Geriatric assessment
  • Ultrasound


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