Lecture 13 - Motor Control & Disorders Flashcards
Basal Ganglia Disorders
Parkinson’s Disease
Huntington’s Disease
Tourette’s Syndrome
Parkinson’s Disease definition
- difficult times making movements, slouched over, make small shuffling steps
- lack of movement
Huntington’s Disease definition
- too much movement
Tourette’s Syndrome definition
- repetition, ticks, OCD, swearing
Parkinson’s Disease
damage to cells in the substantia nigra pars compacta (80% of dopamine producing cells are damaged – therefore, DOPAMINE DEFICIENCY results).
- less/no smooth movements
typically IDIOPATHIC (of unknown cause) but can result from encephalitis, toxins, trauma (e.g., boxer’s encephalopathy), designer drugs (MPTP).
SLIDE 4 PATHWAY - stimulates cortex too little
Parkinson’s Disease
Symptoms
hypokinesia (akinesia, bradykinesia)
- lack of movement or limited movement
(shuffling steps)
RESTING tremors (pill rolling)
- when at rest (ex: hands on knees, rising up - no tremor, at higher area - tremor again)
- almost any part of body can have a tremor
cogwheel rigidity (click clack effect) - intermittent in nature
posture and gait disturbances
- hunched over
- arms don’t swing
PD - hypokinesia
hypokinesia – difficulty initiating movements.
bradykinesia – a slowness in control of movements (bradyphrenia – slowness of thought).
Parkinsonian mask – frozen facial features.
(reptilian stare - droopy face)
Hypokinesia
difficulty initiating movements.
Bradykinesia
a slowness in control of movements (bradyphrenia – slowness of thought).
Parkinsonian mask
frozen facial features.
PD - tremors
resting tremors – can be used to determine the laterality of PD – PD is most often unilateral but can be bilateral.
pill-rolling tremor – refers to a stereotypical movement made at rest that resembles rolling a pill between your fingertips and thumb.
Resting tremors
can be used to determine the laterality of PD – PD is most often UNIlateral but can be BIlateral.
Pill-rolling tremor
refers to a stereotypical movement made at rest that resembles rolling a pill between your fingertips and thumb.
PD – cogwheel rigidity
increased muscle tone in extensor and flexor muscles leads to resistance to movement.
cogwheel rigidity refers small rigid steps in a passive movement (i.e., when the examiner tries to move the patient’s arm she encounters resistance leading to brief rigid steps rather than smooth movement).
PD – postural disturbances
bent posture, sometimes to point of falling.
head droops.
postural adjustments can be impaired – may fall when bumped. (shuffling back instead of quickly moving back)
(or on uneven ground b/c you can’t stabilize self quickly/move hands quickly)
PD – gait disturbances
SHUFFLING gait – very different from Ozzy’s wide based gait!
gradually DIMINISHING DISTANCE between steps.
eventual FREEZING.
virtual lines as treatment. - lazer light on cane - used as a goal (goal-directed movement), step over line each time
Treatment of PD (drugs)
L-dopa
- dopamine does not cross the blood-brain barrier.
- L-dopa is a precursor for dopamine.
anti-cholinergic drugs reduce the uptake of acetylcholine restoring the balance between dopamine and acetylcholine (a balance disrupted by the depletion of dopamine).
new combination medicines like Stalevo. (help with some symptoms)
Treatment of PD (treatments)
PALLIDOTOMIES – Michael J Fox has two!
- the INTERNAL GLOBUS PALLIDUS is lesioned during stereotaxic surgery.
- stimulated first to determine region responsible for excessive inhibition.
INTERNAL STIMULATORS – like a brain pacemaker. An electrode implanted in the thalamus stimulates the motor pathways (bypassing the connections from the basal ganglia).
SLIDE 13 - inhibit GPi/SNr & stimulate thalamus
Pallidotomies
Michael J Fox has two!
- the internal globus pallidus is lesioned during stereotaxic surgery.
- stimulated first to determine region responsible for excessive inhibition.
tend to be done in younger patients who don’t have as much but have TREMORS as a main issue (help with tremors in younger patients)
Internal stimulators
like a brain pacemaker. An electrode implanted in the thalamus stimulates the motor pathways (bypassing the connections from the basal ganglia).
Huntington’s Disease
inherited, autosomal dominant, degenerative disease affecting the caudate.
St. Vitus’ dance – 16th century Germany. Dance in front of statue for good health – mistaken for chorea.
Huntington’s chorea
begins between 30 and 45 years of age. (kids see parent have it & they don’t want (genetic) so suicide rates were high - but now have tests to determine))
death occurs 10 to 15 years after onset.
SLIDE 16 - excites cortex too much
Huntington’s Disease background
Hyperkinesias
- chorea (Greek for dance).
- athetosis – writhing contractions.
- contorted postures – head, arms and legs in constant motion.
also demonstrate bradykinesia – a slowness in control of movement.
more closely associated with degeneration of the caudate.
disease was brought to North America by Europeans fleeing persecution (burned as witches).
European origin to HD in Asian cultures too.
Huntington’s Disease – Nancy Wexler
Nancy Wexler is a scientist whose mother died of HD.
she and her colleagues isolated the gene responsible for HD in a small community in Venezuela with the highest incidence of HD in the world.
- lot of intermarrying
made a genetic test for the gene possible – can determine whether you will develop HD.
- becomes ethical - but should be if you want
Tourette’s syndrome
named after French neurologist Georges Gilles de la Tourette.
primary symptoms are vocal and motor “tics”.
involuntary, repetitive often compulsive movements.
begins in childhood (≈ 11 years old).
face and head are typically affected, although in more severe forms the limbs and whole body can be involved.
