Basal ganglia & movement disorders Flashcards
Myoclonus
Rapid jerking movement
5 parallel pathways through the basal ganglia
Motor Oculomotor Dorsolateral frontal Lateral orbitofrontal Medial frontal-anterior cingulate
Akinesia
Absence of movement; typically used to describe dysfunction that is localized to levels higher than UMNs
Torticollis
Focal dystonia involving the muscles of the neck
Dementia with Lewy Bodies vs. Parkinson’s disease dementia
DLB: onset of dementia w/i year of motor symptoms, fluctuating MS, visual hallucinations
Long-term complications of L-dopa treatment
“on-off” fluctuations, “wearing off” phenomena, peak-dose dyskinesia/dystonia, “off” period dystonia/freezing, visual hallucinations & psychoses
Chorea
Dance, nearly continuous involuntary movements that have a fluid or jerky, constantly varying quality
Dystonia
Sustained muscle contractions, usually resulting in abnormal postures
Essential tremor
Rhythmic, non-neurodegenerative, symmetric tremor that is present upon action or postural response
Characteristics of progressive supranuclear palsy (PSP)
Predominantly axial parkinsonism, prominent gait disorder with early falls, vertical eye movement abnormalities, dysarthria, dysphagia
What are some of the first symptoms of Huntington’s disease?
Decreased activity, restriction of interest, subtle alterations in personality, memory, & motor coordination
Parkinsonism with early falls suggests
PSP
Why do successive generations of Huntington’s disease patients develop symptoms at a younger age?
CAG repeat expands with successive generations
NP deficits in essential tremor
Mild attention/exec dysfx, language, memory Some evidence that essential tremor may increase risk for dementia
Parkinsonism with dystonia suggests
Wilson’s disease
Common causes of myoclonus
Anoxic brain injury, encephalitis, toxic or metabolic encephalopathies
Early neuropsychological deficits in cortical-basal ganglionic degeneration
Attention/executive & language dysfx, memory impairments generally mild with spontaneous recall worse than recognition
Amyotrophic lateral sclerosis (ALS)
Confined to the voluntary motor system, affects UMNs & LMNs; often begins focally in muscle groups
Lenticular (or lentiform) nucleus
Putamen + globus pallidus
Parkinsonism accompanied by early or predominant dementia suggests
Vascular parkinsonism, HD, diffuse Lewy Body disease (DLBD)
Spasticity
Slow, clumsy, stiff movements & hyperreflexia resulting from corticospinal, UMN lesions
Pathology of Parkinson’s disease
Loss of dopaminergic cells in the substantia nigra, projecting to striatum
Lifetime incidence of dementia in Parkinson’s disease
20-30%, up to 70% will develop dementia after 10 years of motor symptoms
Neuroleptic malignant syndrome
Muscle rigidity, hyperthermia, confusion & agitation progressing to somnolence & coma
Common comorbidities of Tourette syndrome
ADHD & OCD/behaviors
Hallervorden-Spatz disease
Inherited progressive illness with onset in late childhood/early adolescence that is characterized by dementia with spasticity, rigidity, dystonia, or chorea; caused by an accumulation of iron in the brain, particularly the GP & SNr
Anteropulsion
Appear to be continually fallowing & shuffling forward (seen in PD)
Postural tremor
Most prominent when patient’s limb is actively held in a position; essential tremor is most common type
Sydenham’s chorea
Streptococcal infection leading to the development of antistreptococcal antibodies; antibodies are believed to cross-react with BG brain antigens
Neurobehavioral symptoms of Sydenham’s chorea
Chorea, facial grimace, ballismus, decreased muscle tone, disruptions of gait & mvmt, attentional & exec deficits, emotional sequelae (anxiety, depression, OCD)
Genetics of Huntington’s disease
Expansion of the trinucleotide repeat CAG on chromosome 4 (repeats of >39 = HD); 50% chance of inheriting from parent
Outputs from the BG to the VL & VA nuclei of the thalamus travel via
Thalamic fasciculus
Net effect of the direct pathway
Inhibition of inhibitory BG output leading to increased cortex activation
Neuropsychological profile of Parkinson’s disease
Slowed psychomotor/info processing speed, early visuoperceptual/constructional deficits, attention/exec dysfx, poor retrieval but intact recognition, depression & apathy
Palatal myoclonus is typically caused by a lesion of the
central tegmental tract
What is the classic cause of ballismus?
Lacunar infarct of the subthalamic nucleus
3 forms of dystonia
Generalized, unilateral, focal
What do MRI studies of PSP show?
