Disorders of Motility Flashcards
This is the isolated activity of an individual muscle fiver which occurs from a few days after interruption of a motor nerve. It is recorded in the EMG as a small, repetitive, short-duration potential.
Fibrillation
This is a visible twitch of a muscle fascicle resulting from contraction of one or several motor units which occurs when a motor neuron becomes diseased, with increased irritability, and then generate spontaneous impulses leading to sporadic discharge of the muscle fibers it controls in isolation from other units. The EMG shows this as large spontaneous muscle action potential.
Fasciculation
This is the simultaneous or sequential spontaneous contractions of multiple motor units, “rippling of muscle”
Myokimia
The Law of Reciprocal Innervation, Antagonists relax at the same rate that agonists contract
Sherrington Law
What are the principal neurotransmitters of the following:
(1) Neuromuscular junction
(2) descending corticospinal tract
(3) Renshaw cells, recurrent inhibition, interneurons that mediate reciprocal inhibition during reflexes
(4) Inhibitory neurotransmitter of interneurons in the posterior horn
(1) Neuromuscular junction - acetylcholine
(2) descending corticospinal tract- glutamate and aspartate
(3) Renshaw cells, recurrent inhibition, interneurons that mediate reciprocal inhibition during reflexes- glycine
(4) Inhibitory neurotransmitter of interneurons in the posterior horn- GABA
How fast does a muscle atrophy after denervation?
A denervated muscle may be reduced by 20-30% of its original bulk within 3-4 months after injury
To which brainstem nuclei does the corticobulbar tract have direct connections to?
The corticobulbar tract has direct connections to the trigeminal, facial, ambiguus, and hypoglossal nuclei
What is Broadbent’s Law?
It describes the pattern of central facial palsy
What is the bundle of fibers from the cortex destined for the facial nucleus which first goes down to the upper medulla before decussating and going back up to the pons called?
Pick’s bundle. It explains why some patients with upper medulla or lower pons lesions have central pattern of facial weakness.
What is usual frequency of clonus?
About 5-7 Hz. Constant by 1 Hz
Which corticospinal fibers cross more rostrally in the medullary pyramids?
Upper limb fibers
Differentiate the different forms of apraxia and their localization
Ideational apraxia- failure to conceive or formulate an action to command - sensory areas 5&7 in dominant parietal lobe, bilateral supplementary and premotor cortices
Ideomotor apraxia- cannot execute pllaned acute with either hand, even if he may remember how to do it- left parietal region
Limb-kinetic apraxia- ill defined clumsiness or maladroitness from inability to fluidly connect or isolate individual movements of the hand and arm
sympathetic apraxia- paralysis on one side obscures apraxia on that side, but there is also a breakdown of fine finger movements on the opposite side
oral-buccal-lingual-apraxia- unable to carry out facial movements on command- left supramarginal gyrus or left motor association cortex
dressing apraxia, constructional apraxia- specific apraxias from non-dominant parietal lobe
What entities can produce the “alien hand” phenomenon?
(1) ACA infarction involving the corpus callosum
(2) lesions of left supplementary motor area
(3) corticobasal ganglionic degeneration
(4) some cases of PCA strokes with sensory loss
What is utilization behavior? Where can it be localized?
Utilization behavior is when a patient obligatorily seizes and uses objects in the surrounding environment
It is associated with extensive bilateral frontal lobe damage
What tests can be used to differentiate psychogenic from true paralysis?
(1) Hoover sign - put hands under both heels, ask pt to push down; then put one hand on top of nonparalyzed leg, the other under the paralyzed leg and ask pt to raise nonparalyzed leg
(2) push knees or arms together; say you are testing the good side
(3) trunk thigh sign- ask pt to sit up with arms crossed at the chest. In true paralysis, Weak limb flexes when trying to sit up.
What are the input structures in the basal ganglia?
The striatum- the caudate nucleus and the putamen
What are the output structures of the basal ganglia?
