Friday, 2 November 2012

Research: cognitive reserve

Ghaffar et al. Occupational attainment as a marker of cognitive reserve in multiple sclerosis. PLoS One. 2012;7(10):e47206. doi: 10.1371/journal.pone.0047206.

Background: Cognitive dysfunction affects half of MSers. Although brain atrophy generally yields the most robust MRI correlations with cognition, significant variance in cognition between individual MSers remains unexplained. Recently, markers of cognitive reserve such as premorbid intelligence have emerged as important predictors of neuropsychological performance in MS. 

Aims: In the present study, the investigators' aimed to extend the cognitive reserve construct by examining the potential contribution of occupational attainment to cognitive decline in MSers. 

Methods: Brain atrophy, estimated premorbid IQ, and occupational attainment were assessed in 72 MSers. The Minimal Assessment of Cognitive Functioning in MS was used to evaluate indices of information processing speed, memory, and executive function. 

Results: Results showed that occupational attainment was a significant predictor of information processing speed, memory, and executive function in hierarchical linear regressions after accounting for brain atrophy and premorbid IQ. These data suggest that MSers with low occupational attainment fare worse cognitively than those with high occupational attainment after controlling for brain atrophy and premorbid IQ. 

Conclusions: Occupation, like premorbid IQ, therefore may make an independent contribution to cognitive outcome in MS. Information regarding an individual's occupation is easily acquired and may serve as a useful proxy for cognitive reserve in clinical settings.



Schwartz CE et al. Cognitive reserve and appraisal in multiple sclerosis Multiple Sclerosis and Related Disorders, 2013; 2:36-44 

Background: Cognitive appraisal processes underlying self-report affect the interpretation of MSer-reported outcomes. These processes are relevant to resilience and adaptability, and may relate to how cognitive reserve protects against disability in MS.

Objectives: To describe how passive and active indicators of cognitive reserve relate to QOL appraisal processes in MS.

Methods: Cross-sectional data (n=860) were drawn from the North American Research Committee on MS (NARCOMS) Registry, from whom additional survey data were collected. Cognitive reserve was measured using the Stern and Sole-Padulles measures. Using the quality of life appraisal profile (QOLAP), they assessed how MSers conceptualize their experiences and how that impacts how they report their quality of life. Multivariate analysis of variance was used to compare groups within sets of appraisal parameters, and t-tests or chi-square tests were used to compare mean item responses within appraisal parameters for continuous or dichotomous variables, respectively.

Results: People high in passive or active reserve report different conceptualizations of QOL, different types of goals, and considering different types of experiences and standards of comparison in responding to QOL questionnaires, as compared to low-reserve individuals. Although item response patterns were slightly different between passive and active indicators, they generally reflect a tendency in high-reserve individuals to emphasize the positive, focus on aspects of their life that are more controllable, and less based in fantasy.

Conclusions: MSers high in cognitive reserve differ in their cognitive appraisals from their low reserve counterparts. These appraisal metrics may predict disease course and other important clinical outcomes in MSers.

"These report mirror what happens in other dementing illnesses such as Alzhiemer's disease; if you have reserve cognitive capacity, as measured by education, occupation, etc., you do better."

"We need to address the problem of why MSers develop cognitive impairment in the first place; the pathological and MRI data suggest focal gray matter pathology and lesions in the pathways that connect cognitive areas is the cause. The bottom line is that we need to prevent cognitive impairment from happening in the first place. Could early aggressive treatment be preventative? Deja vu?"

2 comments:

  1. This is really interesting. My understanding is that this is real protection i.e. not just a relative thing. i.e. it is not just that a person of higher intelligence with cognitive impairment is able to function better than a person of lower intelligence with cognitive impairment because, relatively, they are still functioning at a higher level - but that the person with higher intelligence is protected from suffering cognitive impairment at all (or to a significantly lesser degree). i.e. it is not a person with a 160 IQ falling to 130 versus a person with a 100 IQ falling to 70 - the person with the 160 IQ doesn't fall at all (I know MS impairment is not about IQ as such but hopefully that explains the point/question). Is that a correct interpretation of these and other cognitive reserve studies?

    If so, what does that tell about the mechanism of cognitive impairment? It the protection due to greater neuroplasicity - sometimes said to be the key element of intelligence? If so, could premorbid intelligence actually also mitigate physical disabiliy due to the brain's general greater ability to 're-wire'/better neural connectivity?

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    Replies
    1. I think both are. IQ/general intelligence gives you increased reserves and it may be marker of some intrinsic biology that protects you against the ravages of neurodegeneration.

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