There is enough evidence that meditation helps in Parkinson’s disease symptoms. It helps in improvement of both motor and non-motor symptoms and slows the progression of the disease. To look for a trained teacher you can check on Meditation Australia website. (https://meditationaustralia.org.au/)

In one study, 14 Parkinson’s disease patients underwent an eight-week mindfulness-based intervention, while 13 continued their usual care.

Magnetic resonance imaging MRI scans of their brains were compared before and after the study. The MRIs showed more density in the gray matter (areas of the brain where the nerve cells are concentrated) in the mindfulness group than in the control group. This proves that there is a real change in the brain on doing Meditation.
(Pickut BA, Van Hecke W, Kerckhofs E, et al. Mindfulness based intervention in Parkinson’s disease leads to structural brain changes on MRI: a randomized controlled longitudinal trial. Clin Neurol Neurosurg. 2013;115(12):2419-2425).

In another study group of 12 individuals participated in an eight-week mindfulness-based cognitive therapy course. Through analysis of diaries and interviews with the participants, the study showed that the course helped participants better cope with their emotions related to Parkinson’s disease, both individually and as a group. WE know that about 50% of patients with Parkinson’s Disease can have mental health issues including Depression.
( Fitzpatrick L, Simpson J, Smith A. A qualitative analysis of mindfulness-based cognitive therapy (MBCT) in Parkinson’s disease. Psychol Psychother. 2010;83(Pt 2):179-192 ).

Another recent study showed that stress management training led to a reduction in stress and depression in Parkinson’s patients with tremors. A total of 82 patients with Parkinson’s tremors and 30 individuals used as controls completed an eight-week stress management therapy course. The Parkinson’s group showed improvements in their ability to deal with stress and depression, while the control group had less improvement. Out of 33 of the Parkinson’s patients, 29 said the therapy was helpful when polled 12–18 months after treatment.
( Buhmann C, Jungnickel D, Lehmann E. Stress Management Training (SMT) Improves Coping of Tremor-Boosting Psychosocial Stressors and Depression in Patients with Parkinson’s Disease: A Controlled Prospective Study. Parkinsons Dis. 2018;2018:4240178. )

In a pilot study Parkinson’s patients and their caregivers were studied that included 39 participants (29 patients and 10 caregivers). The study used an eight-week mindfulness program with classes and homework. It showed that symptoms of depression were alleviated for all participants. Patients also experienced fewer mental and emotional symptoms. According to the results, the more involved the participants were in the class and homework, the greater the improvements. It signifies the importance of motivation in symptom improvement.
( Cash, T.V., Ekouevi, V.S., Kilbourn, C. et al. Pilot Study of a Mindfulness-Based Group Intervention for Individuals with Parkinson’s Disease and Their Caregivers. Mindfulness 7, 361–371 (2016)

A study from Brisbane, Australia  total of 14 patients were assessed prior to intervention, after an eight-week mindfulness training, and six months later.
It showed that Parkinson’s patients who completed a group mindfulness program had less stress and depression with improved cognitive and motor function.
(Nadeeka N. W. Dissanayaka, Farah Idu Jion, Nancy A. Pachana, John D. O’Sullivan, Rodney Marsh, Gerard J. Byrne, Paul Harnett, “Mindfulness for Motor and Nonmotor Dysfunctions in Parkinson’s Disease”, Parkinson’s Disease, vol. 2016, Article ID 7109052, 13 pages, 2016.)

Even motor symptoms improved using Mind-Body technique. A decrease in tremors was seen in a study conducted with 20 Parkinson’s patients with moderate to severe tremors. Of the patients, 15 showed no sign of tremors for one to 13 minutes after relaxation guided imagery. The intensity of tremors remained lower even 15 and 30 minutes after the imagery was stopped. Patients reported a decrease in tremors two to 14 hours after the relaxation imagery. The study also looked at the effects of self-relaxation and listening to relaxing music. Relaxing music slightly reduced the intensity of tremors, while self-relaxation did not appear to have an effect. (Schlesinger I, Benyakov O, Erikh I, Suraiya S, Schiller Y. Parkinson’s disease tremor is diminished with relaxation guided imagery. Mov Disord. 2009;24(14):2059-2062.)

Another relaxation guided imagery study showed a reduction in motor fluctuations, or off phase. Out of 21 patients, 19 completed a three-month, home-based relaxation routine involving listening to relaxation guided imagery CDs as well as relaxing music. Listening to the imagery CDs showed an increase in “on” time compared with the beginning of the study, but the relaxing music did not seem to have any effect. (Schlesinger I, Benyakov O, Erikh I, Nassar M. Relaxation guided imagery reduces motor fluctuations in Parkinson’s disease. J Parkinsons Dis. 2014;4(3):431-436.)

In a randomized, controlled, longitudinal study of 30 patients with Parkinson’s, 14 of whom completed mindfulness training, 13 who continued with their usual care, and three who dropped out of the study. It was found thar one who did mindfulness training had reduction in motor impairment. (Pickut B, Vanneste S, Hirsch MA, et al. Mindfulness Training among Individuals with Parkinson’s Disease: Neurobehavioral Effects. Parkinsons Dis. 2015;2015:816404. )