The Digit Symbol Substitution Test can be used for the assessment of cognitive dysfunction [brain fog] in Long COVID.
For information on the use of the The Digit Symbol Substitution Test, please see Measuring Cognitive Dysfunction-“Digit Symbol Substitution Test: The Case for Sensitivity Over Specificity in Neuropsychological Testing”
Posted on December 27, 2022 by Tom Wade MD
Here is the link to the 9 page PDF of Operations Manual of DIGIT SYMBOL SUBSTITUTION TEST
And here is a link to the shorter three page PDF of the the Digit Symbol SubstitutionTest