An Integrative Review of Causes, Manifestations and Evaluation of Cognitive Fatigue among Persons with Multiple Sclerosis

Abstract

Background: Fatigue is the most distinguishing symptom for patients with Multiple Sclerosis (MS) and for some of these patients it can be quite disabling. Studies exploring MS-related fatigue have differentiated this into various dimensions: motor, cognitive, physical, psychosocial, performance, and subjective. It is the cognitive dimension that can have serious consequences such as loss of vocation, independence, and possibly, more relapses or worsening of the disease. Objective: The aims of this integrative review were to explore the advances in understanding cognitive fatigue in MS, as well as its causes and manifestations, and to identify the objective methodologies that best measure cognitive fatigue in MS. Methodology: An integrative review of the scientific literature was performed using methods and criteria following the PRISMA-P2015 guidelines for data extraction. The studies were critically appraised using the Rapid Critical Appraisal and the qualitative study method of Constant Comparison. Results: Twenty-three studies (2010-2019) were identified from the United States and other countries. The majority of articles were published within the last three years. Evaluation of outcomes from these studies was conducted through self-reporting. Cognitive fatigue may result in more relapses among those with relapsing and remitting MS and from those with secondary progressive MS. Cognitive fatigue and physical fatigue should be considered distinct domains. Conclusion and Recommendations: An increasing number of studies focused on cognitive fatigue, however, there is no standard definition or conceptual framework available to understand this phenomenon. Various methodologies were identified to evaluate cognitive fatigue. Additionally, there should be a valid, reliable, and readily available instrument for use in the clinical setting. Keywords: Multiple Sclerosis, Cognitive Fatigue, Fatigue, Integrative Review