The internal globus pallidus and the substantia nigra pars reticulata
What are the ansa lenticularis and fasciculus lenticularis? How are they different?
They are output tracts from the globus pallidus interna to the thalamus (they join the thalamic fasciculus)
The ansa lenticularis sweeps around the internal capsule
The fasciculus lenticularis passes through the internal capsule
Does the thalamus project back to the basal ganglia? How?
Yes.
The centromedian nucleus of the Intralaminar region projects back to the putamen, while the parafascicular nucleus projects to the caudate nucleus.
What are the neurotransmitters involved in the basal ganglia circuitry?
Dopamine (from substantia nigra pars compata)
Glutamate (excitatory projections from cortex to striatum, and from subthalamic nucleus)
GABA (inhibitory neurotransmitter of striatal, pallidal and substantia nigra pars reticulata neurons)
acetylcholine (golgi type 2 nonspiny striatal neurons)
substance P, enkephalin, cholecystokinin, somatostatin, neuropeptide Y
What are the different dopamine receptor types and where are they concentrated in the brain?
D1 and D2- striatum
D3- nucleus accumbens
D4- frontal cortex and certain limbic structures
D5- hippocampus
What is the principal location of the lesion in the ff. conditions:
(1) Parkinson’s disease
(2) Unilateral hemiballismus and hemichorea
(3) Chronic chorea of Huntington type
(4) Athetosis and Dystonia
(5) Palatal and facial myoclonus
(1) Parkinson’s disease- substantia nigra, contralateral
(2) Unilateral hemiballismus and hemichorea- contralateral subthalamic nucleus
(3) Chronic chorea of Huntington type- caudate nucleus and putamen
(4) Athetosis and Dystonia- contralateral striatum
(5) Palatal and facial myoclonus- ipsilateral central tegmental tract with denervation of inferior olivary nucleus and nucleus ambiguus
This is the variable resistance to passive movement where the patient appears unable to relax a group of muscles on request. When the limb muscles are passively stretched, pt appears to actively resist the movement.
Gegenhalten, Paratonia or Oppositional resistance
Give at least 10 conditions that can cause chorea
Inherited conditions such as Huntington’s disease, benign hereditary chorea, neuroacanthosis, dentatorubropallidoluysian atrophy, Wilson disease
Drug induced, such as in patients given neuroleptics like phenothiazines, haloperidol and metoclopromide; oral contraceptives, phenytoin, excess L-dopa and dopa agonist, cocaine
Systemic diseases such as thyrotoxicosis, polycythemia vera, hyperosmolar nonketotic hyperglycemia, toxoplasmosis in AIDS, hyponatremia, hypoglycemia
Hemichorea can be caused by stroke, tumor, vascular malformation
Differentiate chorea, athetosis, ballismus and dystonia
Chorea - involuntary, arrhythmic movements of a forcible, rapid, jerky type
Athetosis- inability to sustain the body part in one position; the maintained body posture is interrupted by relatively slow, sinuous, purposeless movements that have a tendency to flow into one another
Ballismus- uncontrollable, poorly patterned flinging movement of an entire limb
Dystonia- unnatural spasmodic movement of posture that puts the lime in a twisted posture
Give at least 10 conditions that can cause athetosis
Huntington's disease Double athetosis Cerebral palsy (anoxia) Kernicterus Hepatic encephalopathy Chronic intoxication with phenothiazines or haloperidol Wilson's disease Leigh disease and other mitochondrial disorders Nieman-Pick type C Kufs Disease neuroacanthocytosis Ataxia telangectasia Excessive L-dopa AIDS AEDs Vascular lesion of lenticular nucleus or thalamus
Give at least 3 causes of ballismus
When unilateral, from an acute lesion of or near the contralateral subthalamic nucleus
Bilateral may be from metabolic disturbances such as nonketotic hyperosmolar coma, paraneoplastic process
What medication can be given to suppress ballismus?
