– the rhythmic oscillation of a body part, with equal to-and-fro components at regular intervals. Patients often complain of "shaking".
– tremor occurs when patient is at rest (flexion-extension movements of fingers and wrists), rigidity, akinesia, postural disturbances. Disease due to degeneration of substantia nigra. Specifically destruction of dopaminergic neurons projecting to the striatum. Depletion of dopamine leads to loss of inhibition of the output neurons of the basal ganglia, which are inhibitory, and consequently, increased inhibition of thalamocortical neurons.
– action tremor of hands, head,voice. Autosomal dominant. Responds to low doses of alcohol.
Ataxic ("intention") tremor
– due to cerebellar lesions.
– sudden, brief movements ("shock-like"), often described by patients as "jerks". Highly variable in character: regular/irregular, focal/generalized, repetitive/random, single/multiple. Usually arrhythmic. Often elicited by action or external stimuli (noise, light, percussion). Most commonly associated with toxic or metabolic disorders.
– simple or complex motor or vocal phenomena. Most tics appear semi-purposeful and have a verb to describe them, e.g. blinking or rolling (eyes), tossing (head), shrugging (shoulders), kicking, coughing, grunting, sniffing, barking, swearing.
Gilles de la Tourette Syndrome
: Most common tic disorder. Motor and vocal tics beginning in childhood or adolescence. Autosomal dominant. Associated with obsessive/compulsive disorder. Duration > 1 year.
: botulinum toxin
– movements characterized by sustained ("tonic") muscular contractions resulting in abnormal postures. Often referred to by patients as "spasms". Distinguishing characteristics: induced by specific action (e.g. writer's cramp), and relief by sensory "tricks" (ex: patient touches their face to stop sticking their tongue out).
In children, dystonia tends to begin in the lower limbs and become generalized.
In adults, dystonia tends to affect cranial, cervical or upper limb muscles and remain focal.
– slow, repetitive, continuous movements of limbs, best described by the term "writhing". Most cases of athetosis have been associated with perinatal encephalopathies, such as anoxia or kernicterus. Not very common today.
– random, irregular, brief, gentle movements affecting face, trunk and limbs. Movements are irregular and unpredictable, random in timing and distribution. Patients often refer to these as "twitches".
– progressive chorea and dementia inherited in an autosomal dominant fashion, with 100% penetrance. Gene located on short arm of chromosome 4. Fatal generally within 10-20 years. Results from degeneration of striatum.
– violent, irregular, flinging movements of limbs. Usually occurs in a unilateral distribution ("hemiballism"). Associated with lesion in contralateral subthalamic nucleus, most often caused by stroke (infarction), but may be caused by any lesion (Multiple Sclerosis, etc).
Movement disorders associated with antidopaminergic drugs:
(1) Acute dystonic reaction
(2) Akathisia (restlessness)
(3) Drug-induced parkinsonism
(4) Tardive dyskinesia
(5) Neuroleptic malignant syndrome
– hepatolenticular degeneration associated with a defect in copper metabolism. Wide variety of neurologic and psychiatric manifestations. Autosomal recessive. Fatal if not treated. Should be considered in any patient developing a movement disorder before the age of 40.