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Review
. 2023 Jan 4;13(1):96.
doi: 10.3390/brainsci13010096.

Assessing Cognitive Outcomes in Coma Survivors: A Literature Review

Allison Frantz  1   2 , Natalia Incio Serra  1 , Aracely Lopez Almendariz  3 , Catherine Duclos  4   5 , Adrian M Owen  6 , Stefanie Blain-Moraes  2
Affiliations
Review

Assessing Cognitive Outcomes in Coma Survivors: A Literature Review

Allison Frantz et al. Brain Sci. .

Abstract

(1) Background: Although cognitive impairments in coma survivors are common, methods of measuring long-term cognitive outcomes in this population are inconsistent, precluding the development of a strong evidence-base to support clinical decision making. In this literature review, we identify and characterize the measures used to track cognitive recovery in coma survivors to data. (2) Methods: We extracted the instrument used for cognitive assessment, the cognitive domains assessed, methods administration and scoring, and timing of assessment from 134 of 996 screened records. (3) Results: A total of 133 unique cognitive tests and cognitive testing batteries were identified, with 97 cognitive instruments used in less than three articles. The instruments assessed 20 different cognitive domains, with 73 articles also using tests that assess general "cognitive ability". Cognitive instruments ranged from subjective assessments to comprehensive cognitive batteries. There were inconsistent points of reference for the timing of assessment across studies, with few studies repeating assessments at more than one time point, and arbitrary time intervals between tests. (4) Conclusions: Overall, this review illustrates the enormous disparity between studies that track cognitive outcome in coma survivors, and the need for a systematic, patient-accessible method of assessing cognitive functioning in future studies with this population.

Keywords: brain injury; cognitive assessment; cognitive instrument; cognitive outcome; coma; critical care; intensive care; unconsciousness.

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Conflict of interest statement

The authors declare no conflict of interest for this study. The manuscript references cognitive tests from Cambridge Brain Sciences Inc., of which Owen is the Chief Scientific Officer. Under the terms of the existing licensing agreement, Owen and his collaborators are free to use the platform at no cost for their scientific studies and such research projects neither contribute to, nor are influenced by, the activities of the company. As such, there is no overlap between the current study and the activities of Cambridge Brain Sciences Inc., nor was there any cost to the authors, funding bodies or participants who were involved in the study.

Figures

Figure 1
Figure 1
Flowchart outlining the protocol adopted in this narrative review.
Figure 2
Figure 2
Cognitive instruments using single tests appearing in three or more articles included in this review. Articles are arranged by frequency of appearance.
Figure 3
Figure 3
Cognitive instruments using test batteries or battery subsets appearing in three or more articles included in this review. Articles are arranged by frequency of appearance.
Figure 4
Figure 4
Number of articles that assess each cognitive domain. Only cognitive instruments that were listed in three or more articles are included in this analysis.
Figure 5
Figure 5
Number and interval of assessments relative to time since injury. (A). First cognitive assessment timepoint. (B). Timing of second, third and fourth cognitive assessment within a single study.
Figure 6
Figure 6
Total number of articles assessing cognitive outcomes in coma survivors relative to reference points other than “time since injury”. Red bars indicate a first assessment timepoint, orange bars indicate a second assessment, yellow bars indicate a third assessment, and green bars indicate a fourth assessment within the same study.
See this image and copyright information in PMC

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