Haloperidol or phenothiazine may suppress violent movement
What is Segawa disease?
Segawa disease is L-dopa responsive dystonia.
It is familial, and usually autosomal dominant
It has marked diurnal fluctuation of symptoms, with the movement disorder worsening as the day wears on and improving with sleep
What is rapid onset dystonia parkinsonism?
It is a hereditary dystonia, with onset in adolescence or early adulthood
There is rapid evolution, sometimes within hours or days, with severe dystonic spasms, dysarthria, dysphagia and postural instability with bradykinesia
What is another name for pantothenate kinase-associated neurodegeneration?
Hallevorden-Spatz disease
Give at least 10 causes of generalized dystonia
Dystnoia musculorum deformans Double athetosis kernicterus Hallevorden-Spatz disease Huntington disease Wilson disease Lysosomal storage diseases Striatopallidodentatal calcification, can be from hypoparathyroidism Thyroid disease Exposure to neuroleptic drugs, L-dopa, calcium channel blockers, AEDs, anxiolytics
For hemidystonia, stroke, traumatic and perinatal damage
What medication can be given in patients with drug-induced dystonia?
Diphenhydramine or Benztropine 2-3x over 24-48 hours
How can dystonia be managed?
Anticholinergic agents such as trihexyphenidyl, benztropine and ethopropazine may help, especially in children
Tetrabenazine
Stereotactic surgery on pallidum and ventrolateral thalamus; DBS of bilateral posteroventral globus pallidus
For focal dystonia: botox injections
What are the 3 main types of familial paroxysmal choreoathetosis?
(1) Paroxysmal Kinesinegenic Choreoathetosis- AD, tendency to affect males, begins in adolescence or earlier, numerou, brief attacks of choreathetosis provoked by startle, sudden movement or hyperventilation; may have multiple attacks a day
(2) Mount-Reback type- AD, attacks take the form of persistent dystonic spasms (5 min to 4 hours), precipitated by ingestion of alcohol or coffee and fatigue
(3) precipitated by prolonged exercise
What medications can be given to patients with familial paroxysmal choreoathetosis?
First type, paroxysmal kinesinegenic choreoathetosis is responsive to AEDs especially phenytoin and carbamazepine Second type, Mount-Reback type, is responsive to benzodiazepines like clonazepam Third type (exercise-induced), is responsive to benzodiazepines and to acetazolamide
What medications can be given to patients with acquired paroxysmal choreoathetosis?
AEDs and clonazepam may help
Give at least 5 possible causes of acquired paroxysmal dyskinesias
Stroke Trauma Encephalitis Perinatal anoxia Multiple sclerosis Hypoparathyroidism Thyrotoxicosis Nonketotic hyperosmolarity HIV- toxoplasmosis, lymphoma
What toxin can reproduce the symptoms of the parkinsonian syndrome? How was it discovered?
1-methyl-4-phenyl-1,2,3,6, tetrahydropyridine (MPTP). It was discovered in drug addicts who inject themselves with a meperidine analogue
What are the 3 lobes of the cerebellum?
What are the 3 vertical zones?
What are their functions?
3 lobes:
(1) flocculonodular lobe/ archicerebellum/ vestibulocerebelllum- equilibrium
(2) anterior lobe/ paleocerebellum/ spinocerebellum- posture and muscle tone
(3) posterior lobe/ neocerebellum/ pontocerebellum- coordination of skilled movement
3 vertical zones:
(1) vermian zone- coordinates movement of eyes and body with respect to gravity and movement of head in space
(2) intermediate zone- postural tone, individual movement of ipsilateral limb
(3) lateral zone- coordination of movement of ipsilateral limb
What relay area in the thalamus does the cerebellum project to?
Ventrolateral thalamus and Intralaminar nuclei
What is the loop that involves the cerebellum, the reticulotegmental and paramedian reticular nuclei of the pons and the inferior olivary nuclei of the medulla via the central tegmental tract?
