Movement Disorders

Question 1

What are Upper Motor Neuron (pyramidal) disorders?

Answer 1

• generally, cell bodies in the motor cortex send a fibre down to the brain stem where it decussates and then goes to the spinal cord
• lesions at any point in the upper motor neurone pathway will result in the same symptoms throughout (motor problems)
• depends on where in the homounculus the lesion is made even though discrete lesions are rarely made

Question 2

what are some symptoms of UMN pyramidal disorders?

Answer 2

1. weakness –> extensors of upper limbs and flexors of lower limbs
2. spasticity (velocity dependent increase in tone)
3. increased stretch reflexes
4. babinski sign.. toes fan out when you brush them instead of curling inwards

Question 3

What are some symptoms of LOWER motor neuron (LMN) disorders?

Answer 3

• weakness
• reduced muscle bulk (muscle atrophy)
• fasciculations (little twitches)
• reduced stretch reflexes

Question 4

What are three things that make up the extrapyramidal (basal ganglia)?

Answer 4

1. caudate nucleus
2. putamen
3. globus pallidus

putamen + caudate nucleus = striatum

Question 5

What is hypo kinetic and hyperkinetic movement disorders involving the basal ganglia?

Answer 5

1. hypo kinetic (too little movement) .. syndromes characterized by impoverished voluntary movement
2. hyperkinetic (too much movement) –> syndromes characterized by abnormal involuntary movements

Question 6

What are some symptoms of hypo kinetic disorders?

Answer 6

1. bradykinesia (slowness of movement)
2. akinesia –> absence of movement (extreme form of braykinesia)
3. rigidity –> increase in tone in limbs when passively moving
4. akinetic-rigid syndromes –> low/none movement
5. parkinsonism

Question 7

What is parkinsonism characterized by?

Answer 7

• first of all, its NOT a disorder, its a SYNDROME of a disorder it just happens to be named after disorder that has a high prevalence of it
• it is characterized by rest tremor –> tremor that is only involved when the person is at rest, does not occur when the person is making voluntary movements
• bradykinesia –> short, shuffling steps, marked reduction of facial expression
• rigidity
• postural instability –> fall easily

Question 8

What are some pathophysiological signs of parkinson’s disease?

Answer 8

1. neuronal loss in substantia nigra
2. nigrostriatal projections are destroyed
3. neurotransmitter that is involved is dopamine and lack of

in parkinson’s the pathway from the substantia nigra and then to caudate nucleus + putamen (striatum) is a pathway of dopamine which is lost in this disorder

Question 9

How does the substantia nigra neurons project into the striatum?

Answer 9

in the substantia nigra, Tyrosine is made into DOPA and then to Dopamine.. the dopamine then gets released out of the substantia nigra neurons and binds to the D1 and D2 receptors in the striatum ..

Question 10

What are some etiological factors of parking sons?

Answer 10

• its majority unknown

- theres evidence of environmental influences and genetic influences but more towards combination of both

Question 11

What are some treatments for parkinson’s?

Answer 11

since dopamine can’t cross the BBB, drugs that are pure dopamine will not work in this case

instead a drug called Levodopa or L-DOPA has the same compound that can cross the BBB from blood stream and it makes more dopamine in the form of “DOPA–> dopamine” but only as long as the presynaptic nerves in the substantia nigra to the striatum still exist… after they all die out, then L-DOPA will have nothing to work on

Question 12

When does L-DOPA work in a parkingsonian patient?

Answer 12

between the start of the dose there are cycles with peaks that are called plasma levodopa and thats when theres the highest level of levodopa in the plasma, at this point the motor responses (positive) that come from using it will start and last until you take your next dosage of L-dopa

Question 13

When does L-DOPA not work?

Answer 13

• when at the peak dose of the levodopa, the individual does not get their motor problems ‘fixed’ but rather the person gets dyskinesia (abnormal involuntary movements) which results from excessive amounts of dopamine made, and the motor response that comes out of it is not a positive response and lasts a short time

Question 14

What happens in the connections between the substantia nigra and the putamen D1 and D2 receptors in a normal person compared to someone with parking sons?

Answer 14

in normal people, the substantia nigra sends inhibitory signals to the D2 receptors of the putamen and sends excitatory signals to the D1 receptors

in someone with PD, theres no connections to the substantia nigra therefore, both D2 and D1 connections are inhibitory and that causes no movement

Question 15

What kind of a disorder type is PD?

Answer 15

hypo kinetic (lack of movement)

Question 16

what is an example of a hyperkinetic disorder?

Answer 16

huntington’s disorder –> syndromes characterized by abnormal involuntary movement

Question 17

what are some characteristics and symptoms of hyperkinetic disorders?

