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Working memory capacity links cognitive reserve with long-term memory in moderate to severe TBI: a translational approach

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Abstract

Traumatic brain injury (TBI) can have devastating negative consequences on an individuals’ ability to remember information; however, there is variability among memory impairment resulting from TBI. Some individuals exhibit long-term memory (LTM) impairment while others do not. This variability has been explained, at least in part, by the theory of cognitive reserve (CR). The theory suggests that individuals who have spent significant time engaged in intellectually enriching activities (higher CR) are better able to withstand LTM impairment despite neurological injury. The cognitive mechanisms that underlie this relationship are not well-specified. Recent evidence suggests that working memory (WM) capacity may be one mediating variable that can help explain how/why cognitive reserve (CR) protects against LTM impairment. The present research tested this hypothesis in a sample of fifty moderate to severe TBI patients. Specific neuropsychological tests were administered to estimate CR, LTM and WM. The results were congruent with a recent theoretical model that implicates WM capacity as a mediating variable in the relationship between CR and LTM (Sobel’s Z = 2.62, p = 0.009). These data corroborate recent findings in an alternate neurological population and suggest that WM is an underlying mechanism of CR. Additional research is necessary to establish whether (1) WM is an important individual difference variable to include in memory rehabilitation trials and (2) to determine whether rehabilitation and treatment strategies that specifically target WM may also lead to complimentary improvements on diagnostic tests of delayed LTM in TBI and other memory impaired populations.

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Acknowledgments

The authors wish to thank Dr. James F. Sumowski for helpful comments on an early draft of this manuscript. Study supported Northern NJ TBI Model Systems grant H133A070037 to NC. The contents of this article were also developed under the US Department of Education—National Institute on Disability and Rehabilitation Research grant H133P090009. However, the contents do not necessarily represent the policy of the Department of Education, and you should not assume endorsement by the Federal Government.

Conflicts of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest with respect to the present work.

Ethical standard

This study has been approved by the appropriate committee and has therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki.

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Authors and Affiliations

  1. Neuropsychology and Neuroscience Research, Kessler Foundation, 300, Executive Dr., Suite 70, West Orange, NJ, 07052, USA

    Joshua Sandry, John DeLuca & Nancy Chiaravalloti

  2. Department of Physical Medicine and Rehabilitation, Rutgers-New Jersey Medical School, Newark, NJ, USA

    Joshua Sandry, John DeLuca & Nancy Chiaravalloti

  3. Department of Neurology and Neurosciences, Rutgers-New Jersey Medical School, Newark, NJ, USA

    John DeLuca

  4. Traumatic Brain Injury Research, Kessler Foundation, West Orange, NJ, USA

    Nancy Chiaravalloti

Authors
  1. Joshua Sandry
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  2. John DeLuca
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  3. Nancy Chiaravalloti
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Correspondence to Joshua Sandry.

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Sandry, J., DeLuca, J. & Chiaravalloti, N. Working memory capacity links cognitive reserve with long-term memory in moderate to severe TBI: a translational approach. J Neurol 262, 59–64 (2015). https://doi.org/10.1007/s00415-014-7523-4

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  • DOI: https://doi.org/10.1007/s00415-014-7523-4

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