CHOREA AND BALLISMUS
Dr PS Deb
GNRC Hospitals Assam
State of excessive, spontaneous movement,
irregularly timed, non repetitive, randomly
distributed and abnormal in character.
It may very in severity from restlessness with mild
intermittent exaggeration of gesture and
expression, fidgeting movement of hands unstable,
movement of hands.
Unstable gait to continuous flow of disabling violent
Random – distribution, time, and duration
Hypotonia – Reduced long latency reflex
Motor impersistence → inability to sustain vol.
Hung-up reflex – Prolonged contraction of stretched
muscles by late sensory provoked choric movement.
CHOREA MECHANISM - NEUROTRANSMITTER
Reduced: GABA, Sub P, Ach
Increased: Dopamine, NA in Striatum and pallidum,
GABA in SN and GP due to degeneration of striatum,
but gabargic drugs does not reduce chorea
Dopamine Tyrosin hydroxylase enzyme in SN,
chorea reduced by anti dopa drugs and by Ldopa
Ach marginally reduced, choline esterase enzyme mild
reduced, large striatal interneuron well maintained, Ach
agonist does not improve chorea
Chorea reduced by Pallidotomy, Nigrotomy,
Choric discharges on EMG resemble normal
Active inhibition of innervation
Readiness potential not tested
Idea Programming Execution
MECHANISM OF CHOREA
Chorea appears to be a fragments of normal
movements, appearing in inappropriate circumstances
and lacking any purpose
They may be determined by peripheral stimuli which in
ordinary circumstances would be ignored.
Basal ganglia normally filter the mass of cortical input,
they receive to select movement appropriate to the
Striatal damage might prevent normal suppression of
unwanted motor response to external stimuli → Chorea