Week 7 Flashcards
The term “movement disorder” has become synonymous with:
basal ganglia disease and extrapyramidal features
Except for the muscles that activate the eye, which are innervated from midbrain nuclei, all the voluntary muscles of the body are directly innervated by:
motor neurons in the spinal cord and hindbrain
The control of voluntary movements has 3 stages:
planning, initiation and execution
The motor neurons that directly innervate skeletal muscle which constitute the final common pathway by which the nervous system controls movement and are often referred to as:
alpha-motor neurons
In addition to cortical association area, what two areas are involved in planning?
The basal ganglia and cerebellum
The cerebellum is responsible for what in regard to movements?
fine tuning and planning and execution.
Movement disorders can be categorised into:
- akinetic-rigid (move too little)
2. hyperkinetic (move too much)
What does bradykinesia mean?
slow movement
What does hypokinesia mean?
poverty of movement, movements that are smaller than intended
What type of characterisation is Parkinson’s disease best placed into?
hypokinesia
Some people have further divided hypoerkinetic disorders into what two sections?
jerky and non-jerky syndromes
What is myoclonus
sudden, brief, shock like involuntary movements
What is chorea?
from the greek work, “to dance”. Refers to quick, irregular, movement. A fidgety look.
What are tics?
involuntary, somewhat rhythmic, muscle contraction and relaxation involving twitching movement of one or more body parts
What is dystonia?
An abnormal movement in which a person’s muscles contract uncontrollably. Results in repetitive movements or abnormal postures.
Who first described Parkinsons disease?
James Parkinson “shaking palsy”.
What are the major symptoms of parkinson disease?
bradykinesia, tremor and rigidity
According to the UK Parkinson disease society, what is the anchor feature?
bradykinesia
What is bradykinesia
Slowing of the speed of initiation and execution o both purposeful and automatic movements
What is resting tremour?
shakign that occurs in relaxed muscles in Parkinsons
What is rigidity?
repeated movement of arm and leg joins result in muscular stiffness in Parkinsons
Apart from defining cardinal motor features, patients with Parkinsonian syndromes commonly show:
Additional motor and non motor signs
What is dysarthria?
weakness in the muscles used for speech, seen in Parkinsons
What is dysphagia?
difficulty in swallowing foods, as seen in Parkinsons
What are postural deformities?
stooped posture with flexion of the trunk, hallmark in PD.
What is dystonia?
Refers to involuntary muscle contractions that cause repetitive or twisting movement. Seen in PD.
What is a late feature of PD?
dementia: affects 70-80% of patients after prolonged disease lasting 10 or more years.
What are some risk factors for dementia in those with Parkinson’s disease?
- increasing age
- being male
- older age at onset of PD
- visual hallucinations
- more sever motor symptoms
While there are some overlapping symptoms in PD and AD?
AD affects language and memory, PD affects problems solving, speed of thinking, memory and other cognitive functions, as well as mood.
What are other clinical manifestations of PD?
- depressive symptoms
- anxiety
- apathy and fatigue
- psychotic symptoms
For pragmatic clinical purposes, pakinsonian disorders are best grouped into two principal categories:
- degenerative parkinsonism
2. symptomatic or secondary parkinsonism
What is is degenerative parkinsonism?
a variety of sporadic and genetic degenerative diseases cause neurodegeneration
What is symptomatic or secondary parkinsonism?
non-degenerative lesions
What are the sub categories of symptomatic parkinsonism?
- infectious
- toxic
- drug induced
- brain tumours
- metabolic
PD is usually definable in terms of functional or structural disorders affecting:
the nigrostriatal dopamine transmission and/or downstream signalling pathways
The basal ganglia is comprised of a set of brain structures in the:
- telencephalon
- diencephalon
- mesencephalon
The globus pallidus has both the:
internal and external segment
The pars compacta is the source of a clinically important dopaminergic pathway to the striatum. Loss of neurons in this area is the cause of PD. This dopamine pathway is referred to as the:
nigrostriatal dopamine pathway
The basal ganglia can be divided into what two pathways?
- direct excitatory pathway
- indirect inhibitory pathway
Stimulation of direct pathway results in activation of the motor cortex, whereas stimulation of the indirect inhibits the motor cortex.
Dopamine acts on the direct pathway neurons by activating:
dopamine D1 receptors. Stimulate cell activity
Dopamine acts on indirect pathway neurons by activating:
dopamine D2 receptors. These inhibit cell activity.
What revolutionalised treatment in PD?
Levodopa - doesn’t work for the lifetime of the patient.
When people are treated with Levodopa over a long time it can have what effects?
- dopa resistant motor symptoms
- dopa resistant non motor signs
- drug related side effects (psychosis, mood)
What are dopamine agonists as a way to treat PD?
stimulate dopamine receptors
Deep brain stimulation can be administered to severe cases of:
PD - electrodes are implanted directly into the brain.
What is Huntington’s disease caused by?
repeats of the nucleotide sequence CAG on chromosome 4
Why does the loss of indirect pathway neurons in the striatum cause dyskinesias of HD?
role of indirect pathway is to inhibit motor cortex. With the loss of these neurons, the excitatory effect of the direct pathway is no longer kept in check by the inhibition of the indirect pathway.
What is the first manifestation of HD, Chorea?
initially a mild fidgetiness apparent to only the careful observer
What are some drugs which suppress dopaminergic activity, used to help HD?
antipsychotics and dopamine depleting drugs
What is hemiballismus caused by?
unilateral lesion to the sub thalamic nucleus, usually caused by a stroke.
What is hemiballismus characterised by?
involuntary flinging motions of the the extremities
