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Predicting impending death: inconsistency in speed is a selective and early marker
Stuart W S Macdonald1, David F Hultsch, Roger A Dixon
1Aging Research Center, Karolinska Institutet, Stockholm, Sweden. smacd@uvic.ca
Psychology and Aging
|September 24, 2008
Summary
Cognitive inconsistency, specifically in speeded performance, signals neurological decline and impending death in older adults. This marker predicts mortality even when other health and cognitive factors are considered.
Area of Science:
- Neuroscience
- Gerontology
- Cognitive Psychology
Background:
- Deficits in cognitive performance speed and variability are associated with neurological impairment in older adults.
- Understanding early markers of cognitive decline and mortality is crucial for geriatric care and research.
Purpose of the Study:
- To investigate if speed (rate), inconsistency of speed, and accuracy predict terminal decline and mortality.
- To determine the timing and significance of these cognitive markers in relation to death.
Main Methods:
- Utilized 12-year Victoria Longitudinal Study data from 707 adults (aged 59-95).
- Employed Cox regressions and random-effects models to analyze cognitive predictors of mortality.
- Compared data from 442 survivors with 265 decedents.
Main Results:
- Cognitive accuracy predicted mortality, consistent with prior research.
- Speed of performance (rate) independently predicted survival.
- Inconsistency in speed emerged as a significant predictor of survival, independent of all other factors.
- Increases in speed inconsistency accelerated closer to death, moderated by age.
Conclusions:
- Inconsistency in speeded performance serves as an early behavioral indicator of neurological dysfunction.
- This cognitive marker is strongly associated with impending death in older adults.
- The findings highlight the importance of assessing cognitive variability for predicting health trajectories.
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