, Volume 32, Issue 6, pp 923-926
Date: 08 Mar 2006

Significant cognitive dysfunction in non-delirious patients identified during and persisting following critical illness

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Recent studies have shown significant cognitive problems some months after critical illness. However there has been no research examining cognitive function within the intensive care unit (ICU) in non-delirious patients.

Design and setting

A prospective study in an ICU.

Patients and participants

Using the Cambridge Neuropsychological Test Automated Battery (CANTAB), 30 long-stay, tracheal-intubated ICU patients were tested. Prior to testing on ICU the Confusion Assessment Measure (CAM-ICU) was administered and only those patients clearly not delirious and off sedation for several days were tested. The CANTAB tests were repeated a week after ICU discharge on the general ward and then again at 2 months. Sixteen patients completed the follow-up.


While on ICU all 30 patients showed significant problems with strategic thinking and problem solving; 20 patients had some problems with memory. The degree of difficulty with problem solving on ICU was correlated with length of ICU stay (p = 0.011), age (p = 0.036) and length of hospital stay post ICU (p = 0.044). Problems with memory in ICU and on the general ward were correlated with admission APACHE II score (p = 0.004 and p = 0.005 respectively). At the 2-month follow-up 5 of 16 patients (31%) scored below the 25 percentile for memory and 8 of 16 (50%) below the 25 percentile for problem solving (Slater TA, Jones C, Griffiths RD, Wilson S, Benjamin K (2004) Cognitive impairment during and after intensive care: a pilot study. Intensive Care Med 30 [Suppl 1]:S199).


Difficulties with problem solving and poor memory remained a significant issue for 2 months after ICU discharge.