There is no cure for PD; treatment aims to improve the symptoms.[1][16] Initial treatment is typically with the medications levodopa (L-DOPA), MAO-B inhibitors, or dopamine agonists.[3] As the disease progresses, these medications become less effective, while at the same time producing a side effect marked by involuntary muscle movements.[4] At that time, medications may be used in combination and doses may be increased.[14] Diet and certain forms of rehabilitation have shown some effectiveness at improving symptoms.[17][18] Surgery to place microelectrodes for deep brain stimulation has been used to reduce motor symptoms in severe cases where drugs are ineffective.[1] Evidence for treatments for the non-movement-related symptoms of PD, such as sleep disturbances and emotional problems, is less strong.[7]