Bob
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I think this article may help to explain some of Jason's thinking:
To PEM or not to PEM? That is the question for case definition.
By Leonard A. Jason, Ph.D. and Meredyth Evans
DePaul University
27 APR, 2012
http://www.research1st.com/2012/04/27/pem-case-def/
It's a long article, so here are some extracts:
To PEM or not to PEM? That is the question for case definition.
By Leonard A. Jason, Ph.D. and Meredyth Evans
DePaul University
27 APR, 2012
http://www.research1st.com/2012/04/27/pem-case-def/
It's a long article, so here are some extracts:
Jason & Evans said:Jason and colleagues (1999) found that in a group of individuals with ME/CFS, PEM ranged from 40.6-93.8% depending on how the question of this symptom was asked. This lack of uniformity in the way PEM is measured represents a significant problem for the scientific community studying this illness.
Jason & Evans said:Our group developed the ME/CFS Fatigue Types Questionnaire (MFTQ), which has good psychometric properties, and is designed to measure the different types of fatigue experienced by individuals with ME/CFS (Jason et al., 2009). We measured the experience of symptoms in a group of individuals with ME/CFS compared to a healthy group. We found that individuals with ME/CFS experienced several different types of fatigue including postexertional fatigue, wired fatigue, brain fog, energy fatigue and flu-like fatigue compared to the healthy group which only experienced just an overall, general type of fatigue. The MFTQ defined the factor called PEM as abnormal exhaustion following a bout of physical activity. Items from the PEM factor included:
In another study, the above five PEM items from the MFTQ were confirmed as having the best diagnostic sensitivity and specificity (Jason, Evans, Brown, et al. 2011).
- Dead, heavy feeling that occurs quickly after starting to exercise;
- Next day soreness or fatigue after non-strenuous, everyday activities;
- Mentally tired after the slightest effort;
- Physically drained or sick after mild activity; and,
- Minimum exercise makes you physically tired.
...
These five PEM items have been included in a new diagnostic measure: the DePaul Symptom Questionnaire (DSQ), developed by our group at DePaul University to help classify people with all the major case definitions, and we currently are collecting data using this instrument.
Jason & Evans said:Our research group feels that post-exertional malaise is a cardinal feature of ME; the definition recognizes post-exertional malaise as prolonged restoration of muscle power following either mental or physical exertion.