21st November 2023

Miscellaneous Motor Psychopathology

Athetosis

Slow, rhythmic, sinuous movements  – Often described in exam questions as ‘worm like’ movements. It is often confined to the distal limbs and is seen in conditions such as cerebral palsy, stroke and Wilson’s disease.

Chorea

These are brief, irregular movements which are often described as ‘dance like’ in that they flow from one muscle to the next. Distinguishing chorea from athetosis can be difficult; however, in chorea, the individual movements can be identified (like still images from a film), whereas in athetosis, there are just continuously flowing movements (Sanger et al., 2011). There are many causes, including Huntington’s disease and infections.

Sydenham’s chorea

This is a syndrome seen in post-streptococcal infections, such as rheumatic fever (Gordon, 2008). It is most likely due to an immune reaction against the basal ganglia.

Hemiballismus

This is where there are involuntary, large flailing movements of the proximal limbs. Causes include stroke, infections and hyperglycaemia. Hemiballismus are thought to be due to damage to the subthalamic nucleus and other basal ganglia structures (Grandas, 2011).

Myoclonus

These are involuntary jerking movements due to the contraction of muscles (Kojovic et al., 2011). Myoclonus can be innocuous:

– Benign sleep myoclonus of infancy  – Normally occurring phenomenon in the first 6 months of life, where they occur during sleep.

– Hypnic jerks  – Also known as sleep starts, whereby the myoclonic jerks occur when falling asleep.

But it can also be due to other neurological conditions such as epilepsy and multiple sclerosis.