Fifteen Flashcards
What are voluntary movements? What are involuntary movements? What is paralysis? What is paresis? What is bradykinesia? What is akinesia?
Voluntary movements are those movements which are initiated by an act of will and for which the mover assumes responsibility.
Involuntary movements are all movements which are not voluntary.
• Paralysis is absence of movement while paresis is reduced power of movement.
- Bradykinesia is reduced speed and spontaneity of normal movements such as blinking, facial expressions, standing up, walking.
- Akinesia is absence of spontaneous movements.
What is muscle tone? What is hypotonia? What is rigidity? What is spasticity? What kind of muscles is it seen in? What is it often associated with?
- Muscle tone is the degree of resistance of a limb to passive manipulation beyond that contributed by the normal visco-elastic tension of the muscles and joints.
- Hypotonia is a reduction in muscle tone.
- Rigidity is a marked increase in muscle tone in agonists and antagonists evident by passively moving part of an extremity through its range of motion.
• Spasticity is a condition of altered muscle tone and heightened resistance to passive movement (esp. when rapid) in which there is an increase in tone one half
to two thirds of the way through the range of muscle movement producing a clasp-knife type of resistance. Spasticity is typically seen in antigravity muscles.
It is often associated with other pyramidal signs such as weakness, hyperactive tendon reflexes, and extensor plantar responses (Babinski sign).
What is akathisia? What is ataxia? What is dysmetria? What are gegenhalten or counter movements?
- Akathisia is a state of restlessness or inability to sit still.
- Ataxia is a loss of muscular coordination.
- Dysmetria is clumsiness with irregular and uneven displacement of a limb occurring perpendicular to an intended trajectory, most pronounced at the onset and end of a movement, due to cerebellar dysfunction.
- Gegenhalten or Counter movements are noted as resistance to tactile contact and to passive manipulation that is equal in force and opposite in direction to the displacement imposed on the limb by the examiner during passive manipulation,often increasing in force with increasing force applied by the examiner.
What is a tremor? Physiologic tremor? Action tremor? Kinetic Tremor? Postural tremor? Rest tremor? What is asterixis? What is chorea? What is athetosis?
• Tremor is an involuntary, rhythmic and regular oscillation of a body part in any plane, due to the alternate or synchronous action of groups of muscles and their
antagonists. Physiologic tremor occurs in normal people during times of emotional stress and following exercise. Action tremor occurs during a voluntary act. Kinetic tremor occurs during movement. Postural tremor occurs while actively maintaining posture. Rest tremor occurs when limbs are relaxed and inactive.
- Asterixis is recurrent brief lapses of posture observed with arms raised and extended at the elbows and wrists.
- Chorea is a condition marked by excessive spontaneous, irregular, random, brief, abrupt, non-repetitive quasi-purposive involuntary movements with a distal predominance, flowing randomly from one body part to another.
- Athetosis is an involuntary movement characterized by irregular, forceful, slow, writhing movements generally of the extremities, very often with finger movements and with co-contraction of agonists and antagonists.
What is dystonia? What is myoclonus? What is a tic? What is ballismus?
• Dystonia is a condition marked by sustained and patterned muscle contractions of agonist and antagonist muscles (co-contraction), leading to twisting involuntary
movements which are frequently repetitive and which may progress to fixed abnormal postures.
• Myoclonus is a sudden regular or irregular brief, jerky or shock-like involuntary contraction of a muscle, or groups of muscles, as a manifestation of hyperexcitability in the nervous system at any level between the cerebral cortex
and the spinal cord, and not associated with alteration in consciousness.
- Tic is a sudden, brief, stereotyped, more or less complex, repetitive, normally coordinated but inappropriate movement. Tics are preceded by an urge and psychic tension which is relieved after the movement. Tics can be suppressed for a period of time by effort of will.
- Ballismus is a condition marked by extensive, vigorous, fast, poorly patterned,non-adaptive movements of the facial, limb, or truncal musculature most often appearing as violent, flinging proximal movements. It is often due to lesions ofthe subthalamic nucleus of Luys, but can occur from lesions in other parts of the basal ganglia.
What is progressive supranuclear palsy? What are its symptoms? What is its pathophysiology? What is the cause? Prognosis? Treatment?
Progressive supranuclear palsy is one of the “parkinson-plus” syndromes. It entails pseudobulbar palsy (hyper-reflexic weakness of muscles subserved by the lower cranial nerves), supranuclear ocular palsy (loss of voluntary but preservation of reflex eye movements), rigidity, dystonia, gait difficulties and dementia. Neuronal degeneration with neurofibrillary tangles is prominent in the pons and midbrain with de-pigmentation of the substantia nigra. Its cause is unknown and progression is rapid, resulting in a bedridden state within 5 years of onset. Levodopa can ameliorate some of the symptoms.
What is Wilson’s Disease? What is its pathophysiology? What areas of the body does it affect most? What are the signs and symptoms? What is the onset? What is the treatment? What is the prognosis?
