3. Discussion
PD, muscle atrophy
DEGENERATION, MUSCLE ATROPHY, RECRUITMENT, DISORDERS, VITAMIN D DEFICIENCY
To the best of our knowledge, this is one of the first studies where PD patients with DBS were supplemented with vitamin DDBS is one of the treatments used to treat motor symptoms in PD [Recently, we showed that vitamin D deficiency is associated with many disorders in the organism, including muscle atrophy [Patients with PD are often non-active [Dopamine loss is observed in PD due to the degeneration of the substantia nigra [There are several important limitations of this study. First, the sample size is small as recruitment of PD patients with implanted DBS was challenging during the covid pandemic. Nevertheless, only 29 patients without missing data were included in the final analysis. Consequently, although the power of statistical analysis was compromised, the differences between groups proved to be sufficient to show statistical significance. Second, there is a lack of a true control group without DBS to check the impact of the stimulation on the supplementation. Third, we did not measure the complex of B vitamins, which are tightly associated with L-dopa treatment and might influence the results of functional tests. Fourth, patients did not have a dedicated device to control the number of steps per day; they used their mobile phones. Because of that, the quality of control of whether they performed the required physical activity is limited. Therefore, further studies are needed to confirm these results and broaden the investigation process.