akinesia

Akinesia is a neurological symptom characterized by impaired or absent ability to initiate voluntary movement. It often manifests as a reduced tendency to move, especially in response to voluntary goals. Clinically, it is distinguished from bradykinesia (slowness of movement) and hypokinesia (reduced amplitude of movement). In some contexts the term denotes an inability to initiate movements despite preserved motor strength.

In practice, akinesia is a core feature of parkinsonian syndromes and other disorders affecting the basal ganglia. It may present with freezing of gait, reduced spontaneous movement, diminished facial expression, and decreased arm swing. In severe cases, akinesia contributes to akinetic mutism, a state of markedly reduced or absent movement and speech due to extensive frontal-subcortical dysfunction.

Pathophysiology involves disruption of the basal ganglia circuits that regulate movement, often with reduced dopaminergic input from the substantia nigra to the striatum. Many causes share lesions or degeneration in motor networks, including Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, and stroke.

Diagnosis relies on clinical assessment and history; imaging is used to identify underlying disease. Distinguish akinesia from bradykinesia and other movement disorders.

Management targets the underlying condition and symptom relief. In Parkinson's disease, dopaminergic therapies (levodopa, dopamine agonists) can improve akinesia; physical therapy, cueing strategies, and, in selected patients, deep brain stimulation may help. Prognosis depends on the underlying disease and progression; akinesia often worsens as neurodegeneration advances.