Thursday, February 6, 2014

Reasonably Well: Sjögren's and Cognitive Function

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Everyone should read Julia from Reasonably Well’s excellent post entitled Tufts Study: Despite Burden Sjögren’s Syndrome May Not Impede Function that discussed new research on Sjögren’s Syndrome and cognitive difficulties.   You can read the whole extremely informative post here.  I’m going to comment on some of my favorite parts below and add some of my own reactions.

The Tufts Study concludes that Sjogren’s patients despite their perception “appear to function at a level comparable to their healthier peers.”  This is obviously good news, but Julia addressed some of the potential flaws with the study and raises research questions for the future.

Starting with the issue of fatigue, Julia writes:

I noticed that the assessment of fatigue…was not located in the physical section but rather in the Mental/Emotional locale.  There were no physician evaluations of joint pain, pure neurological problems (as opposed to neuropsychiatric), pulmonary issues, renal problems….to name just a few well-documented extra glandular manifestations of Sjögren’s.

She goes on to say (I love this part).

Since fatigue is one of my most disabling symptoms of Sjs and I'm a bit touchy about labeling fatigue as an all in your head symptom, I found it interesting that elsewhere in the discussion section of this study, fatigue is included under the description of "neuropsychiatric problems".

Well, I must say I’m touchy about this too.  And isn’t their bias in the research if fatigue is classified as neuropsychiatric from the beginning?

And I have had a similar experience to Julia where as she writes that for her tired=stupid.  What a perfect equation. I completely relate.  When I’m having complete autoimmune exhaustion, I also have what I would call brain-fog. 

This idea also got me thinking.  Do studies need to include both disease activity and cognitive function? Would it be worth exploring whether “flares” have both cognitive and physical impacts?  And Julia also brings up another super super important point about study design:

This was not a longitudinal study. Study authors would have no data to support their discussion of length of disease related issues.

In another small controlled study on the subject conducted by doctors and psychologists, including the Director of the Penn Sjögren’s Center, Dr. Frederick Vivino, found significantly lower IQ scores and lower verbal memory scores for the Sjögren’s group (click here for the study). No statistically significant differences were found on concentration and processing speed, visual memory, or executive function.  Interestingly Tufts and the Penn Studies used different measures of cognitive function.  While the Penn study also clearly had its limitations with only 17 participants and it did not occur over a period of time, the authors tend to stay away from broad generalizations, and suggest more research including “correlating neuropsychological findings with neuroimaging.”

On the other hand, the abstract of the Study out of Tufts University concludes that "Sjögren's patients perceive deteriorated physical function over time, but they achieve a level of functioning comparable to controls despite the burden of their illness" (click here for the abstract). In my opinion, that language is a bit misleading. Making physical conclusions about a cognitive study makes little sense. 

Perhaps, if a rheumatologist who regularly evaluates patients and the glandular and extraglandular manifestations Sjögren's had been involved in the study, he/she would have taken other issues into account.

While it is always good to see new research on Sjögren’s, it’s also important that the authors identify the scope and limits of their research. 

Thanks Julia for your excellent post and bringing it to the attention of all us Sjöggies.

What did you think of the Tufts Study?  If you could suggest new research on Sjögren's, what would you focus on?

1 comment:

  1. Thanks for this post! You make some excellent points as well.