Tremors are involuntary, rhythmic, alternating, or oscillatory movements of interrelated muscle groups. They typically involve the hands, head, facial structures, vocal cords, trunk, or legs. Tremors can be characterized by Frequency of oscillation (rapid or slow) Amplitude of movement (fine or coarse) Movements or postures that evoke them (eg, rest, action, certain positions) Pathophysiology Tremors […]

Parkinson’s disease is an idiopathic, slowly progressive, degenerative CNS disorder characterized by resting tremor, muscular rigidity, slow and decreased movement, and postural instability. Diagnosis is clinical. Treatment is with levodopa plus carbidopa, other drugs, and, for refractory symptoms, surgery. Parkinson’s disease affects about 0.4% of people > 40 yr, 1% of people ≥ 65 yr, […]

Myoclonus is a brief, shocklike contraction of a muscle or group of muscles. Diagnosis is clinical and by selective testing. Treatment includes correction of reversible causes and sometimes oral drugs (eg, clonazepam, valproate). Physiologic myoclonus may occur as a person falls asleep (nocturnal myoclonus). Myoclonus can result from other disorders and certain drugs (see Table […]

Huntington’s disease is an autosomal dominant disorder characterized by chorea and progressive cognitive deterioration, usually beginning in middle age. Diagnosis is by genetic testing. Treatment is supportive. First-degree relatives are encouraged to have genetic testing. Huntington’s disease affects both sexes equally. The caudate nucleus atrophies, the inhibitory medium spiny neurons in the corpus striatum degenerate, […]

Fragile X–associated tremor/ataxia syndrome (FXTAS) is a genetic disorder affecting mostly men and causing tremor, ataxia, and dementia. FXTAS affects about 1/3000 men. A premutation (an increased number of CGG repeats) occurs in the fragile X mental retardation (FMR1) gene on the X chromosome; if the mutation is full, > 200 repeats occur, causing fragile […]

Dystonias are sustained involuntary muscle contractions, often distorting body posture. Dystonias can be primary or secondary, and they can be generalized, focal, or segmental. Diagnosis is clinical. Treatment of generalized dystonia is often with a combination of anticholinergic drugs, muscle relaxants, and benzodiazepines. Treatment of focal or segmental dystonias is often with botulinum toxin; more […]

Chorea is nonrhythmic, jerky, rapid, nonsuppressible involuntary movements, mostly of distal muscles or the face; movements may merge imperceptibly into purposeful or semipurposeful acts that mask the involuntary movements. Athetosis is nonrhythmic, slow, writhing, sinuous movements predominantly in distal muscles, often alternating with postures of the proximal limbs to produce a continuous, flowing stream of […]

Voluntary movement requires interaction of the corticospinal (pyramidal) tracts, basal ganglia, and cerebellum (the center for motor coordination). The pyramidal tracts pass through the medullary pyramids to connect the cerebral cortex to lower motor centers of the brain stem and spinal cord. The basal ganglia (caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra) […]

Craniocervical junction abnormalities are congenital or acquired abnormalities of the occipital bone, foramen magnum, or first two cervical vertebrae that decrease the space for the lower brain stem and cervical cord. These abnormalities can result in neck pain; syringomyelia; cerebellar, lower cranial nerve, and spinal cord deficits; and vertebrobasilar ischemia. Diagnosis is by MRI or […]

Glossopharyngeal neuralgia is characterized by recurrent attacks of severe pain in the 9th and 10th cranial nerve distribution (posterior pharynx, tonsils, back of the tongue, middle ear, under the angle of the jaw). Diagnosis is clinical. Treatment is usually with carbamazepine or gabapentin. Glossopharyngeal neuralgia sometimes results from nerve compression by an aberrant, pulsating artery […]

Facial nerve (7th cranial nerve) palsy is often idiopathic (formerly called Bell palsy). Idiopathic facial nerve palsy is sudden, unilateral peripheral facial nerve palsy. Symptoms of facial nerve palsy are hemifacial paresis of the upper and lower face. Tests (eg, chest x-ray, serum ACE level) are done to diagnose treatable causes. Treatment may include lubrication […]

Hemifacial spasm refers to unilateral painless, synchronous contractions of facial muscles due to dysfunction of the 7th cranial (facial) nerve and/or its motor nucleus. Hemifacial spasm results from nerve compression by a pulsating blood vessel, similar to that in trigeminal neuralgia. The pulsating blood vessel is often visible on MRI, but diagnosis is ultimately clinical. […]

Trigeminal neuralgia is severe paroxysmal, lancinating facial pain due to a disorder of the 5th cranial nerve. Diagnosis is clinical. Treatment is usually with carbamazepine or gabapentin; sometimes surgery is required. Trigeminal neuralgia affects mainly adults, especially the elderly. Etiology Trigeminal neuralgia is usually caused by an intracranial artery (eg, anterior inferior cerebellar artery, ectatic […]

Sixth cranial nerve palsy affects the lateral rectus muscle, impairing eye abduction. The eye may be slightly adducted when the patient looks straight ahead. The palsy may be secondary to nerve infarction, Wernicke encephalopathy, trauma, infection, or increased intracranial pressure, or it may be idiopathic. Determining the cause requires MRI and often lumbar puncture and […]

Fourth cranial nerve palsy impairs the superior oblique muscle, causing paresis of vertical gaze, mainly in adduction. Fourth cranial (trochlear) nerve palsy is often idiopathic. Few causes have been identified. Causes include closed head injury (common), which may cause unilateral or bilateral palsies, and infarction due to small-vessel disease (eg, in diabetes). Rarely, this palsy […]

Third cranial nerve disorders can impair ocular motility, pupillary function, or both. Symptoms and signs include diplopia, ptosis, and paresis of eye adduction and of upward and downward gaze. If the pupil is affected, it is dilated, and light reflexes are impaired. If the pupil is affected or patients are increasingly unresponsive, CT is done […]