A recommendation of: Hannah D. Loenneker, Inga Liepelt-Scarfone, Klaus Willmes, Hans-Christoph Nuerk, Christina Artemenko Arithmetic deficits in Parkinson’s Disease? – A Registered Report https: //doi. org/10. 31234/osf. io/c9h68ᵥ2
Zoltan Dienes (Mon,) studied this question.