Wilson’s disease (hepatolenticular degeneration) is an inborn error of copper metabolism that is associated with liver cirrhosis and basal ganglia degeneration. Affecting 30 people per million, it is an autosomal recessive condition localized to chromosome 13q14.3. This gene codes for a protein, which transports copper through cell membranes. There are reduced levels of ceruloplasmin, which normally binds 90% of the serum copper. When not bound to ceruloplasmin, copper is toxic. In the brain, it preferentially affects the basal ganglia with spongy degeneration of the putamen. Lesser affected structures include the brainstem, dentate nuclei, substantia nigra, and cortical white matter.
Deposition of copper in the cornea gives a yellow-brown discoloration which is most apparent around the periphery, known as a Kayser-Fleischer ring. Symptoms typically begin in adolescence or young adulthood and include dystonia, dysarthria, parkinsonism, ataxia, and chorea. A peculiar proximal tremor known as “wing-beating” may be seen. Facial dystonia leads to a characteristic “sardonic grin.” Psychiatric disturbances may dominate the presentation in some patients. Liver cirrhosis can develop at any time during the course. The diagnosis is made by demonstrating a decreased serum ceruloplasmin. Urinary copper excretion (measured by a 24 hour urine collection) is elevated. Brain CT scan demonstrates diffuse atrophy. MRI more consistently shows the necrotic changes in the basal ganglia, thalamus, and dentate nuclei. When the diagnosis is in doubt, a liver biopsy should be performed to measure hepatic copper concentration.
Wilson’s disease is a treatable condition and should always be considered in any patient who presents with tremor, dystonia or chorea. Treatment starts by assuring the patient’s diet is not abnormally high in copper content (e.g. shellfish, liver, chocolate, mushrooms). Chelation is required to remove the copper, and penicillamine has been the mainstay of therapy. Once copper excretion falls to the normal range, zinc may be used as maintenance therapy. Neurologic signs and symptoms stabilize once therapy is begun, then improve over several months. Liver transplantation may be necessary in cases of
end-stage liver disease.
What are the signs and symptoms of Huntington Disease? Onset? How does juvenile onset differ? What treatments are there? What are some other causes of chorea?
Huntington disease is a progressive, autosomal dominant disorder caused by a CAG trinucleotide repeat which leads to overproduction of “huntingtin.” Pathologically, there is a loss of neurons in the caudate, putamen and cerebral cortex (layer 3) associated with loss of striatal GABA and its synthesizing enzyme glutamic acid decarboxylase. The clinical triad is chorea, dementia, and personality disturbance. Symptoms begin at an average of 35-40 years of age, including clumsiness, fidgetiness, irritability, and apathy which progresses to choreic movements, dementia, depression and psychotic behavior
over a 15 year course. Suicide is not an infrequent outcome. The chorea results in facial grimacing, movements of the eyebrows and forehead, shrugging of shoulders, and a dancing type of gait. Motor impersistence results in the “milkmaid grip” sign. Chorea
can also be caused by encephalitis, medication adverse effect, pregnancy, autoimmune
disorders (Lupus), postinfectious (Sydenham’s), and metabolic disorders. The genetic anticipation in families with Huntington’s disease is more pronounced when transmitted from an affected male, thus resulting in a far greater percentage of juvenile cases being offspring of affected fathers. The juvenile-onset cases are associated with seizures, more dystonia and rigidity than chorea, and more rapid progression rate. Neuroimaging studies show enlargement of the lateral cerebral ventricles with a characteristic butterfly appearance, caused by atrophy of the caudate nuclei. There is no definitive treatment, but
behavioral symptoms can be ameliorated with antidepressant and antipsychotic medications. Dopamine depleting agents like Tetrabenzine and dopamine blocking drugs can be used to reduce chorea.
What is the most common of all movement disorders? What is the prevalence in people over 60? What is it called if its hereditary? What is a possible pathophys? What are the signs and symptoms? Onset? What can transiently suppress the tremor? what happens after? What are 3 treatments? How does intention tremor differ from it?
Essential tremor is the most common of all movement disorders, affecting >5% of adults over 60 years in some populations. When hereditary (usually autosomal dominant) it is known as familial tremor. Oscillations within the olivocerebellar circuit have been implicated in the pathophysiology; this remains speculative. Onset is usually in adulthood, with symptoms initially being apparent only during times of emotional stress and thus attributed to “nervousness.” The first symptom is an 8-12 Hz postural tremor of both hands which is most obvious when the arms are held outstretched. There is also an action tremor during goal-directed movements that interferes with handwriting, feeding, and other manual tasks but completely disappears at rest. Over time, the frequency of
tremor slows, with an increase in amplitude which affects daily function. It can progress to involve the head (bobbing of the head up-and-down or side-to-side), vocal cords/diaphragm (Katherine Hepburn’s voice), and less often the trunk and lower limbs.
Alcohol transiently suppresses the tremor, but rebound may occur after several hours. Beta blockers and primidone are the mainstay of treatment. Stereotactic deep brain stimulation of the ViM nucleus of the thalamus is very effective when medications fail.