What disease is caused by a lesion to this loop which is present even when a patient is asleep?
Guillain-Mollaret triangle
Palatal myoclonus
What are the deep cerebellar nuclei and what are their functions?
(1) Dentate nucleus- help initiate volitional movement
(2) Interpositus (globose and emboliform)- fire in relation to movement once it has started; smoothness of alternating movements; damps physiologic tremor
(3) fastigial- antigravity muscles and muscles for standign and walking
What are the 3 layers of the cerebellar cortex and what are the predominant cell types in each?
(1) Molecular layer - stellate and basket cells (inhibitory)
(2) Purkinje layer- cell body of Purkinje cells (inhibitory)
(3) Granular layer- granule cells (excitatory), golgi interneurons (inhibitory)
What are the afferent inputs to the cerebellum? What neurotransmitters do they employ?
(1) Mossy Fibers- from spinocerebellar tract, pontine, vestibular and reticular nuclei- Aspartate
(2) Climbing fibers- from inferior olivary nuclei (excitatory to Purkinje cells)- Glutamate via AMPA receptors
(3) Aminergic fibers
Dopaminergic from ventral mesencephalic tegmentum to interpositus and dentate
Serotonergic from raphe nuclei to granule and molecular layers
What are the clinical features of cerebellar disease?
Incoordination/Ataxia of volitional movement
Intention tremor
Disorder of equilibrium/gait
Diminished muscle tone
What other tremors can a patient with a cerebellar lesion have aside from intention tremor?
Wing-beating tremor- coarse, irregular, wide range tremor which may be present in position of repose and enhanced when the patient activates limb muscles, either to sustain a posture of effect a movement
Titubation- rhythmic tremor of the head or upper trunk (3-4 hz) often seen in midline cerebellar disease
Rhythmic oscillation of fingers with similar tempo to PD tremor with certain sustained postures such as with arms extended and hands on knee.
Give at least 10 possible causes of cerebellar ataxia
Intoxication from alcohol, lithium, barbiturates, phenytoin, AED Diamox responsive episodic ataxia Childhood hyperammonemia Post-infectious Viral cerebellar encephalitis Myxedema Extreme hyperthermia with coma at onset Intoxication with mercury compound or toluene Post anoxic Adulterated heroin Brain tumor paranaeoplastic Alcoholic- nutritional Creutzfeldt-Jakob disease Cerebellar ataxia Whipple disease Sprue (gluten enteropathy) Multiple sclerosis Friedrich ataxia Spinocerebellar degeneration Hereditary Cerebellar degeneration Adult form of Fragile X Hereditary metabolic disease Childhood ataxias (ataxic telangectasia, cerebellar agenesis)
Differentiate physiologic tremor, essential tremor, ataxic tremor and parkinsonian tremor based on frequency, predominant location, enhancing and attenuating agents/circumstances and EMG findings
Physiologic tremor - 8-13 Hz- hands- postural- epinephrine and B adrenergics enhance- alcohol, B blocker attenuate
Essential tremor- 4-8 Hz- hands, head, vocal cords- postural- emotion, exercise, fatigue enhance- alcohol, B blocker attenuate -EMG: almost simultaneous burst of activity in agonist and antagonist
Ataxic tremor- 2-4Hz- limbs, trunk, head - action, during exacting part of task- emotional stress enhance-
Parkinsonian tremor- 3-5 Hz- hands, forearm, feet, jaw, lips or tongue- rest- worse when walking, emotional stress - disappear when limb fully supported or during sleep, L-dopa and anticholinergics attenuate- EMG: burst of activity that alternate between opposing muscle groups
Give at least 10 conditions where you can see an enhanced physiologic tremor
Intense fright or anxiety
Intense physical exertion
Metabolic disturbances such as hyperthyroidism, hypercortisolism, hypoglycemia
Pheochromocytoma
Withdrawal from alcohol, other sedative drugs
Toxic effects of several drugs such as lithium, nicotinic acid, xanthines like coffee, tea, aminophiline, cocaine, methylphenidate, other stimulant drugs and corticosteroids)
How can essential tremor and parkinsonian tremor be differentiated in terms of activity?
