Reserve-building activities in multiple sclerosis patients and healthy controls: a descriptive study

Schwartz et al. BMC Neurology (2015) 15:135 DOI 10.1186/s12883-015-0395-0 RESEARCH ARTICLE Open Access Reserve-building activities in multiple sclerosis patients and healthy controls: a descriptive study Carolyn E. Schwartz1,2*, Armon Ayandeh1, Murali Ramanathan3,4, Ralph Benedict4, Michael G. Dwyer5,6, Bianca Weinstock-Guttman4 and Robert Zivadinov5,7 Abstract Background: Cognitive reserve has been implicated as a possible protective factor in multiple sclerosis (MS) but to date no study has compared reserve-building activities across disease course or to healthy controls. This study aims to describe differences in reserve-building activities across the MS disease course and healthy controls. Methods: Secondary analysis of a cross-sectional cohort study that included 276 healthy controls, and subjects with clinically isolated syndrome (CIS; n = 67), relapsing-remitting MS (RRMS; n = 358) and secondary progressive MS (PMS; n = 109). Past reserve-building activities were operationalized as occupational attainment and education. Current activities comprised 6 strenuous and 6 non-strenuous activities, including 5 reserve-building activities and television-watching. Multivariate Analysis of Variance models examined group differences in past and current activities, after adjusting for covariates. Results: There were group differences in past and current reserve-building activities. SPMS patients had lower past reserve-building activities than healthy controls. All forms of MS engaged in fewer strenuous current reserve-building pursuits than healthy controls. RRMS read less than healthy controls. SPMS engaged in fewer job-related non-strenuous activities. All MS groups watched more television than healthy controls. Conclusions: MS patients show significantly fewer past and present reserve-building activities. Although it is difficult to establish causality without future prospective studies, lifestyle-modifying interventions should prioritize expanding MS patients’ repertoire of strenuous and non-strenuous activities. Background The concept of resilience has been the focus of study via diverse social scientific disciplines, including behavioral medicine [1], health psychology [2], epidemiology [3], and education research [2]. Recent clinical research in neurology has revealed that cognitive reserve – a property of the nervous system enhanced by past and current salutogenic stimulating activities – is associated with better cognitive functioning in the face of neurologic illness or injury [4]. Recent work has documented that past and current stimulating activities may be protective against progression in a broad range of disability domains in multiple sclerosis (MS) [5]. The multidimensionality of the factors documented to contribute to * Correspondence: 1 DeltaQuest Foundation, Inc., 31 Mitchell Road, Concord, MA 01742, USA 2 Departments of Medicine and Orthopaedic Surgery, Tufts University Medical School, Boston, MA, USA Full list of author information is available at the end of the article resilience is notable, going beyond cognitive activities or outcomes and extending into physical, creative, intellectual, spiritual, and cultural enrichment. Consequently, we believe the nomenclature should be changed to broaden the implied dimensionality of reserve by referring to the concept of reserve rather than “cognitive reserve”. Reserve is conceptualized as arising from inborn, past, and current resources, and has been operationalized by measurable indicators. Inborn reserve or “brain reserve” has been operationalized as intracranial volume [6], head circumference [6], measured intelligence quotient in early life, and genetic/environmental modifiers [7]. Past reserve-building activities derive from past enrichment and achievement, and have been measured as educational and occupational attainment as well as childhood exposure to stimulating cultural and educational pursuits [8, 9]. Current reserve-building activities refer to current enrichment pursuits, and have been measured as current cultural, intellectual, physical, and spiritual © 2015 Schwartz et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Schwartz et al. BMC Neurology (2015) 15:135 leisure activities [4, 9]. These reserve-building pursuits may require new learning, leading to the development of more dendrites, dendritic spines, synapses, and perhaps even cells, all of which contribute to reserve. In particular, diverse current reserve-building pursuits may be important to maintain reserve by ensuring that more areas of the brain and interconnections remain active and fit. The concept of reserve provides a parsimonious and inclusive framework for examining how an individual can enhance health and well-being by current pursuits that build on childhood experiences and innate capacity [10]. The growing evidence base supporting the relevance and importance of reserve has generally focused on its impact in people dealing with neurological illness or injury, including MS [11], brain injury [12], Parkinson’s disease [13], Alzheimer’s disease [14], cancer chemotherapy [15], and lead exposure [16]. To our knowledge, no work has been done examining multidimensional indicators of reserve in healthy individuals and comparing them to people with an illness. Although it is common practice to compare patients to healthy controls on the basis of cognitive or neuropsychiatric symptoms in studies of MS patients, it is not known how leisure pursuits that would relate to reserve differ between patients and healthy controls. Such a comparison would be useful not only for understanding normative levels of reserve; they would also be helpful for elucidating how levels differ before and after illness. We thus sought to describe indicators of past and current reserve-building activities in a secondary analysis of a relatively large cohort of people with MS and healthy controls. Page 2 of 8 alcohol abuse) and pregnancy. Healthy controls needed to meet the health-screen requirements, and had to have a normal physical and neurological examination. They were recruited from hospital personnel, or were respondents to a local advertisement. Table 1 provides demographic and clinical characteristics of the MS patient groupings and age-, sex- and race-matched healthy controls. Procedure All subjects were assessed with a structured questionnaire administered in-person by a trained interviewer unaware of the (...truncated)