Answer 17

1. tremors
2. chorea
3. ballismus
4. distonia
5. myoclonus
6. tics

Question 18

What is tremor classified as?

Answer 18

involuntary, rhythmic and sinusoidal
- classified by relation to activity (rest (PD), postural (when limbs are out), kinetic(when you’re doing a task)
wtiology is that its a physiological, essential (can be normal), parkinsonian and cerebellar sign of dysfunctions

Question 19

what is a physiological tremor and whats it characterized by?

Answer 19

its the tremor that everyone has usually in the form of sustained posture like if u keep ur arms out for too long or are doing a wallsit for too long

these are common, postural related and aggravated by stress, anxiety, caffeine and drugs

Question 20

what are essential tremors and what is it characterized by?

Answer 20

• common, often benign
• postural/kinetic tremors –> can be due to the same posture or doing a task
• aggravated by stress, anxiety, caffeine and drugs

improved by alcohol and runs in the family

Question 21

what is chorea?

Answer 21

chorea is irregular, unpredictable, purposeless, rapid movements that flow randomly from one body part to another

Question 22

what is huntington’s disease?

Answer 22

huntington’s disease is an inherited neurodegenerative disorder, which is autosomal dominant meaning that 50% chance of getting it if one of ur parents has it

it also has 100% penetrance which means once you have it, you can’t reverse it or stop it from progressing

the age of onset for hunting tons is 35-45 years of age

Question 23

What are some characteristics of huntington’s disease?

Answer 23

motor, cognitive, and behavioural dysfunction

it is inexorably progressive and death 15-20 years after symptom onset

motor problems start with distal limbs and then worsen

patients die from other conditions like being bed ridden and getting blood clots and pneumonia

Question 24

What are the characteristics of the motor dysfunction in Huntington’s?

Answer 24

• chorea (jerky involuntary movements) is usually the earliest sign.. which starts initially in the fingers and toes and gets progressively worse
• dystonia and parkinsonian features occur later
• progressive incoordination, unsteadiness, immobility, dysarthria (slurring of words) and dysphagia (difficulty swallowing)

Question 25

What are the characteristics of the cognitive impairments with Huntington’s?

Answer 25

some degree of cognitive impairment is inevitable .. theres no escape

but its occasionally minimal its usually a motor disorder

Question 26

what are the characteristics of behavioural disorders in huntington’s?

Answer 26

these include gradual change in personality, affective disorders in 30-40% of people with hunting tons, and schizophrenia and other psychoses in 10% of them

theres also a high suicide risk

Question 27

What is the genetics behind huntington’s disease?

Answer 27

• autosomal dominant
• occurs on chromosome number 4
• very low spontaneous mutation rate.. this is very progressive

its characterized by a abnormally high number of CAG repeats on chromosome 4 IT15 gene… the normal person has about 5-35 repeats while in hunting tons they have 40-240.

Gene IT15 produces a protein called Huntingtin and in a transgenic mouse model, it showed reduced levels of associated with aberrant brain development and prenatal theality
- normal levels, even of mutant huntingtin is require for normal brain development though

it has a critical role in neurogenesis

Question 28

What are some treatments for hunting tons?

Answer 28

no known treatment effect at altering disease progression

Question 29

What is Ballismus?

Answer 29

its large amplitude, violent, flinging, movements in proximal muscle groups typically unilateral
- hemiballismus is a result of a sub thalamic nucleus stroke which occurs on one side of the body

Question 30

what is Dystonia?

Answer 30

dystonia is not a muscle problem, its a brain inhibition problem

• the brain keeps the muscles in a contractive state
• sustained muscle contraction often giving rise to twisting, repetitive movements or sustained postures
• its idiopathic but largely genetically caused
• thought to be due to inherited disorders of metabolism
• occurs after focal basal ganglia lesions as well

an example is cervical dystonia (its focal) because its contractions of neck muscle

Question 31

What is focal dystonia?

Answer 31

occurs at one major muscle or body part and its contracting and causing inhibition problems from the brain… i.e cervical dystonia

Question 32

What are task-specific focal dystonia?

Answer 32

these occur at learned movements that have been done a lot and over and over. usually in PROFESSIONALS, such as typist or guitarists who do a lot of work with their proximal muscles groups and often have them twitching or staying in one spot

Question 33

What is generalized dystonia?

Answer 33

Early onset of it is due to the DYT1 gene

• all multiple body parts except face are contracting
• all other neurological exams show to be perfectly normal like IQ, cranial nerves, sensations..etc.. its just the inhibition from the brain motor areas to the body parts from that gene mutation that causes the problems