Hypokinesia

Hypokinesia is one of the classifications of movement disorders, and refers to decreased bodily movement. Hypokinesia is characterized by a partial or complete loss of muscle movement due to a disruption in the basal ganglia.^{[citation needed]} Hypokinesia is a symptom of Parkinson's disease shown as muscle rigidity and an inability to produce movement. It is also associated with mental health disorders and prolonged inactivity due to illness, amongst other diseases.

The other category of movement disorder is hyperkinesia that features an exaggeration of unwanted movement, such as twitching or writhing in Huntington's disease or Tourette syndrome.

Hypokinesia describes a variety of more specific disorders:

The most common cause of hypokinesia is Parkinson's disease, and conditions related to Parkinson's disease.

Other conditions may also cause slowness of movements. These include hypothyroidism and severe depression. These conditions need to be ruled out before a diagnosis of Parkinsonism is made.

Dopamine

The main neurotransmitter thought to be involved in hypokinesia is dopamine. Essential to the basal ganglionic-thalamocortical loop, which processes motor function, dopamine depletion is common in these areas of hypokinesic patients. Bradykinesia is correlated with lateralized dopaminergic depletion in the substantia nigra. The dopamine pathway in the substantia nigra is essential to motor function, and commonly a lesion in this area correlates with displayed hypokinesia. Tremor and rigidity, however, seem to be only partially due to dopamine deficits in the substantia nigra, suggesting other processes are involved in motor control. Treatments for hypokinesia often either attempt to prevent dopamine degradation by MAO-B or increase the amount of neurotransmitter present in the system.

GABA and glutamate