8. Motor Disorders Flashcards
What are the three motor tracts?
Pyramidal - corticospinal and corticobulbar tracts; and extrapyramidal.
Where is the cerebellum located?
Posterior cranial fossa.
How is the cerebellum separated from the occipital and parietal lobes?
By the tenorium cerebelli.
How is the cerebellum separated from the pons?
By the 4th ventricle.
What does the cerebellum consist of?
Vermis and two lateral hemispheres.
What is the role of the vermis of the cerebellum?
Regulate trunk musculature.
What is the role of the lateral cerebellar hemispheres?
Regulate distal structures.
How does the cerebellum communicate with the brainstem?
Via cerebellar peduncles - superior cerebellar peduncle attaches to midbrain, middle to pons, and inferior to medulla.
What presentation would a midline cerebellar lesion cause?
Truncal ataxia and abnormal gait.
What presentation would extension of a midline cerebellar lesion cause?
Truncal ataxia and abnormal gait along with 4th cranial nerve lesions, ipsilateral arm tremors, compression of 4th ventricle - hydrocephalus.
Which side do cerebellar hemisphere lesions cause symptoms on?
Ipsilateral.
What are the symptoms of cerebellar lesions?
DANISH - dysdiadochokinesia, ataxia, nystagmus, intention tremor, scanning dysarthria, heel-shin test positive.
What are the structures in the basal ganglia?
Caudate, lentiform nucleus (putamen, globus pallidus externa, globus pallidus interna), substantia nigra (pars compacta and pars reticularis).
What is the role of the basal ganglia?
Stimulates motor activity in the cerebral cortex.
Where are dopaminergic neurones found?
Substantia nigra pars compacta.
What is the overall net effect of direct and indirect pathways in the basal ganglia?
Thalamic stimulation of the motor cortex.
What are the effects of basal ganglia disorder?
Abnormal motor control, altered posture, affects muscle tone, dyskinesia.
What is Parkinson’s disease?
Chronic, progressive movement disorder due to degeneration of substantia nigra causing a deficiency of dopamine.
What are the triad of signs that characterise Parkinson’s?
Bradykinesia, tremor, and rigidity.
What are the associated features of Parkinson;s?
Hypophonia, reduced facial expression, micrographia, dementia, depression.
What is Huntington’s disease?
Autosomal-dominant, progressive neurodegenerative disorder.
When does Huntington’s disease normally start presenting?
30-50 years.
What are the symptoms of Huntington’s disease?
Chorea (abnormal movements), dystonia (abnormal tone in trunk), incoordination, cognitive decline, behavioural difficulties.
What cell changes are associated with Huntington’s disease?
Cell loss in basal ganglia and cortex.
