1. Chorea is a state of excessive, spontaneous, irregular movements that are randomly distributed and abnormal in character. It can range from mild restlessness to violent disabling movements.
2. Ballismus involves proximal, flinging, violent involuntary movements. Both chorea and ballismus are associated with basal ganglia dysfunction and abnormal neurotransmitter levels like decreased GABA and increased dopamine.
3. Causes of chorea and ballismus include infections, metabolic and endocrine disorders, drugs, trauma, vascular events, tumors, and hereditary conditions like Huntington's disease. Treatment involves reducing dopamine levels with antipsychotics or GABA agonists, as well as surgical procedures like pallidotomy or thalamotomy
2. CHOREA
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
movement.
Random – distribution, time, and duration
3. CHOREA
Associated with
Hypotonia – Reduced long latency reflex
Motor impersistence → inability to sustain vol.
movement
Pronator sign
Milkmaids sign
Trombone tongue
Hung-up reflex – Prolonged contraction of stretched
muscles by late sensory provoked choric movement.
5. CHOREA MECHANISM - NEUROTRANSMITTER
DISTURBANCE
Reduced: GABA, Sub P, Ach
Increased: Dopamine, NA in Striatum and pallidum,
Somatostatine
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
6. CHOREA PATHOGENESIS
PET -
Histochemistry
Drug effect
Surgical
Chorea reduced by Pallidotomy, Nigrotomy,
Thalamotomy
Pathological
Animal Model
7. ELECTROPHYSIOLOGICAL
Choric discharges on EMG resemble normal
voluntary contraction
Active inhibition of innervation
Readiness potential not tested
id
Idea Programming Execution
Discharge DischargeChorea
Association
Cortex
Basal
Ganglia
Motor
Cortex
8. 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
circumstances.
Striatal damage might prevent normal suppression of
unwanted motor response to external stimuli → Chorea
15. MECHANISM OF BALLISMUS
Surgical Pallidotomy, Nigrotomy, thalamotomy
reduces ballismus
Animal Substantia Nigra lesion causes
hemiballismus
Experimental destruction of Striata nigra no
ballismus, 20% destruction → hemiballismus
Striatal dopamine increased
Subthalamic GABA reduced
16. SITE OF LESION CAUSES BALLISMUS
Sbuthalamus
Pallidum
Substantia nigra
Thalamus
Post. Central gyrus
Superior frontal gyrus
Precentral gyrus