Movement Disorders Flashcards
What subcortical gray-matter structures constitute the basal ganglia and are involved in movement disorders?
striatum (caudate nucleus and putamen), globus pallidus, subthalamic nucleus, substantia nigra
What neurotransmitters are crucial in the basal ganglia?
- Dopamine
- Acetylcholine
- GABA
What are functions of the extrapyramidal tract?
- Modulates the corticospinal tract
- Promotes, inhibits, and sequences movement
- Maintains muscle tone and posture
What is hypokinesia versus hyperkinesia?
Forms of dyskinesia
Hypokinesia - too little movement, such as in PD and parkinsonism, associated with bradykinesia and akinesia
Hyperkinesia - excessive movement, often in the form of tremor, athetosis, chorea, hemiballismus
What are the cardinal and classic signs of Parkinson’s disease (PD)?
- Tremor, usually slow and pill-rolling
- Rigidity, cogwheel or lead-pipe
- Bradykinesia, absence of reduction of arm swinging when walking, absence or reduction of gestures when talking
- Postural instability
Other signs include:
masked facies; hypophonia, micrographia, shuffling gait, dysphagia
What are two types of postural instability?
- Fixation disorder: inability or difficulty in maintaining a part of the body in normal position
- Equilibrium disorder: difficulty standing or sitting unsupported
Do movement symptoms in PD appear unilaterally or bilaterally?
- Typically first develop in asymmetric or unilateral pattern
- As disease progresses bilaterally, it continues to predominate on the side initially involved
What is the neuropathology of PD?
- Loss of DA cells in substantia nigra, particularly the lateral ventral tier; leads to DA depletion in striatum, affecting dorsolateral putamen mostly
- Lewy bodies in substantia nigra
- alpha-synuclein pathology outside the nigro-striatal system affecting the autonomic nervous system, lower brainstem, limbic system, and olfactory bulbs; may contribute to nonmotor syptoms
Risk factors for PD?
- viral encephalitis
- drugs with DA antagonistic properties
- toxic substances
- expsoure to MPTP, herbicides, pesticides, manganese, iron
- drinking contaminated well water
- genetic mutations - linked to parkinsonism
How many patients with PD develop dementia?
20-30%
What are risk factors for developing dementia in PD?
- Age over 70
- UPDRS score >25
- Comorbid depression
- Levodopa side effects of mania, agitation, disorientation, or psychosis
- Facial masking at presentation
- Cerebrovascular disease
- low SES
- Initial symptoms other than tremor
How many patients with PD have depression?
Up to 40%
What’s the age of onset for PD and age-related impact on disease course?
- Onset before 40-45 has slower progression, fewer cognitive difficulties
- Later onset has more rapid progression and more cognitive deficits
How do PD subtypes impact disease course?
- Tremor dominant subtype has a more benign course
- Nontremor subtype, including bradykinesia and rigidity as primary sx, disease more likely leads to dementia
What are the earliest motor and nonmotor signs of PD?
- numbness, pain, difficulty with dexterity, changes in handwriting
- decreased smell, hyposomnia, sleep disorders, constipation
Describe the stages of PD?
Stage 1: unilateral sx, usually tremor, mild, not disabling
Stage 2: bilateral sx, minimal disability, posture and gait affected
Stage 3: slowing of mvmnt, poor equilibrium, moderate dysfunction
Stage 4: severe sx, limited walking ability, rigidity, bradykinesia, unable to live independently, tremor may lessen
Stage 5: cachectic stage, cannot stand or walk, requires constant nursing care
What are treatment considerations in early to middle stages of PD?
- Medications: selegiline, dopamine agonists, coenzyme Q10 early on, adding levodopa
- Nonpharmacological: exercise, voice therapy, speech/swallowing therapy, biofeedback, balance exercises
What are treatment considerations in late stages of PD?
- Medication combinations
- Deep brain stimulation
- Pallidotomy, thalamotomy, subthalamotomy
- Assistive devices
- Treatment of nonmotor sx
What are expectations for neuropsych assessment results in PD?
- Intelligence: intact
- Attention: slowed complex attn, impaired working memory
- Processing speed: impaired
- Language: reduced output, naming gradually declines later stages
- Visuospatial: micrographia, poor perceptual judgment, angular orientation, constructional praxis
- Memory: impaired initial learning but benefits from cues, recognition, recall aids
- EF: impaired
- Sensorimotor: impaired
- Emotional: depression and anxiety are common
How many patients with PD respond to levodopa?
Almost 80% show improvement with levodopa
What psychotic symptoms may occur in PD?
- PD patients may have visual hallucinations that usually fluctuate throughout the daytime and worsen at night, typically include visions of people and animals
- Psychosis in PD correlates with dementia, illness duration, and severity, number and strength of dopaminergic meds, signs of excessive medication
How much of a role do genetic factors play in PD?
- only 10-15% of PD patients have a first-degree relative with PD
- only 5% have an identified genetic cause
- More significant role when onset occurs before age 50
What genetic marker is associated with Huntington’s (HD)?
- Autosomal dominant pattern
- CAG trinucleotide repeats (>36) on chromosome 4
- Number of CAG repeats is inversely related to age of onset
- between 36-40 repeats is reduced penetrance (+/- affected), while >40 is full penetrance
