the target nuclei, has come under scrutiny due to its associated risks of hemorrhages, dysarthria or tetanic contractions. Recently, susceptibility-weighted imaging, a type of MRI, has shown incredible power in its ability to distinguish these deep brain nuclei and is being used in DBS to reduce the overuse of EFM. DBS is recommended to PD patients without important neuropsychiatric contraindications who have motor fluctuations and tremor badly controlled by medication, or to those who are intolerant to medication. DBS is effective in suppressing symptoms of PD, especially tremor. A recent clinical study led to recommendations on identifying which Parkinson's patients are most likely to benefit from DBS. Diet Muscles and nerves that control the digestive process may be affected by PD, so it is common to experience constipation and gastroparesis (food remaining in the stomach for a longer period of time than normal). A balanced diet is recommended to help improve digestion. Diet should include high-fiber foods and plenty of water. Levodopa and proteins use the same transportation system in the intestine and the blood–brain barrier, competing between them for access. When taken together, the consequences of such competition is a reduced effectiveness of the drug. Therefore, when levodopa is introduced, excessive proteins are discouraged, while in advanced stages, additional intake of low-protein products such as bread or pasta is recommended for similar reasons. To minimize interaction with proteins, levodopa is recommended to be taken 30 minutes before meals. At the same time, regimens for PD restrict proteins during breakfast and lunch and are usually taken at dinner. As the disease advances, dysphagia may appear. In such cases, specific measures include the use of thickening agents for liquid intake, special postures when eating, and gastrostomy in the worst cases. Rehabilitation Studies of rehabilitation in Parkinson's disease are scarce and are of low quality. Partial evidence indicates speech or mobility problems can improve with rehabilitation. Regular physical exercise and/or therapy can be beneficial to maintain and improve mobility, flexibility, strength, gait speed, and quality of life. Exercise may also improve constipation. Exercise interventions have been shown to benefit patients with Parkinson's disease in regards to physical functioning, health-related quality of life, and balance and fall risk. In a review of 14 studies examining the effects of exercise on persons with Parkinson's disease, no adverse events or side effects occurred following any of the exercise interventions. Five proposed mechanisms by which exercise