6- Motor Disorders Flashcards
What are the signs of cerebellar disease? (mnemonic= DANISH)
D-dysdiadochokinesia A-ataxia N-nystagmus I-intention tremor S-slurred speech (dysarthria) H-hypotonia
What is nystagmus?
Flickering eye movement due to malcoordination of extra-ocular muscles
What is dysarthria?
Slurred speech from malcoordination of muscles of larynx and tongue
What is dysdiadochokinesia?
Difficulty with rapidly alternating movements
What is an intention tremor?
A tremor that worsens as target is approached
What is the cause of Parkinson’s disease?
Degeneration of dopaminergic neurones in substantial nigra pars compacta
What are some signs and symptoms of Parkinson’s disease?
Tremor, rigidity, bradykinesia, dementia, depression
What other symptoms of Parkinson’s are caused by the bradykinesia?
Hypophonia- quiet speech from bradykinesia of larynx and tongue muscles
Decreased facial movement
Micrographia- small handwriting from bradykinesia of hands
Why does bradykinesia occur in Parkinson’s disease?
Due to loss of cortical excitation
What is the inheritance pattern of Huntington’s chorea?
Autosomal dominant
What is the average age of onset for Huntington’s chorea?
30-50 years old
What is the cause of the hyperkinetic features of Huntington’s chorea?
Loss of inhibitory projections from striatum to Globus pallidus externa
What are some features of Huntington’s chorea?
Chorea, dystonia, loss of co-ordination
What is hemiballismus?
Rare condition causing involuntary unilateral explosive movements
What is the basic sections of the cerebellum?
Two lateral hemispheres with midline vermis between them
Which areas of the brain stem do the cerebellar peduncles (superior, middle, inferior) communicate with?
Superior- Midbrain
Middle- Pons
Inferior- Medulla
Where does the cerebellum receive sensory information from?
Ipsilateral spinal cord and contralateral sensory cortices (via corticopontocerebellar pathway)
Which structure together form the striatum?
Caudate and putamen
How does an increase in thalamic activity affect cortical activity?
Increase in thalamic activity will cause an increase in cortical activity
Via which structure do the basal ganglia communicate with the motor cortex?
Thalamus
What roles do the basal ganglia and cerebellum have in performing a task like picking up a cup?
Basal ganglia- determine appropriate movements to perform task
Cerebellum- determines appropriate sequence of these movements to perform the task
By which receptors does dopamine exert an inhibitory effect on the indirect pathway?
D2
By which receptors does dopamine exert an excitatory effect on the direct pathway?
D1 receptors
Stimulation of the indirect pathway has what effect on thalamic activity and therefore also on cortical activity?
Decreased thalamic and cortical activity
Stimulation of the direct pathway has what effect on thalamic activity and therefore also on cortical activity?
Increased thalamic and therefore increased cortical activity
