Movement Disorders Flashcards
Upper Motor Neuron Disorders-Symptoms
Weakness in extensors of upper limbs and felxors of lwoer limbs
Spasticity
increased stretch reflexes
Babinski sign
Upper Motor Neurons
Cell bodies in the cortex, axons to internal capsal and cross in the spinal cord
Parasaggital-legs
lateral-hands
lower lateral-face
Lower Motor Nueron Disorders-symptoms
Weakness
REduced muscle bulk
Fasciculations (twitches)
REduced stretch reflexes
They are the peripheral or cranial nerves.
Basal Ganglia
Motor dysfunction is in the striatum.
Output is the job od the globus pallidus.
Movement Disorders: Basal Ganglia
Hypokinetic-syndromes characterized by impoverished voluntary movement
Hyperkinetic-syndromes characterized by abnormal involuntary movements.
Hypokinetic Disorders
Bradykinesia-slowness Akinesia-no movement rigidity akinetic-rigid syndromes parkinsonism increased tone in limbs whe passively moved
Parkinsonism
Rest tremor bradykinesia Rigidity Postural instability Same symptoms as hypokinetic syndroms. Tremor stops with voluntary movement-visual input plays a major role
Parkinson’s disease Pathology
Neuronal loss in the substantia nigra
nigrostrital projections
Neurotransmitter is dopamine
Dopamine production
Tyrosine to DOPA to dopamine
continously formed from amino acids. Trapped in the presynaptic vessicle then interacts with post synaptic receptors.
Parkinson Treatment
Levodopa as a precurosr to dopamine in order to cross the brain blood barrier.
Plasma Levodopa fluctuates but usually buffering th body limits this.
However, motor fluctuations occurs whn it depletes too quickly and can cause bradykenesia
At peak dosage, dyskensia can occur which is involuntary muscle movements (overdose at the peak basically)
Treatment for Parkinsons-lesions
Leasion to internal global pallidus on other side of the body
Deep Brian stimulation
If stumulated-turns that part off so stimulate subthalamic nucleus or internal global pallidus
combination of meds and stimulation is needed
Extrapyramidal Disorders
Hypokinetic-syndomres characterized by impoverish voluntary movement
Hyperkinetic-syndromes characterized by abnormal involuntary movements
Hyperkinetic
Tremor Chorea Ballismus Dystonia Myoclonus Tics
Tremor
Involuntary, rythmic, sinusoidal
Classified by:
relation to activity-rest, posteral, kinetic
Etiology:
Physiological, essential, parkinsonian, cerebellar
Physiological Tremor
Common
Postural
Aggravated by stress, anxiety, caffeine, drugs
Essetial Tremor
Common, often benign
posterual or kinetic tremor
aggravated by stress, anxiety, caffeine and drugs
Alcohol-responsive.
Action tremor
Deep brain stimulation to the ventral lateal nuceli thalamus to decrease disabling tremors
Chorea
Irregular, unpredictable, purposeless, rapid movements that flow randomly from one body part to another
Related to Huntingtons
Huntingtons Disease
Inherited neurodegenerative disorder
Autosomal dominant
100% penetrance
age of onset 35-45 years
100% heritability
Motor, cognition and behavioural dysfunction
Inexorably progressive-death 15-20 years after symptom onset
personality change and schizo associtation
Huntingtons Clinical features
Motor dysfunction:
-chorea is usually the earliest sign. initially in the fingers, toes and face and it is progressive
-dystonia and parkinsonian features later
-progressive incoordination, unsteadiness, immonbility, dysarthria, dysphagia
Cognitive Impairment:
-some degree is inevitable
-occasionally minimal
Behavioural Disorders:
-gradual change in personality
-affective disorders in 30-40%
-schizophrenia and other psychoses in 10%
-high suicidal risk
Huntingtons Neurobiology
Shrunken head of caudate nucleus
Expanded ventricles
Thinned Cortex
Loss of tissue means a loss of neurons
Huntingtons Genetics
Short arm tip of chromosome 4 Autosomal dominant Very low spontaneous mutation rate IT15 gene-everyone has this protein and it is needed for life/brain development. normally there is 5-35 (CAG) repeat 40-240 repeat gives you Huntingtons More repeats means an earlier onset
Huntingtin
Transgenic mouse:
reduced levels associated with aberrant brain development and perinatal lethality
-normal levels, even of mutant huntingtin is required for normal brain development
Critcal role in neurogenesis
Huntington’s treatment
No known treatemnt effective at altering disease progression
Ballismus
Large amplitude, violent, flinging movements in proximal muscle groups, typically unilateral
Hemiballismus: subthalamic nucleus stroke
Dystonia
Sustained muscle contraction, often giving ride to twisting, repetitive movements or to sustained postures
idiopathic (genetic?), inherited disorders of metabolism, focal basal ganglia lesions-stroke of the basal ganglia.
1. Focal-muscle contraction causing postoral abnormality.
2. Task-specific-whem brain has put effort into learning and professionalizing a task
3. Generalized-early onset with DYT1 mutation. Surgery to stimulate the internal globus pallidus bilaterally.
