This is an experimental study (Interventional self-controlled trial, pretest-posttest design). The goal of this clinical trial is to evaluate the effect of vitamin D3 supplementation on quantitative EEG in male Parkinson's disease patients with hypovitaminosis D. The main question it aims to answer is: Vitamin D3 supplementation has effect on brain waves in male Parkinson's disease patients with hypovitaminosis D. Researcher will compare the effect of vitamin D3 supplementation on brain waves in male Parkinson's disease patients with hypovitaminosis D with their pre intervention ( baseline ) condition on brain waves to assess whether there will be any improvement of brain electrical activity by quantitative electroencephalogram (QEEG). Participants will : Take vitamin D3 orally for 8 weeks (50,000 IU/week) Visit the medical university after 8 weeks for evaluation of serum 25(OH)D level and QEEG Must bring the empty strips of vitamin D supplement with them during their visit.