title: A longitudinal study of delirium phenomenology indicates widespread neural dysfunction.
abstract: OBJECTIVE
  Delirium affects all higher cortical functions supporting complex information processing consistent with widespread neural network impairment. We evaluated the relative prominence of delirium symptoms throughout episodes to assess whether impaired consciousness is selectively affecting certain brain functions at different timepoints.
  
  
  METHODS
  Twice-weekly assessments of 100 consecutive patients with DSM-IV delirium in a palliative care unit used the Delirium Rating Scale Revised-98 (DRS-R98) and Cognitive Test for Delirium (CTD). A mixed-effects model was employed to estimate changes in severity of individual symptoms over time.
  
  
  RESULTS
  Mean age = 7 0.2 ± 10.5 years, 51% were male, and 27 had a comorbid dementia. A total of 323 assessments (range 2-9 per case) were conducted, but up to 6 are reported herein. Frequency and severity of individual DRS-R98 symptoms was very consistent over time even though the majority of patients (80%) experienced fluctuation in symptom severity over the course of hours or minutes. Over time, DRS-R98 items for attention (88-100%), sleep-wake cycle disturbance (90-100%), and any motor disturbance (87-100%), and CTD attention and vigilance were most frequently and consistently impaired. Mixed-effects regression modeling identified only very small magnitudes of change in individual symptoms over time, including the three core domains.
  
  
  CONCLUSIONS
  Attention is disproportionately impaired during the entire episode of delirium, consistent with thalamic dysfunction underlying both an impaired state of consciousness and well-known EEG slowing. All individual symptoms and three core domains remain relatively stable despite small fluctuations in symptom severity for a given day, which supports a consistent state of impaired higher cortical functions throughout an episode of delirium.
authors.affiliation: Department of Adult Psychiatry,University Hospital Limerick,Limerick,Ireland.
authors.forename: Maeve
authors.initials: M
authors.lastname: Leonard
authors.affiliation: University of Limerick Medical School,Limerick,Ireland.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Adamis
authors.affiliation: Statistical Consulting Unit,University of Limerick,Limerick,Ireland.
authors.forename: Jean
authors.initials: J
authors.lastname: Saunders
authors.affiliation: Tufts University School of Medicine,Medford, Massachusetts.
authors.forename: Paula
authors.initials: P
authors.lastname: Trzepacz
authors.affiliation: Department of Adult Psychiatry,University Hospital Limerick,Limerick,Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Meagher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003693:Delirium / Q000503:physiopathology* / Q000523:psychology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010166:Palliative Care; D012720:Severity of Illness Index
keywords: Core domains