Essential tremor is more prominent when pt is trying to maintain a static limb posture, but may also be present when performing movements like writing or putting spoon or glass to lips, may interfere with daily activities
Parkinsonian tremor more prominent when limb is in attititude of repose, may be diminished by movement and then would reassert itself once the limb assumes a new position (But if limb is completely supported, will also vanish), can be seen or even worsen as person walks- does not significantly interfere with daily activities
What is a rubral tremor and when can it be seen?
A rubral tremor is a 2-5 Hz, rhythmic, wing-beating movement, of higher amplitude than an intention tremor, associated with every movement movement, including maintaining posture, which is seen in patients with lesions in the midbrain affecting the dentatorubrothalamic fivers and medial part of the ventral tegmental tract
It can be seen in pts with MS, Wilson disease, vascular lesions, rarely in pts on antipsychotic medications
What is a primary orthostatic tremor and how can it be treated?
A primary orthostatic tremor is a rare but striking 14-16 Hz tremor isolated to the legs, which occur only during quiet standing and ceases almost immediately upon walking.
Pts may respond to clonazepam, gabapentin, primidone or sodium valproate
What are the features of psychogenic tremor that may differentiate it from other tremors of organic cause?
Psychogenic tremors are:
(1) usually restricted to a single limb, often the dominant hand
(2) gross in nature, less regular
(3) they may diminish in amplitude or disappear when pt is distracted or asked to do a complex movement with the opposite hand (whereas essential tremors are enhanced by this maneuver–Froment sign)
(4) If examiner restrains affected hand and arm, tremor may move to more proximal part of limb or another body part
(5) present in repose and during movement
(6) often acquire the frequency of a willed movement ina different limb
What is palatal tremor? How can it be treated?
Palatal tremor is a rare disorder where there is rapid, rhythmic, involuntary movement of the soft palate, it is at 26-420 cycles per minute for the essential type and 107-164 cycles per minute for the symptomatic type.
The essential type ceases during sleep, but the symptomatic type DOES NOT!
The symptomatic type is due to a diverse group of brainstem lesions that interrupt the central tegmental tract
Treatment includes clonazepam, sodium valproate, gabapentin, tetrabenazine, haloperidol and even botulinum toxin injections
What is asterixis and in what conditions can it be seen?
Asterixis is the arrhythmic lapse of sustained posture that allow gravity or inherent elasticity of muscles to produce a movement which the patient then corrects and sometimes overshoots.
It can be seen in hepatic encephalopathy, hypercapnea, uremia and other toxic and metabolic encephalopathies; may also be evoked by phenytoin and other AEDs, unilateral asterixis may be due to stroke (particularly of the thalamus)
Give examples of conditions that fall under focal/regional myoclonus, diffuse myoclonus and spinal/segmental myoclonus
Focal/Regional myoclonus
- Benign epilepsy with rolandic spikes
- Some degenerative neurologic conditions such as Corticobasal degeneration
Diffuse myoclonus
- essential/ familial myoclonus
- myoclonic epilepsy such as JME, familial myoclonic epilepsy of Unverricht and Lundborg, Lafora Body disease, baltic myoclonus, cherry red spot myoclonus syndrome, gaucher disease-early adult neuropathic form
- Infectious such as the Creutsfeldt-Jakob disease
- degenerative conditions such as AD, LBD, corticobasal degeneration, and occasionally Wilson disease
- Acquired metabolic disorders such as uremia and anoxic encephalopathy;
- Drug intoxication with haloperidol, lithium or amphetamines
- hashimoto thyroiditis, Whipple disease
- Tetanus and stychnine poisoning
- Opsoclonus-myoclonus syndromes in neuroblastoma, lung, breast or ovarian CA
- postinfectious, including SSPE
Spinal/Segmental myoclonus
- myelitis such as zoster myelitis, post infectious transverse myelitis or even MS
- epidural cord compression
- paraneoplastic syndrome as in breast cancer
Give examples of conditions with stimulus sensitive (reflex) myoclonus
Familial myoclonic epilepsy of Unverricht and Lundborg
Lafora body disease
Give examples of myoclonic dementias (Disease has both myoclonus and Dementia)
Familial myoclonic epilepsy of Unverricht and Lundborg
Creutzfeldt- Jakob disease
Subacute sclerosing panencephalitis
What type of myoclonus is present when pt performs fast movements, especially when directed to a target? It is almost always associated with cerebellar ataxia and is responsive to barbiturates and valproic acid.