Cerebellar (intention) tremor is slower in frequency (3-4 hz), and is most notable during manual activities requiring precise movements. Unlike essential tremor, the movements
can occur in more than one plane simultaneously and are associated with other cerebellar signs, including ataxia and dysmetria.
What is dystonia characterized by? What are some possible etiologies? What are some treatments?
Dystonia is characterized by sustained muscle contractions that cause twisting and repetitive movements or abnormal postures. The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, metabolic causes, toxins, medications particularly neuroleptics. Treatments include medications, injection of Botulinum toxin into dystonic muscles and deep brain stimulation of the globus pallidus interna in refractory cases.
What is tourette’s syndrome? What are the signs and symptoms? How is a diagnosis made? What is it associated with? How can it be treated?
Tourette’s syndrome is a chronic motor and vocal tic disorder. Motor tics are abrupt, stereotyped, seemingly purposeless movements, which can be briefly voluntarily
suppressed. Examples of simple motor tics include forceful blinking, grimacing, eye deviation, head jerking, or wrist flicking. Complex tics involve coordinated contraction of a series of muscle groups. Vocal tics include barking, throat-clearing, sniffing, grunting, clicking, etc. Complex vocal tics are words or word fragments and can include
coprolalia (obscene speech). Tics increase during times of emotional excitation or stress.
The criteria for diagnosis of Tourette’s syndrome include presence of multiple motor and at least one vocal tic at some time during the course, duration longer than 1 year (with no more than 3 tic-free months during that year), onset prior to age 18 years, marked distress or significant impairment in social, occupational, or other important areas of functioning, and absence of possible confounding agents or conditions (stimulant medications, Huntington’s disease, postviral encephalitis).
Up to 20% of school-aged children develop a transitory tic, but Tourette’s syndrome occurs only in an estimated 30-50 per 100,000 people. Males are affected more often (3:1). Associated conditions include attention-deficit-hyperactivity-disorder (ADHD) in about one third, learning disabilities in a fourth, and obsessive-compulsive disorder in up to half. When significantly disabling, the tics can be suppressed using dopamine-blocking agents such as haloperidol or pimozide. Clonidine (a centrally-acting alpha-adrenergic agent) can be helpful in some cases. Caution must be exercised when prescribing a stimulant for co-existent ADHD, as tics are sometimes exacerbated.
What is the cause of cerebellar ataxia? What are the signs and symptoms? Pathophysiology?
Cerebellar ataxia results from dysfunction of the cerebellum and less often those areas in the brainstem, ventrolateral thalamus, and frontal lobes which interact with the cerebellum. Damage to the midline cerebellum or fastigial nucleus results in truncal ataxia in which the gait is wide-based, erratic and reeling (eg. rostral vermis degeneration in chronic alcoholism). Unilateral hemispheric lesions produce ipsilateral limb ataxia and
falling toward the side of the lesion. Sensory ataxia is seen in patients with large-fiber sensory neuropathies, and in those with disorders affecting the posterior spinal columns and/or spinocerebellar tracts. Some diseases affect a combination of the above (vitamin B12 deficiency and Friedreich’s ataxia).
What is the most common type of hereditary progressive ataxia? What is the cause? What are 2 associated findings? What are the signs and symptoms? Onset? Treatment? Prognosis?
Friedreich’s ataxia is the most common type of hereditary, progressive ataxia, affecting 1-2 per 100,000 population. It is an autosomal recessive disorder localized to chromosome 9q13, which codes for Frataxin, a mitochondrial protein which appears to be involved in iron homeostasis. The specific disturbance is an unstable GAA trinucleotide repeat expansion (nl < 22 copies). Pathologically, there is gross atrophy of the spinal
cord with specific degeneration of the posterior columns, spinocerebellar tracts, corticospinal tracts, posterior rootlets, and peripheral nerves. Cardiomyopathy and
diabetes mellitus are associated findings. Early signs include high arches in the feet, “hammer-toes”, and kyphoscoliosis. Onset of gait ataxia is usually before 10 years of age, spreading to involve the upper limbs in months to years. Speech becomes dysarthric. The examination shows talipes equinovarus and pes cavus (Friedreich’s foot), kyphoscoliosis, nystagmus, wide-based stance and gait (for which the patient partially compensates by constantly shifting from side-to-side), dysmetria, speech which is slow, slurred, and explosive, positive Romberg sign, diminished/absent tendon reflexes,
extensor plantar responses, and marked loss of position and vibration senses. The course is relentlessly progressive over years to decades with no known mechanism to reverse or stabilize the disease. Typical survival is 30-40 years.
What are some other causes of ataxia?
There are a number of other hereditary ataxias, many of which have a specified genetic locus and a commercial test available. In addition, acquired conditions which affect the cerebellum and its inflow/outflow tracts include trauma, infections, neoplasm, paraneoplastic disorders, demyelination, metabolic alterations including hypoxia/ischemia, medications, toxins, and heatstroke.