Atrophy of midbrain & pons, particularly upper midbrain
Cognitive changes associated with Huntington’s disease
Poor decision-making, cognitive flexibility; mild encoding deficit & moderately impaired retrieval in context of relatively intact memory storage; poor vigilance; visuospatial difficulties; early speech changes (reduced phrase length, impaired fluency)
Rubral tremor
Most likely caused by lesions of the superior cerebellar peduncles or other cerebellar circuitry, may also be caused by MS or brainstem infarcts; involves head & trunk titubation or palatal myoclonus
Striatum
Caudate + putamen; receives all inputs to the BG
Cortical-basal ganglionic degeneration
Combo of cortex (apraxia, cortical sensory deficits, alien limb phenomenon) + basal ganglia involvement (akinesia, rigidity, dystonia)
Which subtype of MSA is associated with the most extensive cognitive deficits?
Striatonigral degeneration
Botox acts by
Interfering with the presynaptic release of ACH at the neuromuscular junction
Onset of PD is most common between the ages of
40 & 70
Paratonia (gegenhalten)
Active resistance of movement of limbs; observed in patients with frontal lobe lesions
Which subtype of MSA is associated with autonomic disturbance?
Shy-Drager syndrome
Palatal myoclonus
Markedly rhythmic & notably persistent during sleep, w/ movements of the palate occurring at a rate of 1-2 hz & ST extending to the face or proximal upper extremities
Chorea gravidarum
chorea occurring during pregnancy or while on oral contraceptives; may represent an initial episode or recurrence of SLE or Sydenham’s chorea
Spastmodic dysphonia
Focal dystonia involving the laryngeal muscles
Cogwheel rigidity
Ratchet-like interruptions in tone that can be felt as the limb is bend; characteristic of PD
Ballismus
Movements of the proximal limb muscles with a larger-amplitude, more rotatory or flinging quality than chorea
Neuropsych profile of PSP
Attention/exec dysfx, slowed processing speed, memory deficits; depression & behavior changes with later stages
Main components of the basal ganglia
Caudate nucleus, putamen, globus pallidus, subthalamic nucleus, substantia nigra
Athetosis
Twisting movements of the limbs, trunk, face; associated with damage to the contralateral striatum
Myasthenia gravis
Autoimmune neuromuscular disorder associated with decreased post-synaptic nicotinic acetylcholine receptors at the neuromuscular junction
Myerson’s sign
Inability to suppress blinking when the glabella (center of brow) is tapped repeatedly (seen in PD)
Benign familial chorea
Autosomal dominant inheritance, nonprogressive, without emotional or cognitive decline
Tardive dyskinesia
Nonreversible, involuntary mvmt disorder resulting from dopamine hypersensitivity after long-term neuroleptic therapy
Depression can precede the onset of neuro symptoms in Huntington’s by
2-20 years
Tourette syndrome diagnostic criteria
2+ motor tics & 1+ phonic tic over a 1 year period before the age of 18 years
Wilson’s disease
Autosomal recessive disorder of biliary copper excretion that cause progressive degeneration of the liver & BG
Rigidity
Increased resistance to passive movement of a limb
Neurological manifestations of Wilson’s disease
Gradual onset dysarthria, dystonia (‘risus sardonicus’), rigidity, tremor, choreathetosis, prominent psych disturbances, Kayser-Fleischer rings
Net effect of the indirect pathway
Inhibition of cortex
Parkinsonism + ataxia suggests
Multiple-system atrophy (olivopontocerebellar atrophy)
Motor symptoms of Huntington’s disease
Choreiform movement (within a year after onset of psych symptoms), unsteady gait, eye movement abnormalities, difficulty with speech & swallowing
Psychosis in Huntington’s disease is more common in
Early-adult-onset cases
Retropulsion
if the pt is pulled backward slightly, a series of several backward steps are taken to regain balance (seen in PD)
Physiological tremor
Believed to be caused by enhancement of normal tremor present in all individuals; can be caused by drugs, meds, metabolic derangements, ETOH withdrawal, intense fear, anxiety, etc.
Poliomyelitis
Polio-caused motor neuron virus infecting anterior horn cells of spinal cord & lower brainstem; not associated with cognitive impairment
Acute onset of parkinsonism is suggestive of
Vascular or drug-induced parkinsonism
Symptoms of Parkinson’s disease
TRAP = tremor, rigidity, akinesia, postural instability
Blepharospasm
Focal dystonia involving the facial muscles around the eyes
Neuropsych profile of juvenile-onset Huntington’s disease
Consistent with severe ADHD, decreased cognitive efficiency, mental inflexibility, memory deterioration, changes in engagement & language skills
Behavioral changes are the presenting manifestation in what percentage of Huntington’s cases?
79%
Asterixis
Flapping tremor; known as “liver flap” in hepatic failure
Bradykinesia
Slowed movements, often caused by increased inhibitory outflow from the BG to the thalamus
3 types of multiple system atrophy
Olivopontocerebellar atrophy - primarily cerebellar features Shy-Drager Syndrome Striatonigral degeneration
Where do neurons degenerate in Huntington’s disease?
Striatum, which can cause the lateral ventricles to appear enlarged on MRI or CT scans
Parkinsonism accompanied by unilateral apraxia & reflex myoclonus suggests
Cortical-basal ganglionic degeneration
Hypokinesia
Decreased amount of movements
