Author response: Muscle-targeted nutritional support for rehabilitation in patients with parkinsonian syndrome

We gratefully acknowledge Estrada-Bellmann et al. for the interest in our study.1 Indeed, we recognize the importance of discriminating different clinical entities in the broad spectrum of parkinsonian syndromes. To confirm the diagnosis, all patients attending and followed at the Parkinson Institute, where recruitment took place, underwent a brain imaging evaluation (MRI)2,3 and are not recruited in trials/studies before a 2-year follow-up (unless differently indicated). In respect to treatment effect, as stated, the analysis refitted on patients with Parkinson disease (PD) provided results consistent with primary analysis. No formal comparison has been performed between patients with PD and parkinsonism because of the small number of the latter. We reanalyzed data and found no interaction between treatment and diagnosis ( p = 0.88). However, these additional results need to be interpreted cautiously because the small sample size could be associated with the high risk of bias. Therefore, the only possible solution to address the pertinent question raised is to design an ad hoc trial in this area.