Basal ganglia disorders Flashcards
Huntington Disease (HD)
ages the indirect pathway (no brakes!)
Autosomal dominant; age of onset is 3rd to 4th decade
Huntington Disease (HD) impairments
Chorea, oculomotor problems, dystonia, ataxia, dysarthria, dysphagia, cognitive issues
Parkinson Disease (PD)
Damages the direct pathway (no accelerator!)
Symptoms develop after age 50 years
Parkinson Disease (PD) impairments
Bradykinesia, cogwheel rigidity, postural instability, poor balance, poor coordination, depression, cognitive issues
neurotransmitter for Cortical motor areas produce excitation of the striatum
Glutamate
neurotransmitter for Substantia nigra to the striatum adjusts the signals to the output nuclei
dopamine
Basal ganglia inhibits 3 areas:
Motor thalamus, Pedunculopontine tegmental nucleus (PPN) and midbrain locomotor region
Basal ganglia chart
•Loss of dopamine to putamen causes
- Reduces activity in motor areas of the cerebral cortex
- Decreases voluntary movements
Loss of acetylcholine-producing cells in PPN disinhibits the reticulospinal tracts
•Excessive contraction of postural muscles
Toxic Parkinsonism
Agent orange, pesticides, permethrin, CO, synthetic heroin MPTP
Rigidity
increased muscle tone with resistance to passive stretch
Cogwheel Rigidity
your muscle will be stiff, like in other forms of rigidity. But you might also have tremors in the same muscle when it’s at rest.
Festinating gait
decrease in step length and heel strike resulting in small steps and shuffling
INCREASED step cadence
Freezing gait
abrupt stopping of movement without intention to do so
Often triggered by visual stimuli
Resting tremor
involuntary, rhythmic shaking movement
Bradykinesia
slowed bodily movements; including slowed alternating movements such as finger tapping, making a fist, hand dexterity, and gait
Hypokinesia
less movement: often seen in facial expressions
Diagnosis requires 2 of 4 cardinal features
Tremor
Rigidity
Akinesia (hypokinesia and bradykinesia)
Postural instability/impaired balance or coordinationSubtle onset; including flexed posture of head, shoulders, and hips
Basal Ganglia Loops
Motor Channel, Oculomotor channel, Emotional/Limbic Channel
Motor Channel associated with
movement in both PD and HD
Oculomotor channel associated with
regulation of eye movements
Emotional/Limbic Channel
limbic cortex, hippocampal, and amygdala connections
Prefrontal Channel
cognition
Stage 1 Parkinson’s impacts in CNS
- Lesions in the olfactory bulb, dorsal IX/X nucleus of brainstem
- Decreased smell and taste
Stage 2 Parkinson’s impacts in CNS
- Lesions in pontine tegmentum (locus coeruleus, reticular formation, raphe nuclei)
- Alertness, posture, awareness of environment
Stage 3 Parkinson’s impacts in CNS
- Involvement of nigrostriatal system (substantia nigra)
- Voluntary movement
Stage 4 Parkinson’s impacts in CNS
- Lesions in hypothalamus, thalamus and cortex (temporal)
- Language, planning, sensory integration
Stage 5 Parkinson’s impacts in CNS
- Sensory association areas of neocortex and prefrontal neocortex
- Risk-reward judgements, personality, emotional regulation
Stage 6 Parkinson’s impacts in CNS
•First-order association areas of neocortex
Postural Control
ability to achieve, maintain, and regain balance
Postural Instability causes in PD
- PD causes smaller functional limits of stability (LOS)
- Narrowing of BOS
- Abnormal coactivation response results in rigid body and inability to access postural synergies (ankle or hip strategies)
- Difficulty regulating feed-forward or anticipatory responses; responses are slowed
Huntington’s Disease symptoms
- development of emotional, behavioral, and psychiatric abnormalities;
- loss of previously acquired intellectual or cognitive functioning;
- movement abnormalities (motor disturbances).
Huntington’s disease pathophysiology
- Degeneration of striatum and cerebral cortex
- Decreases signals from basal ganglia output nuclei
- Disinhibition of the motor thalamus and PPN
- Excessive motor output from cerebral cortex
Chorea
•involuntary, rapid, irregular, jerky movements that may affect the face, arms, legs, or trunk.
Dementia
•gradual loss of thought processing and acquired intellectual abilities.
Disorientation
•There may be impairment of memory, abstract thinking, and judgment; improper perceptions of time, place, or identity.
Personality disintegration
•increased agitation and personality changes
Dysphagia
present in both PD and HD
Athetosis
•is characterized by slow, involuntary, writhing, twisting, “wormlike” movements.
Greater involvement in distal UE
Aerobic Exercise benefits for HD
•Improves fitness and motor function
Supervised gait training
- Improves spatiotemporal factors
- Improves walking speed and step length
Balance Training & Exercise
- Improves balance but does not reduce falls
- Core stability for control. Application of principles of strength and coordination
Physical Activity and Exercise Outcomes in Huntington Disease (PACE-HD)
Used to track progress in HD patients
Checks if
FOGS
Is a cognitive screening tool
- F= Family story
- O= Orientation. Person, Place, Time
- G= General information. Current events, President, etc
- S= Spelling. Ask to spell “word” forward and backward
Montreal Cognitive Assessment
- Quick test
- Available in 36 languages
- <26 indicates cognitive impairment
- Sensitive for patient with HD
