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. Author manuscript; available in PMC: 2013 Jul 1.
Published in final edited form as: Crit Care Med. 2012 Jul;40(7):2022–2032. doi: 10.1097/CCM.0b013e318250acc0

Table 3.

Relationship between Brain Volumes at Three months versus Long-term cognitive impairments at Twelve-month follow-up

Neurocognitive domains and brain
anatomical regions 		Neurocognitive scores differences (95% CI)
associated with brain volumes		 P-value
Global cognitive performance (RBANS)
   -   VBR −11.17 (−21.12, −1.22) 0.04
   -   Gray Matter, cm3 6.68 (0.27, 13.09) 0.05
   -  White Matter, cm3 3.71 (−2.84, 10.25) 0.28
Executive functioning
   -  Superior frontal lobe, cm3 4.78 (−0.32, 9.89) 0.08
   -  Thalamus, cm3 8.28 (1.59, 14.97) 0.02
   -  rACC, cm3 3.77 (−1.1, 8.63) 0.14
   -  Cerebellum, cm3 6.48 (0.63, 12.33) 0.04
Immediate Memory
   -   Hippocampus, cm3 3.35 (−1.56, 8.26) 0.19
Visual attention
   -  Superior frontal lobe, cm3 6.67 (2.78, 10.56) 0.003
   -  Thalamus, cm3 8.3 (2.74, 13.86) 0.008
   -  rACC, cm3 4.60 (0.58, 8.62) 0.03
   -   Cerebellum, cm3 7.96 (3.42, 12.49) 0.002
a

The point estimate (95% confidence interval) represents differences in neurocognitive scores at twelve-month follow-up for patients with brain volumes at the 75th vs. the 25th percentile of our population. Tests reflect several different domains of cognitive function, as described in the Appendix 1

EXAMPLE: When considering the relationship of VBR at 3 months versus cognitive impairment at 12 months, a patient with a VBR of 5 (75th percentile of VBR of our population) had an RBANS global score which was, on average, 11 points lower than a patient with a VBR of 2.18 (25th percentile), indicating that more atrophy (i.e., greater ventricle-to-brain ratio) at three months was associated with worse global cognitive performance at 12 months. This neuropsychological test battery index score drop of 11 points could potentially represent a change in category (e.g., low average to borderline) according to the classification scheme shown for the RBANS in.Appendix 1

b
As described in the Appendix 1 the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) score are age and education adjusted index scores (all with a mean of 100 and a standard deviation of 15), which rely on the following classification scheme:
Index Score Classification
130 and above Very superior
120–129 Superior
110–119 High average
90–109 Average
80–89 Low average
70–79 Borderline
69 and below Extremely low

All results adjusted for age and presence of sepsis in the ICU.

Abbreviations: CI, confidence interval; RBANS, Repeatable Battery for the Assessment of Neuropsychological Status; VBR, ventricle-to-brain ratio; rACC, rostral anterior cingulate cortex