Abstract
Dear Madam,
We would like to thank the author of Letter to the Editor: “Comparison of virtual reality rehabilitation and conventional rehabilitation in Parkinson’s disease: a randomised controlled trial” [1] for raising important issues about our research [2], and we are grateful for the opportunity to provide clarification.
We agree with the author of Letter to the Editor: “Comparison of virtual reality rehabilitation and conventional rehabilitation in Parkinson’s disease: a randomised controlled trial” [1] that the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire is not validated for use in patients with Parkinson’s disease (PD) for the measurement of upper limb function, and no high-quality studies to date have investigated its validity or the responsiveness of upper limb function in this population [3]. However, despite the lack of scientific evidence for use of the DASH questionnaire in patients with PD, a recent study investigating how trunk alignment contributes to upper limb function in patients with PD used the DASH questionnaire to study upper limb function [4].
Concerning the discrepancies raised between the published article [2] and the registered protocol – specifically, the addition of an exclusion criterion related to drugs and the performance of spirometry – we modified some issues during the study in order to be more rigorous as we noticed that both the pharmacotherapy and cardiorespiratory function could affect the motor performance of patients. Erroneously, we did not modify the protocol accordingly.
As noted by the author of Letter to the Editor: “Comparison of virtual reality rehabilitation and conventional rehabilitation in Parkinson’s disease: a randomised controlled trial” [1], there was another difference between the protocol and the published article [2] concerning cardiological evaluation. The cardiological effects of rehabilitation, both conventional and virtual, is another aspect that we would like to investigate in patients with PD, but this was not the aim of the published study. Indeed, the study evaluated several functional aspects, and we did not want to overburden the results and make the article difficult to read. This was also the reason why the KNGF (Royal Dutch Society for Physical Therapy) recommendations were not detailed in the text [5].
Conflict of interest: None declared.