Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Caroline L Gaglio; Mohammed F Islam; Joseph Cotler; Leonard A Jason

doi:10.1515/em-2021-0033

Orthostatic intolerance and neurocognitive impairment in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Epidemiol Methods. 2022 Oct 10;11(1):20210033. doi: 10.1515/em-2021-0033. eCollection 2022 Jan.

Authors

Caroline L Gaglio¹, Mohammed F Islam^{2

3}, Joseph Cotler², Leonard A Jason²

Affiliations

¹ Department of Psychology, Adler University, Chicago, IL, USA.
² Center for Community Research, DePaul University, Chicago, USA.
³ Department of Psychology, Chicago State University, Chicago, IL, USA.

Abstract

Objectives: The Institute of Medicine (IOM 2015. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington: The National Academies Press) suggested new criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), which requires an endorsement of either neurocognitive impairment or orthostatic intolerance (OI) in addition to other core symptoms. While some research supports the inclusion of OI as a core symptom, others argue that overlap with neurocognitive impairment does not justify the either/or option. The current study assessed methods of operationalizing OI using items from the DePaul Symptom Questionnaire (DSQ-1 and -2) as a part of the IOM criteria. Evaluating the relationship between OI and neurocognitive symptoms may lead to a better understanding of diagnostic criteria for ME/CFS.

Methods: Two-hundred and forty-two participants completed the DSQ. We examined how many participants met the IOM criteria while endorsing different frequencies and severities of various OI symptoms.

Results: Neurocognitive impairment was reported by 93.4% of respondents. OI without concurrent neurocognitive symptoms only allowed for an additional 1.7-4.5% of participants to meet IOM criteria.

Conclusions: Neurocognitive symptoms and OI overlap in ME/CFS, and our results do not support the IOM's inclusion of neurocognitive impairment and OI as interchangeable symptoms. Furthermore, our findings highlight the need for a uniform method of defining and measuring OI via self-report in order to accurately study OI as a symptom of ME/CFS.

Keywords: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; diagnostic criteria; neurocognitive impairment; orthostatic intolerance.