Patient-reported outcome measures (PROMs) are influenced by psychosocial factors. One study assessed whether priming affects scores on PROMs. Priming is the influence of a response to one stimulus by exposure to another stimulus. Patients with musculoskeletal illness that were primed with a positively phrased version of the Pain Catastrophizing Scale (PCS) reported fewer limitations compared with patients who were either negatively primed or not primed at all (1). 

Grip strength is a performance-based measure of upper extremity function that might be influenced by priming. Another study addressed the influence of questionnaire content on performance measurement, such as grip strength, between patients who complete the standard PCS compared with patients who complete a positively adjusted PCS. It was found that positive priming leads to an increase in mean and maximum grip strength when compared with the standard questionnaire that uses negative terms rather than positive (2). Both of these studies suggest that influences on mindset can influence PROM scores.  

References

1. Claessen FM, Mellema JJ, Stoop N, Lubberts B, Ring D, Poolman RW. Influence of Priming on Patient-Reported Outcome Measures: A Randomized Controlled Trial. Psychosomatics. 2015 Oct 1. pii: S0033-3182(15)00154-1. doi: 10.1016/j.psym.2015.09.005. [Epub ahead of print] PubMed PMID: 26683347.
2. Özkan S, Claessen FMAP, Eberlin KR, Lee SP, Ring DC, Vranceanu AM. The Effect of Priming With Questionnaire Content on Grip Strength in Patients With Hand and Upper Extremity Illness. Hand (N Y). 2017 Sep;12(5):484-489. doi: 10.1177/1558944716681975. Epub 2016 Dec 20. PubMed PMID: 28832217.