Table 1 Abnormal movement categories and their pathological origin listed in alphabetical order
From: Abnormal movements in critical care patients with brain injury: a diagnostic approach
Abnormal movement | Definition | Pathophysiological origin |
|---|---|---|
Chorea | Involuntary, purposeless, nonrhythmic, non-sustained movements that flow from one body part to the other | Poorly understood. Could be due to loss of normal pallidal inhibitory input |
Hemiballismus: a severe form of chorea, is characterized by vigorous irregular high amplitude movements on one side of the body | Hemiballismus happens secondary to injury of the subthalamic nucleus | |
Clonus | Rhythmic involuntary muscular contractions and relaxations | Upper motor neuron injury and its descending pathways |
Dystonia | Sustained twisting movements that are often frequent and progresses to prolonged abnormal postures | Basal ganglia. Abnormalities are also seen in the cortex and reduction in spinal cord and brainstem inhibition |
Myoclonus | Sudden, brief involuntary movements which may be caused by muscle contractions (positive myoclonus) | Widespread origin depending on the injury or type: cortical, subcortical (basal ganglia), brainstem or spinal cord in segmental myoclonus |
Asterixis is considered a negative myoclonus secondary to sudden loss of tone | ||
NCSE | Unilateral eye deviation, lip smacking, automatisms and some movements of the fingers | Cortical in origin |
Paroxysmal posturing | Involuntary flexor or extensor posturing on one side or bilateral spontaneously or with pain. Opisthotonus posturing refers to hyperextension of the neck and back “arching position” | Damage above the red nucleus (flexion posturing) or below (extensor posturing) Midbrain injury or tetanus (opisthotonus) |
Shivering | High frequency involuntary muscular contractions involving one group or more of muscles | Thermoregulatory (due to hypothermia) or non-thermoregulatory (not well understood) |
Tics | Abnormal movements (motor) or sounds (phonic) which can be simple muscle jerks or complex when they consist of sequential movements in different parts of the body | May be related to abnormalities in the basal ganglia |
Tremor | Oscillatory rhythmic movement that affects one or more parts of the body | Likely related to the presence of central oscillator in the basal ganglia or cerebellum |