Which types of pts was this myoclonus initially described?
Intention or action (postanoxic) myoclonus.
Described in a group of patients recovering from hypoxic encephalopathy
What is the most common mutation in hyperexplexia?
What physical maneuver can be done to dampen the startle response in these patients?
Hyperexplexia/ Hyperekplexia/ Startle disease/ Latah/ Myriachit
The most common mutation is in the 1 subunit of the inhibitory glycene receptor (GLRA1)
Vigerano maneuver- flex neck and bring arms close to torso
Give at least 5 possible causes of focal dystonia
Focal dystonias may be a result of:
- tardive dyskinesia from neuroleptic drugs
- degenerative diseases like PD, corticobasal degeneration, progressive supranuclear palsy
- metabolic disorders such as Wilson disease and nonwilsonian hepatolenticular degeneration
- stroke (rare)
- acquired systemic disorders such as hypoxia, AIDS, drugs and SLE
What gene abnormality has been seen in a few patients with spasmodic torticollis?
DYT1 gene abnormality
What is a gestes?
A contactual stimulus such as placing a hand on the chin, etc which can reduce spasms in pts with spasmodic torticollis
What are the most prominently affected muscles in spasmodic torticollis?
Sternocleidomastoid
Levator scapulae
Trapezius
What syndrome is characterized by lingual, facial and oromandibular spasms, which appear in late adult life (peak at 6th decade) affecting women more than men?
Meige or Brueghel syndrome
What is PANDAS syndrome?
Pediatric autoimmune neuropschiatric disorders with streptococcal infection
- tics, obsessive compulsive behaviors?
What treatment can be given for tics, including Gilles de la Tourette syndrome?
Alpha2 adrenergic agonists such as clonidine and guanfacine
neuroleptics such as haloperidol, pimozide, sulpirid, tiapride and risperidone
tentrabenazine
botox
DBS
naltrexone
Hyperactivity in tourette’s may be managed with clonidine or methylphenidate
Isolated or limited motor tics in males generally an inherited trait is often greatly aided by clonazepam
How much of the gait cycle is spent on the stance phase? on Double limb support?
Stance phase: 60-65%
Double-limb support: 20-25%
Differentiate cerebellar, sensory ataxic, parkinsonian, frontal lobe gaits based on cadence, step-length, base and other associated symptoms
Cerebellar- irregular cadence- slightly short step length- wide base- may veer
Sensory ataxic- normal cadence-short step length- slightly wide base- stamping of feet, (+) Romberg
Parkinsonian- slow cadence until festination- short step length- normal base- leaning forward, shuffling, freezing, difficulty with initiation
Frontal lobe- slow cadence- short step length- slightly wide base- difficulty starting or stopping, magnetic
What is astasia-abasia?
Astasia-abasia is the term used to describe a psychogenic gait disorder in which patients although unable to stand or walk, display more or less normal use of their legs while in bed and have an otherwise normal neuro exam and body carriage
